From 97374c0faa57a5afe170cfe760cf4c82368a983a Mon Sep 17 00:00:00 2001 From: Michael Young Date: Nov 01 2022 17:09:30 +0000 Subject: several security updates x86: unintended memory sharing between guests [XSA-412, CVE-2022-42327] Xenstore: Guests can crash xenstored [XSA-414, CVE-2022-42309] Xenstore: Guests can create orphaned Xenstore nodes [XSA-415, CVE-2022-42310] Xenstore: guests can let run xenstored out of memory [XSA-326, CVE-2022-42311, CVE-2022-42312, CVE-2022-42313, CVE-2022-42314, CVE-2022-42315, CVE-2022-42316, CVE-2022-42317, CVE-2022-42318] Xenstore: Guests can cause Xenstore to not free temporary memory [XSA-416, CVE-2022-42319] Xenstore: Guests can get access to Xenstore nodes of deleted domains [XSA-417, CVE-2022-42320] Xenstore: Guests can crash xenstored via exhausting the stack [XSA-418, CVE-2022-42321] Xenstore: Cooperating guests can create arbitrary numbers of nodes [XSA-419, CVE-2022-42322, CVE-2022-42323] Oxenstored 32->31 bit integer truncation issues [XSA-420, CVE-2022-42324] Xenstore: Guests can create arbitrary number of nodes via transactions [XSA-421, CVE-2022-42325, CVE-2022-42326] --- diff --git a/xen.spec b/xen.spec index 99e4234..db387f5 100644 --- a/xen.spec +++ b/xen.spec @@ -55,7 +55,7 @@ Summary: Xen is a virtual machine monitor Name: xen Version: 4.16.2 -Release: 2%{?dist} +Release: 3%{?dist} License: GPLv2+ and LGPLv2+ and BSD URL: http://xen.org/ Source0: https://downloads.xenproject.org/release/xen/%{version}/xen-%{version}.tar.gz @@ -126,6 +126,49 @@ Patch58: xsa409-4.13-0002-xen-arm-Construct-the-P2M-pages-pool-for-guests.patch Patch59: xsa409-4.13-0003-xen-arm-libxl-Implement-XEN_DOMCTL_shadow_op-for-Arm.patch Patch60: xsa409-4.13-0004-xen-arm-Allocate-and-free-P2M-pages-from-the-P2M-poo.patch Patch61: xsa411.patch +Patch62: xsa412-4.16.patch +Patch63: xsa414.patch +Patch64: xsa415.patch +Patch65: xsa326-4.16-oxenstored-01.patch +Patch66: xsa326-4.16-oxenstored-02.patch +Patch67: xsa326-4.16-oxenstored-03.patch +Patch68: xsa326-4.16-oxenstored-04.patch +Patch69: xsa326-4.16-oxenstored-05.patch +Patch70: xsa326-4.16-oxenstored-06.patch +Patch71: xsa326-4.16-oxenstored-07.patch +Patch72: xsa326-4.16-oxenstored-08.patch +Patch73: xsa326-4.16-xenstored-01.patch +Patch74: xsa326-4.16-xenstored-02.patch +Patch75: xsa326-4.16-xenstored-03.patch +Patch76: xsa326-4.16-xenstored-04.patch +Patch77: xsa326-4.16-xenstored-05.patch +Patch78: xsa326-4.16-xenstored-06.patch +Patch79: xsa326-4.16-xenstored-07.patch +Patch80: xsa326-4.16-xenstored-08.patch +Patch81: xsa326-4.16-xenstored-09.patch +Patch82: xsa326-4.16-xenstored-10.patch +Patch83: xsa326-4.16-xenstored-11.patch +Patch84: xsa326-4.16-xenstored-12.patch +Patch85: xsa326-4.16-xenstored-13.patch +Patch86: xsa326-4.16-xenstored-14.patch +Patch87: xsa326-4.16-xenstored-15.patch +Patch88: xsa326-4.16-xenstored-16.patch +Patch89: xsa416-4.16.patch +Patch90: xsa417.patch +Patch91: xsa418-4.16-01.patch +Patch92: xsa418-4.16-02.patch +Patch93: xsa418-4.16-03.patch +Patch94: xsa418-4.16-04.patch +Patch95: xsa418-4.16-05.patch +Patch96: xsa418-4.16-06.patch +Patch97: xsa418-4.16-07.patch +Patch98: xsa419-oxenstored.patch +Patch99: xsa419-xenstored-01.patch +Patch100: xsa419-xenstored-02.patch +Patch101: xsa419-xenstored-03.patch +Patch102: xsa420.patch +Patch103: xsa421-01.patch +Patch104: xsa421-02.patch %if %build_qemutrad @@ -353,6 +396,49 @@ manage Xen virtual machines. %patch59 -p1 %patch60 -p1 %patch61 -p1 +%patch62 -p1 +%patch63 -p1 +%patch64 -p1 +%patch65 -p1 +%patch66 -p1 +%patch67 -p1 +%patch68 -p1 +%patch69 -p1 +%patch70 -p1 +%patch71 -p1 +%patch72 -p1 +%patch73 -p1 +%patch74 -p1 +%patch75 -p1 +%patch76 -p1 +%patch77 -p1 +%patch78 -p1 +%patch79 -p1 +%patch80 -p1 +%patch81 -p1 +%patch82 -p1 +%patch83 -p1 +%patch84 -p1 +%patch85 -p1 +%patch86 -p1 +%patch87 -p1 +%patch88 -p1 +%patch89 -p1 +%patch90 -p1 +%patch91 -p1 +%patch92 -p1 +%patch93 -p1 +%patch94 -p1 +%patch95 -p1 +%patch96 -p1 +%patch97 -p1 +%patch98 -p1 +%patch99 -p1 +%patch100 -p1 +%patch101 -p1 +%patch102 -p1 +%patch103 -p1 +%patch104 -p1 # qemu-xen-traditional patches pushd tools/qemu-xen-traditional @@ -968,6 +1054,26 @@ fi %endif %changelog +* Tue Nov 01 2022 Michael Young - 4.16.2-3 +- x86: unintended memory sharing between guests [XSA-412, CVE-2022-42327] +- Xenstore: Guests can crash xenstored [XSA-414, CVE-2022-42309] +- Xenstore: Guests can create orphaned Xenstore nodes [XSA-415, + CVE-2022-42310] +- Xenstore: guests can let run xenstored out of memory [XSA-326, + CVE-2022-42311, CVE-2022-42312, CVE-2022-42313, CVE-2022-42314, + CVE-2022-42315, CVE-2022-42316, CVE-2022-42317, CVE-2022-42318] +- Xenstore: Guests can cause Xenstore to not free temporary memory + [XSA-416, CVE-2022-42319] +- Xenstore: Guests can get access to Xenstore nodes of deleted domains + [XSA-417, CVE-2022-42320] +- Xenstore: Guests can crash xenstored via exhausting the stack + [XSA-418, CVE-2022-42321] +- Xenstore: Cooperating guests can create arbitrary numbers of nodes + [XSA-419, CVE-2022-42322, CVE-2022-42323] +- Oxenstored 32->31 bit integer truncation issues [XSA-420, CVE-2022-42324] +- Xenstore: Guests can create arbitrary number of nodes via transactions + [XSA-421, CVE-2022-42325, CVE-2022-42326] + * Fri Oct 14 2022 Michael Young - 4.16.2-2 - Arm: unbounded memory consumption for 2nd-level page tables [XSA-409, CVE-2022-33747] (#2135268) diff --git a/xsa326-4.16-oxenstored-01.patch b/xsa326-4.16-oxenstored-01.patch new file mode 100644 index 0000000..848a5d0 --- /dev/null +++ b/xsa326-4.16-oxenstored-01.patch @@ -0,0 +1,55 @@ +From 8d6bb4ac40619877130533b11655829101b31d04 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:01 +0100 +Subject: tools/ocaml/xenstored: Synchronise defaults with oxenstore.conf.in +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +We currently have 2 different set of defaults in upstream Xen git tree: +* defined in the source code, only used if there is no config file +* defined in the oxenstored.conf.in upstream Xen + +An oxenstored.conf file is not mandatory, and if missing, maxrequests in +particular has an unsafe default. + +Resync the defaults from oxenstored.conf.in into the source code. + +This is part of XSA-326 / CVE-2022-42316. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/xenstored/define.ml b/tools/ocaml/xenstored/define.ml +index ebe18b8e312c..6b06f808595b 100644 +--- a/tools/ocaml/xenstored/define.ml ++++ b/tools/ocaml/xenstored/define.ml +@@ -21,9 +21,9 @@ let xs_daemon_socket = Paths.xen_run_stored ^ "/socket" + + let default_config_dir = Paths.xen_config_dir + +-let maxwatch = ref (50) +-let maxtransaction = ref (20) +-let maxrequests = ref (-1) (* maximum requests per transaction *) ++let maxwatch = ref (100) ++let maxtransaction = ref (10) ++let maxrequests = ref (1024) (* maximum requests per transaction *) + + let conflict_burst_limit = ref 5.0 + let conflict_max_history_seconds = ref 0.05 +diff --git a/tools/ocaml/xenstored/quota.ml b/tools/ocaml/xenstored/quota.ml +index abcac912805a..6e3d6401ae89 100644 +--- a/tools/ocaml/xenstored/quota.ml ++++ b/tools/ocaml/xenstored/quota.ml +@@ -20,8 +20,8 @@ exception Transaction_opened + + let warn fmt = Logging.warn "quota" fmt + let activate = ref true +-let maxent = ref (10000) +-let maxsize = ref (4096) ++let maxent = ref (1000) ++let maxsize = ref (2048) + + type t = { + maxent: int; (* max entities per domU *) diff --git a/xsa326-4.16-oxenstored-02.patch b/xsa326-4.16-oxenstored-02.patch new file mode 100644 index 0000000..7680efb --- /dev/null +++ b/xsa326-4.16-oxenstored-02.patch @@ -0,0 +1,94 @@ +From 78d5af44ab13bb18c87b6ad75e505bd374379cb3 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Thu, 28 Jul 2022 17:08:15 +0100 +Subject: tools/ocaml/xenstored: Check for maxrequests before performing + operations +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Previously we'd perform the operation, record the updated tree in the +transaction record, then try to insert a watchop path and the reply packet. + +If we exceeded max requests we would've returned EQUOTA, but still: +* have performed the operation on the transaction's tree +* have recorded the watchop, making this queue effectively unbounded + +It is better if we check whether we'd have room to store the operation before +performing the transaction, and raise EQUOTA there. Then the transaction +record won't grow. + +This is part of XSA-326 / CVE-2022-42317. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/xenstored/process.ml b/tools/ocaml/xenstored/process.ml +index 27790d4a5c41..dd58e6979cf9 100644 +--- a/tools/ocaml/xenstored/process.ml ++++ b/tools/ocaml/xenstored/process.ml +@@ -389,6 +389,7 @@ let input_handle_error ~cons ~doms ~fct ~con ~t ~req = + let reply_error e = + Packet.Error e in + try ++ Transaction.check_quota_exn ~perm:(Connection.get_perm con) t; + fct con t doms cons req.Packet.data + with + | Define.Invalid_path -> reply_error "EINVAL" +@@ -681,9 +682,10 @@ let process_packet ~store ~cons ~doms ~con ~req = + in + + let response = try ++ Transaction.check_quota_exn ~perm:(Connection.get_perm con) t; + if tid <> Transaction.none then + (* Remember the request and response for this operation in case we need to replay the transaction *) +- Transaction.add_operation ~perm:(Connection.get_perm con) t req response; ++ Transaction.add_operation t req response; + response + with Quota.Limit_reached -> + Packet.Error "EQUOTA" +diff --git a/tools/ocaml/xenstored/transaction.ml b/tools/ocaml/xenstored/transaction.ml +index 17b1bdf2eaf9..294143e2335b 100644 +--- a/tools/ocaml/xenstored/transaction.ml ++++ b/tools/ocaml/xenstored/transaction.ml +@@ -85,6 +85,7 @@ type t = { + oldroot: Store.Node.t; + mutable paths: (Xenbus.Xb.Op.operation * Store.Path.t) list; + mutable operations: (Packet.request * Packet.response) list; ++ mutable quota_reached: bool; + mutable read_lowpath: Store.Path.t option; + mutable write_lowpath: Store.Path.t option; + } +@@ -127,6 +128,7 @@ let make ?(internal=false) id store = + oldroot = Store.get_root store; + paths = []; + operations = []; ++ quota_reached = false; + read_lowpath = None; + write_lowpath = None; + } in +@@ -143,13 +145,19 @@ let get_root t = Store.get_root t.store + + let is_read_only t = t.paths = [] + let add_wop t ty path = t.paths <- (ty, path) :: t.paths +-let add_operation ~perm t request response = ++let get_operations t = List.rev t.operations ++ ++let check_quota_exn ~perm t = + if !Define.maxrequests >= 0 + && not (Perms.Connection.is_dom0 perm) +- && List.length t.operations >= !Define.maxrequests +- then raise Quota.Limit_reached; ++ && (t.quota_reached || List.length t.operations >= !Define.maxrequests) ++ then begin ++ t.quota_reached <- true; ++ raise Quota.Limit_reached; ++ end ++ ++let add_operation t request response = + t.operations <- (request, response) :: t.operations +-let get_operations t = List.rev t.operations + let set_read_lowpath t path = t.read_lowpath <- get_lowest path t.read_lowpath + let set_write_lowpath t path = t.write_lowpath <- get_lowest path t.write_lowpath + diff --git a/xsa326-4.16-oxenstored-03.patch b/xsa326-4.16-oxenstored-03.patch new file mode 100644 index 0000000..0b42411 --- /dev/null +++ b/xsa326-4.16-oxenstored-03.patch @@ -0,0 +1,119 @@ +From 600c45e49c2060e077c06ab19078da89aa8e2e08 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:07 +0100 +Subject: tools/ocaml: GC parameter tuning +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +By default the OCaml garbage collector would return memory to the OS only +after unused memory is 5x live memory. Tweak this to 120% instead, which +would match the major GC speed. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/xenstored/define.ml b/tools/ocaml/xenstored/define.ml +index 6b06f808595b..ba63a8147e09 100644 +--- a/tools/ocaml/xenstored/define.ml ++++ b/tools/ocaml/xenstored/define.ml +@@ -25,6 +25,7 @@ let maxwatch = ref (100) + let maxtransaction = ref (10) + let maxrequests = ref (1024) (* maximum requests per transaction *) + ++let gc_max_overhead = ref 120 (* 120% see comment in xenstored.ml *) + let conflict_burst_limit = ref 5.0 + let conflict_max_history_seconds = ref 0.05 + let conflict_rate_limit_is_aggregate = ref true +diff --git a/tools/ocaml/xenstored/xenstored.ml b/tools/ocaml/xenstored/xenstored.ml +index d44ae673c42a..3b57ad016dfb 100644 +--- a/tools/ocaml/xenstored/xenstored.ml ++++ b/tools/ocaml/xenstored/xenstored.ml +@@ -104,6 +104,7 @@ let parse_config filename = + ("quota-maxsize", Config.Set_int Quota.maxsize); + ("quota-maxrequests", Config.Set_int Define.maxrequests); + ("quota-path-max", Config.Set_int Define.path_max); ++ ("gc-max-overhead", Config.Set_int Define.gc_max_overhead); + ("test-eagain", Config.Set_bool Transaction.test_eagain); + ("persistent", Config.Set_bool Disk.enable); + ("xenstored-log-file", Config.String Logging.set_xenstored_log_destination); +@@ -265,6 +266,67 @@ let to_file store cons fds file = + (fun () -> close_out channel) + end + ++(* ++ By default OCaml's GC only returns memory to the OS when it exceeds a ++ configurable 'max overhead' setting. ++ The default is 500%, that is 5/6th of the OCaml heap needs to be free ++ and only 1/6th live for a compaction to be triggerred that would ++ release memory back to the OS. ++ If the limit is not hit then the OCaml process can reuse that memory ++ for its own purposes, but other processes won't be able to use it. ++ ++ There is also a 'space overhead' setting that controls how much work ++ each major GC slice does, and by default aims at having no more than ++ 80% or 120% (depending on version) garbage values compared to live ++ values. ++ This doesn't have as much relevance to memory returned to the OS as ++ long as space_overhead <= max_overhead, because compaction is only ++ triggerred at the end of major GC cycles. ++ ++ The defaults are too large once the program starts using ~100MiB of ++ memory, at which point ~500MiB would be unavailable to other processes ++ (which would be fine if this was the main process in this VM, but it is ++ not). ++ ++ Max overhead can also be set to 0, however this is for testing purposes ++ only (setting it lower than 'space overhead' wouldn't help because the ++ major GC wouldn't run fast enough, and compaction does have a ++ performance cost: we can only compact contiguous regions, so memory has ++ to be moved around). ++ ++ Max overhead controls how often the heap is compacted, which is useful ++ if there are burst of activity followed by long periods of idle state, ++ or if a domain quits, etc. Compaction returns memory to the OS. ++ ++ wasted = live * space_overhead / 100 ++ ++ For globally overriding the GC settings one can use OCAMLRUNPARAM, ++ however we provide a config file override to be consistent with other ++ oxenstored settings. ++ ++ One might want to dynamically adjust the overhead setting based on used ++ memory, i.e. to use a fixed upper bound in bytes, not percentage. However ++ measurements show that such adjustments increase GC overhead massively, ++ while still not guaranteeing that memory is returned any more quickly ++ than with a percentage based setting. ++ ++ The allocation policy could also be tweaked, e.g. first fit would reduce ++ fragmentation and thus memory usage, but the documentation warns that it ++ can be sensibly slower, and indeed one of our own testcases can trigger ++ such a corner case where it is multiple times slower, so it is best to keep ++ the default allocation policy (next-fit/best-fit depending on version). ++ ++ There are other tweaks that can be attempted in the future, e.g. setting ++ 'ulimit -v' to 75% of RAM, however getting the kernel to actually return ++ NULL from allocations is difficult even with that setting, and without a ++ NULL the emergency GC won't be triggerred. ++ Perhaps cgroup limits could help, but for now tweak the safest only. ++*) ++ ++let tweak_gc () = ++ Gc.set { (Gc.get ()) with Gc.max_overhead = !Define.gc_max_overhead } ++ ++ + let _ = + let cf = do_argv in + let pidfile = +@@ -274,6 +336,8 @@ let _ = + default_pidfile + in + ++ tweak_gc (); ++ + (try + Unixext.mkdir_rec (Filename.dirname pidfile) 0o755 + with _ -> diff --git a/xsa326-4.16-oxenstored-04.patch b/xsa326-4.16-oxenstored-04.patch new file mode 100644 index 0000000..0f2534b --- /dev/null +++ b/xsa326-4.16-oxenstored-04.patch @@ -0,0 +1,85 @@ +From fd6d9cd3d20e496bdbf3e0a07354f65de0bcf4ae Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Fri, 29 Jul 2022 18:53:29 +0100 +Subject: tools/ocaml/libs/xb: hide type of Xb.t +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Hiding the type will make it easier to change the implementation +in the future without breaking code that relies on it. + +No functional change. + +Signed-off-by: Edwin Török +Acked-by: Christian Lindig +(cherry picked from commit 7ade30a1451734d041363c750a65d322e25b47ba) + +Reported-by: Julien Grall +diff --git a/tools/ocaml/libs/xb/xb.ml b/tools/ocaml/libs/xb/xb.ml +index 104d319d7747..8404ddd8a682 100644 +--- a/tools/ocaml/libs/xb/xb.ml ++++ b/tools/ocaml/libs/xb/xb.ml +@@ -196,6 +196,9 @@ let peek_output con = Queue.peek con.pkt_out + let input_len con = Queue.length con.pkt_in + let has_in_packet con = Queue.length con.pkt_in > 0 + let get_in_packet con = Queue.pop con.pkt_in ++let has_partial_input con = match con.partial_in with ++ | HaveHdr _ -> true ++ | NoHdr (n, _) -> n < Partial.header_size () + let has_more_input con = + match con.backend with + | Fd _ -> false +diff --git a/tools/ocaml/libs/xb/xb.mli b/tools/ocaml/libs/xb/xb.mli +index 3a00da6cddc1..794e35bb343e 100644 +--- a/tools/ocaml/libs/xb/xb.mli ++++ b/tools/ocaml/libs/xb/xb.mli +@@ -66,13 +66,7 @@ type backend_mmap = { + type backend_fd = { fd : Unix.file_descr; } + type backend = Fd of backend_fd | Xenmmap of backend_mmap + type partial_buf = HaveHdr of Partial.pkt | NoHdr of int * bytes +-type t = { +- backend : backend; +- pkt_in : Packet.t Queue.t; +- pkt_out : Packet.t Queue.t; +- mutable partial_in : partial_buf; +- mutable partial_out : string; +-} ++type t + val init_partial_in : unit -> partial_buf + val reconnect : t -> unit + val queue : t -> Packet.t -> unit +@@ -97,6 +91,7 @@ val has_output : t -> bool + val peek_output : t -> Packet.t + val input_len : t -> int + val has_in_packet : t -> bool ++val has_partial_input : t -> bool + val get_in_packet : t -> Packet.t + val has_more_input : t -> bool + val is_selectable : t -> bool +diff --git a/tools/ocaml/xenstored/connection.ml b/tools/ocaml/xenstored/connection.ml +index 65f99ea6f28a..38b47363a173 100644 +--- a/tools/ocaml/xenstored/connection.ml ++++ b/tools/ocaml/xenstored/connection.ml +@@ -125,9 +125,7 @@ let get_perm con = + let set_target con target_domid = + con.perm <- Perms.Connection.set_target (get_perm con) ~perms:[Perms.READ; Perms.WRITE] target_domid + +-let is_backend_mmap con = match con.xb.Xenbus.Xb.backend with +- | Xenbus.Xb.Xenmmap _ -> true +- | _ -> false ++let is_backend_mmap con = Xenbus.Xb.is_mmap con.xb + + let send_reply con tid rid ty data = + if (String.length data) > xenstore_payload_max && (is_backend_mmap con) then +@@ -280,9 +278,7 @@ let get_transaction con tid = + + let do_input con = Xenbus.Xb.input con.xb + let has_input con = Xenbus.Xb.has_in_packet con.xb +-let has_partial_input con = match con.xb.Xenbus.Xb.partial_in with +- | HaveHdr _ -> true +- | NoHdr (n, _) -> n < Xenbus.Partial.header_size () ++let has_partial_input con = Xenbus.Xb.has_partial_input con.xb + let pop_in con = Xenbus.Xb.get_in_packet con.xb + let has_more_input con = Xenbus.Xb.has_more_input con.xb + diff --git a/xsa326-4.16-oxenstored-05.patch b/xsa326-4.16-oxenstored-05.patch new file mode 100644 index 0000000..8b253a9 --- /dev/null +++ b/xsa326-4.16-oxenstored-05.patch @@ -0,0 +1,214 @@ +From f13fe5903361953e4ccf8602b9c8df7e64568d55 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:02 +0100 +Subject: tools/ocaml: Change Xb.input to return Packet.t option +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +The queue here would only ever hold at most one element. This will simplify +follow-up patches. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/libs/xb/xb.ml b/tools/ocaml/libs/xb/xb.ml +index 8404ddd8a682..165fd4a1edf4 100644 +--- a/tools/ocaml/libs/xb/xb.ml ++++ b/tools/ocaml/libs/xb/xb.ml +@@ -45,7 +45,6 @@ type partial_buf = HaveHdr of Partial.pkt | NoHdr of int * bytes + type t = + { + backend: backend; +- pkt_in: Packet.t Queue.t; + pkt_out: Packet.t Queue.t; + mutable partial_in: partial_buf; + mutable partial_out: string; +@@ -62,7 +61,6 @@ let reconnect t = match t.backend with + Xs_ring.close backend.mmap; + backend.eventchn_notify (); + (* Clear our old connection state *) +- Queue.clear t.pkt_in; + Queue.clear t.pkt_out; + t.partial_in <- init_partial_in (); + t.partial_out <- "" +@@ -124,7 +122,6 @@ let output con = + + (* NB: can throw Reconnect *) + let input con = +- let newpacket = ref false in + let to_read = + match con.partial_in with + | HaveHdr partial_pkt -> Partial.to_complete partial_pkt +@@ -143,21 +140,19 @@ let input con = + if Partial.to_complete partial_pkt = 0 then ( + let pkt = Packet.of_partialpkt partial_pkt in + con.partial_in <- init_partial_in (); +- Queue.push pkt con.pkt_in; +- newpacket := true +- ) ++ Some pkt ++ ) else None + | NoHdr (i, buf) -> + (* we complete the partial header *) + if sz > 0 then + Bytes.blit b 0 buf (Partial.header_size () - i) sz; + con.partial_in <- if sz = i then +- HaveHdr (Partial.of_string (Bytes.to_string buf)) else NoHdr (i - sz, buf) +- ); +- !newpacket ++ HaveHdr (Partial.of_string (Bytes.to_string buf)) else NoHdr (i - sz, buf); ++ None ++ ) + + let newcon backend = { + backend = backend; +- pkt_in = Queue.create (); + pkt_out = Queue.create (); + partial_in = init_partial_in (); + partial_out = ""; +@@ -193,9 +188,6 @@ let has_output con = has_new_output con || has_old_output con + + let peek_output con = Queue.peek con.pkt_out + +-let input_len con = Queue.length con.pkt_in +-let has_in_packet con = Queue.length con.pkt_in > 0 +-let get_in_packet con = Queue.pop con.pkt_in + let has_partial_input con = match con.partial_in with + | HaveHdr _ -> true + | NoHdr (n, _) -> n < Partial.header_size () +diff --git a/tools/ocaml/libs/xb/xb.mli b/tools/ocaml/libs/xb/xb.mli +index 794e35bb343e..91c682162cea 100644 +--- a/tools/ocaml/libs/xb/xb.mli ++++ b/tools/ocaml/libs/xb/xb.mli +@@ -77,7 +77,7 @@ val write_fd : backend_fd -> 'a -> string -> int -> int + val write_mmap : backend_mmap -> 'a -> string -> int -> int + val write : t -> string -> int -> int + val output : t -> bool +-val input : t -> bool ++val input : t -> Packet.t option + val newcon : backend -> t + val open_fd : Unix.file_descr -> t + val open_mmap : Xenmmap.mmap_interface -> (unit -> unit) -> t +@@ -89,10 +89,7 @@ val has_new_output : t -> bool + val has_old_output : t -> bool + val has_output : t -> bool + val peek_output : t -> Packet.t +-val input_len : t -> int +-val has_in_packet : t -> bool + val has_partial_input : t -> bool +-val get_in_packet : t -> Packet.t + val has_more_input : t -> bool + val is_selectable : t -> bool + val get_fd : t -> Unix.file_descr +diff --git a/tools/ocaml/libs/xs/xsraw.ml b/tools/ocaml/libs/xs/xsraw.ml +index d982fb24dbb1..451f8b38dbcc 100644 +--- a/tools/ocaml/libs/xs/xsraw.ml ++++ b/tools/ocaml/libs/xs/xsraw.ml +@@ -94,26 +94,18 @@ let pkt_send con = + done + + (* receive one packet - can sleep *) +-let pkt_recv con = +- let workdone = ref false in +- while not !workdone +- do +- workdone := Xb.input con.xb +- done; +- Xb.get_in_packet con.xb ++let rec pkt_recv con = ++ match Xb.input con.xb with ++ | Some packet -> packet ++ | None -> pkt_recv con + + let pkt_recv_timeout con timeout = + let fd = Xb.get_fd con.xb in + let r, _, _ = Unix.select [ fd ] [] [] timeout in + if r = [] then + true, None +- else ( +- let workdone = Xb.input con.xb in +- if workdone then +- false, (Some (Xb.get_in_packet con.xb)) +- else +- false, None +- ) ++ else ++ false, Xb.input con.xb + + let queue_watchevent con data = + let ls = split_string ~limit:2 '\000' data in +diff --git a/tools/ocaml/xenstored/connection.ml b/tools/ocaml/xenstored/connection.ml +index 38b47363a173..cc20e047d2b9 100644 +--- a/tools/ocaml/xenstored/connection.ml ++++ b/tools/ocaml/xenstored/connection.ml +@@ -277,9 +277,7 @@ let get_transaction con tid = + Hashtbl.find con.transactions tid + + let do_input con = Xenbus.Xb.input con.xb +-let has_input con = Xenbus.Xb.has_in_packet con.xb + let has_partial_input con = Xenbus.Xb.has_partial_input con.xb +-let pop_in con = Xenbus.Xb.get_in_packet con.xb + let has_more_input con = Xenbus.Xb.has_more_input con.xb + + let has_output con = Xenbus.Xb.has_output con.xb +@@ -307,7 +305,7 @@ let is_bad con = match con.dom with None -> false | Some dom -> Domain.is_bad_do + Restrictions below can be relaxed once xenstored learns to dump more + of its live state in a safe way *) + let has_extra_connection_data con = +- let has_in = has_input con || has_partial_input con in ++ let has_in = has_partial_input con in + let has_out = has_output con in + let has_socket = con.dom = None in + let has_nondefault_perms = make_perm con.dom <> con.perm in +diff --git a/tools/ocaml/xenstored/process.ml b/tools/ocaml/xenstored/process.ml +index 6a3435c265d3..2d67456a2aa0 100644 +--- a/tools/ocaml/xenstored/process.ml ++++ b/tools/ocaml/xenstored/process.ml +@@ -195,10 +195,9 @@ let parse_live_update args = + | _ when Unix.gettimeofday () < t.deadline -> false + | l -> + warn "timeout reached: have to wait, migrate or shutdown %d domains:" (List.length l); +- let msgs = List.rev_map (fun con -> Printf.sprintf "%s: %d tx, in: %b, out: %b, perm: %s" ++ let msgs = List.rev_map (fun con -> Printf.sprintf "%s: %d tx, out: %b, perm: %s" + (Connection.get_domstr con) + (Connection.number_of_transactions con) +- (Connection.has_input con) + (Connection.has_output con) + (Connection.get_perm con |> Perms.Connection.to_string) + ) l in +@@ -705,16 +704,17 @@ let do_input store cons doms con = + info "%s requests a reconnect" (Connection.get_domstr con); + History.reconnect con; + info "%s reconnection complete" (Connection.get_domstr con); +- false ++ None + | Failure exp -> + error "caught exception %s" exp; + error "got a bad client %s" (sprintf "%-8s" (Connection.get_domstr con)); + Connection.mark_as_bad con; +- false ++ None + in + +- if newpacket then ( +- let packet = Connection.pop_in con in ++ match newpacket with ++ | None -> () ++ | Some packet -> + let tid, rid, ty, data = Xenbus.Xb.Packet.unpack packet in + let req = {Packet.tid=tid; Packet.rid=rid; Packet.ty=ty; Packet.data=data} in + +@@ -724,8 +724,7 @@ let do_input store cons doms con = + (Xenbus.Xb.Op.to_string ty) (sanitize_data data); *) + process_packet ~store ~cons ~doms ~con ~req; + write_access_log ~ty ~tid ~con:(Connection.get_domstr con) ~data; +- Connection.incr_ops con; +- ) ++ Connection.incr_ops con + + let do_output _store _cons _doms con = + if Connection.has_output con then ( diff --git a/xsa326-4.16-oxenstored-06.patch b/xsa326-4.16-oxenstored-06.patch new file mode 100644 index 0000000..c8ebc34 --- /dev/null +++ b/xsa326-4.16-oxenstored-06.patch @@ -0,0 +1,127 @@ +From 2440a8b69a118fe14e73eb6cab4a050922866f1a Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:03 +0100 +Subject: tools/ocaml/xb: Add BoundedQueue +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Ensures we cannot store more than [capacity] elements in a [Queue]. Replacing +all Queue with this module will then ensure at compile time that all Queues +are correctly bound checked. + +Each element in the queue has a class with its own limits. This, in a +subsequent change, will ensure that command responses can proceed during a +flood of watch events. + +No functional change. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/libs/xb/xb.ml b/tools/ocaml/libs/xb/xb.ml +index 165fd4a1edf4..4197a3888a68 100644 +--- a/tools/ocaml/libs/xb/xb.ml ++++ b/tools/ocaml/libs/xb/xb.ml +@@ -17,6 +17,98 @@ + module Op = struct include Op end + module Packet = struct include Packet end + ++module BoundedQueue : sig ++ type ('a, 'b) t ++ ++ (** [create ~capacity ~classify ~limit] creates a queue with maximum [capacity] elements. ++ This is burst capacity, each element is further classified according to [classify], ++ and each class can have its own [limit]. ++ [capacity] is enforced as an overall limit. ++ The [limit] can be dynamic, and can be smaller than the number of elements already queued of that class, ++ in which case those elements are considered to use "burst capacity". ++ *) ++ val create: capacity:int -> classify:('a -> 'b) -> limit:('b -> int) -> ('a, 'b) t ++ ++ (** [clear q] discards all elements from [q] *) ++ val clear: ('a, 'b) t -> unit ++ ++ (** [can_push q] when [length q < capacity]. *) ++ val can_push: ('a, 'b) t -> 'b -> bool ++ ++ (** [push e q] adds [e] at the end of queue [q] if [can_push q], or returns [None]. *) ++ val push: 'a -> ('a, 'b) t -> unit option ++ ++ (** [pop q] removes and returns first element in [q], or raises [Queue.Empty]. *) ++ val pop: ('a, 'b) t -> 'a ++ ++ (** [peek q] returns the first element in [q], or raises [Queue.Empty]. *) ++ val peek : ('a, 'b) t -> 'a ++ ++ (** [length q] returns the current number of elements in [q] *) ++ val length: ('a, 'b) t -> int ++ ++ (** [debug string_of_class q] prints queue usage statistics in an unspecified internal format. *) ++ val debug: ('b -> string) -> (_, 'b) t -> string ++end = struct ++ type ('a, 'b) t = ++ { q: 'a Queue.t ++ ; capacity: int ++ ; classify: 'a -> 'b ++ ; limit: 'b -> int ++ ; class_count: ('b, int) Hashtbl.t ++ } ++ ++ let create ~capacity ~classify ~limit = ++ { capacity; q = Queue.create (); classify; limit; class_count = Hashtbl.create 3 } ++ ++ let get_count t classification = try Hashtbl.find t.class_count classification with Not_found -> 0 ++ ++ let can_push_internal t classification class_count = ++ Queue.length t.q < t.capacity && class_count < t.limit classification ++ ++ let ok = Some () ++ ++ let push e t = ++ let classification = t.classify e in ++ let class_count = get_count t classification in ++ if can_push_internal t classification class_count then begin ++ Queue.push e t.q; ++ Hashtbl.replace t.class_count classification (class_count + 1); ++ ok ++ end ++ else ++ None ++ ++ let can_push t classification = ++ can_push_internal t classification @@ get_count t classification ++ ++ let clear t = ++ Queue.clear t.q; ++ Hashtbl.reset t.class_count ++ ++ let pop t = ++ let e = Queue.pop t.q in ++ let classification = t.classify e in ++ let () = match get_count t classification - 1 with ++ | 0 -> Hashtbl.remove t.class_count classification (* reduces memusage *) ++ | n -> Hashtbl.replace t.class_count classification n ++ in ++ e ++ ++ let peek t = Queue.peek t.q ++ let length t = Queue.length t.q ++ ++ let debug string_of_class t = ++ let b = Buffer.create 128 in ++ Printf.bprintf b "BoundedQueue capacity: %d, used: {" t.capacity; ++ Hashtbl.iter (fun packet_class count -> ++ Printf.bprintf b " %s: %d" (string_of_class packet_class) count ++ ) t.class_count; ++ Printf.bprintf b "}"; ++ Buffer.contents b ++end ++ ++ + exception End_of_file + exception Eagain + exception Noent diff --git a/xsa326-4.16-oxenstored-07.patch b/xsa326-4.16-oxenstored-07.patch new file mode 100644 index 0000000..ef02467 --- /dev/null +++ b/xsa326-4.16-oxenstored-07.patch @@ -0,0 +1,872 @@ +From bc0f05e6f3a3c93c853ceffd1f6d2022dc30fb77 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:04 +0100 +Subject: tools/ocaml: Limit maximum in-flight requests / outstanding replies +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Introduce a limit on the number of outstanding reply packets in the xenbus +queue. This limits the number of in-flight requests: when the output queue is +full we'll stop processing inputs until the output queue has room again. + +To avoid a busy loop on the Unix socket we only add it to the watched input +file descriptor set if we'd be able to call `input` on it. Even though Dom0 +is trusted and exempt from quotas a flood of events might cause a backlog +where events are produced faster than daemons in Dom0 can consume them, which +could lead to an unbounded queue size and OOM. + +Therefore the xenbus queue limit must apply to all connections, Dom0 is not +exempt from it, although if everything works correctly it will eventually +catch up. + +This prevents a malicious guest from sending more commands while it has +outstanding watch events or command replies in its input ring. However if it +can cause the generation of watch events by other means (e.g. by Dom0, or +another cooperative guest) and stop reading its own ring then watch events +would've queued up without limit. + +The xenstore protocol doesn't have a back-pressure mechanism, and doesn't +allow dropping watch events. In fact, dropping watch events is known to break +some pieces of normal functionality. This leaves little choice to safely +implement the xenstore protocol without exposing the xenstore daemon to +out-of-memory attacks. + +Implement the fix as pipes with bounded buffers: +* Use a bounded buffer for watch events +* The watch structure will have a bounded receiving pipe of watch events +* The source will have an "overflow" pipe of pending watch events it couldn't + deliver + +Items are queued up on one end and are sent as far along the pipe as possible: + + source domain -> watch -> xenbus of target -> xenstore ring/socket of target + +If the pipe is "full" at any point then back-pressure is applied and we prevent +more items from being queued up. For the source domain this means that we'll +stop accepting new commands as long as its pipe buffer is not empty. + +Before we try to enqueue an item we first check whether it is possible to send +it further down the pipe, by attempting to recursively flush the pipes. This +ensures that we retain the order of events as much as possible. + +We might break causality of watch events if the target domain's queue is full +and we need to start using the watch's queue. This is a breaking change in +the xenstore protocol, but only for domains which are not processing their +incoming ring as expected. + +When a watch is deleted its entire pending queue is dropped (no code is needed +for that, because it is part of the 'watch' type). + +There is a cache of watches that have pending events that we attempt to flush +at every cycle if possible. + +Introduce 3 limits here: +* quota-maxwatchevents on watch event destination: when this is hit the + source will not be allowed to queue up more watch events. +* quota-maxoustanding which is the number of responses not read from the ring: + once exceeded, no more inputs are processed until all outstanding replies + are consumed by the client. +* overflow queue on the watch event source: all watches that cannot be stored + on destination are queued up here, a single command can trigger multiple + watches (e.g. due to recursion). + +The overflow queue currently doesn't have an upper bound, it is difficult to +accurately calculate one as it depends on whether you are Dom0 and how many +watches each path has registered and how many watch events you can trigger +with a single command (e.g. a commit). However these events were already +using memory, this just moves them elsewhere, and as long as we correctly +block a domain it shouldn't result in unbounded memory usage. + +Note that Dom0 is not excluded from these checks, it is important that Dom0 is +especially not excluded when it is the source, since there are many ways in +which a guest could trigger Dom0 to send it watch events. + +This should protect against malicious frontends as long as the backend follows +the PV xenstore protocol and only exposes paths needed by the frontend, and +changes those paths at most once as a reaction to guest events, or protocol +state. + +The queue limits are per watch, and per domain-pair, so even if one +communication channel would be "blocked", others would keep working, and the +domain itself won't get blocked as long as it doesn't overflow the queue of +watch events. + +Similarly a malicious backend could cause the frontend to get blocked, but +this watch queue protects the frontend as well as long as it follows the PV +protocol. (Although note that protection against malicious backends is only a +best effort at the moment) + +This is part of XSA-326 / CVE-2022-42318. + +Reported-by: Julien Grall +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/libs/xb/xb.ml b/tools/ocaml/libs/xb/xb.ml +index 4197a3888a68..b292ed7a874d 100644 +--- a/tools/ocaml/libs/xb/xb.ml ++++ b/tools/ocaml/libs/xb/xb.ml +@@ -134,14 +134,44 @@ type backend = Fd of backend_fd | Xenmmap of backend_mmap + + type partial_buf = HaveHdr of Partial.pkt | NoHdr of int * bytes + ++(* ++ separate capacity reservation for replies and watch events: ++ this allows a domain to keep working even when under a constant flood of ++ watch events ++*) ++type capacity = { maxoutstanding: int; maxwatchevents: int } ++ ++module Queue = BoundedQueue ++ ++type packet_class = ++ | CommandReply ++ | Watchevent ++ ++let string_of_packet_class = function ++ | CommandReply -> "command_reply" ++ | Watchevent -> "watch_event" ++ + type t = + { + backend: backend; +- pkt_out: Packet.t Queue.t; ++ pkt_out: (Packet.t, packet_class) Queue.t; + mutable partial_in: partial_buf; + mutable partial_out: string; ++ capacity: capacity + } + ++let to_read con = ++ match con.partial_in with ++ | HaveHdr partial_pkt -> Partial.to_complete partial_pkt ++ | NoHdr (i, _) -> i ++ ++let debug t = ++ Printf.sprintf "XenBus state: partial_in: %d needed, partial_out: %d bytes, pkt_out: %d packets, %s" ++ (to_read t) ++ (String.length t.partial_out) ++ (Queue.length t.pkt_out) ++ (BoundedQueue.debug string_of_packet_class t.pkt_out) ++ + let init_partial_in () = NoHdr + (Partial.header_size (), Bytes.make (Partial.header_size()) '\000') + +@@ -199,7 +229,8 @@ let output con = + let s = if String.length con.partial_out > 0 then + con.partial_out + else if Queue.length con.pkt_out > 0 then +- Packet.to_string (Queue.pop con.pkt_out) ++ let pkt = Queue.pop con.pkt_out in ++ Packet.to_string pkt + else + "" in + (* send data from s, and save the unsent data to partial_out *) +@@ -212,12 +243,15 @@ let output con = + (* after sending one packet, partial is empty *) + con.partial_out = "" + ++(* we can only process an input packet if we're guaranteed to have room ++ to store the response packet *) ++let can_input con = Queue.can_push con.pkt_out CommandReply ++ + (* NB: can throw Reconnect *) + let input con = +- let to_read = +- match con.partial_in with +- | HaveHdr partial_pkt -> Partial.to_complete partial_pkt +- | NoHdr (i, _) -> i in ++ if not (can_input con) then None ++ else ++ let to_read = to_read con in + + (* try to get more data from input stream *) + let b = Bytes.make to_read '\000' in +@@ -243,11 +277,22 @@ let input con = + None + ) + +-let newcon backend = { ++let classify t = ++ match t.Packet.ty with ++ | Op.Watchevent -> Watchevent ++ | _ -> CommandReply ++ ++let newcon ~capacity backend = ++ let limit = function ++ | CommandReply -> capacity.maxoutstanding ++ | Watchevent -> capacity.maxwatchevents ++ in ++ { + backend = backend; +- pkt_out = Queue.create (); ++ pkt_out = Queue.create ~capacity:(capacity.maxoutstanding + capacity.maxwatchevents) ~classify ~limit; + partial_in = init_partial_in (); + partial_out = ""; ++ capacity = capacity; + } + + let open_fd fd = newcon (Fd { fd = fd; }) +diff --git a/tools/ocaml/libs/xb/xb.mli b/tools/ocaml/libs/xb/xb.mli +index 91c682162cea..71b2754ca788 100644 +--- a/tools/ocaml/libs/xb/xb.mli ++++ b/tools/ocaml/libs/xb/xb.mli +@@ -66,10 +66,11 @@ type backend_mmap = { + type backend_fd = { fd : Unix.file_descr; } + type backend = Fd of backend_fd | Xenmmap of backend_mmap + type partial_buf = HaveHdr of Partial.pkt | NoHdr of int * bytes ++type capacity = { maxoutstanding: int; maxwatchevents: int } + type t + val init_partial_in : unit -> partial_buf + val reconnect : t -> unit +-val queue : t -> Packet.t -> unit ++val queue : t -> Packet.t -> unit option + val read_fd : backend_fd -> 'a -> bytes -> int -> int + val read_mmap : backend_mmap -> 'a -> bytes -> int -> int + val read : t -> bytes -> int -> int +@@ -78,13 +79,14 @@ val write_mmap : backend_mmap -> 'a -> string -> int -> int + val write : t -> string -> int -> int + val output : t -> bool + val input : t -> Packet.t option +-val newcon : backend -> t +-val open_fd : Unix.file_descr -> t +-val open_mmap : Xenmmap.mmap_interface -> (unit -> unit) -> t ++val newcon : capacity:capacity -> backend -> t ++val open_fd : Unix.file_descr -> capacity:capacity -> t ++val open_mmap : Xenmmap.mmap_interface -> (unit -> unit) -> capacity:capacity -> t + val close : t -> unit + val is_fd : t -> bool + val is_mmap : t -> bool + val output_len : t -> int ++val can_input: t -> bool + val has_new_output : t -> bool + val has_old_output : t -> bool + val has_output : t -> bool +@@ -93,3 +95,4 @@ val has_partial_input : t -> bool + val has_more_input : t -> bool + val is_selectable : t -> bool + val get_fd : t -> Unix.file_descr ++val debug: t -> string +diff --git a/tools/ocaml/libs/xs/queueop.ml b/tools/ocaml/libs/xs/queueop.ml +index 9ff5bbd529ce..4e532cdaeacb 100644 +--- a/tools/ocaml/libs/xs/queueop.ml ++++ b/tools/ocaml/libs/xs/queueop.ml +@@ -16,9 +16,10 @@ + open Xenbus + + let data_concat ls = (String.concat "\000" ls) ^ "\000" ++let queue con pkt = let r = Xb.queue con pkt in assert (r <> None) + let queue_path ty (tid: int) (path: string) con = + let data = data_concat [ path; ] in +- Xb.queue con (Xb.Packet.create tid 0 ty data) ++ queue con (Xb.Packet.create tid 0 ty data) + + (* operations *) + let directory tid path con = queue_path Xb.Op.Directory tid path con +@@ -27,48 +28,48 @@ let read tid path con = queue_path Xb.Op.Read tid path con + let getperms tid path con = queue_path Xb.Op.Getperms tid path con + + let debug commands con = +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Debug (data_concat commands)) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Debug (data_concat commands)) + + let watch path data con = + let data = data_concat [ path; data; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Watch data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Watch data) + + let unwatch path data con = + let data = data_concat [ path; data; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Unwatch data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Unwatch data) + + let transaction_start con = +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Transaction_start (data_concat [])) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Transaction_start (data_concat [])) + + let transaction_end tid commit con = + let data = data_concat [ (if commit then "T" else "F"); ] in +- Xb.queue con (Xb.Packet.create tid 0 Xb.Op.Transaction_end data) ++ queue con (Xb.Packet.create tid 0 Xb.Op.Transaction_end data) + + let introduce domid mfn port con = + let data = data_concat [ Printf.sprintf "%u" domid; + Printf.sprintf "%nu" mfn; + string_of_int port; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Introduce data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Introduce data) + + let release domid con = + let data = data_concat [ Printf.sprintf "%u" domid; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Release data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Release data) + + let resume domid con = + let data = data_concat [ Printf.sprintf "%u" domid; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Resume data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Resume data) + + let getdomainpath domid con = + let data = data_concat [ Printf.sprintf "%u" domid; ] in +- Xb.queue con (Xb.Packet.create 0 0 Xb.Op.Getdomainpath data) ++ queue con (Xb.Packet.create 0 0 Xb.Op.Getdomainpath data) + + let write tid path value con = + let data = path ^ "\000" ^ value (* no NULL at the end *) in +- Xb.queue con (Xb.Packet.create tid 0 Xb.Op.Write data) ++ queue con (Xb.Packet.create tid 0 Xb.Op.Write data) + + let mkdir tid path con = queue_path Xb.Op.Mkdir tid path con + let rm tid path con = queue_path Xb.Op.Rm tid path con + + let setperms tid path perms con = + let data = data_concat [ path; perms ] in +- Xb.queue con (Xb.Packet.create tid 0 Xb.Op.Setperms data) ++ queue con (Xb.Packet.create tid 0 Xb.Op.Setperms data) +diff --git a/tools/ocaml/libs/xs/xsraw.ml b/tools/ocaml/libs/xs/xsraw.ml +index 451f8b38dbcc..cbd17280600c 100644 +--- a/tools/ocaml/libs/xs/xsraw.ml ++++ b/tools/ocaml/libs/xs/xsraw.ml +@@ -36,8 +36,10 @@ type con = { + let close con = + Xb.close con.xb + ++let capacity = { Xb.maxoutstanding = 1; maxwatchevents = 0; } ++ + let open_fd fd = { +- xb = Xb.open_fd fd; ++ xb = Xb.open_fd ~capacity fd; + watchevents = Queue.create (); + } + +diff --git a/tools/ocaml/xenstored/connection.ml b/tools/ocaml/xenstored/connection.ml +index cc20e047d2b9..9624a5f9da2c 100644 +--- a/tools/ocaml/xenstored/connection.ml ++++ b/tools/ocaml/xenstored/connection.ml +@@ -20,12 +20,84 @@ open Stdext + + let xenstore_payload_max = 4096 (* xen/include/public/io/xs_wire.h *) + ++type 'a bounded_sender = 'a -> unit option ++(** a bounded sender accepts an ['a] item and returns: ++ None - if there is no room to accept the item ++ Some () - if it has successfully accepted/sent the item ++ *) ++ ++module BoundedPipe : sig ++ type 'a t ++ ++ (** [create ~capacity ~destination] creates a bounded pipe with a ++ local buffer holding at most [capacity] items. Once the buffer is ++ full it will not accept further items. items from the pipe are ++ flushed into [destination] as long as it accepts items. The ++ destination could be another pipe. ++ *) ++ val create: capacity:int -> destination:'a bounded_sender -> 'a t ++ ++ (** [is_empty t] returns whether the local buffer of [t] is empty. *) ++ val is_empty : _ t -> bool ++ ++ (** [length t] the number of items in the internal buffer *) ++ val length: _ t -> int ++ ++ (** [flush_pipe t] sends as many items from the local buffer as possible, ++ which could be none. *) ++ val flush_pipe: _ t -> unit ++ ++ (** [push t item] tries to [flush_pipe] and then push [item] ++ into the pipe if its [capacity] allows. ++ Returns [None] if there is no more room ++ *) ++ val push : 'a t -> 'a bounded_sender ++end = struct ++ (* items are enqueued in [q], and then flushed to [connect_to] *) ++ type 'a t = ++ { q: 'a Queue.t ++ ; destination: 'a bounded_sender ++ ; capacity: int ++ } ++ ++ let create ~capacity ~destination = ++ { q = Queue.create (); capacity; destination } ++ ++ let rec flush_pipe t = ++ if not Queue.(is_empty t.q) then ++ let item = Queue.peek t.q in ++ match t.destination item with ++ | None -> () (* no room *) ++ | Some () -> ++ (* successfully sent item to next stage *) ++ let _ = Queue.pop t.q in ++ (* continue trying to send more items *) ++ flush_pipe t ++ ++ let push t item = ++ (* first try to flush as many items from this pipe as possible to make room, ++ it is important to do this first to preserve the order of the items ++ *) ++ flush_pipe t; ++ if Queue.length t.q < t.capacity then begin ++ (* enqueue, instead of sending directly. ++ this ensures that [out] sees the items in the same order as we receive them ++ *) ++ Queue.push item t.q; ++ Some (flush_pipe t) ++ end else None ++ ++ let is_empty t = Queue.is_empty t.q ++ let length t = Queue.length t.q ++end ++ + type watch = { + con: t; + token: string; + path: string; + base: string; + is_relative: bool; ++ pending_watchevents: Xenbus.Xb.Packet.t BoundedPipe.t; + } + + and t = { +@@ -38,8 +110,36 @@ and t = { + anonid: int; + mutable stat_nb_ops: int; + mutable perm: Perms.Connection.t; ++ pending_source_watchevents: (watch * Xenbus.Xb.Packet.t) BoundedPipe.t + } + ++module Watch = struct ++ module T = struct ++ type t = watch ++ ++ let compare w1 w2 = ++ (* cannot compare watches from different connections *) ++ assert (w1.con == w2.con); ++ match String.compare w1.token w2.token with ++ | 0 -> String.compare w1.path w2.path ++ | n -> n ++ end ++ module Set = Set.Make(T) ++ ++ let flush_events t = ++ BoundedPipe.flush_pipe t.pending_watchevents; ++ not (BoundedPipe.is_empty t.pending_watchevents) ++ ++ let pending_watchevents t = ++ BoundedPipe.length t.pending_watchevents ++end ++ ++let source_flush_watchevents t = ++ BoundedPipe.flush_pipe t.pending_source_watchevents ++ ++let source_pending_watchevents t = ++ BoundedPipe.length t.pending_source_watchevents ++ + let mark_as_bad con = + match con.dom with + |None -> () +@@ -67,7 +167,8 @@ let watch_create ~con ~path ~token = { + token = token; + path = path; + base = get_path con; +- is_relative = path.[0] <> '/' && path.[0] <> '@' ++ is_relative = path.[0] <> '/' && path.[0] <> '@'; ++ pending_watchevents = BoundedPipe.create ~capacity:!Define.maxwatchevents ~destination:(Xenbus.Xb.queue con.xb) + } + + let get_con w = w.con +@@ -93,6 +194,9 @@ let make_perm dom = + Perms.Connection.create ~perms:[Perms.READ; Perms.WRITE] domid + + let create xbcon dom = ++ let destination (watch, pkt) = ++ BoundedPipe.push watch.pending_watchevents pkt ++ in + let id = + match dom with + | None -> let old = !anon_id_next in incr anon_id_next; old +@@ -109,6 +213,16 @@ let create xbcon dom = + anonid = id; + stat_nb_ops = 0; + perm = make_perm dom; ++ ++ (* the actual capacity will be lower, this is used as an overflow ++ buffer: anything that doesn't fit elsewhere gets put here, only ++ limited by the amount of watches that you can generate with a ++ single xenstore command (which is finite, although possibly very ++ large in theory for Dom0). Once the pipe here has any contents the ++ domain is blocked from sending more commands until it is empty ++ again though. ++ *) ++ pending_source_watchevents = BoundedPipe.create ~capacity:Sys.max_array_length ~destination + } + in + Logging.new_connection ~tid:Transaction.none ~con:(get_domstr con); +@@ -127,11 +241,17 @@ let set_target con target_domid = + + let is_backend_mmap con = Xenbus.Xb.is_mmap con.xb + +-let send_reply con tid rid ty data = ++let packet_of con tid rid ty data = + if (String.length data) > xenstore_payload_max && (is_backend_mmap con) then +- Xenbus.Xb.queue con.xb (Xenbus.Xb.Packet.create tid rid Xenbus.Xb.Op.Error "E2BIG\000") ++ Xenbus.Xb.Packet.create tid rid Xenbus.Xb.Op.Error "E2BIG\000" + else +- Xenbus.Xb.queue con.xb (Xenbus.Xb.Packet.create tid rid ty data) ++ Xenbus.Xb.Packet.create tid rid ty data ++ ++let send_reply con tid rid ty data = ++ let result = Xenbus.Xb.queue con.xb (packet_of con tid rid ty data) in ++ (* should never happen: we only process an input packet when there is room for an output packet *) ++ (* and the limit for replies is different from the limit for watch events *) ++ assert (result <> None) + + let send_error con tid rid err = send_reply con tid rid Xenbus.Xb.Op.Error (err ^ "\000") + let send_ack con tid rid ty = send_reply con tid rid ty "OK\000" +@@ -181,11 +301,11 @@ let del_watch con path token = + apath, w + + let del_watches con = +- Hashtbl.clear con.watches; ++ Hashtbl.reset con.watches; + con.nb_watches <- 0 + + let del_transactions con = +- Hashtbl.clear con.transactions ++ Hashtbl.reset con.transactions + + let list_watches con = + let ll = Hashtbl.fold +@@ -208,21 +328,29 @@ let lookup_watch_perm path = function + let lookup_watch_perms oldroot root path = + lookup_watch_perm path oldroot @ lookup_watch_perm path (Some root) + +-let fire_single_watch_unchecked watch = ++let fire_single_watch_unchecked source watch = + let data = Utils.join_by_null [watch.path; watch.token; ""] in +- send_reply watch.con Transaction.none 0 Xenbus.Xb.Op.Watchevent data ++ let pkt = packet_of watch.con Transaction.none 0 Xenbus.Xb.Op.Watchevent data in ++ ++ match BoundedPipe.push source.pending_source_watchevents (watch, pkt) with ++ | Some () -> () (* packet queued *) ++ | None -> ++ (* a well behaved Dom0 shouldn't be able to trigger this, ++ if it happens it is likely a Dom0 bug causing runaway memory usage ++ *) ++ failwith "watch event overflow, cannot happen" + +-let fire_single_watch (oldroot, root) watch = ++let fire_single_watch source (oldroot, root) watch = + let abspath = get_watch_path watch.con watch.path |> Store.Path.of_string in + let perms = lookup_watch_perms oldroot root abspath in + if Perms.can_fire_watch watch.con.perm perms then +- fire_single_watch_unchecked watch ++ fire_single_watch_unchecked source watch + else + let perms = perms |> List.map (Perms.Node.to_string ~sep:" ") |> String.concat ", " in + let con = get_domstr watch.con in + Logging.watch_not_fired ~con perms (Store.Path.to_string abspath) + +-let fire_watch roots watch path = ++let fire_watch source roots watch path = + let new_path = + if watch.is_relative && path.[0] = '/' + then begin +@@ -232,7 +360,7 @@ let fire_watch roots watch path = + end else + path + in +- fire_single_watch roots { watch with path = new_path } ++ fire_single_watch source roots { watch with path = new_path } + + (* Search for a valid unused transaction id. *) + let rec valid_transaction_id con proposed_id = +@@ -280,6 +408,7 @@ let do_input con = Xenbus.Xb.input con.xb + let has_partial_input con = Xenbus.Xb.has_partial_input con.xb + let has_more_input con = Xenbus.Xb.has_more_input con.xb + ++let can_input con = Xenbus.Xb.can_input con.xb && BoundedPipe.is_empty con.pending_source_watchevents + let has_output con = Xenbus.Xb.has_output con.xb + let has_old_output con = Xenbus.Xb.has_old_output con.xb + let has_new_output con = Xenbus.Xb.has_new_output con.xb +@@ -323,7 +452,7 @@ let prevents_live_update con = not (is_bad con) + && (has_extra_connection_data con || has_transaction_data con) + + let has_more_work con = +- has_more_input con || not (has_old_output con) && has_new_output con ++ (has_more_input con && can_input con) || not (has_old_output con) && has_new_output con + + let incr_ops con = con.stat_nb_ops <- con.stat_nb_ops + 1 + +diff --git a/tools/ocaml/xenstored/connections.ml b/tools/ocaml/xenstored/connections.ml +index 3c7429fe7f61..7d68c583b43a 100644 +--- a/tools/ocaml/xenstored/connections.ml ++++ b/tools/ocaml/xenstored/connections.ml +@@ -22,22 +22,30 @@ type t = { + domains: (int, Connection.t) Hashtbl.t; + ports: (Xeneventchn.t, Connection.t) Hashtbl.t; + mutable watches: Connection.watch list Trie.t; ++ mutable has_pending_watchevents: Connection.Watch.Set.t + } + + let create () = { + anonymous = Hashtbl.create 37; + domains = Hashtbl.create 37; + ports = Hashtbl.create 37; +- watches = Trie.create () ++ watches = Trie.create (); ++ has_pending_watchevents = Connection.Watch.Set.empty; + } + ++let get_capacity () = ++ (* not multiplied by maxwatch on purpose: 2nd queue in watch itself! *) ++ { Xenbus.Xb.maxoutstanding = !Define.maxoutstanding; maxwatchevents = !Define.maxwatchevents } ++ + let add_anonymous cons fd = +- let xbcon = Xenbus.Xb.open_fd fd in ++ let capacity = get_capacity () in ++ let xbcon = Xenbus.Xb.open_fd fd ~capacity in + let con = Connection.create xbcon None in + Hashtbl.add cons.anonymous (Xenbus.Xb.get_fd xbcon) con + + let add_domain cons dom = +- let xbcon = Xenbus.Xb.open_mmap (Domain.get_interface dom) (fun () -> Domain.notify dom) in ++ let capacity = get_capacity () in ++ let xbcon = Xenbus.Xb.open_mmap ~capacity (Domain.get_interface dom) (fun () -> Domain.notify dom) in + let con = Connection.create xbcon (Some dom) in + Hashtbl.add cons.domains (Domain.get_id dom) con; + match Domain.get_port dom with +@@ -48,7 +56,9 @@ let select ?(only_if = (fun _ -> true)) cons = + Hashtbl.fold (fun _ con (ins, outs) -> + if (only_if con) then ( + let fd = Connection.get_fd con in +- (fd :: ins, if Connection.has_output con then fd :: outs else outs) ++ let in_fds = if Connection.can_input con then fd :: ins else ins in ++ let out_fds = if Connection.has_output con then fd :: outs else outs in ++ in_fds, out_fds + ) else (ins, outs) + ) + cons.anonymous ([], []) +@@ -67,10 +77,17 @@ let del_watches_of_con con watches = + | [] -> None + | ws -> Some ws + ++let del_watches cons con = ++ Connection.del_watches con; ++ cons.watches <- Trie.map (del_watches_of_con con) cons.watches; ++ cons.has_pending_watchevents <- ++ cons.has_pending_watchevents |> Connection.Watch.Set.filter @@ fun w -> ++ Connection.get_con w != con ++ + let del_anonymous cons con = + try + Hashtbl.remove cons.anonymous (Connection.get_fd con); +- cons.watches <- Trie.map (del_watches_of_con con) cons.watches; ++ del_watches cons con; + Connection.close con + with exn -> + debug "del anonymous %s" (Printexc.to_string exn) +@@ -85,7 +102,7 @@ let del_domain cons id = + | Some p -> Hashtbl.remove cons.ports p + | None -> ()) + | None -> ()); +- cons.watches <- Trie.map (del_watches_of_con con) cons.watches; ++ del_watches cons con; + Connection.close con + with exn -> + debug "del domain %u: %s" id (Printexc.to_string exn) +@@ -136,31 +153,33 @@ let del_watch cons con path token = + cons.watches <- Trie.set cons.watches key watches; + watch + +-let del_watches cons con = +- Connection.del_watches con; +- cons.watches <- Trie.map (del_watches_of_con con) cons.watches +- + (* path is absolute *) +-let fire_watches ?oldroot root cons path recurse = ++let fire_watches ?oldroot source root cons path recurse = + let key = key_of_path path in + let path = Store.Path.to_string path in + let roots = oldroot, root in + let fire_watch _ = function + | None -> () +- | Some watches -> List.iter (fun w -> Connection.fire_watch roots w path) watches ++ | Some watches -> List.iter (fun w -> Connection.fire_watch source roots w path) watches + in + let fire_rec _x = function + | None -> () + | Some watches -> +- List.iter (Connection.fire_single_watch roots) watches ++ List.iter (Connection.fire_single_watch source roots) watches + in + Trie.iter_path fire_watch cons.watches key; + if recurse then + Trie.iter fire_rec (Trie.sub cons.watches key) + ++let send_watchevents cons con = ++ cons.has_pending_watchevents <- ++ cons.has_pending_watchevents |> Connection.Watch.Set.filter Connection.Watch.flush_events; ++ Connection.source_flush_watchevents con ++ + let fire_spec_watches root cons specpath = ++ let source = find_domain cons 0 in + iter cons (fun con -> +- List.iter (Connection.fire_single_watch (None, root)) (Connection.get_watches con specpath)) ++ List.iter (Connection.fire_single_watch source (None, root)) (Connection.get_watches con specpath)) + + let set_target cons domain target_domain = + let con = find_domain cons domain in +@@ -197,6 +216,16 @@ let debug cons = + let domains = Hashtbl.fold (fun _ con accu -> Connection.debug con :: accu) cons.domains [] in + String.concat "" (domains @ anonymous) + ++let debug_watchevents cons con = ++ (* == (physical equality) ++ has to be used here because w.con.xb.backend might contain a [unit->unit] value causing regular ++ comparison to fail due to having a 'functional value' which cannot be compared. ++ *) ++ let s = cons.has_pending_watchevents |> Connection.Watch.Set.filter (fun w -> w.con == con) in ++ let pending = s |> Connection.Watch.Set.elements ++ |> List.map (fun w -> Connection.Watch.pending_watchevents w) |> List.fold_left (+) 0 in ++ Printf.sprintf "Watches with pending events: %d, pending events total: %d" (Connection.Watch.Set.cardinal s) pending ++ + let filter ~f cons = + let fold _ v acc = if f v then v :: acc else acc in + [] +diff --git a/tools/ocaml/xenstored/define.ml b/tools/ocaml/xenstored/define.ml +index ba63a8147e09..327b6d795ec7 100644 +--- a/tools/ocaml/xenstored/define.ml ++++ b/tools/ocaml/xenstored/define.ml +@@ -24,6 +24,13 @@ let default_config_dir = Paths.xen_config_dir + let maxwatch = ref (100) + let maxtransaction = ref (10) + let maxrequests = ref (1024) (* maximum requests per transaction *) ++let maxoutstanding = ref (1024) (* maximum outstanding requests, i.e. in-flight requests / domain *) ++let maxwatchevents = ref (1024) ++(* ++ maximum outstanding watch events per watch, ++ recommended >= maxoutstanding to avoid blocking backend transactions due to ++ malicious frontends ++ *) + + let gc_max_overhead = ref 120 (* 120% see comment in xenstored.ml *) + let conflict_burst_limit = ref 5.0 +diff --git a/tools/ocaml/xenstored/oxenstored.conf.in b/tools/ocaml/xenstored/oxenstored.conf.in +index 4ae48e42d47d..9d034e744b4b 100644 +--- a/tools/ocaml/xenstored/oxenstored.conf.in ++++ b/tools/ocaml/xenstored/oxenstored.conf.in +@@ -62,6 +62,8 @@ quota-maxwatch = 100 + quota-transaction = 10 + quota-maxrequests = 1024 + quota-path-max = 1024 ++quota-maxoutstanding = 1024 ++quota-maxwatchevents = 1024 + + # Activate filed base backend + persistent = false +diff --git a/tools/ocaml/xenstored/process.ml b/tools/ocaml/xenstored/process.ml +index 2d67456a2aa0..6dcedfda86e4 100644 +--- a/tools/ocaml/xenstored/process.ml ++++ b/tools/ocaml/xenstored/process.ml +@@ -57,7 +57,7 @@ let split_one_path data con = + | path :: "" :: [] -> Store.Path.create path (Connection.get_path con) + | _ -> raise Invalid_Cmd_Args + +-let process_watch t cons = ++let process_watch source t cons = + let oldroot = t.Transaction.oldroot in + let newroot = Store.get_root t.store in + let ops = Transaction.get_paths t |> List.rev in +@@ -67,8 +67,9 @@ let process_watch t cons = + | Xenbus.Xb.Op.Rm -> true, None, oldroot + | Xenbus.Xb.Op.Setperms -> false, Some oldroot, newroot + | _ -> raise (Failure "huh ?") in +- Connections.fire_watches ?oldroot root cons (snd op) recurse in +- List.iter (fun op -> do_op_watch op cons) ops ++ Connections.fire_watches ?oldroot source root cons (snd op) recurse in ++ List.iter (fun op -> do_op_watch op cons) ops; ++ Connections.send_watchevents cons source + + let create_implicit_path t perm path = + let dirname = Store.Path.get_parent path in +@@ -234,6 +235,20 @@ let do_debug con t _domains cons data = + | "watches" :: _ -> + let watches = Connections.debug cons in + Some (watches ^ "\000") ++ | "xenbus" :: domid :: _ -> ++ let domid = int_of_string domid in ++ let con = Connections.find_domain cons domid in ++ let s = Printf.sprintf "xenbus: %s; overflow queue length: %d, can_input: %b, has_more_input: %b, has_old_output: %b, has_new_output: %b, has_more_work: %b. pending: %s" ++ (Xenbus.Xb.debug con.xb) ++ (Connection.source_pending_watchevents con) ++ (Connection.can_input con) ++ (Connection.has_more_input con) ++ (Connection.has_old_output con) ++ (Connection.has_new_output con) ++ (Connection.has_more_work con) ++ (Connections.debug_watchevents cons con) ++ in ++ Some s + | "mfn" :: domid :: _ -> + let domid = int_of_string domid in + let con = Connections.find_domain cons domid in +@@ -342,7 +357,7 @@ let reply_ack fct con t doms cons data = + fct con t doms cons data; + Packet.Ack (fun () -> + if Transaction.get_id t = Transaction.none then +- process_watch t cons ++ process_watch con t cons + ) + + let reply_data fct con t doms cons data = +@@ -501,7 +516,7 @@ let do_watch con t _domains cons data = + Packet.Ack (fun () -> + (* xenstore.txt says this watch is fired immediately, + implying even if path doesn't exist or is unreadable *) +- Connection.fire_single_watch_unchecked watch) ++ Connection.fire_single_watch_unchecked con watch) + + let do_unwatch con _t _domains cons data = + let (node, token) = +@@ -532,7 +547,7 @@ let do_transaction_end con t domains cons data = + if not success then + raise Transaction_again; + if commit then begin +- process_watch t cons; ++ process_watch con t cons; + match t.Transaction.ty with + | Transaction.No -> + () (* no need to record anything *) +@@ -699,7 +714,8 @@ let process_packet ~store ~cons ~doms ~con ~req = + let do_input store cons doms con = + let newpacket = + try +- Connection.do_input con ++ if Connection.can_input con then Connection.do_input con ++ else None + with Xenbus.Xb.Reconnect -> + info "%s requests a reconnect" (Connection.get_domstr con); + History.reconnect con; +@@ -727,6 +743,7 @@ let do_input store cons doms con = + Connection.incr_ops con + + let do_output _store _cons _doms con = ++ Connection.source_flush_watchevents con; + if Connection.has_output con then ( + if Connection.has_new_output con then ( + let packet = Connection.peek_output con in +diff --git a/tools/ocaml/xenstored/xenstored.ml b/tools/ocaml/xenstored/xenstored.ml +index 3b57ad016dfb..c799e20f1145 100644 +--- a/tools/ocaml/xenstored/xenstored.ml ++++ b/tools/ocaml/xenstored/xenstored.ml +@@ -103,6 +103,8 @@ let parse_config filename = + ("quota-maxentity", Config.Set_int Quota.maxent); + ("quota-maxsize", Config.Set_int Quota.maxsize); + ("quota-maxrequests", Config.Set_int Define.maxrequests); ++ ("quota-maxoutstanding", Config.Set_int Define.maxoutstanding); ++ ("quota-maxwatchevents", Config.Set_int Define.maxwatchevents); + ("quota-path-max", Config.Set_int Define.path_max); + ("gc-max-overhead", Config.Set_int Define.gc_max_overhead); + ("test-eagain", Config.Set_bool Transaction.test_eagain); diff --git a/xsa326-4.16-oxenstored-08.patch b/xsa326-4.16-oxenstored-08.patch new file mode 100644 index 0000000..8a47200 --- /dev/null +++ b/xsa326-4.16-oxenstored-08.patch @@ -0,0 +1,49 @@ +From 09aa10649f75a262028e9a9b7d859ef7efb23d54 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Thu, 29 Sep 2022 13:07:35 +0200 +Subject: SUPPORT.md: clarify support of untrusted driver domains with + oxenstored + +Add a support statement for the scope of support regarding different +Xenstore variants. Especially oxenstored does not (yet) have security +support of untrusted driver domains, as those might drive oxenstored +out of memory by creating lots of watch events for the guests they are +servicing. + +Add a statement regarding Live Update support of oxenstored. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: George Dunlap +Acked-by: Julien Grall +Reviewed-by: Christian Lindig + +diff --git a/SUPPORT.md b/SUPPORT.md +index 85726102eab8..7d0cb34c8f6f 100644 +--- a/SUPPORT.md ++++ b/SUPPORT.md +@@ -179,13 +179,18 @@ Support for running qemu-xen device model in a linux stubdomain. + + Status: Tech Preview + +-## Liveupdate of C xenstored daemon ++## Xenstore + +- Status: Tech Preview ++### C xenstored daemon + +-## Liveupdate of OCaml xenstored daemon ++ Status: Supported ++ Status, Liveupdate: Tech Preview + +- Status: Tech Preview ++### OCaml xenstored daemon ++ ++ Status: Supported ++ Status, untrusted driver domains: Supported, not security supported ++ Status, Liveupdate: Not functional + + ## Toolstack/3rd party + diff --git a/xsa326-4.16-xenstored-01.patch b/xsa326-4.16-xenstored-01.patch new file mode 100644 index 0000000..b4a4b0e --- /dev/null +++ b/xsa326-4.16-xenstored-01.patch @@ -0,0 +1,205 @@ +From 5192f13a41661b1c1b9e0889d57c0f5b41925c39 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:07 +0200 +Subject: tools/xenstore: split up send_reply() + +Today send_reply() is used for both, normal request replies and watch +events. + +Split it up into send_reply() and send_event(). This will be used to +add some event specific handling. + +add_event() can be merged into send_event(), removing the need for an +intermediate memory allocation. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index e9c9695fd16e..249ad5ec6fb1 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -767,49 +767,32 @@ static void send_error(struct connection *conn, int error) + void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + const void *data, unsigned int len) + { +- struct buffered_data *bdata; ++ struct buffered_data *bdata = conn->in; ++ ++ assert(type != XS_WATCH_EVENT); + + if ( len > XENSTORE_PAYLOAD_MAX ) { + send_error(conn, E2BIG); + return; + } + +- /* Replies reuse the request buffer, events need a new one. */ +- if (type != XS_WATCH_EVENT) { +- bdata = conn->in; +- /* Drop asynchronous responses, e.g. errors for watch events. */ +- if (!bdata) +- return; +- bdata->inhdr = true; +- bdata->used = 0; +- conn->in = NULL; +- } else { +- /* Message is a child of the connection for auto-cleanup. */ +- bdata = new_buffer(conn); ++ if (!bdata) ++ return; ++ bdata->inhdr = true; ++ bdata->used = 0; + +- /* +- * Allocation failure here is unfortunate: we have no way to +- * tell anybody about it. +- */ +- if (!bdata) +- return; +- } + if (len <= DEFAULT_BUFFER_SIZE) + bdata->buffer = bdata->default_buffer; +- else ++ else { + bdata->buffer = talloc_array(bdata, char, len); +- if (!bdata->buffer) { +- if (type == XS_WATCH_EVENT) { +- /* Same as above: no way to tell someone. */ +- talloc_free(bdata); ++ if (!bdata->buffer) { ++ send_error(conn, ENOMEM); + return; + } +- /* re-establish request buffer for sending ENOMEM. */ +- conn->in = bdata; +- send_error(conn, ENOMEM); +- return; + } + ++ conn->in = NULL; ++ + /* Update relevant header fields and fill in the message body. */ + bdata->hdr.msg.type = type; + bdata->hdr.msg.len = len; +@@ -817,8 +800,39 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); ++} + +- return; ++/* ++ * Send a watch event. ++ * As this is not directly related to the current command, errors can't be ++ * reported. ++ */ ++void send_event(struct connection *conn, const char *path, const char *token) ++{ ++ struct buffered_data *bdata; ++ unsigned int len; ++ ++ len = strlen(path) + 1 + strlen(token) + 1; ++ /* Don't try to send over-long events. */ ++ if (len > XENSTORE_PAYLOAD_MAX) ++ return; ++ ++ bdata = new_buffer(conn); ++ if (!bdata) ++ return; ++ ++ bdata->buffer = talloc_array(bdata, char, len); ++ if (!bdata->buffer) { ++ talloc_free(bdata); ++ return; ++ } ++ strcpy(bdata->buffer, path); ++ strcpy(bdata->buffer + strlen(path) + 1, token); ++ bdata->hdr.msg.type = XS_WATCH_EVENT; ++ bdata->hdr.msg.len = len; ++ ++ /* Queue for later transmission. */ ++ list_add_tail(&bdata->list, &conn->out_list); + } + + /* Some routines (write, mkdir, etc) just need a non-error return */ +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 0004fa848c83..9af9af4390bd 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -187,6 +187,7 @@ unsigned int get_string(const struct buffered_data *data, unsigned int offset); + + void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + const void *data, unsigned int len); ++void send_event(struct connection *conn, const char *path, const char *token); + + /* Some routines (write, mkdir, etc) just need a non-error return */ + void send_ack(struct connection *conn, enum xsd_sockmsg_type type); +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index aca0a71bada1..99a2c266b28a 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -86,35 +86,6 @@ static const char *get_watch_path(const struct watch *watch, const char *name) + } + + /* +- * Send a watch event. +- * Temporary memory allocations are done with ctx. +- */ +-static void add_event(struct connection *conn, +- const void *ctx, +- struct watch *watch, +- const char *name) +-{ +- /* Data to send (node\0token\0). */ +- unsigned int len; +- char *data; +- +- name = get_watch_path(watch, name); +- +- len = strlen(name) + 1 + strlen(watch->token) + 1; +- /* Don't try to send over-long events. */ +- if (len > XENSTORE_PAYLOAD_MAX) +- return; +- +- data = talloc_array(ctx, char, len); +- if (!data) +- return; +- strcpy(data, name); +- strcpy(data + strlen(name) + 1, watch->token); +- send_reply(conn, XS_WATCH_EVENT, data, len); +- talloc_free(data); +-} +- +-/* + * Check permissions of a specific watch to fire: + * Either the node itself or its parent have to be readable by the connection + * the watch has been setup for. In case a watch event is created due to +@@ -190,10 +161,14 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, + list_for_each_entry(watch, &i->watches, list) { + if (exact) { + if (streq(name, watch->node)) +- add_event(i, ctx, watch, name); ++ send_event(i, ++ get_watch_path(watch, name), ++ watch->token); + } else { + if (is_child(name, watch->node)) +- add_event(i, ctx, watch, name); ++ send_event(i, ++ get_watch_path(watch, name), ++ watch->token); + } + } + } +@@ -292,7 +267,7 @@ int do_watch(struct connection *conn, struct buffered_data *in) + send_ack(conn, XS_WATCH); + + /* We fire once up front: simplifies clients and restart. */ +- add_event(conn, in, watch, watch->node); ++ send_event(conn, get_watch_path(watch, watch->node), watch->token); + + return 0; + } diff --git a/xsa326-4.16-xenstored-02.patch b/xsa326-4.16-xenstored-02.patch new file mode 100644 index 0000000..540ab03 --- /dev/null +++ b/xsa326-4.16-xenstored-02.patch @@ -0,0 +1,108 @@ +From 0a4c86f8a8febd85610496470123adfc4fbc1c5d Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:07 +0200 +Subject: tools/xenstore: add helpers to free struct buffered_data + +Add two helpers for freeing struct buffered_data: free_buffered_data() +for freeing one instance and conn_free_buffered_data() for freeing all +instances for a connection. + +This is avoiding duplicated code and will help later when more actions +are needed when freeing a struct buffered_data. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 249ad5ec6fb1..527a1ebdeded 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -211,6 +211,21 @@ void reopen_log(void) + } + } + ++static void free_buffered_data(struct buffered_data *out, ++ struct connection *conn) ++{ ++ list_del(&out->list); ++ talloc_free(out); ++} ++ ++void conn_free_buffered_data(struct connection *conn) ++{ ++ struct buffered_data *out; ++ ++ while ((out = list_top(&conn->out_list, struct buffered_data, list))) ++ free_buffered_data(out, conn); ++} ++ + static bool write_messages(struct connection *conn) + { + int ret; +@@ -254,8 +269,7 @@ static bool write_messages(struct connection *conn) + + trace_io(conn, out, 1); + +- list_del(&out->list); +- talloc_free(out); ++ free_buffered_data(out, conn); + + return true; + } +@@ -1506,18 +1520,12 @@ static struct { + */ + void ignore_connection(struct connection *conn) + { +- struct buffered_data *out, *tmp; +- + trace("CONN %p ignored\n", conn); + + conn->is_ignored = true; + conn_delete_all_watches(conn); + conn_delete_all_transactions(conn); +- +- list_for_each_entry_safe(out, tmp, &conn->out_list, list) { +- list_del(&out->list); +- talloc_free(out); +- } ++ conn_free_buffered_data(conn); + + talloc_free(conn->in); + conn->in = NULL; +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 9af9af4390bd..e7ee87825c3b 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -276,6 +276,8 @@ int remember_string(struct hashtable *hash, const char *str); + + void set_tdb_key(const char *name, TDB_DATA *key); + ++void conn_free_buffered_data(struct connection *conn); ++ + const char *dump_state_global(FILE *fp); + const char *dump_state_buffered_data(FILE *fp, const struct connection *c, + struct xs_state_connection *sc); +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index d03c7d93a9e7..93c4c1edcdd1 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -411,15 +411,10 @@ static struct domain *find_domain_by_domid(unsigned int domid) + static void domain_conn_reset(struct domain *domain) + { + struct connection *conn = domain->conn; +- struct buffered_data *out; + + conn_delete_all_watches(conn); + conn_delete_all_transactions(conn); +- +- while ((out = list_top(&conn->out_list, struct buffered_data, list))) { +- list_del(&out->list); +- talloc_free(out); +- } ++ conn_free_buffered_data(conn); + + talloc_free(conn->in); + diff --git a/xsa326-4.16-xenstored-03.patch b/xsa326-4.16-xenstored-03.patch new file mode 100644 index 0000000..a3a0d81 --- /dev/null +++ b/xsa326-4.16-xenstored-03.patch @@ -0,0 +1,192 @@ +From a6c4198242bf69bea1825492b7665b559023390c Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:07 +0200 +Subject: tools/xenstore: reduce number of watch events + +When removing a watched node outside of a transaction, two watch events +are being produced instead of just a single one. + +When finalizing a transaction watch events can be generated for each +node which is being modified, even if outside a transaction such +modifications might not have resulted in a watch event. + +This happens e.g.: + +- for nodes which are only modified due to added/removed child entries +- for nodes being removed or created implicitly (e.g. creation of a/b/c + is implicitly creating a/b, resulting in watch events for a, a/b and + a/b/c instead of a/b/c only) + +Avoid these additional watch events, in order to reduce the needed +memory inside Xenstore for queueing them. + +This is being achieved by adding event flags to struct accessed_node +specifying whether an event should be triggered, and whether it should +be an exact match of the modified path. Both flags can be set from +fire_watches() instead of implying them only. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 527a1ebdeded..bf2243873901 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1295,7 +1295,7 @@ static void delete_child(struct connection *conn, + } + + static int delete_node(struct connection *conn, const void *ctx, +- struct node *parent, struct node *node) ++ struct node *parent, struct node *node, bool watch_exact) + { + char *name; + +@@ -1307,7 +1307,7 @@ static int delete_node(struct connection *conn, const void *ctx, + node->children); + child = name ? read_node(conn, node, name) : NULL; + if (child) { +- if (delete_node(conn, ctx, node, child)) ++ if (delete_node(conn, ctx, node, child, true)) + return errno; + } else { + trace("delete_node: Error deleting child '%s/%s'!\n", +@@ -1319,7 +1319,12 @@ static int delete_node(struct connection *conn, const void *ctx, + talloc_free(name); + } + +- fire_watches(conn, ctx, node->name, node, true, NULL); ++ /* ++ * Fire the watches now, when we can still see the node permissions. ++ * This fine as we are single threaded and the next possible read will ++ * be handled only after the node has been really removed. ++ */ ++ fire_watches(conn, ctx, node->name, node, watch_exact, NULL); + delete_node_single(conn, node); + delete_child(conn, parent, basename(node->name)); + talloc_free(node); +@@ -1345,13 +1350,7 @@ static int _rm(struct connection *conn, const void *ctx, struct node *node, + return (errno == ENOMEM) ? ENOMEM : EINVAL; + node->parent = parent; + +- /* +- * Fire the watches now, when we can still see the node permissions. +- * This fine as we are single threaded and the next possible read will +- * be handled only after the node has been really removed. +- */ +- fire_watches(conn, ctx, name, node, false, NULL); +- return delete_node(conn, ctx, parent, node); ++ return delete_node(conn, ctx, parent, node, false); + } + + +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index faf6c930e42a..54432907fc76 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -130,6 +130,10 @@ struct accessed_node + + /* Transaction node in data base? */ + bool ta_node; ++ ++ /* Watch event flags. */ ++ bool fire_watch; ++ bool watch_exact; + }; + + struct changed_domain +@@ -324,6 +328,29 @@ int access_node(struct connection *conn, struct node *node, + } + + /* ++ * A watch event should be fired for a node modified inside a transaction. ++ * Set the corresponding information. A non-exact event is replacing an exact ++ * one, but not the other way round. ++ */ ++void queue_watches(struct connection *conn, const char *name, bool watch_exact) ++{ ++ struct accessed_node *i; ++ ++ i = find_accessed_node(conn->transaction, name); ++ if (!i) { ++ conn->transaction->fail = true; ++ return; ++ } ++ ++ if (!i->fire_watch) { ++ i->fire_watch = true; ++ i->watch_exact = watch_exact; ++ } else if (!watch_exact) { ++ i->watch_exact = false; ++ } ++} ++ ++/* + * Finalize transaction: + * Walk through accessed nodes and check generation against global data. + * If all entries match, read the transaction entries and write them without +@@ -377,15 +404,15 @@ static int finalize_transaction(struct connection *conn, + ret = tdb_store(tdb_ctx, key, data, + TDB_REPLACE); + talloc_free(data.dptr); +- if (ret) +- goto err; +- fire_watches(conn, trans, i->node, NULL, false, +- i->perms.p ? &i->perms : NULL); + } else { +- fire_watches(conn, trans, i->node, NULL, false, ++ ret = tdb_delete(tdb_ctx, key); ++ } ++ if (ret) ++ goto err; ++ if (i->fire_watch) { ++ fire_watches(conn, trans, i->node, NULL, ++ i->watch_exact, + i->perms.p ? &i->perms : NULL); +- if (tdb_delete(tdb_ctx, key)) +- goto err; + } + } + +diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h +index 14062730e3c9..0093cac807e3 100644 +--- a/tools/xenstore/xenstored_transaction.h ++++ b/tools/xenstore/xenstored_transaction.h +@@ -42,6 +42,9 @@ void transaction_entry_dec(struct transaction *trans, unsigned int domid); + int access_node(struct connection *conn, struct node *node, + enum node_access_type type, TDB_DATA *key); + ++/* Queue watches for a modified node. */ ++void queue_watches(struct connection *conn, const char *name, bool watch_exact); ++ + /* Prepend the transaction to name if appropriate. */ + int transaction_prepend(struct connection *conn, const char *name, + TDB_DATA *key); +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index 99a2c266b28a..205d9d8ea116 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -29,6 +29,7 @@ + #include "xenstore_lib.h" + #include "utils.h" + #include "xenstored_domain.h" ++#include "xenstored_transaction.h" + + extern int quota_nb_watch_per_domain; + +@@ -143,9 +144,11 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, + struct connection *i; + struct watch *watch; + +- /* During transactions, don't fire watches. */ +- if (conn && conn->transaction) ++ /* During transactions, don't fire watches, but queue them. */ ++ if (conn && conn->transaction) { ++ queue_watches(conn, name, exact); + return; ++ } + + /* Create an event for each watch. */ + list_for_each_entry(i, &connections, list) { diff --git a/xsa326-4.16-xenstored-04.patch b/xsa326-4.16-xenstored-04.patch new file mode 100644 index 0000000..facbba4 --- /dev/null +++ b/xsa326-4.16-xenstored-04.patch @@ -0,0 +1,302 @@ +From 2feed737530592688382c655680982e10951c1ec Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:07 +0200 +Subject: tools/xenstore: let unread watch events time out + +A future modification will limit the number of outstanding requests +for a domain, where "outstanding" means that the response of the +request or any resulting watch event hasn't been consumed yet. + +In order to avoid a malicious guest being capable to block other guests +by not reading watch events, add a timeout for watch events. In case a +watch event hasn't been consumed after this timeout, it is being +deleted. Set the default timeout to 20 seconds (a random value being +not too high). + +In order to support to specify other timeout values in future, use a +generic command line option for that purpose: + +--timeout|-w watch-event= + +This is part of XSA-326 / CVE-2022-42311. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index bf2243873901..45244c021cd3 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -108,6 +108,8 @@ int quota_max_transaction = 10; + int quota_nb_perms_per_node = 5; + int quota_max_path_len = XENSTORE_REL_PATH_MAX; + ++unsigned int timeout_watch_event_msec = 20000; ++ + void trace(const char *fmt, ...) + { + va_list arglist; +@@ -211,19 +213,92 @@ void reopen_log(void) + } + } + ++static uint64_t get_now_msec(void) ++{ ++ struct timespec now_ts; ++ ++ if (clock_gettime(CLOCK_MONOTONIC, &now_ts)) ++ barf_perror("Could not find time (clock_gettime failed)"); ++ ++ return now_ts.tv_sec * 1000 + now_ts.tv_nsec / 1000000; ++} ++ + static void free_buffered_data(struct buffered_data *out, + struct connection *conn) + { ++ struct buffered_data *req; ++ + list_del(&out->list); ++ ++ /* ++ * Update conn->timeout_msec with the next found timeout value in the ++ * queued pending requests. ++ */ ++ if (out->timeout_msec) { ++ conn->timeout_msec = 0; ++ list_for_each_entry(req, &conn->out_list, list) { ++ if (req->timeout_msec) { ++ conn->timeout_msec = req->timeout_msec; ++ break; ++ } ++ } ++ } ++ + talloc_free(out); + } + ++static void check_event_timeout(struct connection *conn, uint64_t msecs, ++ int *ptimeout) ++{ ++ uint64_t delta; ++ struct buffered_data *out, *tmp; ++ ++ if (!conn->timeout_msec) ++ return; ++ ++ delta = conn->timeout_msec - msecs; ++ if (conn->timeout_msec <= msecs) { ++ delta = 0; ++ list_for_each_entry_safe(out, tmp, &conn->out_list, list) { ++ /* ++ * Only look at buffers with timeout and no data ++ * already written to the ring. ++ */ ++ if (out->timeout_msec && out->inhdr && !out->used) { ++ if (out->timeout_msec > msecs) { ++ conn->timeout_msec = out->timeout_msec; ++ delta = conn->timeout_msec - msecs; ++ break; ++ } ++ ++ /* ++ * Free out without updating conn->timeout_msec, ++ * as the update is done in this loop already. ++ */ ++ out->timeout_msec = 0; ++ trace("watch event path %s for domain %u timed out\n", ++ out->buffer, conn->id); ++ free_buffered_data(out, conn); ++ } ++ } ++ if (!delta) { ++ conn->timeout_msec = 0; ++ return; ++ } ++ } ++ ++ if (*ptimeout == -1 || *ptimeout > delta) ++ *ptimeout = delta; ++} ++ + void conn_free_buffered_data(struct connection *conn) + { + struct buffered_data *out; + + while ((out = list_top(&conn->out_list, struct buffered_data, list))) + free_buffered_data(out, conn); ++ ++ conn->timeout_msec = 0; + } + + static bool write_messages(struct connection *conn) +@@ -411,6 +486,7 @@ static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout) + { + struct connection *conn; + struct wrl_timestampt now; ++ uint64_t msecs; + + if (fds) + memset(fds, 0, sizeof(struct pollfd) * current_array_size); +@@ -431,10 +507,12 @@ static void initialize_fds(int *p_sock_pollfd_idx, int *ptimeout) + + wrl_gettime_now(&now); + wrl_log_periodic(now); ++ msecs = get_now_msec(); + + list_for_each_entry(conn, &connections, list) { + if (conn->domain) { + wrl_check_timeout(conn->domain, now, ptimeout); ++ check_event_timeout(conn, msecs, ptimeout); + if (conn_can_read(conn) || + (conn_can_write(conn) && + !list_empty(&conn->out_list))) +@@ -794,6 +872,7 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + return; + bdata->inhdr = true; + bdata->used = 0; ++ bdata->timeout_msec = 0; + + if (len <= DEFAULT_BUFFER_SIZE) + bdata->buffer = bdata->default_buffer; +@@ -845,6 +924,12 @@ void send_event(struct connection *conn, const char *path, const char *token) + bdata->hdr.msg.type = XS_WATCH_EVENT; + bdata->hdr.msg.len = len; + ++ if (timeout_watch_event_msec && domain_is_unprivileged(conn)) { ++ bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; ++ if (!conn->timeout_msec) ++ conn->timeout_msec = bdata->timeout_msec; ++ } ++ + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); + } +@@ -2201,6 +2286,9 @@ static void usage(void) + " -t, --transaction limit the number of transaction allowed per domain,\n" + " -A, --perm-nb limit the number of permissions per node,\n" + " -M, --path-max limit the allowed Xenstore node path length,\n" ++" -w, --timeout = set the timeout in seconds for ,\n" ++" allowed timeout candidates are:\n" ++" watch-event: time a watch-event is kept pending\n" + " -R, --no-recovery to request that no recovery should be attempted when\n" + " the store is corrupted (debug only),\n" + " -I, --internal-db store database in memory, not on disk\n" +@@ -2223,6 +2311,7 @@ static struct option options[] = { + { "transaction", 1, NULL, 't' }, + { "perm-nb", 1, NULL, 'A' }, + { "path-max", 1, NULL, 'M' }, ++ { "timeout", 1, NULL, 'w' }, + { "no-recovery", 0, NULL, 'R' }, + { "internal-db", 0, NULL, 'I' }, + { "verbose", 0, NULL, 'V' }, +@@ -2236,6 +2325,39 @@ int dom0_domid = 0; + int dom0_event = 0; + int priv_domid = 0; + ++static int get_optval_int(const char *arg) ++{ ++ char *end; ++ long val; ++ ++ val = strtol(arg, &end, 10); ++ if (!*arg || *end || val < 0 || val > INT_MAX) ++ barf("invalid parameter value \"%s\"\n", arg); ++ ++ return val; ++} ++ ++static bool what_matches(const char *arg, const char *what) ++{ ++ unsigned int what_len = strlen(what); ++ ++ return !strncmp(arg, what, what_len) && arg[what_len] == '='; ++} ++ ++static void set_timeout(const char *arg) ++{ ++ const char *eq = strchr(arg, '='); ++ int val; ++ ++ if (!eq) ++ barf("quotas must be specified via =\n"); ++ val = get_optval_int(eq + 1); ++ if (what_matches(arg, "watch-event")) ++ timeout_watch_event_msec = val * 1000; ++ else ++ barf("unknown timeout \"%s\"\n", arg); ++} ++ + int main(int argc, char *argv[]) + { + int opt; +@@ -2250,7 +2372,7 @@ int main(int argc, char *argv[]) + orig_argc = argc; + orig_argv = argv; + +- while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:T:RVW:U", options, ++ while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:T:RVW:w:U", options, + NULL)) != -1) { + switch (opt) { + case 'D': +@@ -2300,6 +2422,9 @@ int main(int argc, char *argv[]) + quota_max_path_len = min(XENSTORE_REL_PATH_MAX, + quota_max_path_len); + break; ++ case 'w': ++ set_timeout(optarg); ++ break; + case 'e': + dom0_event = strtol(optarg, NULL, 10); + break; +@@ -2741,6 +2866,12 @@ static void add_buffered_data(struct buffered_data *bdata, + barf("error restoring buffered data"); + + memcpy(bdata->buffer, data, len); ++ if (bdata->hdr.msg.type == XS_WATCH_EVENT && timeout_watch_event_msec && ++ domain_is_unprivileged(conn)) { ++ bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; ++ if (!conn->timeout_msec) ++ conn->timeout_msec = bdata->timeout_msec; ++ } + + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index e7ee87825c3b..8a81fc693f01 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -27,6 +27,7 @@ + #include + #include + #include ++#include + #include + + #include "xenstore_lib.h" +@@ -67,6 +68,8 @@ struct buffered_data + char raw[sizeof(struct xsd_sockmsg)]; + } hdr; + ++ uint64_t timeout_msec; ++ + /* The actual data. */ + char *buffer; + char default_buffer[DEFAULT_BUFFER_SIZE]; +@@ -118,6 +121,7 @@ struct connection + + /* Buffered output data */ + struct list_head out_list; ++ uint64_t timeout_msec; + + /* Transaction context for current request (NULL if none). */ + struct transaction *transaction; +@@ -244,6 +248,8 @@ extern int dom0_event; + extern int priv_domid; + extern int quota_nb_entry_per_domain; + ++extern unsigned int timeout_watch_event_msec; ++ + /* Map the kernel's xenstore page. */ + void *xenbus_map(void); + void unmap_xenbus(void *interface); diff --git a/xsa326-4.16-xenstored-05.patch b/xsa326-4.16-xenstored-05.patch new file mode 100644 index 0000000..77f9c25 --- /dev/null +++ b/xsa326-4.16-xenstored-05.patch @@ -0,0 +1,443 @@ +From 2eee122a45eb4a218596b103ce7f0759a824cf2e Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:08 +0200 +Subject: tools/xenstore: limit outstanding requests + +Add another quota for limiting the number of outstanding requests of a +guest. As the way to specify quotas on the command line is becoming +rather nasty, switch to a new scheme using [--quota|-Q] = +allowing to add more quotas in future easily. + +Set the default value to 20 (basically a random value not seeming to +be too high or too low). + +A request is said to be outstanding if any message generated by this +request (the direct response plus potential watch events) is not yet +completely stored into a ring buffer. The initial watch event sent as +a result of registering a watch is an exception. + +Note that across a live update the relation to buffered watch events +for other domains is lost. + +Use talloc_zero() for allocating the domain structure in order to have +all per-domain quota zeroed initially. + +This is part of XSA-326 / CVE-2022-42312. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 45244c021cd3..488d540f3a32 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -107,6 +107,7 @@ int quota_max_entry_size = 2048; /* 2K */ + int quota_max_transaction = 10; + int quota_nb_perms_per_node = 5; + int quota_max_path_len = XENSTORE_REL_PATH_MAX; ++int quota_req_outstanding = 20; + + unsigned int timeout_watch_event_msec = 20000; + +@@ -223,12 +224,24 @@ static uint64_t get_now_msec(void) + return now_ts.tv_sec * 1000 + now_ts.tv_nsec / 1000000; + } + ++/* ++ * Remove a struct buffered_data from the list of outgoing data. ++ * A struct buffered_data related to a request having caused watch events to be ++ * sent is kept until all those events have been written out. ++ * Each watch event is referencing the related request via pend.req, while the ++ * number of watch events caused by a request is kept in pend.ref.event_cnt ++ * (those two cases are mutually exclusive, so the two fields can share memory ++ * via a union). ++ * The struct buffered_data is freed only if no related watch event is ++ * referencing it. The related return data can be freed right away. ++ */ + static void free_buffered_data(struct buffered_data *out, + struct connection *conn) + { + struct buffered_data *req; + + list_del(&out->list); ++ out->on_out_list = false; + + /* + * Update conn->timeout_msec with the next found timeout value in the +@@ -244,6 +257,30 @@ static void free_buffered_data(struct buffered_data *out, + } + } + ++ if (out->hdr.msg.type == XS_WATCH_EVENT) { ++ req = out->pend.req; ++ if (req) { ++ req->pend.ref.event_cnt--; ++ if (!req->pend.ref.event_cnt && !req->on_out_list) { ++ if (req->on_ref_list) { ++ domain_outstanding_domid_dec( ++ req->pend.ref.domid); ++ list_del(&req->list); ++ } ++ talloc_free(req); ++ } ++ } ++ } else if (out->pend.ref.event_cnt) { ++ /* Hang out off from conn. */ ++ talloc_steal(NULL, out); ++ if (out->buffer != out->default_buffer) ++ talloc_free(out->buffer); ++ list_add(&out->list, &conn->ref_list); ++ out->on_ref_list = true; ++ return; ++ } else ++ domain_outstanding_dec(conn); ++ + talloc_free(out); + } + +@@ -405,6 +442,7 @@ int delay_request(struct connection *conn, struct buffered_data *in, + static int destroy_conn(void *_conn) + { + struct connection *conn = _conn; ++ struct buffered_data *req; + + /* Flush outgoing if possible, but don't block. */ + if (!conn->domain) { +@@ -418,6 +456,11 @@ static int destroy_conn(void *_conn) + break; + close(conn->fd); + } ++ ++ conn_free_buffered_data(conn); ++ list_for_each_entry(req, &conn->ref_list, list) ++ req->on_ref_list = false; ++ + if (conn->target) + talloc_unlink(conn, conn->target); + list_del(&conn->list); +@@ -893,6 +936,8 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); ++ bdata->on_out_list = true; ++ domain_outstanding_inc(conn); + } + + /* +@@ -900,7 +945,8 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + * As this is not directly related to the current command, errors can't be + * reported. + */ +-void send_event(struct connection *conn, const char *path, const char *token) ++void send_event(struct buffered_data *req, struct connection *conn, ++ const char *path, const char *token) + { + struct buffered_data *bdata; + unsigned int len; +@@ -930,8 +976,13 @@ void send_event(struct connection *conn, const char *path, const char *token) + conn->timeout_msec = bdata->timeout_msec; + } + ++ bdata->pend.req = req; ++ if (req) ++ req->pend.ref.event_cnt++; ++ + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); ++ bdata->on_out_list = true; + } + + /* Some routines (write, mkdir, etc) just need a non-error return */ +@@ -1740,6 +1791,7 @@ static void handle_input(struct connection *conn) + return; + } + in = conn->in; ++ in->pend.ref.domid = conn->id; + + /* Not finished header yet? */ + if (in->inhdr) { +@@ -1808,6 +1860,7 @@ struct connection *new_connection(const struct interface_funcs *funcs) + new->is_stalled = false; + new->transaction_started = 0; + INIT_LIST_HEAD(&new->out_list); ++ INIT_LIST_HEAD(&new->ref_list); + INIT_LIST_HEAD(&new->watches); + INIT_LIST_HEAD(&new->transaction_list); + INIT_LIST_HEAD(&new->delayed); +@@ -2286,6 +2339,9 @@ static void usage(void) + " -t, --transaction limit the number of transaction allowed per domain,\n" + " -A, --perm-nb limit the number of permissions per node,\n" + " -M, --path-max limit the allowed Xenstore node path length,\n" ++" -Q, --quota = set the quota to the value , allowed\n" ++" quotas are:\n" ++" outstanding: number of outstanding requests\n" + " -w, --timeout = set the timeout in seconds for ,\n" + " allowed timeout candidates are:\n" + " watch-event: time a watch-event is kept pending\n" +@@ -2311,6 +2367,7 @@ static struct option options[] = { + { "transaction", 1, NULL, 't' }, + { "perm-nb", 1, NULL, 'A' }, + { "path-max", 1, NULL, 'M' }, ++ { "quota", 1, NULL, 'Q' }, + { "timeout", 1, NULL, 'w' }, + { "no-recovery", 0, NULL, 'R' }, + { "internal-db", 0, NULL, 'I' }, +@@ -2358,6 +2415,20 @@ static void set_timeout(const char *arg) + barf("unknown timeout \"%s\"\n", arg); + } + ++static void set_quota(const char *arg) ++{ ++ const char *eq = strchr(arg, '='); ++ int val; ++ ++ if (!eq) ++ barf("quotas must be specified via =\n"); ++ val = get_optval_int(eq + 1); ++ if (what_matches(arg, "outstanding")) ++ quota_req_outstanding = val; ++ else ++ barf("unknown quota \"%s\"\n", arg); ++} ++ + int main(int argc, char *argv[]) + { + int opt; +@@ -2372,8 +2443,8 @@ int main(int argc, char *argv[]) + orig_argc = argc; + orig_argv = argv; + +- while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:T:RVW:w:U", options, +- NULL)) != -1) { ++ while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:Q:T:RVW:w:U", ++ options, NULL)) != -1) { + switch (opt) { + case 'D': + no_domain_init = true; +@@ -2422,6 +2493,9 @@ int main(int argc, char *argv[]) + quota_max_path_len = min(XENSTORE_REL_PATH_MAX, + quota_max_path_len); + break; ++ case 'Q': ++ set_quota(optarg); ++ break; + case 'w': + set_timeout(optarg); + break; +@@ -2875,6 +2949,14 @@ static void add_buffered_data(struct buffered_data *bdata, + + /* Queue for later transmission. */ + list_add_tail(&bdata->list, &conn->out_list); ++ bdata->on_out_list = true; ++ /* ++ * Watch events are never "outstanding", but the request causing them ++ * are instead kept "outstanding" until all watch events caused by that ++ * request have been delivered. ++ */ ++ if (bdata->hdr.msg.type != XS_WATCH_EVENT) ++ domain_outstanding_inc(conn); + } + + void read_state_buffered_data(const void *ctx, struct connection *conn, +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 8a81fc693f01..db09f463a657 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -56,6 +56,8 @@ struct xs_state_connection; + struct buffered_data + { + struct list_head list; ++ bool on_out_list; ++ bool on_ref_list; + + /* Are we still doing the header? */ + bool inhdr; +@@ -63,6 +65,17 @@ struct buffered_data + /* How far are we? */ + unsigned int used; + ++ /* Outstanding request accounting. */ ++ union { ++ /* ref is being used for requests. */ ++ struct { ++ unsigned int event_cnt; /* # of outstanding events. */ ++ unsigned int domid; /* domid of request. */ ++ } ref; ++ /* req is being used for watch events. */ ++ struct buffered_data *req; /* request causing event. */ ++ } pend; ++ + union { + struct xsd_sockmsg msg; + char raw[sizeof(struct xsd_sockmsg)]; +@@ -123,6 +136,9 @@ struct connection + struct list_head out_list; + uint64_t timeout_msec; + ++ /* Referenced requests no longer pending. */ ++ struct list_head ref_list; ++ + /* Transaction context for current request (NULL if none). */ + struct transaction *transaction; + +@@ -191,7 +207,8 @@ unsigned int get_string(const struct buffered_data *data, unsigned int offset); + + void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + const void *data, unsigned int len); +-void send_event(struct connection *conn, const char *path, const char *token); ++void send_event(struct buffered_data *req, struct connection *conn, ++ const char *path, const char *token); + + /* Some routines (write, mkdir, etc) just need a non-error return */ + void send_ack(struct connection *conn, enum xsd_sockmsg_type type); +@@ -247,6 +264,7 @@ extern int dom0_domid; + extern int dom0_event; + extern int priv_domid; + extern int quota_nb_entry_per_domain; ++extern int quota_req_outstanding; + + extern unsigned int timeout_watch_event_msec; + +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index 93c4c1edcdd1..850085a92c76 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -78,6 +78,9 @@ struct domain + /* number of watch for this domain */ + int nbwatch; + ++ /* Number of outstanding requests. */ ++ int nboutstanding; ++ + /* write rate limit */ + wrl_creditt wrl_credit; /* [ -wrl_config_writecost, +_dburst ] */ + struct wrl_timestampt wrl_timestamp; +@@ -183,8 +186,12 @@ static bool domain_can_read(struct connection *conn) + { + struct xenstore_domain_interface *intf = conn->domain->interface; + +- if (domain_is_unprivileged(conn) && conn->domain->wrl_credit < 0) +- return false; ++ if (domain_is_unprivileged(conn)) { ++ if (conn->domain->wrl_credit < 0) ++ return false; ++ if (conn->domain->nboutstanding >= quota_req_outstanding) ++ return false; ++ } + + return (intf->req_cons != intf->req_prod); + } +@@ -331,7 +338,7 @@ static struct domain *alloc_domain(const void *context, unsigned int domid) + { + struct domain *domain; + +- domain = talloc(context, struct domain); ++ domain = talloc_zero(context, struct domain); + if (!domain) { + errno = ENOMEM; + return NULL; +@@ -392,9 +399,6 @@ static int new_domain(struct domain *domain, int port, bool restore) + domain->conn->domain = domain; + domain->conn->id = domain->domid; + +- domain->nbentry = 0; +- domain->nbwatch = 0; +- + return 0; + } + +@@ -938,6 +942,28 @@ int domain_watch(struct connection *conn) + : 0; + } + ++void domain_outstanding_inc(struct connection *conn) ++{ ++ if (!conn || !conn->domain) ++ return; ++ conn->domain->nboutstanding++; ++} ++ ++void domain_outstanding_dec(struct connection *conn) ++{ ++ if (!conn || !conn->domain) ++ return; ++ conn->domain->nboutstanding--; ++} ++ ++void domain_outstanding_domid_dec(unsigned int domid) ++{ ++ struct domain *d = find_domain_by_domid(domid); ++ ++ if (d) ++ d->nboutstanding--; ++} ++ + static wrl_creditt wrl_config_writecost = WRL_FACTOR; + static wrl_creditt wrl_config_rate = WRL_RATE * WRL_FACTOR; + static wrl_creditt wrl_config_dburst = WRL_DBURST * WRL_FACTOR; +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 1e929b8f8c6f..4f51b005291a 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -64,6 +64,9 @@ int domain_entry(struct connection *conn); + void domain_watch_inc(struct connection *conn); + void domain_watch_dec(struct connection *conn); + int domain_watch(struct connection *conn); ++void domain_outstanding_inc(struct connection *conn); ++void domain_outstanding_dec(struct connection *conn); ++void domain_outstanding_domid_dec(unsigned int domid); + + /* Special node permission handling. */ + int set_perms_special(struct connection *conn, const char *name, +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index 205d9d8ea116..0755ffa375ba 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -142,6 +142,7 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, + struct node *node, bool exact, struct node_perms *perms) + { + struct connection *i; ++ struct buffered_data *req; + struct watch *watch; + + /* During transactions, don't fire watches, but queue them. */ +@@ -150,6 +151,8 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, + return; + } + ++ req = domain_is_unprivileged(conn) ? conn->in : NULL; ++ + /* Create an event for each watch. */ + list_for_each_entry(i, &connections, list) { + /* introduce/release domain watches */ +@@ -164,12 +167,12 @@ void fire_watches(struct connection *conn, const void *ctx, const char *name, + list_for_each_entry(watch, &i->watches, list) { + if (exact) { + if (streq(name, watch->node)) +- send_event(i, ++ send_event(req, i, + get_watch_path(watch, name), + watch->token); + } else { + if (is_child(name, watch->node)) +- send_event(i, ++ send_event(req, i, + get_watch_path(watch, name), + watch->token); + } +@@ -269,8 +272,12 @@ int do_watch(struct connection *conn, struct buffered_data *in) + trace_create(watch, "watch"); + send_ack(conn, XS_WATCH); + +- /* We fire once up front: simplifies clients and restart. */ +- send_event(conn, get_watch_path(watch, watch->node), watch->token); ++ /* ++ * We fire once up front: simplifies clients and restart. ++ * This event will not be linked to the XS_WATCH request. ++ */ ++ send_event(NULL, conn, get_watch_path(watch, watch->node), ++ watch->token); + + return 0; + } diff --git a/xsa326-4.16-xenstored-06.patch b/xsa326-4.16-xenstored-06.patch new file mode 100644 index 0000000..b2be7ce --- /dev/null +++ b/xsa326-4.16-xenstored-06.patch @@ -0,0 +1,85 @@ +From c8057cb483abf2cd4060b39616423e19283fbd0a Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:08 +0200 +Subject: tools/xenstore: don't buffer multiple identical watch events + +A guest not reading its Xenstore response buffer fast enough might +pile up lots of Xenstore watch events buffered. Reduce the generated +load by dropping new events which already have an identical copy +pending. + +The special events "@..." are excluded from that handling as there are +known use cases where the handler is relying on each event to be sent +individually. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 488d540f3a32..f1fa97b8cf50 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -916,6 +916,7 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + bdata->inhdr = true; + bdata->used = 0; + bdata->timeout_msec = 0; ++ bdata->watch_event = false; + + if (len <= DEFAULT_BUFFER_SIZE) + bdata->buffer = bdata->default_buffer; +@@ -948,7 +949,7 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + void send_event(struct buffered_data *req, struct connection *conn, + const char *path, const char *token) + { +- struct buffered_data *bdata; ++ struct buffered_data *bdata, *bd; + unsigned int len; + + len = strlen(path) + 1 + strlen(token) + 1; +@@ -970,12 +971,29 @@ void send_event(struct buffered_data *req, struct connection *conn, + bdata->hdr.msg.type = XS_WATCH_EVENT; + bdata->hdr.msg.len = len; + ++ /* ++ * Check whether an identical event is pending already. ++ * Special events are excluded from that check. ++ */ ++ if (path[0] != '@') { ++ list_for_each_entry(bd, &conn->out_list, list) { ++ if (bd->watch_event && bd->hdr.msg.len == len && ++ !memcmp(bdata->buffer, bd->buffer, len)) { ++ trace("dropping duplicate watch %s %s for domain %u\n", ++ path, token, conn->id); ++ talloc_free(bdata); ++ return; ++ } ++ } ++ } ++ + if (timeout_watch_event_msec && domain_is_unprivileged(conn)) { + bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; + if (!conn->timeout_msec) + conn->timeout_msec = bdata->timeout_msec; + } + ++ bdata->watch_event = true; + bdata->pend.req = req; + if (req) + req->pend.ref.event_cnt++; +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index db09f463a657..b9b50e81c7b4 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -62,6 +62,9 @@ struct buffered_data + /* Are we still doing the header? */ + bool inhdr; + ++ /* Is this a watch event? */ ++ bool watch_event; ++ + /* How far are we? */ + unsigned int used; + diff --git a/xsa326-4.16-xenstored-07.patch b/xsa326-4.16-xenstored-07.patch new file mode 100644 index 0000000..dfcdc14 --- /dev/null +++ b/xsa326-4.16-xenstored-07.patch @@ -0,0 +1,53 @@ +From 5eac692b841633be3e85f0125c59fa02af103989 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:08 +0200 +Subject: tools/xenstore: fix connection->id usage + +Don't use conn->id for privilege checks, but domain_is_unprivileged(). + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_control.c b/tools/xenstore/xenstored_control.c +index 7b4300ef7777..adb8d51b043b 100644 +--- a/tools/xenstore/xenstored_control.c ++++ b/tools/xenstore/xenstored_control.c +@@ -891,7 +891,7 @@ int do_control(struct connection *conn, struct buffered_data *in) + unsigned int cmd, num, off; + char **vec = NULL; + +- if (conn->id != 0) ++ if (domain_is_unprivileged(conn)) + return EACCES; + + off = get_string(in, 0); +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index b9b50e81c7b4..b1a70488b989 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -123,7 +123,7 @@ struct connection + /* The index of pollfd in global pollfd array */ + int pollfd_idx; + +- /* Who am I? 0 for socket connections. */ ++ /* Who am I? Domid of connection. */ + unsigned int id; + + /* Is this connection ignored? */ +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 54432907fc76..ee1b09031a3b 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -477,7 +477,8 @@ int do_transaction_start(struct connection *conn, struct buffered_data *in) + if (conn->transaction) + return EBUSY; + +- if (conn->id && conn->transaction_started > quota_max_transaction) ++ if (domain_is_unprivileged(conn) && ++ conn->transaction_started > quota_max_transaction) + return ENOSPC; + + /* Attach transaction to input for autofree until it's complete */ diff --git a/xsa326-4.16-xenstored-08.patch b/xsa326-4.16-xenstored-08.patch new file mode 100644 index 0000000..5aa12c8 --- /dev/null +++ b/xsa326-4.16-xenstored-08.patch @@ -0,0 +1,326 @@ +From f9f3171441b5fcb3339cf612400794fc26cd2ec2 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:08 +0200 +Subject: tools/xenstore: simplify and fix per domain node accounting + +The accounting of nodes can be simplified now that each connection +holds the associated domid. + +Fix the node accounting to cover nodes created for a domain before it +has been introduced. This requires to react properly to an allocation +failure inside domain_entry_inc() by returning an error code. + +Especially in error paths the node accounting has to be fixed in some +cases. + +This is part of XSA-326 / CVE-2022-42313. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index f1fa97b8cf50..692d863fce35 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -638,7 +638,7 @@ struct node *read_node(struct connection *conn, const void *ctx, + + /* Permissions are struct xs_permissions. */ + node->perms.p = hdr->perms; +- if (domain_adjust_node_perms(node)) { ++ if (domain_adjust_node_perms(conn, node)) { + talloc_free(node); + return NULL; + } +@@ -660,7 +660,7 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + void *p; + struct xs_tdb_record_hdr *hdr; + +- if (domain_adjust_node_perms(node)) ++ if (domain_adjust_node_perms(conn, node)) + return errno; + + data.dsize = sizeof(*hdr) +@@ -1272,13 +1272,17 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + return NULL; + } + +-static int destroy_node(struct connection *conn, struct node *node) ++static void destroy_node_rm(struct node *node) + { + if (streq(node->name, "/")) + corrupt(NULL, "Destroying root node!"); + + tdb_delete(tdb_ctx, node->key); ++} + ++static int destroy_node(struct connection *conn, struct node *node) ++{ ++ destroy_node_rm(node); + domain_entry_dec(conn, node); + + /* +@@ -1328,8 +1332,12 @@ static struct node *create_node(struct connection *conn, const void *ctx, + goto err; + + /* Account for new node */ +- if (i->parent) +- domain_entry_inc(conn, i); ++ if (i->parent) { ++ if (domain_entry_inc(conn, i)) { ++ destroy_node_rm(i); ++ return NULL; ++ } ++ } + } + + return node; +@@ -1614,10 +1622,27 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) + old_perms = node->perms; + domain_entry_dec(conn, node); + node->perms = perms; +- domain_entry_inc(conn, node); ++ if (domain_entry_inc(conn, node)) { ++ node->perms = old_perms; ++ /* ++ * This should never fail because we had a reference on the ++ * domain before and Xenstored is single-threaded. ++ */ ++ domain_entry_inc(conn, node); ++ return ENOMEM; ++ } ++ ++ if (write_node(conn, node, false)) { ++ int saved_errno = errno; + +- if (write_node(conn, node, false)) ++ domain_entry_dec(conn, node); ++ node->perms = old_perms; ++ /* No failure possible as above. */ ++ domain_entry_inc(conn, node); ++ ++ errno = saved_errno; + return errno; ++ } + + fire_watches(conn, in, name, node, false, &old_perms); + send_ack(conn, XS_SET_PERMS); +@@ -3122,7 +3147,9 @@ void read_state_node(const void *ctx, const void *state) + set_tdb_key(name, &key); + if (write_node_raw(NULL, &key, node, true)) + barf("write node error restoring node"); +- domain_entry_inc(&conn, node); ++ ++ if (domain_entry_inc(&conn, node)) ++ barf("node accounting error restoring node"); + + talloc_free(node); + } +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index 850085a92c76..260952e09096 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -16,6 +16,7 @@ + along with this program; If not, see . + */ + ++#include + #include + #include + #include +@@ -363,6 +364,18 @@ static struct domain *find_or_alloc_domain(const void *ctx, unsigned int domid) + return domain ? : alloc_domain(ctx, domid); + } + ++static struct domain *find_or_alloc_existing_domain(unsigned int domid) ++{ ++ struct domain *domain; ++ xc_dominfo_t dominfo; ++ ++ domain = find_domain_struct(domid); ++ if (!domain && get_domain_info(domid, &dominfo)) ++ domain = alloc_domain(NULL, domid); ++ ++ return domain; ++} ++ + static int new_domain(struct domain *domain, int port, bool restore) + { + int rc; +@@ -782,30 +795,28 @@ void domain_deinit(void) + xenevtchn_unbind(xce_handle, virq_port); + } + +-void domain_entry_inc(struct connection *conn, struct node *node) ++int domain_entry_inc(struct connection *conn, struct node *node) + { + struct domain *d; ++ unsigned int domid; + + if (!conn) +- return; ++ return 0; + +- if (node->perms.p && node->perms.p[0].id != conn->id) { +- if (conn->transaction) { +- transaction_entry_inc(conn->transaction, +- node->perms.p[0].id); +- } else { +- d = find_domain_by_domid(node->perms.p[0].id); +- if (d) +- d->nbentry++; +- } +- } else if (conn->domain) { +- if (conn->transaction) { +- transaction_entry_inc(conn->transaction, +- conn->domain->domid); +- } else { +- conn->domain->nbentry++; +- } ++ domid = node->perms.p ? node->perms.p[0].id : conn->id; ++ ++ if (conn->transaction) { ++ transaction_entry_inc(conn->transaction, domid); ++ } else { ++ d = (domid == conn->id && conn->domain) ? conn->domain ++ : find_or_alloc_existing_domain(domid); ++ if (d) ++ d->nbentry++; ++ else ++ return ENOMEM; + } ++ ++ return 0; + } + + /* +@@ -841,7 +852,7 @@ static int chk_domain_generation(unsigned int domid, uint64_t gen) + * Remove permissions for no longer existing domains in order to avoid a new + * domain with the same domid inheriting the permissions. + */ +-int domain_adjust_node_perms(struct node *node) ++int domain_adjust_node_perms(struct connection *conn, struct node *node) + { + unsigned int i; + int ret; +@@ -851,8 +862,14 @@ int domain_adjust_node_perms(struct node *node) + return errno; + + /* If the owner doesn't exist any longer give it to priv domain. */ +- if (!ret) ++ if (!ret) { ++ /* ++ * In theory we'd need to update the number of dom0 nodes here, ++ * but we could be called for a read of the node. So better ++ * avoid the risk to overflow the node count of dom0. ++ */ + node->perms.p[0].id = priv_domid; ++ } + + for (i = 1; i < node->perms.num; i++) { + if (node->perms.p[i].perms & XS_PERM_IGNORE) +@@ -871,25 +888,25 @@ int domain_adjust_node_perms(struct node *node) + void domain_entry_dec(struct connection *conn, struct node *node) + { + struct domain *d; ++ unsigned int domid; + + if (!conn) + return; + +- if (node->perms.p && node->perms.p[0].id != conn->id) { +- if (conn->transaction) { +- transaction_entry_dec(conn->transaction, +- node->perms.p[0].id); +- } else { +- d = find_domain_by_domid(node->perms.p[0].id); +- if (d && d->nbentry) +- d->nbentry--; +- } +- } else if (conn->domain && conn->domain->nbentry) { +- if (conn->transaction) { +- transaction_entry_dec(conn->transaction, +- conn->domain->domid); ++ domid = node->perms.p ? node->perms.p[0].id : conn->id; ++ ++ if (conn->transaction) { ++ transaction_entry_dec(conn->transaction, domid); ++ } else { ++ d = (domid == conn->id && conn->domain) ? conn->domain ++ : find_domain_struct(domid); ++ if (d) { ++ d->nbentry--; + } else { +- conn->domain->nbentry--; ++ errno = ENOENT; ++ corrupt(conn, ++ "Node \"%s\" owned by non-existing domain %u\n", ++ node->name, domid); + } + } + } +@@ -899,13 +916,23 @@ int domain_entry_fix(unsigned int domid, int num, bool update) + struct domain *d; + int cnt; + +- d = find_domain_by_domid(domid); +- if (!d) +- return 0; ++ if (update) { ++ d = find_domain_struct(domid); ++ assert(d); ++ } else { ++ /* ++ * We are called first with update == false in order to catch ++ * any error. So do a possible allocation and check for error ++ * only in this case, as in the case of update == true nothing ++ * can go wrong anymore as the allocation already happened. ++ */ ++ d = find_or_alloc_existing_domain(domid); ++ if (!d) ++ return -1; ++ } + + cnt = d->nbentry + num; +- if (cnt < 0) +- cnt = 0; ++ assert(cnt >= 0); + + if (update) + d->nbentry = cnt; +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 4f51b005291a..d6519904d831 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -54,10 +54,10 @@ const char *get_implicit_path(const struct connection *conn); + bool domain_is_unprivileged(struct connection *conn); + + /* Remove node permissions for no longer existing domains. */ +-int domain_adjust_node_perms(struct node *node); ++int domain_adjust_node_perms(struct connection *conn, struct node *node); + + /* Quota manipulation */ +-void domain_entry_inc(struct connection *conn, struct node *); ++int domain_entry_inc(struct connection *conn, struct node *); + void domain_entry_dec(struct connection *conn, struct node *); + int domain_entry_fix(unsigned int domid, int num, bool update); + int domain_entry(struct connection *conn); +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index ee1b09031a3b..86caf6c398be 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -519,8 +519,12 @@ static int transaction_fix_domains(struct transaction *trans, bool update) + + list_for_each_entry(d, &trans->changed_domains, list) { + cnt = domain_entry_fix(d->domid, d->nbentry, update); +- if (!update && cnt >= quota_nb_entry_per_domain) +- return ENOSPC; ++ if (!update) { ++ if (cnt >= quota_nb_entry_per_domain) ++ return ENOSPC; ++ if (cnt < 0) ++ return ENOMEM; ++ } + } + + return 0; diff --git a/xsa326-4.16-xenstored-09.patch b/xsa326-4.16-xenstored-09.patch new file mode 100644 index 0000000..e2c163c --- /dev/null +++ b/xsa326-4.16-xenstored-09.patch @@ -0,0 +1,244 @@ +From 71aac6f7e89d5c101adb9e82eea7031e16d34e46 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:09 +0200 +Subject: tools/xenstore: limit max number of nodes accessed in a transaction + +Today a guest is free to access as many nodes in a single transaction +as it wants. This can lead to unbounded memory consumption in Xenstore +as there is the need to keep track of all nodes having been accessed +during a transaction. + +In oxenstored the number of requests in a transaction is being limited +via a quota maxrequests (default is 1024). As multiple accesses of a +node are not problematic in C Xenstore, limit the number of accessed +nodes. + +In order to let read_node() detect a quota error in case too many nodes +are being accessed, check the return value of access_node() and return +NULL in case an error has been seen. Introduce __must_check and add it +to the access_node() prototype. + +This is part of XSA-326 / CVE-2022-42314. + +Reported-by: Julien Grall +Suggested-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/include/xen-tools/libs.h b/tools/include/xen-tools/libs.h +index a16e0c380709..bafc90e2f603 100644 +--- a/tools/include/xen-tools/libs.h ++++ b/tools/include/xen-tools/libs.h +@@ -63,4 +63,8 @@ + #define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1)) + #endif + ++#ifndef __must_check ++#define __must_check __attribute__((__warn_unused_result__)) ++#endif ++ + #endif /* __XEN_TOOLS_LIBS__ */ +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 692d863fce35..f835aa1b2f1f 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -106,6 +106,7 @@ int quota_nb_watch_per_domain = 128; + int quota_max_entry_size = 2048; /* 2K */ + int quota_max_transaction = 10; + int quota_nb_perms_per_node = 5; ++int quota_trans_nodes = 1024; + int quota_max_path_len = XENSTORE_REL_PATH_MAX; + int quota_req_outstanding = 20; + +@@ -595,6 +596,7 @@ struct node *read_node(struct connection *conn, const void *ctx, + TDB_DATA key, data; + struct xs_tdb_record_hdr *hdr; + struct node *node; ++ int err; + + node = talloc(ctx, struct node); + if (!node) { +@@ -616,14 +618,13 @@ struct node *read_node(struct connection *conn, const void *ctx, + if (data.dptr == NULL) { + if (tdb_error(tdb_ctx) == TDB_ERR_NOEXIST) { + node->generation = NO_GENERATION; +- access_node(conn, node, NODE_ACCESS_READ, NULL); +- errno = ENOENT; ++ err = access_node(conn, node, NODE_ACCESS_READ, NULL); ++ errno = err ? : ENOENT; + } else { + log("TDB error on read: %s", tdb_errorstr(tdb_ctx)); + errno = EIO; + } +- talloc_free(node); +- return NULL; ++ goto error; + } + + node->parent = NULL; +@@ -638,19 +639,36 @@ struct node *read_node(struct connection *conn, const void *ctx, + + /* Permissions are struct xs_permissions. */ + node->perms.p = hdr->perms; +- if (domain_adjust_node_perms(conn, node)) { +- talloc_free(node); +- return NULL; +- } ++ if (domain_adjust_node_perms(conn, node)) ++ goto error; + + /* Data is binary blob (usually ascii, no nul). */ + node->data = node->perms.p + hdr->num_perms; + /* Children is strings, nul separated. */ + node->children = node->data + node->datalen; + +- access_node(conn, node, NODE_ACCESS_READ, NULL); ++ if (access_node(conn, node, NODE_ACCESS_READ, NULL)) ++ goto error; + + return node; ++ ++ error: ++ err = errno; ++ talloc_free(node); ++ errno = err; ++ return NULL; ++} ++ ++static bool read_node_can_propagate_errno(void) ++{ ++ /* ++ * 2 error cases for read_node() can always be propagated up: ++ * ENOMEM, because this has nothing to do with the node being in the ++ * data base or not, but is caused by a general lack of memory. ++ * ENOSPC, because this is related to hitting quota limits which need ++ * to be respected. ++ */ ++ return errno == ENOMEM || errno == ENOSPC; + } + + int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, +@@ -767,7 +785,7 @@ static int ask_parents(struct connection *conn, const void *ctx, + node = read_node(conn, ctx, name); + if (node) + break; +- if (errno == ENOMEM) ++ if (read_node_can_propagate_errno()) + return errno; + } while (!streq(name, "/")); + +@@ -829,7 +847,7 @@ static struct node *get_node(struct connection *conn, + } + } + /* Clean up errno if they weren't supposed to know. */ +- if (!node && errno != ENOMEM) ++ if (!node && !read_node_can_propagate_errno()) + errno = errno_from_parents(conn, ctx, name, errno, perm); + return node; + } +@@ -1235,7 +1253,7 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + + /* If parent doesn't exist, create it. */ + parent = read_node(conn, parentname, parentname); +- if (!parent) ++ if (!parent && errno == ENOENT) + parent = construct_node(conn, ctx, parentname); + if (!parent) + return NULL; +@@ -1509,7 +1527,7 @@ static int _rm(struct connection *conn, const void *ctx, struct node *node, + + parent = read_node(conn, ctx, parentname); + if (!parent) +- return (errno == ENOMEM) ? ENOMEM : EINVAL; ++ return read_node_can_propagate_errno() ? errno : EINVAL; + node->parent = parent; + + return delete_node(conn, ctx, parent, node, false); +@@ -1539,7 +1557,7 @@ static int do_rm(struct connection *conn, struct buffered_data *in) + return 0; + } + /* Restore errno, just in case. */ +- if (errno != ENOMEM) ++ if (!read_node_can_propagate_errno()) + errno = ENOENT; + } + return errno; +@@ -2384,6 +2402,8 @@ static void usage(void) + " -M, --path-max limit the allowed Xenstore node path length,\n" + " -Q, --quota = set the quota to the value , allowed\n" + " quotas are:\n" ++" transaction-nodes: number of accessed node per\n" ++" transaction\n" + " outstanding: number of outstanding requests\n" + " -w, --timeout = set the timeout in seconds for ,\n" + " allowed timeout candidates are:\n" +@@ -2468,6 +2488,8 @@ static void set_quota(const char *arg) + val = get_optval_int(eq + 1); + if (what_matches(arg, "outstanding")) + quota_req_outstanding = val; ++ else if (what_matches(arg, "transaction-nodes")) ++ quota_trans_nodes = val; + else + barf("unknown quota \"%s\"\n", arg); + } +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index b1a70488b989..245f9258235f 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -268,6 +268,7 @@ extern int dom0_event; + extern int priv_domid; + extern int quota_nb_entry_per_domain; + extern int quota_req_outstanding; ++extern int quota_trans_nodes; + + extern unsigned int timeout_watch_event_msec; + +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 86caf6c398be..7bd41eb475e3 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -156,6 +156,9 @@ struct transaction + /* Connection-local identifier for this transaction. */ + uint32_t id; + ++ /* Node counter. */ ++ unsigned int nodes; ++ + /* Generation when transaction started. */ + uint64_t generation; + +@@ -260,6 +263,11 @@ int access_node(struct connection *conn, struct node *node, + + i = find_accessed_node(trans, node->name); + if (!i) { ++ if (trans->nodes >= quota_trans_nodes && ++ domain_is_unprivileged(conn)) { ++ ret = ENOSPC; ++ goto err; ++ } + i = talloc_zero(trans, struct accessed_node); + if (!i) + goto nomem; +@@ -297,6 +305,7 @@ int access_node(struct connection *conn, struct node *node, + i->ta_node = true; + } + } ++ trans->nodes++; + list_add_tail(&i->list, &trans->accessed); + } + +diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h +index 0093cac807e3..e3cbd6b23095 100644 +--- a/tools/xenstore/xenstored_transaction.h ++++ b/tools/xenstore/xenstored_transaction.h +@@ -39,8 +39,8 @@ void transaction_entry_inc(struct transaction *trans, unsigned int domid); + void transaction_entry_dec(struct transaction *trans, unsigned int domid); + + /* This node was accessed. */ +-int access_node(struct connection *conn, struct node *node, +- enum node_access_type type, TDB_DATA *key); ++int __must_check access_node(struct connection *conn, struct node *node, ++ enum node_access_type type, TDB_DATA *key); + + /* Queue watches for a modified node. */ + void queue_watches(struct connection *conn, const char *name, bool watch_exact); diff --git a/xsa326-4.16-xenstored-10.patch b/xsa326-4.16-xenstored-10.patch new file mode 100644 index 0000000..30e6b50 --- /dev/null +++ b/xsa326-4.16-xenstored-10.patch @@ -0,0 +1,88 @@ +From 90013d6a735491a7b93a6832eb2a51e5633254f5 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:09 +0200 +Subject: tools/xenstore: move the call of setup_structure() to dom0 + introduction + +Setting up the basic structure when introducing dom0 has the advantage +to be able to add proper node memory accounting for the added nodes +later. + +This makes it possible to do proper node accounting, too. + +An additional requirement to make that work fine is to correct the +owner of the created nodes to be dom0_domid instead of domid 0. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index f835aa1b2f1f..5171d34c947e 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -2039,7 +2039,8 @@ static int tdb_flags; + static void manual_node(const char *name, const char *child) + { + struct node *node; +- struct xs_permissions perms = { .id = 0, .perms = XS_PERM_NONE }; ++ struct xs_permissions perms = { .id = dom0_domid, ++ .perms = XS_PERM_NONE }; + + node = talloc_zero(NULL, struct node); + if (!node) +@@ -2078,7 +2079,7 @@ static void tdb_logger(TDB_CONTEXT *tdb, int level, const char * fmt, ...) + } + } + +-static void setup_structure(bool live_update) ++void setup_structure(bool live_update) + { + char *tdbname; + +@@ -2101,6 +2102,7 @@ static void setup_structure(bool live_update) + manual_node("/", "tool"); + manual_node("/tool", "xenstored"); + manual_node("/tool/xenstored", NULL); ++ domain_entry_fix(dom0_domid, 3, true); + } + + check_store(); +@@ -2614,9 +2616,6 @@ int main(int argc, char *argv[]) + + init_pipe(reopen_log_pipe); + +- /* Setup the database */ +- setup_structure(live_update); +- + /* Listen to hypervisor. */ + if (!no_domain_init && !live_update) { + domain_init(-1); +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 245f9258235f..2c77ec7ee0f4 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -231,6 +231,7 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + struct node *read_node(struct connection *conn, const void *ctx, + const char *name); + ++void setup_structure(bool live_update); + struct connection *new_connection(const struct interface_funcs *funcs); + struct connection *get_connection_by_id(unsigned int conn_id); + void ignore_connection(struct connection *conn); +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index 260952e09096..f04b7aae8a32 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -470,6 +470,9 @@ static struct domain *introduce_domain(const void *ctx, + } + domain->interface = interface; + ++ if (is_master_domain) ++ setup_structure(restore); ++ + /* Now domain belongs to its connection. */ + talloc_steal(domain->conn, domain); + diff --git a/xsa326-4.16-xenstored-11.patch b/xsa326-4.16-xenstored-11.patch new file mode 100644 index 0000000..49f1497 --- /dev/null +++ b/xsa326-4.16-xenstored-11.patch @@ -0,0 +1,280 @@ +From 6af17b8bf52b9dfdc6a5ecd3efbcea9fddd57d91 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:09 +0200 +Subject: tools/xenstore: add infrastructure to keep track of per domain memory + usage + +The amount of memory a domain can consume in Xenstore is limited by +various quota today, but even with sane quota a domain can still +consume rather large memory quantities. + +Add the infrastructure for keeping track of the amount of memory a +domain is consuming in Xenstore. Note that this is only the memory a +domain has direct control over, so any internal administration data +needed by Xenstore only is not being accounted for. + +There are two quotas defined: a soft quota which will result in a +warning issued via syslog() when it is exceeded, and a hard quota +resulting in a stop of accepting further requests or watch events as +long as the hard quota would be violated by accepting those. + +Setting any of those quotas to 0 will disable it. + +As default values use 2MB per domain for the soft limit (this basically +covers the allowed case to create 1000 nodes needing 2kB each), and +2.5MB for the hard limit. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 5171d34c947e..b2bf6740d430 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -109,6 +109,8 @@ int quota_nb_perms_per_node = 5; + int quota_trans_nodes = 1024; + int quota_max_path_len = XENSTORE_REL_PATH_MAX; + int quota_req_outstanding = 20; ++int quota_memory_per_domain_soft = 2 * 1024 * 1024; /* 2 MB */ ++int quota_memory_per_domain_hard = 2 * 1024 * 1024 + 512 * 1024; /* 2.5 MB */ + + unsigned int timeout_watch_event_msec = 20000; + +@@ -2406,7 +2408,14 @@ static void usage(void) + " quotas are:\n" + " transaction-nodes: number of accessed node per\n" + " transaction\n" ++" memory: total used memory per domain for nodes,\n" ++" transactions, watches and requests, above\n" ++" which Xenstore will stop talking to domain\n" + " outstanding: number of outstanding requests\n" ++" -q, --quota-soft = set a soft quota to the value ,\n" ++" causing a warning to be issued via syslog() if the\n" ++" limit is violated, allowed quotas are:\n" ++" memory: see above\n" + " -w, --timeout = set the timeout in seconds for ,\n" + " allowed timeout candidates are:\n" + " watch-event: time a watch-event is kept pending\n" +@@ -2433,6 +2442,7 @@ static struct option options[] = { + { "perm-nb", 1, NULL, 'A' }, + { "path-max", 1, NULL, 'M' }, + { "quota", 1, NULL, 'Q' }, ++ { "quota-soft", 1, NULL, 'q' }, + { "timeout", 1, NULL, 'w' }, + { "no-recovery", 0, NULL, 'R' }, + { "internal-db", 0, NULL, 'I' }, +@@ -2480,7 +2490,7 @@ static void set_timeout(const char *arg) + barf("unknown timeout \"%s\"\n", arg); + } + +-static void set_quota(const char *arg) ++static void set_quota(const char *arg, bool soft) + { + const char *eq = strchr(arg, '='); + int val; +@@ -2488,11 +2498,16 @@ static void set_quota(const char *arg) + if (!eq) + barf("quotas must be specified via =\n"); + val = get_optval_int(eq + 1); +- if (what_matches(arg, "outstanding")) ++ if (what_matches(arg, "outstanding") && !soft) + quota_req_outstanding = val; +- else if (what_matches(arg, "transaction-nodes")) ++ else if (what_matches(arg, "transaction-nodes") && !soft) + quota_trans_nodes = val; +- else ++ else if (what_matches(arg, "memory")) { ++ if (soft) ++ quota_memory_per_domain_soft = val; ++ else ++ quota_memory_per_domain_hard = val; ++ } else + barf("unknown quota \"%s\"\n", arg); + } + +@@ -2510,7 +2525,7 @@ int main(int argc, char *argv[]) + orig_argc = argc; + orig_argv = argv; + +- while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:Q:T:RVW:w:U", ++ while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:Q:q:T:RVW:w:U", + options, NULL)) != -1) { + switch (opt) { + case 'D': +@@ -2561,7 +2576,10 @@ int main(int argc, char *argv[]) + quota_max_path_len); + break; + case 'Q': +- set_quota(optarg); ++ set_quota(optarg, false); ++ break; ++ case 'q': ++ set_quota(optarg, true); + break; + case 'w': + set_timeout(optarg); +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 2c77ec7ee0f4..373af18297bf 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -270,6 +270,8 @@ extern int priv_domid; + extern int quota_nb_entry_per_domain; + extern int quota_req_outstanding; + extern int quota_trans_nodes; ++extern int quota_memory_per_domain_soft; ++extern int quota_memory_per_domain_hard; + + extern unsigned int timeout_watch_event_msec; + +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index f04b7aae8a32..94fd561e9de4 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -76,6 +76,13 @@ struct domain + /* number of entry from this domain in the store */ + int nbentry; + ++ /* Amount of memory allocated for this domain. */ ++ int memory; ++ bool soft_quota_reported; ++ bool hard_quota_reported; ++ time_t mem_last_msg; ++#define MEM_WARN_MINTIME_SEC 10 ++ + /* number of watch for this domain */ + int nbwatch; + +@@ -192,6 +199,9 @@ static bool domain_can_read(struct connection *conn) + return false; + if (conn->domain->nboutstanding >= quota_req_outstanding) + return false; ++ if (conn->domain->memory >= quota_memory_per_domain_hard && ++ quota_memory_per_domain_hard) ++ return false; + } + + return (intf->req_cons != intf->req_prod); +@@ -950,6 +960,89 @@ int domain_entry(struct connection *conn) + : 0; + } + ++static bool domain_chk_quota(struct domain *domain, int mem) ++{ ++ time_t now; ++ ++ if (!domain || !domid_is_unprivileged(domain->domid) || ++ (domain->conn && domain->conn->is_ignored)) ++ return false; ++ ++ now = time(NULL); ++ ++ if (mem >= quota_memory_per_domain_hard && ++ quota_memory_per_domain_hard) { ++ if (domain->hard_quota_reported) ++ return true; ++ syslog(LOG_ERR, "Domain %u exceeds hard memory quota, Xenstore interface to domain stalled\n", ++ domain->domid); ++ domain->mem_last_msg = now; ++ domain->hard_quota_reported = true; ++ return true; ++ } ++ ++ if (now - domain->mem_last_msg >= MEM_WARN_MINTIME_SEC) { ++ if (domain->hard_quota_reported) { ++ domain->mem_last_msg = now; ++ domain->hard_quota_reported = false; ++ syslog(LOG_INFO, "Domain %u below hard memory quota again\n", ++ domain->domid); ++ } ++ if (mem >= quota_memory_per_domain_soft && ++ quota_memory_per_domain_soft && ++ !domain->soft_quota_reported) { ++ domain->mem_last_msg = now; ++ domain->soft_quota_reported = true; ++ syslog(LOG_WARNING, "Domain %u exceeds soft memory quota\n", ++ domain->domid); ++ } ++ if (mem < quota_memory_per_domain_soft && ++ domain->soft_quota_reported) { ++ domain->mem_last_msg = now; ++ domain->soft_quota_reported = false; ++ syslog(LOG_INFO, "Domain %u below soft memory quota again\n", ++ domain->domid); ++ } ++ ++ } ++ ++ return false; ++} ++ ++int domain_memory_add(unsigned int domid, int mem, bool no_quota_check) ++{ ++ struct domain *domain; ++ ++ domain = find_domain_struct(domid); ++ if (domain) { ++ /* ++ * domain_chk_quota() will print warning and also store whether ++ * the soft/hard quota has been hit. So check no_quota_check ++ * *after*. ++ */ ++ if (domain_chk_quota(domain, domain->memory + mem) && ++ !no_quota_check) ++ return ENOMEM; ++ domain->memory += mem; ++ } else { ++ /* ++ * The domain the memory is to be accounted for should always ++ * exist, as accounting is done either for a domain related to ++ * the current connection, or for the domain owning a node ++ * (which is always existing, as the owner of the node is ++ * tested to exist and replaced by domid 0 if not). ++ * So not finding the related domain MUST be an error in the ++ * data base. ++ */ ++ errno = ENOENT; ++ corrupt(NULL, "Accounting called for non-existing domain %u\n", ++ domid); ++ return ENOENT; ++ } ++ ++ return 0; ++} ++ + void domain_watch_inc(struct connection *conn) + { + if (!conn || !conn->domain) +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index d6519904d831..633c9a0a0a1f 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -61,6 +61,26 @@ int domain_entry_inc(struct connection *conn, struct node *); + void domain_entry_dec(struct connection *conn, struct node *); + int domain_entry_fix(unsigned int domid, int num, bool update); + int domain_entry(struct connection *conn); ++int domain_memory_add(unsigned int domid, int mem, bool no_quota_check); ++ ++/* ++ * domain_memory_add_chk(): to be used when memory quota should be checked. ++ * Not to be used when specifying a negative mem value, as lowering the used ++ * memory should always be allowed. ++ */ ++static inline int domain_memory_add_chk(unsigned int domid, int mem) ++{ ++ return domain_memory_add(domid, mem, false); ++} ++/* ++ * domain_memory_add_nochk(): to be used when memory quota should not be ++ * checked, e.g. when lowering memory usage, or in an error case for undoing ++ * a previous memory adjustment. ++ */ ++static inline void domain_memory_add_nochk(unsigned int domid, int mem) ++{ ++ domain_memory_add(domid, mem, true); ++} + void domain_watch_inc(struct connection *conn); + void domain_watch_dec(struct connection *conn); + int domain_watch(struct connection *conn); diff --git a/xsa326-4.16-xenstored-12.patch b/xsa326-4.16-xenstored-12.patch new file mode 100644 index 0000000..517f2a0 --- /dev/null +++ b/xsa326-4.16-xenstored-12.patch @@ -0,0 +1,76 @@ +From ae7042f024af7584251f776a12d9bb24d13fecaf Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:09 +0200 +Subject: tools/xenstore: add memory accounting for responses + +Add the memory accounting for queued responses. + +In case adding a watch event for a guest is causing the hard memory +quota of that guest to be violated, the event is dropped. This will +ensure that it is impossible to drive another guest past its memory +quota by generating insane amounts of events for that guest. This is +especially important for protecting driver domains from that attack +vector. + +This is part of XSA-326 / CVE-2022-42315. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index b2bf6740d430..ecab6cfbbe15 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -260,6 +260,8 @@ static void free_buffered_data(struct buffered_data *out, + } + } + ++ domain_memory_add_nochk(conn->id, -out->hdr.msg.len - sizeof(out->hdr)); ++ + if (out->hdr.msg.type == XS_WATCH_EVENT) { + req = out->pend.req; + if (req) { +@@ -938,11 +940,14 @@ void send_reply(struct connection *conn, enum xsd_sockmsg_type type, + bdata->timeout_msec = 0; + bdata->watch_event = false; + +- if (len <= DEFAULT_BUFFER_SIZE) ++ if (len <= DEFAULT_BUFFER_SIZE) { + bdata->buffer = bdata->default_buffer; +- else { ++ /* Don't check quota, path might be used for returning error. */ ++ domain_memory_add_nochk(conn->id, len + sizeof(bdata->hdr)); ++ } else { + bdata->buffer = talloc_array(bdata, char, len); +- if (!bdata->buffer) { ++ if (!bdata->buffer || ++ domain_memory_add_chk(conn->id, len + sizeof(bdata->hdr))) { + send_error(conn, ENOMEM); + return; + } +@@ -1007,6 +1012,11 @@ void send_event(struct buffered_data *req, struct connection *conn, + } + } + ++ if (domain_memory_add_chk(conn->id, len + sizeof(bdata->hdr))) { ++ talloc_free(bdata); ++ return; ++ } ++ + if (timeout_watch_event_msec && domain_is_unprivileged(conn)) { + bdata->timeout_msec = get_now_msec() + timeout_watch_event_msec; + if (!conn->timeout_msec) +@@ -3039,6 +3049,12 @@ static void add_buffered_data(struct buffered_data *bdata, + */ + if (bdata->hdr.msg.type != XS_WATCH_EVENT) + domain_outstanding_inc(conn); ++ /* ++ * We are restoring the state after Live-Update and the new quota may ++ * be smaller. So ignore it. The limit will be applied for any resource ++ * after the state has been fully restored. ++ */ ++ domain_memory_add_nochk(conn->id, len + sizeof(bdata->hdr)); + } + + void read_state_buffered_data(const void *ctx, struct connection *conn, diff --git a/xsa326-4.16-xenstored-13.patch b/xsa326-4.16-xenstored-13.patch new file mode 100644 index 0000000..c37dd1e --- /dev/null +++ b/xsa326-4.16-xenstored-13.patch @@ -0,0 +1,89 @@ +From 4628ae0a56b037dcdc8a3e42c543c5b9fd9990cf Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: add memory accounting for watches + +Add the memory accounting for registered watches. + +When a socket connection is destroyed, the associated watches are +removed, too. In order to keep memory accounting correct the watches +must be removed explicitly via a call of conn_delete_all_watches() from +destroy_conn(). + +This is part of XSA-326 / CVE-2022-42315. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index ecab6cfbbe15..d86942f5aa77 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -463,6 +463,7 @@ static int destroy_conn(void *_conn) + } + + conn_free_buffered_data(conn); ++ conn_delete_all_watches(conn); + list_for_each_entry(req, &conn->ref_list, list) + req->on_ref_list = false; + +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index 0755ffa375ba..fdf9b2d653a0 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -211,7 +211,7 @@ static int check_watch_path(struct connection *conn, const void *ctx, + } + + static struct watch *add_watch(struct connection *conn, char *path, char *token, +- bool relative) ++ bool relative, bool no_quota_check) + { + struct watch *watch; + +@@ -222,6 +222,9 @@ static struct watch *add_watch(struct connection *conn, char *path, char *token, + watch->token = talloc_strdup(watch, token); + if (!watch->node || !watch->token) + goto nomem; ++ if (domain_memory_add(conn->id, strlen(path) + strlen(token), ++ no_quota_check)) ++ goto nomem; + + if (relative) + watch->relative_path = get_implicit_path(conn); +@@ -265,7 +268,7 @@ int do_watch(struct connection *conn, struct buffered_data *in) + if (domain_watch(conn) > quota_nb_watch_per_domain) + return E2BIG; + +- watch = add_watch(conn, vec[0], vec[1], relative); ++ watch = add_watch(conn, vec[0], vec[1], relative, false); + if (!watch) + return errno; + +@@ -296,6 +299,8 @@ int do_unwatch(struct connection *conn, struct buffered_data *in) + list_for_each_entry(watch, &conn->watches, list) { + if (streq(watch->node, node) && streq(watch->token, vec[1])) { + list_del(&watch->list); ++ domain_memory_add_nochk(conn->id, -strlen(watch->node) - ++ strlen(watch->token)); + talloc_free(watch); + domain_watch_dec(conn); + send_ack(conn, XS_UNWATCH); +@@ -311,6 +316,8 @@ void conn_delete_all_watches(struct connection *conn) + + while ((watch = list_top(&conn->watches, struct watch, list))) { + list_del(&watch->list); ++ domain_memory_add_nochk(conn->id, -strlen(watch->node) - ++ strlen(watch->token)); + talloc_free(watch); + domain_watch_dec(conn); + } +@@ -373,7 +380,7 @@ void read_state_watch(const void *ctx, const void *state) + if (!path) + barf("allocation error for read watch"); + +- if (!add_watch(conn, path, token, relative)) ++ if (!add_watch(conn, path, token, relative, true)) + barf("error adding watch"); + } + diff --git a/xsa326-4.16-xenstored-14.patch b/xsa326-4.16-xenstored-14.patch new file mode 100644 index 0000000..df898c4 --- /dev/null +++ b/xsa326-4.16-xenstored-14.patch @@ -0,0 +1,334 @@ +From b8bd74e5e962955211ab0c5c1924ebf2bb526799 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: add memory accounting for nodes + +Add the memory accounting for Xenstore nodes. In order to make this +not too complicated allow for some sloppiness when writing nodes. Any +hard quota violation will result in no further requests to be accepted. + +This is part of XSA-326 / CVE-2022-42315. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index d86942f5aa77..16504de42017 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -591,6 +591,117 @@ void set_tdb_key(const char *name, TDB_DATA *key) + key->dsize = strlen(name); + } + ++static void get_acc_data(TDB_DATA *key, struct node_account_data *acc) ++{ ++ TDB_DATA old_data; ++ struct xs_tdb_record_hdr *hdr; ++ ++ if (acc->memory < 0) { ++ old_data = tdb_fetch(tdb_ctx, *key); ++ /* No check for error, as the node might not exist. */ ++ if (old_data.dptr == NULL) { ++ acc->memory = 0; ++ } else { ++ hdr = (void *)old_data.dptr; ++ acc->memory = old_data.dsize; ++ acc->domid = hdr->perms[0].id; ++ } ++ talloc_free(old_data.dptr); ++ } ++} ++ ++/* ++ * Per-transaction nodes need to be accounted for the transaction owner. ++ * Those nodes are stored in the data base with the transaction generation ++ * count prepended (e.g. 123/local/domain/...). So testing for the node's ++ * key not to start with "/" is sufficient. ++ */ ++static unsigned int get_acc_domid(struct connection *conn, TDB_DATA *key, ++ unsigned int domid) ++{ ++ return (!conn || key->dptr[0] == '/') ? domid : conn->id; ++} ++ ++int do_tdb_write(struct connection *conn, TDB_DATA *key, TDB_DATA *data, ++ struct node_account_data *acc, bool no_quota_check) ++{ ++ struct xs_tdb_record_hdr *hdr = (void *)data->dptr; ++ struct node_account_data old_acc = {}; ++ unsigned int old_domid, new_domid; ++ int ret; ++ ++ if (!acc) ++ old_acc.memory = -1; ++ else ++ old_acc = *acc; ++ ++ get_acc_data(key, &old_acc); ++ old_domid = get_acc_domid(conn, key, old_acc.domid); ++ new_domid = get_acc_domid(conn, key, hdr->perms[0].id); ++ ++ /* ++ * Don't check for ENOENT, as we want to be able to switch orphaned ++ * nodes to new owners. ++ */ ++ if (old_acc.memory) ++ domain_memory_add_nochk(old_domid, ++ -old_acc.memory - key->dsize); ++ ret = domain_memory_add(new_domid, data->dsize + key->dsize, ++ no_quota_check); ++ if (ret) { ++ /* Error path, so no quota check. */ ++ if (old_acc.memory) ++ domain_memory_add_nochk(old_domid, ++ old_acc.memory + key->dsize); ++ return ret; ++ } ++ ++ /* TDB should set errno, but doesn't even set ecode AFAICT. */ ++ if (tdb_store(tdb_ctx, *key, *data, TDB_REPLACE) != 0) { ++ domain_memory_add_nochk(new_domid, -data->dsize - key->dsize); ++ /* Error path, so no quota check. */ ++ if (old_acc.memory) ++ domain_memory_add_nochk(old_domid, ++ old_acc.memory + key->dsize); ++ errno = EIO; ++ return errno; ++ } ++ ++ if (acc) { ++ /* Don't use new_domid, as it might be a transaction node. */ ++ acc->domid = hdr->perms[0].id; ++ acc->memory = data->dsize; ++ } ++ ++ return 0; ++} ++ ++int do_tdb_delete(struct connection *conn, TDB_DATA *key, ++ struct node_account_data *acc) ++{ ++ struct node_account_data tmp_acc; ++ unsigned int domid; ++ ++ if (!acc) { ++ acc = &tmp_acc; ++ acc->memory = -1; ++ } ++ ++ get_acc_data(key, acc); ++ ++ if (tdb_delete(tdb_ctx, *key)) { ++ errno = EIO; ++ return errno; ++ } ++ ++ if (acc->memory) { ++ domid = get_acc_domid(conn, key, acc->domid); ++ domain_memory_add_nochk(domid, -acc->memory - key->dsize); ++ } ++ ++ return 0; ++} ++ + /* + * If it fails, returns NULL and sets errno. + * Temporary memory allocations will be done with ctx. +@@ -644,9 +755,15 @@ struct node *read_node(struct connection *conn, const void *ctx, + + /* Permissions are struct xs_permissions. */ + node->perms.p = hdr->perms; ++ node->acc.domid = node->perms.p[0].id; ++ node->acc.memory = data.dsize; + if (domain_adjust_node_perms(conn, node)) + goto error; + ++ /* If owner is gone reset currently accounted memory size. */ ++ if (node->acc.domid != node->perms.p[0].id) ++ node->acc.memory = 0; ++ + /* Data is binary blob (usually ascii, no nul). */ + node->data = node->perms.p + hdr->num_perms; + /* Children is strings, nul separated. */ +@@ -715,12 +832,9 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + p += node->datalen; + memcpy(p, node->children, node->childlen); + +- /* TDB should set errno, but doesn't even set ecode AFAICT. */ +- if (tdb_store(tdb_ctx, *key, data, TDB_REPLACE) != 0) { +- corrupt(conn, "Write of %s failed", key->dptr); +- errno = EIO; +- return errno; +- } ++ if (do_tdb_write(conn, key, &data, &node->acc, no_quota_check)) ++ return EIO; ++ + return 0; + } + +@@ -1222,7 +1336,7 @@ static void delete_node_single(struct connection *conn, struct node *node) + if (access_node(conn, node, NODE_ACCESS_DELETE, &key)) + return; + +- if (tdb_delete(tdb_ctx, key) != 0) { ++ if (do_tdb_delete(conn, &key, &node->acc) != 0) { + corrupt(conn, "Could not delete '%s'", node->name); + return; + } +@@ -1295,6 +1409,7 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + /* No children, no data */ + node->children = node->data = NULL; + node->childlen = node->datalen = 0; ++ node->acc.memory = 0; + node->parent = parent; + return node; + +@@ -1303,17 +1418,17 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + return NULL; + } + +-static void destroy_node_rm(struct node *node) ++static void destroy_node_rm(struct connection *conn, struct node *node) + { + if (streq(node->name, "/")) + corrupt(NULL, "Destroying root node!"); + +- tdb_delete(tdb_ctx, node->key); ++ do_tdb_delete(conn, &node->key, &node->acc); + } + + static int destroy_node(struct connection *conn, struct node *node) + { +- destroy_node_rm(node); ++ destroy_node_rm(conn, node); + domain_entry_dec(conn, node); + + /* +@@ -1365,7 +1480,7 @@ static struct node *create_node(struct connection *conn, const void *ctx, + /* Account for new node */ + if (i->parent) { + if (domain_entry_inc(conn, i)) { +- destroy_node_rm(i); ++ destroy_node_rm(conn, i); + return NULL; + } + } +@@ -2291,7 +2406,7 @@ static int clean_store_(TDB_CONTEXT *tdb, TDB_DATA key, TDB_DATA val, + if (!hashtable_search(reachable, name)) { + log("clean_store: '%s' is orphaned!", name); + if (recovery) { +- tdb_delete(tdb, key); ++ do_tdb_delete(NULL, &key, NULL); + } + } + +@@ -3149,6 +3264,7 @@ void read_state_node(const void *ctx, const void *state) + if (!node) + barf("allocation error restoring node"); + ++ node->acc.memory = 0; + node->name = name; + node->generation = ++generation; + node->datalen = sn->data_len; +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 373af18297bf..da9ecce67f31 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -176,6 +176,11 @@ struct node_perms { + struct xs_permissions *p; + }; + ++struct node_account_data { ++ unsigned int domid; ++ int memory; /* -1 if unknown */ ++}; ++ + struct node { + const char *name; + /* Key used to update TDB */ +@@ -198,6 +203,9 @@ struct node { + /* Children, each nul-terminated. */ + unsigned int childlen; + char *children; ++ ++ /* Allocation information for node currently in store. */ ++ struct node_account_data acc; + }; + + /* Return the only argument in the input. */ +@@ -306,6 +314,10 @@ extern xengnttab_handle **xgt_handle; + int remember_string(struct hashtable *hash, const char *str); + + void set_tdb_key(const char *name, TDB_DATA *key); ++int do_tdb_write(struct connection *conn, TDB_DATA *key, TDB_DATA *data, ++ struct node_account_data *acc, bool no_quota_check); ++int do_tdb_delete(struct connection *conn, TDB_DATA *key, ++ struct node_account_data *acc); + + void conn_free_buffered_data(struct connection *conn); + +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 7bd41eb475e3..ace9a11d77bb 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -153,6 +153,9 @@ struct transaction + /* List of all transactions active on this connection. */ + struct list_head list; + ++ /* Connection this transaction is associated with. */ ++ struct connection *conn; ++ + /* Connection-local identifier for this transaction. */ + uint32_t id; + +@@ -286,6 +289,8 @@ int access_node(struct connection *conn, struct node *node, + + introduce = true; + i->ta_node = false; ++ /* acc.memory < 0 means "unknown, get size from TDB". */ ++ node->acc.memory = -1; + + /* + * Additional transaction-specific node for read type. We only +@@ -410,11 +415,11 @@ static int finalize_transaction(struct connection *conn, + goto err; + hdr = (void *)data.dptr; + hdr->generation = ++generation; +- ret = tdb_store(tdb_ctx, key, data, +- TDB_REPLACE); ++ ret = do_tdb_write(conn, &key, &data, NULL, ++ true); + talloc_free(data.dptr); + } else { +- ret = tdb_delete(tdb_ctx, key); ++ ret = do_tdb_delete(conn, &key, NULL); + } + if (ret) + goto err; +@@ -425,7 +430,7 @@ static int finalize_transaction(struct connection *conn, + } + } + +- if (i->ta_node && tdb_delete(tdb_ctx, ta_key)) ++ if (i->ta_node && do_tdb_delete(conn, &ta_key, NULL)) + goto err; + list_del(&i->list); + talloc_free(i); +@@ -453,7 +458,7 @@ static int destroy_transaction(void *_transaction) + i->node); + if (trans_name) { + set_tdb_key(trans_name, &key); +- tdb_delete(tdb_ctx, key); ++ do_tdb_delete(trans->conn, &key, NULL); + } + } + list_del(&i->list); +@@ -497,6 +502,7 @@ int do_transaction_start(struct connection *conn, struct buffered_data *in) + + INIT_LIST_HEAD(&trans->accessed); + INIT_LIST_HEAD(&trans->changed_domains); ++ trans->conn = conn; + trans->fail = false; + trans->generation = ++generation; + diff --git a/xsa326-4.16-xenstored-15.patch b/xsa326-4.16-xenstored-15.patch new file mode 100644 index 0000000..8a42a36 --- /dev/null +++ b/xsa326-4.16-xenstored-15.patch @@ -0,0 +1,54 @@ +From c55a1ea0a5ea7f6a3dc850cb015a49ba9ec571ab Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: add exports for quota variables + +Some quota variables are not exported via header files. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index da9ecce67f31..bfd3fc1e9df3 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -275,6 +275,11 @@ extern TDB_CONTEXT *tdb_ctx; + extern int dom0_domid; + extern int dom0_event; + extern int priv_domid; ++extern int quota_nb_watch_per_domain; ++extern int quota_max_transaction; ++extern int quota_max_entry_size; ++extern int quota_nb_perms_per_node; ++extern int quota_max_path_len; + extern int quota_nb_entry_per_domain; + extern int quota_req_outstanding; + extern int quota_trans_nodes; +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index ace9a11d77bb..28774813de83 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -175,7 +175,6 @@ struct transaction + bool fail; + }; + +-extern int quota_max_transaction; + uint64_t generation; + + static struct accessed_node *find_accessed_node(struct transaction *trans, +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index fdf9b2d653a0..85362bcce314 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -31,8 +31,6 @@ + #include "xenstored_domain.h" + #include "xenstored_transaction.h" + +-extern int quota_nb_watch_per_domain; +- + struct watch + { + /* Watches on this connection */ diff --git a/xsa326-4.16-xenstored-16.patch b/xsa326-4.16-xenstored-16.patch new file mode 100644 index 0000000..c2a8953 --- /dev/null +++ b/xsa326-4.16-xenstored-16.patch @@ -0,0 +1,238 @@ +From 05cc2af50ba43431d6d50aff758e968833aab9c6 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: add control command for setting and showing quota + +Add a xenstore-control command "quota" to: +- show current quota settings +- change quota settings +- show current quota related values of a domain + +Note that in the case the new quota is lower than existing one, +Xenstored may continue to handle requests from a domain exceeding the +new limit (depends on which one has been broken) and the amount of +resource used will not change. However the domain will not be able to +create more resource (associated to the quota) until it is back to below +the limit. + +This is part of XSA-326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt +index 334dc8b6fdf5..a7d006519ae8 100644 +--- a/docs/misc/xenstore.txt ++++ b/docs/misc/xenstore.txt +@@ -366,6 +366,17 @@ CONTROL |[|] + print| + print to syslog (xenstore runs as daemon) or + to console (xenstore runs as stubdom) ++ quota|[set |] ++ without parameters: print the current quota settings ++ with "set ": set the quota to new value ++ (The admin should make sure all the domain usage is ++ below the quota. If it is not, then Xenstored may continue to ++ handle requests from the domain as long as the resource ++ violating the new quota setting isn't increased further) ++ with "": print quota related accounting data for ++ the domain ++ quota-soft|[set ] ++ like the "quota" command, but for soft-quota. + help + return list of supported commands for CONTROL + +diff --git a/tools/xenstore/xenstored_control.c b/tools/xenstore/xenstored_control.c +index adb8d51b043b..1031a81c3874 100644 +--- a/tools/xenstore/xenstored_control.c ++++ b/tools/xenstore/xenstored_control.c +@@ -196,6 +196,115 @@ static int do_control_log(void *ctx, struct connection *conn, + return 0; + } + ++struct quota { ++ const char *name; ++ int *quota; ++ const char *descr; ++}; ++ ++static const struct quota hard_quotas[] = { ++ { "nodes", "a_nb_entry_per_domain, "Nodes per domain" }, ++ { "watches", "a_nb_watch_per_domain, "Watches per domain" }, ++ { "transactions", "a_max_transaction, "Transactions per domain" }, ++ { "outstanding", "a_req_outstanding, ++ "Outstanding requests per domain" }, ++ { "transaction-nodes", "a_trans_nodes, ++ "Max. number of accessed nodes per transaction" }, ++ { "memory", "a_memory_per_domain_hard, ++ "Total Xenstore memory per domain (error level)" }, ++ { "node-size", "a_max_entry_size, "Max. size of a node" }, ++ { "path-max", "a_max_path_len, "Max. length of a node path" }, ++ { "permissions", "a_nb_perms_per_node, ++ "Max. number of permissions per node" }, ++ { NULL, NULL, NULL } ++}; ++ ++static const struct quota soft_quotas[] = { ++ { "memory", "a_memory_per_domain_soft, ++ "Total Xenstore memory per domain (warning level)" }, ++ { NULL, NULL, NULL } ++}; ++ ++static int quota_show_current(const void *ctx, struct connection *conn, ++ const struct quota *quotas) ++{ ++ char *resp; ++ unsigned int i; ++ ++ resp = talloc_strdup(ctx, "Quota settings:\n"); ++ if (!resp) ++ return ENOMEM; ++ ++ for (i = 0; quotas[i].quota; i++) { ++ resp = talloc_asprintf_append(resp, "%-17s: %8d %s\n", ++ quotas[i].name, *quotas[i].quota, ++ quotas[i].descr); ++ if (!resp) ++ return ENOMEM; ++ } ++ ++ send_reply(conn, XS_CONTROL, resp, strlen(resp) + 1); ++ ++ return 0; ++} ++ ++static int quota_set(const void *ctx, struct connection *conn, ++ char **vec, int num, const struct quota *quotas) ++{ ++ unsigned int i; ++ int val; ++ ++ if (num != 2) ++ return EINVAL; ++ ++ val = atoi(vec[1]); ++ if (val < 1) ++ return EINVAL; ++ ++ for (i = 0; quotas[i].quota; i++) { ++ if (!strcmp(vec[0], quotas[i].name)) { ++ *quotas[i].quota = val; ++ send_ack(conn, XS_CONTROL); ++ return 0; ++ } ++ } ++ ++ return EINVAL; ++} ++ ++static int quota_get(const void *ctx, struct connection *conn, ++ char **vec, int num) ++{ ++ if (num != 1) ++ return EINVAL; ++ ++ return domain_get_quota(ctx, conn, atoi(vec[0])); ++} ++ ++static int do_control_quota(void *ctx, struct connection *conn, ++ char **vec, int num) ++{ ++ if (num == 0) ++ return quota_show_current(ctx, conn, hard_quotas); ++ ++ if (!strcmp(vec[0], "set")) ++ return quota_set(ctx, conn, vec + 1, num - 1, hard_quotas); ++ ++ return quota_get(ctx, conn, vec, num); ++} ++ ++static int do_control_quota_s(void *ctx, struct connection *conn, ++ char **vec, int num) ++{ ++ if (num == 0) ++ return quota_show_current(ctx, conn, soft_quotas); ++ ++ if (!strcmp(vec[0], "set")) ++ return quota_set(ctx, conn, vec + 1, num - 1, soft_quotas); ++ ++ return EINVAL; ++} ++ + #ifdef __MINIOS__ + static int do_control_memreport(void *ctx, struct connection *conn, + char **vec, int num) +@@ -847,6 +956,8 @@ static struct cmd_s cmds[] = { + { "memreport", do_control_memreport, "[]" }, + #endif + { "print", do_control_print, "" }, ++ { "quota", do_control_quota, "[set |]" }, ++ { "quota-soft", do_control_quota_s, "[set ]" }, + { "help", do_control_help, "" }, + }; + +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index 94fd561e9de4..e7c6886ccf47 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -31,6 +31,7 @@ + #include "xenstored_domain.h" + #include "xenstored_transaction.h" + #include "xenstored_watch.h" ++#include "xenstored_control.h" + + #include + #include +@@ -345,6 +346,38 @@ static struct domain *find_domain_struct(unsigned int domid) + return NULL; + } + ++int domain_get_quota(const void *ctx, struct connection *conn, ++ unsigned int domid) ++{ ++ struct domain *d = find_domain_struct(domid); ++ char *resp; ++ int ta; ++ ++ if (!d) ++ return ENOENT; ++ ++ ta = d->conn ? d->conn->transaction_started : 0; ++ resp = talloc_asprintf(ctx, "Domain %u:\n", domid); ++ if (!resp) ++ return ENOMEM; ++ ++#define ent(t, e) \ ++ resp = talloc_asprintf_append(resp, "%-16s: %8d\n", #t, e); \ ++ if (!resp) return ENOMEM ++ ++ ent(nodes, d->nbentry); ++ ent(watches, d->nbwatch); ++ ent(transactions, ta); ++ ent(outstanding, d->nboutstanding); ++ ent(memory, d->memory); ++ ++#undef ent ++ ++ send_reply(conn, XS_CONTROL, resp, strlen(resp) + 1); ++ ++ return 0; ++} ++ + static struct domain *alloc_domain(const void *context, unsigned int domid) + { + struct domain *domain; +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 633c9a0a0a1f..904faa923afb 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -87,6 +87,8 @@ int domain_watch(struct connection *conn); + void domain_outstanding_inc(struct connection *conn); + void domain_outstanding_dec(struct connection *conn); + void domain_outstanding_domid_dec(unsigned int domid); ++int domain_get_quota(const void *ctx, struct connection *conn, ++ unsigned int domid); + + /* Special node permission handling. */ + int set_perms_special(struct connection *conn, const char *name, diff --git a/xsa412-4.16.patch b/xsa412-4.16.patch new file mode 100644 index 0000000..f37fc21 --- /dev/null +++ b/xsa412-4.16.patch @@ -0,0 +1,245 @@ +From: Andrew Cooper +Subject: x86/vmx: Revert "VMX: use a single, global APIC access page" + +The claim "No accesses would ever go to this page." is false. A consequence +of how Intel's APIC Acceleration works, and Xen's choice to have per-domain +P2Ms (rather than per-vCPU P2Ms) means that the APIC page is fully read-write +to any vCPU which is not in xAPIC mode. + +This reverts commit 58850b9074d3e7affdf3bc94c84e417ecfa4d165. + +This is XSA-412 / CVE-2022-42327. + +Signed-off-by: Andrew Cooper +Reviewed-by: Jan Beulich + +diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c +index d429d76c18c9..3f4276531322 100644 +--- a/xen/arch/x86/hvm/vmx/vmx.c ++++ b/xen/arch/x86/hvm/vmx/vmx.c +@@ -66,7 +66,8 @@ boolean_param("force-ept", opt_force_ept); + static void vmx_ctxt_switch_from(struct vcpu *v); + static void vmx_ctxt_switch_to(struct vcpu *v); + +-static int alloc_vlapic_mapping(void); ++static int vmx_alloc_vlapic_mapping(struct domain *d); ++static void vmx_free_vlapic_mapping(struct domain *d); + static void vmx_install_vlapic_mapping(struct vcpu *v); + static void vmx_update_guest_cr(struct vcpu *v, unsigned int cr, + unsigned int flags); +@@ -77,8 +78,6 @@ static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content); + static int vmx_msr_write_intercept(unsigned int msr, uint64_t msr_content); + static void vmx_invlpg(struct vcpu *v, unsigned long linear); + +-static mfn_t __read_mostly apic_access_mfn = INVALID_MFN_INITIALIZER; +- + /* Values for domain's ->arch.hvm_domain.pi_ops.flags. */ + #define PI_CSW_FROM (1u << 0) + #define PI_CSW_TO (1u << 1) +@@ -402,6 +401,7 @@ static int vmx_domain_initialise(struct domain *d) + .to = vmx_ctxt_switch_to, + .tail = vmx_do_resume, + }; ++ int rc; + + d->arch.ctxt_switch = &csw; + +@@ -411,15 +411,24 @@ static int vmx_domain_initialise(struct domain *d) + */ + d->arch.hvm.vmx.exec_sp = is_hardware_domain(d) || opt_ept_exec_sp; + ++ if ( (rc = vmx_alloc_vlapic_mapping(d)) != 0 ) ++ return rc; ++ + return 0; + } + ++static void vmx_domain_relinquish_resources(struct domain *d) ++{ ++ vmx_free_vlapic_mapping(d); ++} ++ + static void domain_creation_finished(struct domain *d) + { + gfn_t gfn = gaddr_to_gfn(APIC_DEFAULT_PHYS_BASE); ++ mfn_t apic_access_mfn = d->arch.hvm.vmx.apic_access_mfn; + bool ipat; + +- if ( !has_vlapic(d) || mfn_eq(apic_access_mfn, INVALID_MFN) ) ++ if ( mfn_eq(apic_access_mfn, _mfn(0)) ) + return; + + ASSERT(epte_get_entry_emt(d, gfn, apic_access_mfn, 0, &ipat, +@@ -2481,6 +2490,7 @@ static struct hvm_function_table __initdata vmx_function_table = { + .cpu_up_prepare = vmx_cpu_up_prepare, + .cpu_dead = vmx_cpu_dead, + .domain_initialise = vmx_domain_initialise, ++ .domain_relinquish_resources = vmx_domain_relinquish_resources, + .domain_creation_finished = domain_creation_finished, + .vcpu_initialise = vmx_vcpu_initialise, + .vcpu_destroy = vmx_vcpu_destroy, +@@ -2731,7 +2741,7 @@ const struct hvm_function_table * __init start_vmx(void) + { + set_in_cr4(X86_CR4_VMXE); + +- if ( vmx_vmcs_init() || alloc_vlapic_mapping() ) ++ if ( vmx_vmcs_init() ) + { + printk("VMX: failed to initialise.\n"); + return NULL; +@@ -3305,36 +3315,55 @@ static int vmx_msr_read_intercept(unsigned int msr, uint64_t *msr_content) + return X86EMUL_EXCEPTION; + } + +-static int __init alloc_vlapic_mapping(void) ++static int vmx_alloc_vlapic_mapping(struct domain *d) + { + struct page_info *pg; + mfn_t mfn; + +- if ( !cpu_has_vmx_virtualize_apic_accesses ) ++ if ( !has_vlapic(d) || !cpu_has_vmx_virtualize_apic_accesses ) + return 0; + +- pg = alloc_domheap_page(NULL, 0); ++ pg = alloc_domheap_page(d, MEMF_no_refcount); + if ( !pg ) + return -ENOMEM; + +- /* +- * Signal to shadow code that this page cannot be refcounted. This also +- * makes epte_get_entry_emt() recognize this page as "special". +- */ +- page_suppress_refcounting(pg); ++ if ( !get_page_and_type(pg, d, PGT_writable_page) ) ++ { ++ /* ++ * The domain can't possibly know about this page yet, so failure ++ * here is a clear indication of something fishy going on. ++ */ ++ domain_crash(d); ++ return -ENODATA; ++ } + + mfn = page_to_mfn(pg); + clear_domain_page(mfn); +- apic_access_mfn = mfn; ++ d->arch.hvm.vmx.apic_access_mfn = mfn; + + return 0; + } + ++static void vmx_free_vlapic_mapping(struct domain *d) ++{ ++ mfn_t mfn = d->arch.hvm.vmx.apic_access_mfn; ++ ++ d->arch.hvm.vmx.apic_access_mfn = _mfn(0); ++ if ( !mfn_eq(mfn, _mfn(0)) ) ++ { ++ struct page_info *pg = mfn_to_page(mfn); ++ ++ put_page_alloc_ref(pg); ++ put_page_and_type(pg); ++ } ++} ++ + static void vmx_install_vlapic_mapping(struct vcpu *v) + { ++ mfn_t apic_access_mfn = v->domain->arch.hvm.vmx.apic_access_mfn; + paddr_t virt_page_ma, apic_page_ma; + +- if ( !has_vlapic(v->domain) || mfn_eq(apic_access_mfn, INVALID_MFN) ) ++ if ( mfn_eq(apic_access_mfn, _mfn(0)) ) + return; + + ASSERT(cpu_has_vmx_virtualize_apic_accesses); +diff --git a/xen/arch/x86/mm/shadow/set.c b/xen/arch/x86/mm/shadow/set.c +index 87e9c6eeb219..bd6c68b547c9 100644 +--- a/xen/arch/x86/mm/shadow/set.c ++++ b/xen/arch/x86/mm/shadow/set.c +@@ -101,14 +101,6 @@ shadow_get_page_from_l1e(shadow_l1e_t sl1e, struct domain *d, p2m_type_t type) + owner = page_get_owner(pg); + } + +- /* +- * Check whether refcounting is suppressed on this page. For example, +- * VMX'es APIC access MFN is just a surrogate page. It doesn't actually +- * get accessed, and hence there's no need to refcount it. +- */ +- if ( pg && page_refcounting_suppressed(pg) ) +- return 0; +- + if ( owner == dom_io ) + owner = NULL; + +diff --git a/xen/arch/x86/mm/shadow/types.h b/xen/arch/x86/mm/shadow/types.h +index 6970e7d6ea4a..814a4018535a 100644 +--- a/xen/arch/x86/mm/shadow/types.h ++++ b/xen/arch/x86/mm/shadow/types.h +@@ -276,16 +276,9 @@ int shadow_set_l4e(struct domain *d, shadow_l4e_t *sl4e, + static void inline + shadow_put_page_from_l1e(shadow_l1e_t sl1e, struct domain *d) + { +- mfn_t mfn = shadow_l1e_get_mfn(sl1e); +- + if ( !shadow_mode_refcounts(d) ) + return; + +- if ( mfn_valid(mfn) && +- /* See the respective comment in shadow_get_page_from_l1e(). */ +- page_refcounting_suppressed(mfn_to_page(mfn)) ) +- return; +- + put_page_from_l1e(sl1e, d); + } + +diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h b/xen/include/asm-x86/hvm/vmx/vmcs.h +index 03c9ccf627ab..8073af323b96 100644 +--- a/xen/include/asm-x86/hvm/vmx/vmcs.h ++++ b/xen/include/asm-x86/hvm/vmx/vmcs.h +@@ -58,6 +58,7 @@ struct ept_data { + #define _VMX_DOMAIN_PML_ENABLED 0 + #define VMX_DOMAIN_PML_ENABLED (1ul << _VMX_DOMAIN_PML_ENABLED) + struct vmx_domain { ++ mfn_t apic_access_mfn; + /* VMX_DOMAIN_* */ + unsigned int status; + +diff --git a/xen/include/asm-x86/mm.h b/xen/include/asm-x86/mm.h +index 7bdf9c2290d8..e1bcea57a8f5 100644 +--- a/xen/include/asm-x86/mm.h ++++ b/xen/include/asm-x86/mm.h +@@ -83,7 +83,7 @@ + #define PGC_state_offlined PG_mask(2, 6) + #define PGC_state_free PG_mask(3, 6) + #define page_state_is(pg, st) (((pg)->count_info&PGC_state) == PGC_state_##st) +-/* Page is not reference counted (see below for caveats) */ ++/* Page is not reference counted */ + #define _PGC_extra PG_shift(7) + #define PGC_extra PG_mask(1, 7) + +@@ -375,24 +375,6 @@ void zap_ro_mpt(mfn_t mfn); + + bool is_iomem_page(mfn_t mfn); + +-/* +- * Pages with no owner which may get passed to functions wanting to +- * refcount them can be marked PGC_extra to bypass this refcounting (which +- * would fail due to the lack of an owner). +- * +- * (For pages with owner PGC_extra has different meaning.) +- */ +-static inline void page_suppress_refcounting(struct page_info *pg) +-{ +- ASSERT(!page_get_owner(pg)); +- pg->count_info |= PGC_extra; +-} +- +-static inline bool page_refcounting_suppressed(const struct page_info *pg) +-{ +- return !page_get_owner(pg) && (pg->count_info & PGC_extra); +-} +- + struct platform_bad_page { + unsigned long mfn; + unsigned int order; diff --git a/xsa414.patch b/xsa414.patch new file mode 100644 index 0000000..27ab0c2 --- /dev/null +++ b/xsa414.patch @@ -0,0 +1,112 @@ +From: Julien Grall +Subject: tools/xenstore: create_node: Don't defer work to undo any changes on + failure + +XSA-115 extended destroy_node() to update the node accounting for the +connection. The implementation is assuming the connection is the parent +of the node, however all the nodes are allocated using a separate context +(see process_message()). This will result to crash (or corrupt) xenstored +as the pointer is wrongly used. + +In case of an error, any changes to the database or update to the +accounting will now be reverted in create_node() by calling directly +destroy_node(). This has the nice advantage to remove the loop to unset +the destructors in case of success. + +Take the opportunity to free the nodes right now as they are not +going to be reachable (the function returns NULL) and are just wasting +resources. + +This is XSA-414 / CVE-2022-42309. + +Reported-by: Julien Grall +Fixes: 0bfb2101f243 ("tools/xenstore: fix node accounting after failed node creation") +Signed-off-by: Julien Grall +Reviewed-by: Juergen Gross + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 8867f93431d4..c30d14cbf2ab 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1084,9 +1084,8 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + return NULL; + } + +-static int destroy_node(void *_node) ++static int destroy_node(struct connection *conn, struct node *node) + { +- struct node *node = _node; + TDB_DATA key; + + if (streq(node->name, "/")) +@@ -1095,7 +1094,7 @@ static int destroy_node(void *_node) + set_tdb_key(node->name, &key); + tdb_delete(tdb_ctx, key); + +- domain_entry_dec(talloc_parent(node), node); ++ domain_entry_dec(conn, node); + + return 0; + } +@@ -1104,7 +1103,8 @@ static struct node *create_node(struct connection *conn, const void *ctx, + const char *name, + void *data, unsigned int datalen) + { +- struct node *node, *i; ++ struct node *node, *i, *j; ++ int ret; + + node = construct_node(conn, ctx, name); + if (!node) +@@ -1126,23 +1126,40 @@ static struct node *create_node(struct connection *conn, const void *ctx, + /* i->parent is set for each new node, so check quota. */ + if (i->parent && + domain_entry(conn) >= quota_nb_entry_per_domain) { +- errno = ENOSPC; +- return NULL; ++ ret = ENOSPC; ++ goto err; + } +- if (write_node(conn, i, false)) +- return NULL; + +- /* Account for new node, set destructor for error case. */ +- if (i->parent) { ++ ret = write_node(conn, i, false); ++ if (ret) ++ goto err; ++ ++ /* Account for new node */ ++ if (i->parent) + domain_entry_inc(conn, i); +- talloc_set_destructor(i, destroy_node); +- } + } + +- /* OK, now remove destructors so they stay around */ +- for (i = node; i->parent; i = i->parent) +- talloc_set_destructor(i, NULL); + return node; ++ ++err: ++ /* ++ * We failed to update TDB for some of the nodes. Undo any work that ++ * have already been done. ++ */ ++ for (j = node; j != i; j = j->parent) ++ destroy_node(conn, j); ++ ++ /* We don't need to keep the nodes around, so free them. */ ++ i = node; ++ while (i) { ++ j = i; ++ i = i->parent; ++ talloc_free(j); ++ } ++ ++ errno = ret; ++ ++ return NULL; + } + + /* path, data... */ diff --git a/xsa415.patch b/xsa415.patch new file mode 100644 index 0000000..b6f6971 --- /dev/null +++ b/xsa415.patch @@ -0,0 +1,134 @@ +From: Julien Grall +Subject: tools/xenstore: Fail a transaction if it is not possible to create a + node + +Commit f2bebf72c4d5 "xenstore: rework of transaction handling" moved +out from copying the entire database everytime a new transaction is +opened to track the list of nodes changed. + +The content of all the nodes accessed during a transaction will be +temporarily stored in TDB using a different key. + +The function create_node() may write/update multiple nodes if the child +doesn't exist. In case of a failure, the function will revert any +changes (this include any update to TDB). Unfortunately, the function +which reverts the changes (i.e. destroy_node()) will not use the correct +key to delete any update or even request the transaction to fail. + +This means that if a client decide to go ahead with committing the +transaction, orphan nodes will be created because they were not linked +to an existing node (create_node() will write the nodes backwards). + +Once some nodes have been partially updated in a transaction, it is not +easily possible to undo any changes. So rather than continuing and hit +weird issue while committing, it is much saner to fail the transaction. + +This will have an impact on any client that decides to commit even if it +can't write a node. Although, it is not clear why a normal client would +want to do that... + +Lastly, update destroy_node() to use the correct key for deleting the +node. Rather than recreating it (this will allocate memory and +therefore fail), stash the key in the structure node. + +This is XSA-415 / CVE-2022-42310. + +Reported-by: Julien Grall +Signed-off-by: Julien Grall +Reviewed-by: Juergen Gross + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index c30d14cbf2ab..55b79e4c032e 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -562,15 +562,17 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + return 0; + } + ++/* ++ * Write the node. If the node is written, caller can find the key used in ++ * node->key. This can later be used if the change needs to be reverted. ++ */ + static int write_node(struct connection *conn, struct node *node, + bool no_quota_check) + { +- TDB_DATA key; +- +- if (access_node(conn, node, NODE_ACCESS_WRITE, &key)) ++ if (access_node(conn, node, NODE_ACCESS_WRITE, &node->key)) + return errno; + +- return write_node_raw(conn, &key, node, no_quota_check); ++ return write_node_raw(conn, &node->key, node, no_quota_check); + } + + unsigned int perm_for_conn(struct connection *conn, +@@ -1086,16 +1088,21 @@ static struct node *construct_node(struct connection *conn, const void *ctx, + + static int destroy_node(struct connection *conn, struct node *node) + { +- TDB_DATA key; +- + if (streq(node->name, "/")) + corrupt(NULL, "Destroying root node!"); + +- set_tdb_key(node->name, &key); +- tdb_delete(tdb_ctx, key); ++ tdb_delete(tdb_ctx, node->key); + + domain_entry_dec(conn, node); + ++ /* ++ * It is not possible to easily revert the changes in a transaction. ++ * So if the failure happens in a transaction, mark it as fail to ++ * prevent any commit. ++ */ ++ if ( conn->transaction ) ++ fail_transaction(conn->transaction); ++ + return 0; + } + +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index 742812a97469..7d0fe77e7989 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -155,6 +155,8 @@ struct node_perms { + + struct node { + const char *name; ++ /* Key used to update TDB */ ++ TDB_DATA key; + + /* Parent (optional) */ + struct node *parent; +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index cd07fb0f218b..faf6c930e42a 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -580,6 +580,11 @@ void transaction_entry_dec(struct transaction *trans, unsigned int domid) + list_add_tail(&d->list, &trans->changed_domains); + } + ++void fail_transaction(struct transaction *trans) ++{ ++ trans->fail = true; ++} ++ + void conn_delete_all_transactions(struct connection *conn) + { + struct transaction *trans; +diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h +index 43a162bea3f3..14062730e3c9 100644 +--- a/tools/xenstore/xenstored_transaction.h ++++ b/tools/xenstore/xenstored_transaction.h +@@ -46,6 +46,9 @@ int access_node(struct connection *conn, struct node *node, + int transaction_prepend(struct connection *conn, const char *name, + TDB_DATA *key); + ++/* Mark the transaction as failed. This will prevent it to be committed. */ ++void fail_transaction(struct transaction *trans); ++ + void conn_delete_all_transactions(struct connection *conn); + int check_transactions(struct hashtable *hash); + diff --git a/xsa416-4.16.patch b/xsa416-4.16.patch new file mode 100644 index 0000000..0df409a --- /dev/null +++ b/xsa416-4.16.patch @@ -0,0 +1,704 @@ +From 80d128b14482d2e9342184d2d9949367851c4d14 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: don't use conn->in as context for temporary + allocations + +Using the struct buffered data pointer of the current processed request +for temporary data allocations has a major drawback: the used area (and +with that the temporary data) is freed only after the response of the +request has been written to the ring page or has been read via the +socket. This can happen much later in case a guest isn't reading its +responses fast enough. + +As the temporary data can be safely freed after creating the response, +add a temporary context for that purpose and use that for allocating +the temporary memory, as it was already the case before commit +cc0612464896 ("xenstore: add small default data buffer to internal +struct"). + +Some sub-functions need to gain the "const" attribute for the talloc +context. + +This is XSA-416 / CVE-2022-42319. + +Reported-by: Julien Grall +Fixes: cc0612464896 ("xenstore: add small default data buffer to internal struct") +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_control.c b/tools/xenstore/xenstored_control.c +index 1031a81c3874..d0350c6ad861 100644 +--- a/tools/xenstore/xenstored_control.c ++++ b/tools/xenstore/xenstored_control.c +@@ -155,7 +155,7 @@ bool lu_is_pending(void) + + struct cmd_s { + char *cmd; +- int (*func)(void *, struct connection *, char **, int); ++ int (*func)(const void *, struct connection *, char **, int); + char *pars; + /* + * max_pars can be used to limit the size of the parameter vector, +@@ -167,7 +167,7 @@ struct cmd_s { + unsigned int max_pars; + }; + +-static int do_control_check(void *ctx, struct connection *conn, ++static int do_control_check(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num) +@@ -179,7 +179,7 @@ static int do_control_check(void *ctx, struct connection *conn, + return 0; + } + +-static int do_control_log(void *ctx, struct connection *conn, ++static int do_control_log(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num != 1) +@@ -281,7 +281,7 @@ static int quota_get(const void *ctx, struct connection *conn, + return domain_get_quota(ctx, conn, atoi(vec[0])); + } + +-static int do_control_quota(void *ctx, struct connection *conn, ++static int do_control_quota(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num == 0) +@@ -293,7 +293,7 @@ static int do_control_quota(void *ctx, struct connection *conn, + return quota_get(ctx, conn, vec, num); + } + +-static int do_control_quota_s(void *ctx, struct connection *conn, ++static int do_control_quota_s(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num == 0) +@@ -306,7 +306,7 @@ static int do_control_quota_s(void *ctx, struct connection *conn, + } + + #ifdef __MINIOS__ +-static int do_control_memreport(void *ctx, struct connection *conn, ++static int do_control_memreport(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num) +@@ -318,7 +318,7 @@ static int do_control_memreport(void *ctx, struct connection *conn, + return 0; + } + #else +-static int do_control_logfile(void *ctx, struct connection *conn, ++static int do_control_logfile(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num != 1) +@@ -333,7 +333,7 @@ static int do_control_logfile(void *ctx, struct connection *conn, + return 0; + } + +-static int do_control_memreport(void *ctx, struct connection *conn, ++static int do_control_memreport(const void *ctx, struct connection *conn, + char **vec, int num) + { + FILE *fp; +@@ -373,7 +373,7 @@ static int do_control_memreport(void *ctx, struct connection *conn, + } + #endif + +-static int do_control_print(void *ctx, struct connection *conn, ++static int do_control_print(const void *ctx, struct connection *conn, + char **vec, int num) + { + if (num != 1) +@@ -875,7 +875,7 @@ static const char *lu_start(const void *ctx, struct connection *conn, + return NULL; + } + +-static int do_control_lu(void *ctx, struct connection *conn, ++static int do_control_lu(const void *ctx, struct connection *conn, + char **vec, int num) + { + const char *ret = NULL; +@@ -922,7 +922,7 @@ static int do_control_lu(void *ctx, struct connection *conn, + } + #endif + +-static int do_control_help(void *, struct connection *, char **, int); ++static int do_control_help(const void *, struct connection *, char **, int); + + static struct cmd_s cmds[] = { + { "check", do_control_check, "" }, +@@ -961,7 +961,7 @@ static struct cmd_s cmds[] = { + { "help", do_control_help, "" }, + }; + +-static int do_control_help(void *ctx, struct connection *conn, ++static int do_control_help(const void *ctx, struct connection *conn, + char **vec, int num) + { + int cmd, len = 0; +@@ -997,7 +997,8 @@ static int do_control_help(void *ctx, struct connection *conn, + return 0; + } + +-int do_control(struct connection *conn, struct buffered_data *in) ++int do_control(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + unsigned int cmd, num, off; + char **vec = NULL; +@@ -1017,11 +1018,11 @@ int do_control(struct connection *conn, struct buffered_data *in) + num = xs_count_strings(in->buffer, in->used); + if (cmds[cmd].max_pars) + num = min(num, cmds[cmd].max_pars); +- vec = talloc_array(in, char *, num); ++ vec = talloc_array(ctx, char *, num); + if (!vec) + return ENOMEM; + if (get_strings(in, vec, num) < num) + return EIO; + +- return cmds[cmd].func(in, conn, vec + 1, num - 1); ++ return cmds[cmd].func(ctx, conn, vec + 1, num - 1); + } +diff --git a/tools/xenstore/xenstored_control.h b/tools/xenstore/xenstored_control.h +index 98b6fbcea2b1..a8cb76559ba1 100644 +--- a/tools/xenstore/xenstored_control.h ++++ b/tools/xenstore/xenstored_control.h +@@ -16,7 +16,8 @@ + along with this program; If not, see . + */ + +-int do_control(struct connection *conn, struct buffered_data *in); ++int do_control(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + void lu_read_state(void); + + struct connection *lu_get_connection(void); +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 16504de42017..411cc0e44714 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1248,11 +1248,13 @@ static struct node *get_node_canonicalized(struct connection *conn, + return get_node(conn, ctx, *canonical_name, perm); + } + +-static int send_directory(struct connection *conn, struct buffered_data *in) ++static int send_directory(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node *node; + +- node = get_node_canonicalized(conn, in, onearg(in), NULL, XS_PERM_READ); ++ node = get_node_canonicalized(conn, ctx, onearg(in), NULL, ++ XS_PERM_READ); + if (!node) + return errno; + +@@ -1261,7 +1263,7 @@ static int send_directory(struct connection *conn, struct buffered_data *in) + return 0; + } + +-static int send_directory_part(struct connection *conn, ++static int send_directory_part(const void *ctx, struct connection *conn, + struct buffered_data *in) + { + unsigned int off, len, maxlen, genlen; +@@ -1273,7 +1275,8 @@ static int send_directory_part(struct connection *conn, + return EINVAL; + + /* First arg is node name. */ +- node = get_node_canonicalized(conn, in, in->buffer, NULL, XS_PERM_READ); ++ node = get_node_canonicalized(conn, ctx, in->buffer, NULL, ++ XS_PERM_READ); + if (!node) + return errno; + +@@ -1300,7 +1303,7 @@ static int send_directory_part(struct connection *conn, + break; + } + +- data = talloc_array(in, char, genlen + len + 1); ++ data = talloc_array(ctx, char, genlen + len + 1); + if (!data) + return ENOMEM; + +@@ -1316,11 +1319,13 @@ static int send_directory_part(struct connection *conn, + return 0; + } + +-static int do_read(struct connection *conn, struct buffered_data *in) ++static int do_read(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node *node; + +- node = get_node_canonicalized(conn, in, onearg(in), NULL, XS_PERM_READ); ++ node = get_node_canonicalized(conn, ctx, onearg(in), NULL, ++ XS_PERM_READ); + if (!node) + return errno; + +@@ -1510,7 +1515,8 @@ static struct node *create_node(struct connection *conn, const void *ctx, + } + + /* path, data... */ +-static int do_write(struct connection *conn, struct buffered_data *in) ++static int do_write(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + unsigned int offset, datalen; + struct node *node; +@@ -1524,12 +1530,12 @@ static int do_write(struct connection *conn, struct buffered_data *in) + offset = strlen(vec[0]) + 1; + datalen = in->used - offset; + +- node = get_node_canonicalized(conn, in, vec[0], &name, XS_PERM_WRITE); ++ node = get_node_canonicalized(conn, ctx, vec[0], &name, XS_PERM_WRITE); + if (!node) { + /* No permissions, invalid input? */ + if (errno != ENOENT) + return errno; +- node = create_node(conn, in, name, in->buffer + offset, ++ node = create_node(conn, ctx, name, in->buffer + offset, + datalen); + if (!node) + return errno; +@@ -1540,18 +1546,19 @@ static int do_write(struct connection *conn, struct buffered_data *in) + return errno; + } + +- fire_watches(conn, in, name, node, false, NULL); ++ fire_watches(conn, ctx, name, node, false, NULL); + send_ack(conn, XS_WRITE); + + return 0; + } + +-static int do_mkdir(struct connection *conn, struct buffered_data *in) ++static int do_mkdir(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node *node; + char *name; + +- node = get_node_canonicalized(conn, in, onearg(in), &name, ++ node = get_node_canonicalized(conn, ctx, onearg(in), &name, + XS_PERM_WRITE); + + /* If it already exists, fine. */ +@@ -1561,10 +1568,10 @@ static int do_mkdir(struct connection *conn, struct buffered_data *in) + return errno; + if (!name) + return ENOMEM; +- node = create_node(conn, in, name, NULL, 0); ++ node = create_node(conn, ctx, name, NULL, 0); + if (!node) + return errno; +- fire_watches(conn, in, name, node, false, NULL); ++ fire_watches(conn, ctx, name, node, false, NULL); + } + send_ack(conn, XS_MKDIR); + +@@ -1662,24 +1669,25 @@ static int _rm(struct connection *conn, const void *ctx, struct node *node, + } + + +-static int do_rm(struct connection *conn, struct buffered_data *in) ++static int do_rm(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node *node; + int ret; + char *name; + char *parentname; + +- node = get_node_canonicalized(conn, in, onearg(in), &name, ++ node = get_node_canonicalized(conn, ctx, onearg(in), &name, + XS_PERM_WRITE); + if (!node) { + /* Didn't exist already? Fine, if parent exists. */ + if (errno == ENOENT) { + if (!name) + return ENOMEM; +- parentname = get_parent(in, name); ++ parentname = get_parent(ctx, name); + if (!parentname) + return errno; +- node = read_node(conn, in, parentname); ++ node = read_node(conn, ctx, parentname); + if (node) { + send_ack(conn, XS_RM); + return 0; +@@ -1694,7 +1702,7 @@ static int do_rm(struct connection *conn, struct buffered_data *in) + if (streq(name, "/")) + return EINVAL; + +- ret = _rm(conn, in, node, name); ++ ret = _rm(conn, ctx, node, name); + if (ret) + return ret; + +@@ -1704,13 +1712,15 @@ static int do_rm(struct connection *conn, struct buffered_data *in) + } + + +-static int do_get_perms(struct connection *conn, struct buffered_data *in) ++static int do_get_perms(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node *node; + char *strings; + unsigned int len; + +- node = get_node_canonicalized(conn, in, onearg(in), NULL, XS_PERM_READ); ++ node = get_node_canonicalized(conn, ctx, onearg(in), NULL, ++ XS_PERM_READ); + if (!node) + return errno; + +@@ -1723,7 +1733,8 @@ static int do_get_perms(struct connection *conn, struct buffered_data *in) + return 0; + } + +-static int do_set_perms(struct connection *conn, struct buffered_data *in) ++static int do_set_perms(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct node_perms perms, old_perms; + char *name, *permstr; +@@ -1740,7 +1751,7 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) + + permstr = in->buffer + strlen(in->buffer) + 1; + +- perms.p = talloc_array(in, struct xs_permissions, perms.num); ++ perms.p = talloc_array(ctx, struct xs_permissions, perms.num); + if (!perms.p) + return ENOMEM; + if (!xs_strings_to_perms(perms.p, perms.num, permstr)) +@@ -1755,7 +1766,7 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) + } + + /* We must own node to do this (tools can do this too). */ +- node = get_node_canonicalized(conn, in, in->buffer, &name, ++ node = get_node_canonicalized(conn, ctx, in->buffer, &name, + XS_PERM_WRITE | XS_PERM_OWNER); + if (!node) + return errno; +@@ -1790,7 +1801,7 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) + return errno; + } + +- fire_watches(conn, in, name, node, false, &old_perms); ++ fire_watches(conn, ctx, name, node, false, &old_perms); + send_ack(conn, XS_SET_PERMS); + + return 0; +@@ -1798,7 +1809,8 @@ static int do_set_perms(struct connection *conn, struct buffered_data *in) + + static struct { + const char *str; +- int (*func)(struct connection *conn, struct buffered_data *in); ++ int (*func)(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + unsigned int flags; + #define XS_FLAG_NOTID (1U << 0) /* Ignore transaction id. */ + #define XS_FLAG_PRIV (1U << 1) /* Privileged domain only. */ +@@ -1874,6 +1886,7 @@ static void process_message(struct connection *conn, struct buffered_data *in) + struct transaction *trans; + enum xsd_sockmsg_type type = in->hdr.msg.type; + int ret; ++ void *ctx; + + /* At least send_error() and send_reply() expects conn->in == in */ + assert(conn->in == in); +@@ -1898,10 +1911,17 @@ static void process_message(struct connection *conn, struct buffered_data *in) + return; + } + ++ ctx = talloc_new(NULL); ++ if (!ctx) { ++ send_error(conn, ENOMEM); ++ return; ++ } ++ + assert(conn->transaction == NULL); + conn->transaction = trans; + +- ret = wire_funcs[type].func(conn, in); ++ ret = wire_funcs[type].func(ctx, conn, in); ++ talloc_free(ctx); + if (ret) + send_error(conn, ret); + +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index e7c6886ccf47..fb732d0a14c3 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -330,7 +330,7 @@ bool domain_is_unprivileged(struct connection *conn) + domid_is_unprivileged(conn->domain->domid); + } + +-static char *talloc_domain_path(void *context, unsigned int domid) ++static char *talloc_domain_path(const void *context, unsigned int domid) + { + return talloc_asprintf(context, "/local/domain/%u", domid); + } +@@ -534,7 +534,8 @@ static struct domain *introduce_domain(const void *ctx, + } + + /* domid, gfn, evtchn, path */ +-int do_introduce(struct connection *conn, struct buffered_data *in) ++int do_introduce(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct domain *domain; + char *vec[3]; +@@ -552,7 +553,7 @@ int do_introduce(struct connection *conn, struct buffered_data *in) + if (port <= 0) + return EINVAL; + +- domain = introduce_domain(in, domid, port, false); ++ domain = introduce_domain(ctx, domid, port, false); + if (!domain) + return errno; + +@@ -575,7 +576,8 @@ static struct domain *find_connected_domain(unsigned int domid) + return domain; + } + +-int do_set_target(struct connection *conn, struct buffered_data *in) ++int do_set_target(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + char *vec[2]; + unsigned int domid, tdomid; +@@ -619,7 +621,8 @@ static struct domain *onearg_domain(struct connection *conn, + } + + /* domid */ +-int do_release(struct connection *conn, struct buffered_data *in) ++int do_release(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct domain *domain; + +@@ -634,7 +637,8 @@ int do_release(struct connection *conn, struct buffered_data *in) + return 0; + } + +-int do_resume(struct connection *conn, struct buffered_data *in) ++int do_resume(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct domain *domain; + +@@ -649,7 +653,8 @@ int do_resume(struct connection *conn, struct buffered_data *in) + return 0; + } + +-int do_get_domain_path(struct connection *conn, struct buffered_data *in) ++int do_get_domain_path(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + char *path; + const char *domid_str = onearg(in); +@@ -657,18 +662,17 @@ int do_get_domain_path(struct connection *conn, struct buffered_data *in) + if (!domid_str) + return EINVAL; + +- path = talloc_domain_path(conn, atoi(domid_str)); ++ path = talloc_domain_path(ctx, atoi(domid_str)); + if (!path) + return errno; + + send_reply(conn, XS_GET_DOMAIN_PATH, path, strlen(path) + 1); + +- talloc_free(path); +- + return 0; + } + +-int do_is_domain_introduced(struct connection *conn, struct buffered_data *in) ++int do_is_domain_introduced(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + int result; + unsigned int domid; +@@ -689,7 +693,8 @@ int do_is_domain_introduced(struct connection *conn, struct buffered_data *in) + } + + /* Allow guest to reset all watches */ +-int do_reset_watches(struct connection *conn, struct buffered_data *in) ++int do_reset_watches(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + conn_delete_all_watches(conn); + conn_delete_all_transactions(conn); +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 904faa923afb..b9e152890149 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -24,25 +24,32 @@ void handle_event(void); + void check_domains(void); + + /* domid, mfn, eventchn, path */ +-int do_introduce(struct connection *conn, struct buffered_data *in); ++int do_introduce(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* domid */ +-int do_is_domain_introduced(struct connection *conn, struct buffered_data *in); ++int do_is_domain_introduced(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* domid */ +-int do_release(struct connection *conn, struct buffered_data *in); ++int do_release(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* domid */ +-int do_resume(struct connection *conn, struct buffered_data *in); ++int do_resume(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* domid, target */ +-int do_set_target(struct connection *conn, struct buffered_data *in); ++int do_set_target(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* domid */ +-int do_get_domain_path(struct connection *conn, struct buffered_data *in); ++int do_get_domain_path(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* Allow guest to reset all watches */ +-int do_reset_watches(struct connection *conn, struct buffered_data *in); ++int do_reset_watches(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + void domain_init(int evtfd); + void dom0_init(void); +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 28774813de83..3e3eb47326cc 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -481,7 +481,8 @@ struct transaction *transaction_lookup(struct connection *conn, uint32_t id) + return ERR_PTR(-ENOENT); + } + +-int do_transaction_start(struct connection *conn, struct buffered_data *in) ++int do_transaction_start(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct transaction *trans, *exists; + char id_str[20]; +@@ -494,8 +495,8 @@ int do_transaction_start(struct connection *conn, struct buffered_data *in) + conn->transaction_started > quota_max_transaction) + return ENOSPC; + +- /* Attach transaction to input for autofree until it's complete */ +- trans = talloc_zero(in, struct transaction); ++ /* Attach transaction to ctx for autofree until it's complete */ ++ trans = talloc_zero(ctx, struct transaction); + if (!trans) + return ENOMEM; + +@@ -544,7 +545,8 @@ static int transaction_fix_domains(struct transaction *trans, bool update) + return 0; + } + +-int do_transaction_end(struct connection *conn, struct buffered_data *in) ++int do_transaction_end(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + const char *arg = onearg(in); + struct transaction *trans; +@@ -562,8 +564,8 @@ int do_transaction_end(struct connection *conn, struct buffered_data *in) + if (!conn->transaction_started) + conn->ta_start_time = 0; + +- /* Attach transaction to in for auto-cleanup */ +- talloc_steal(in, trans); ++ /* Attach transaction to ctx for auto-cleanup */ ++ talloc_steal(ctx, trans); + + if (streq(arg, "T")) { + if (trans->fail) +diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h +index e3cbd6b23095..39d7f81c5127 100644 +--- a/tools/xenstore/xenstored_transaction.h ++++ b/tools/xenstore/xenstored_transaction.h +@@ -29,8 +29,10 @@ struct transaction; + + extern uint64_t generation; + +-int do_transaction_start(struct connection *conn, struct buffered_data *node); +-int do_transaction_end(struct connection *conn, struct buffered_data *in); ++int do_transaction_start(const void *ctx, struct connection *conn, ++ struct buffered_data *node); ++int do_transaction_end(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + struct transaction *transaction_lookup(struct connection *conn, uint32_t id); + +diff --git a/tools/xenstore/xenstored_watch.c b/tools/xenstore/xenstored_watch.c +index 85362bcce314..316c08b7f754 100644 +--- a/tools/xenstore/xenstored_watch.c ++++ b/tools/xenstore/xenstored_watch.c +@@ -243,7 +243,7 @@ static struct watch *add_watch(struct connection *conn, char *path, char *token, + return NULL; + } + +-int do_watch(struct connection *conn, struct buffered_data *in) ++int do_watch(const void *ctx, struct connection *conn, struct buffered_data *in) + { + struct watch *watch; + char *vec[2]; +@@ -252,7 +252,7 @@ int do_watch(struct connection *conn, struct buffered_data *in) + if (get_strings(in, vec, ARRAY_SIZE(vec)) != ARRAY_SIZE(vec)) + return EINVAL; + +- errno = check_watch_path(conn, in, &(vec[0]), &relative); ++ errno = check_watch_path(conn, ctx, &(vec[0]), &relative); + if (errno) + return errno; + +@@ -283,7 +283,8 @@ int do_watch(struct connection *conn, struct buffered_data *in) + return 0; + } + +-int do_unwatch(struct connection *conn, struct buffered_data *in) ++int do_unwatch(const void *ctx, struct connection *conn, ++ struct buffered_data *in) + { + struct watch *watch; + char *node, *vec[2]; +@@ -291,7 +292,7 @@ int do_unwatch(struct connection *conn, struct buffered_data *in) + if (get_strings(in, vec, ARRAY_SIZE(vec)) != ARRAY_SIZE(vec)) + return EINVAL; + +- node = xenstore_canonicalize(conn, in, vec[0]); ++ node = xenstore_canonicalize(conn, ctx, vec[0]); + if (!node) + return ENOMEM; + list_for_each_entry(watch, &conn->watches, list) { +diff --git a/tools/xenstore/xenstored_watch.h b/tools/xenstore/xenstored_watch.h +index 0e693f0839cd..091890edca96 100644 +--- a/tools/xenstore/xenstored_watch.h ++++ b/tools/xenstore/xenstored_watch.h +@@ -21,8 +21,10 @@ + + #include "xenstored_core.h" + +-int do_watch(struct connection *conn, struct buffered_data *in); +-int do_unwatch(struct connection *conn, struct buffered_data *in); ++int do_watch(const void *ctx, struct connection *conn, ++ struct buffered_data *in); ++int do_unwatch(const void *ctx, struct connection *conn, ++ struct buffered_data *in); + + /* Fire all watches: !exact means all the children are affected (ie. rm). */ + void fire_watches(struct connection *conn, const void *tmp, const char *name, diff --git a/xsa417.patch b/xsa417.patch new file mode 100644 index 0000000..3f10bf7 --- /dev/null +++ b/xsa417.patch @@ -0,0 +1,135 @@ +From 67d5ecd609b8f12346eadb40e547cd7e01d825dc Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:10 +0200 +Subject: tools/xenstore: fix checking node permissions + +Today chk_domain_generation() is being used to check whether a node +permission entry is still valid or whether it is referring to a domain +no longer existing. This is done by comparing the node's and the +domain's generation count. + +In case no struct domain is existing for a checked domain, but the +domain itself is valid, chk_domain_generation() assumes it is being +called due to the first node created for a new domain and it will +return success. + +This might be wrong in case the checked permission is related to an +old domain, which has just been replaced with a new domain using the +same domid. + +Fix that by letting chk_domain_generation() fail in case a struct +domain isn't found. In order to cover the case of the first node for +a new domain try to allocate the needed struct domain explicitly when +processing the related SET_PERMS command. In case a referenced domain +isn't existing, flag the related permission to be ignored right away. + +This is XSA-417 / CVE-2022-42320. + +Reported-by: Juergen Gross +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 66bbeaf6bfb0..a0c176fa203e 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1753,6 +1753,11 @@ static int do_set_perms(const void *ctx, struct connection *conn, + if (!xs_strings_to_perms(perms.p, perms.num, permstr)) + return errno; + ++ if (domain_alloc_permrefs(&perms) < 0) ++ return ENOMEM; ++ if (perms.p[0].perms & XS_PERM_IGNORE) ++ return ENOENT; ++ + /* First arg is node name. */ + if (strstarts(in->buffer, "@")) { + if (set_perms_special(conn, in->buffer, &perms)) +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index b9ff4ded8360..98b401fdec30 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -907,7 +907,6 @@ int domain_entry_inc(struct connection *conn, struct node *node) + * count (used for testing whether a node permission is older than a domain). + * + * Return values: +- * -1: error + * 0: domain has higher generation count (it is younger than a node with the + * given count), or domain isn't existing any longer + * 1: domain is older than the node +@@ -915,20 +914,38 @@ int domain_entry_inc(struct connection *conn, struct node *node) + static int chk_domain_generation(unsigned int domid, uint64_t gen) + { + struct domain *d; +- xc_dominfo_t dominfo; + + if (!xc_handle && domid == 0) + return 1; + + d = find_domain_struct(domid); +- if (d) +- return (d->generation <= gen) ? 1 : 0; + +- if (!get_domain_info(domid, &dominfo)) +- return 0; ++ return (d && d->generation <= gen) ? 1 : 0; ++} + +- d = alloc_domain(NULL, domid); +- return d ? 1 : -1; ++/* ++ * Allocate all missing struct domain referenced by a permission set. ++ * Any permission entries for not existing domains will be marked to be ++ * ignored. ++ */ ++int domain_alloc_permrefs(struct node_perms *perms) ++{ ++ unsigned int i, domid; ++ struct domain *d; ++ xc_dominfo_t dominfo; ++ ++ for (i = 0; i < perms->num; i++) { ++ domid = perms->p[i].id; ++ d = find_domain_struct(domid); ++ if (!d) { ++ if (!get_domain_info(domid, &dominfo)) ++ perms->p[i].perms |= XS_PERM_IGNORE; ++ else if (!alloc_domain(NULL, domid)) ++ return ENOMEM; ++ } ++ } ++ ++ return 0; + } + + /* +@@ -941,8 +958,6 @@ int domain_adjust_node_perms(struct connection *conn, struct node *node) + int ret; + + ret = chk_domain_generation(node->perms.p[0].id, node->generation); +- if (ret < 0) +- return errno; + + /* If the owner doesn't exist any longer give it to priv domain. */ + if (!ret) { +@@ -959,8 +974,6 @@ int domain_adjust_node_perms(struct connection *conn, struct node *node) + continue; + ret = chk_domain_generation(node->perms.p[i].id, + node->generation); +- if (ret < 0) +- return errno; + if (!ret) + node->perms.p[i].perms |= XS_PERM_IGNORE; + } +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 209442190911..7fe0a21d9e45 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -63,6 +63,7 @@ bool domain_is_unprivileged(struct connection *conn); + + /* Remove node permissions for no longer existing domains. */ + int domain_adjust_node_perms(struct connection *conn, struct node *node); ++int domain_alloc_permrefs(struct node_perms *perms); + + /* Quota manipulation */ + int domain_entry_inc(struct connection *conn, struct node *); diff --git a/xsa418-4.16-01.patch b/xsa418-4.16-01.patch new file mode 100644 index 0000000..c4a17b4 --- /dev/null +++ b/xsa418-4.16-01.patch @@ -0,0 +1,119 @@ +From d1e6dca486599ab914af7b38b3782b237d3d603b Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:11 +0200 +Subject: tools/xenstore: remove recursion from construct_node() + +In order to reduce stack usage due to recursion, switch +construct_node() to use a loop instead. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index c676ee4e4e4f..3907c35643e9 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1377,45 +1377,69 @@ static int add_child(const void *ctx, struct node *parent, const char *name) + static struct node *construct_node(struct connection *conn, const void *ctx, + const char *name) + { +- struct node *parent, *node; +- char *parentname = get_parent(ctx, name); ++ const char **names = NULL; ++ unsigned int levels = 0; ++ struct node *node = NULL; ++ struct node *parent = NULL; ++ const char *parentname = talloc_strdup(ctx, name); + + if (!parentname) + return NULL; + +- /* If parent doesn't exist, create it. */ +- parent = read_node(conn, parentname, parentname); +- if (!parent && errno == ENOENT) +- parent = construct_node(conn, ctx, parentname); +- if (!parent) +- return NULL; ++ /* Walk the path up until an existing node is found. */ ++ while (!parent) { ++ names = talloc_realloc(ctx, names, const char *, levels + 1); ++ if (!names) ++ goto nomem; + +- /* Add child to parent. */ +- if (add_child(ctx, parent, name)) +- goto nomem; ++ /* ++ * names[0] is the name of the node to construct initially, ++ * names[1] is its parent, and so on. ++ */ ++ names[levels] = parentname; ++ parentname = get_parent(ctx, parentname); ++ if (!parentname) ++ return NULL; + +- /* Allocate node */ +- node = talloc(ctx, struct node); +- if (!node) +- goto nomem; +- node->name = talloc_strdup(node, name); +- if (!node->name) +- goto nomem; ++ /* Try to read parent node until we found an existing one. */ ++ parent = read_node(conn, ctx, parentname); ++ if (!parent && (errno != ENOENT || !strcmp(parentname, "/"))) ++ return NULL; + +- /* Inherit permissions, except unprivileged domains own what they create */ +- node->perms.num = parent->perms.num; +- node->perms.p = talloc_memdup(node, parent->perms.p, +- node->perms.num * sizeof(*node->perms.p)); +- if (!node->perms.p) +- goto nomem; +- if (domain_is_unprivileged(conn)) +- node->perms.p[0].id = conn->id; ++ levels++; ++ } ++ ++ /* Walk the path down again constructing the missing nodes. */ ++ for (; levels > 0; levels--) { ++ /* Add child to parent. */ ++ if (add_child(ctx, parent, names[levels - 1])) ++ goto nomem; ++ ++ /* Allocate node */ ++ node = talloc(ctx, struct node); ++ if (!node) ++ goto nomem; ++ node->name = talloc_steal(node, names[levels - 1]); ++ ++ /* Inherit permissions, unpriv domains own what they create. */ ++ node->perms.num = parent->perms.num; ++ node->perms.p = talloc_memdup(node, parent->perms.p, ++ node->perms.num * ++ sizeof(*node->perms.p)); ++ if (!node->perms.p) ++ goto nomem; ++ if (domain_is_unprivileged(conn)) ++ node->perms.p[0].id = conn->id; ++ ++ /* No children, no data */ ++ node->children = node->data = NULL; ++ node->childlen = node->datalen = 0; ++ node->acc.memory = 0; ++ node->parent = parent; ++ ++ parent = node; ++ } + +- /* No children, no data */ +- node->children = node->data = NULL; +- node->childlen = node->datalen = 0; +- node->acc.memory = 0; +- node->parent = parent; + return node; + + nomem: diff --git a/xsa418-4.16-02.patch b/xsa418-4.16-02.patch new file mode 100644 index 0000000..874bab2 --- /dev/null +++ b/xsa418-4.16-02.patch @@ -0,0 +1,103 @@ +From c13d85a2fe94bbf3cb8186b89324c5d1b4f9a61f Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:11 +0200 +Subject: tools/xenstore: don't let remove_child_entry() call corrupt() + +In case of write_node() returning an error, remove_child_entry() will +call corrupt() today. This could result in an endless recursion, as +remove_child_entry() is called by corrupt(), too: + +corrupt() + check_store() + check_store_() + remove_child_entry() + +Fix that by letting remove_child_entry() return an error instead and +let the caller decide what to do. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 3907c35643e9..f433a45dc217 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1608,15 +1608,15 @@ static void memdel(void *mem, unsigned off, unsigned len, unsigned total) + memmove(mem + off, mem + off + len, total - off - len); + } + +-static void remove_child_entry(struct connection *conn, struct node *node, +- size_t offset) ++static int remove_child_entry(struct connection *conn, struct node *node, ++ size_t offset) + { + size_t childlen = strlen(node->children + offset); + + memdel(node->children, offset, childlen + 1, node->childlen); + node->childlen -= childlen + 1; +- if (write_node(conn, node, true)) +- corrupt(conn, "Can't update parent node '%s'", node->name); ++ ++ return write_node(conn, node, true); + } + + static void delete_child(struct connection *conn, +@@ -1626,7 +1626,9 @@ static void delete_child(struct connection *conn, + + for (i = 0; i < node->childlen; i += strlen(node->children+i) + 1) { + if (streq(node->children+i, childname)) { +- remove_child_entry(conn, node, i); ++ if (remove_child_entry(conn, node, i)) ++ corrupt(conn, "Can't update parent node '%s'", ++ node->name); + return; + } + } +@@ -2325,6 +2327,17 @@ int remember_string(struct hashtable *hash, const char *str) + return hashtable_insert(hash, k, (void *)1); + } + ++static int rm_child_entry(struct node *node, size_t off, size_t len) ++{ ++ if (!recovery) ++ return off; ++ ++ if (remove_child_entry(NULL, node, off)) ++ log("check_store: child entry could not be removed from '%s'", ++ node->name); ++ ++ return off - len - 1; ++} + + /** + * A node has a children field that names the children of the node, separated +@@ -2377,12 +2390,7 @@ static int check_store_(const char *name, struct hashtable *reachable) + if (hashtable_search(children, childname)) { + log("check_store: '%s' is duplicated!", + childname); +- +- if (recovery) { +- remove_child_entry(NULL, node, +- i); +- i -= childlen + 1; +- } ++ i = rm_child_entry(node, i, childlen); + } + else { + if (!remember_string(children, +@@ -2399,11 +2407,7 @@ static int check_store_(const char *name, struct hashtable *reachable) + } else if (errno != ENOMEM) { + log("check_store: No child '%s' found!\n", + childname); +- +- if (recovery) { +- remove_child_entry(NULL, node, i); +- i -= childlen + 1; +- } ++ i = rm_child_entry(node, i, childlen); + } else { + log("check_store: ENOMEM"); + ret = ENOMEM; diff --git a/xsa418-4.16-03.patch b/xsa418-4.16-03.patch new file mode 100644 index 0000000..321ccf0 --- /dev/null +++ b/xsa418-4.16-03.patch @@ -0,0 +1,243 @@ +From aac9b51b6fbbbd16c910f69365345528c5bec106 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:11 +0200 +Subject: tools/xenstore: add generic treewalk function + +Add a generic function to walk the complete node tree. It will start +at "/" and descend recursively into each child, calling a function +specified by the caller. Depending on the return value of the user +specified function the walk will be aborted, continued, or the current +child will be skipped by not descending into its children. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index f433a45dc217..2cda3ee375ab 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1838,6 +1838,135 @@ static int do_set_perms(const void *ctx, struct connection *conn, + return 0; + } + ++static char *child_name(const void *ctx, const char *s1, const char *s2) ++{ ++ if (strcmp(s1, "/")) ++ return talloc_asprintf(ctx, "%s/%s", s1, s2); ++ return talloc_asprintf(ctx, "/%s", s2); ++} ++ ++static int rm_from_parent(struct connection *conn, struct node *parent, ++ const char *name) ++{ ++ size_t off; ++ ++ if (!parent) ++ return WALK_TREE_ERROR_STOP; ++ ++ for (off = parent->childoff - 1; off && parent->children[off - 1]; ++ off--); ++ if (remove_child_entry(conn, parent, off)) { ++ log("treewalk: child entry could not be removed from '%s'", ++ parent->name); ++ return WALK_TREE_ERROR_STOP; ++ } ++ parent->childoff = off; ++ ++ return WALK_TREE_OK; ++} ++ ++static int walk_call_func(const void *ctx, struct connection *conn, ++ struct node *node, struct node *parent, void *arg, ++ int (*func)(const void *ctx, struct connection *conn, ++ struct node *node, void *arg)) ++{ ++ int ret; ++ ++ if (!func) ++ return WALK_TREE_OK; ++ ++ ret = func(ctx, conn, node, arg); ++ if (ret == WALK_TREE_RM_CHILDENTRY && parent) ++ ret = rm_from_parent(conn, parent, node->name); ++ ++ return ret; ++} ++ ++int walk_node_tree(const void *ctx, struct connection *conn, const char *root, ++ struct walk_funcs *funcs, void *arg) ++{ ++ int ret = 0; ++ void *tmpctx; ++ char *name; ++ struct node *node = NULL; ++ struct node *parent = NULL; ++ ++ tmpctx = talloc_new(ctx); ++ if (!tmpctx) { ++ errno = ENOMEM; ++ return WALK_TREE_ERROR_STOP; ++ } ++ name = talloc_strdup(tmpctx, root); ++ if (!name) { ++ errno = ENOMEM; ++ talloc_free(tmpctx); ++ return WALK_TREE_ERROR_STOP; ++ } ++ ++ /* Continue the walk until an error is returned. */ ++ while (ret >= 0) { ++ /* node == NULL possible only for the initial loop iteration. */ ++ if (node) { ++ /* Go one step up if ret or if last child finished. */ ++ if (ret || node->childoff >= node->childlen) { ++ parent = node->parent; ++ /* Call function AFTER processing a node. */ ++ ret = walk_call_func(ctx, conn, node, parent, ++ arg, funcs->exit); ++ /* Last node, so exit loop. */ ++ if (!parent) ++ break; ++ talloc_free(node); ++ /* Continue with parent. */ ++ node = parent; ++ continue; ++ } ++ /* Get next child of current node. */ ++ name = child_name(tmpctx, node->name, ++ node->children + node->childoff); ++ if (!name) { ++ ret = WALK_TREE_ERROR_STOP; ++ break; ++ } ++ /* Point to next child. */ ++ node->childoff += strlen(node->children + ++ node->childoff) + 1; ++ /* Descent into children. */ ++ parent = node; ++ } ++ /* Read next node (root node or next child). */ ++ node = read_node(conn, tmpctx, name); ++ if (!node) { ++ /* Child not found - should not happen! */ ++ /* ENOENT case can be handled by supplied function. */ ++ if (errno == ENOENT && funcs->enoent) ++ ret = funcs->enoent(ctx, conn, parent, name, ++ arg); ++ else ++ ret = WALK_TREE_ERROR_STOP; ++ if (!parent) ++ break; ++ if (ret == WALK_TREE_RM_CHILDENTRY) ++ ret = rm_from_parent(conn, parent, name); ++ if (ret < 0) ++ break; ++ talloc_free(name); ++ node = parent; ++ continue; ++ } ++ talloc_free(name); ++ node->parent = parent; ++ node->childoff = 0; ++ /* Call function BEFORE processing a node. */ ++ ret = walk_call_func(ctx, conn, node, parent, arg, ++ funcs->enter); ++ } ++ ++ talloc_free(tmpctx); ++ ++ return ret < 0 ? ret : WALK_TREE_OK; ++} ++ + static struct { + const char *str; + int (*func)(const void *ctx, struct connection *conn, +@@ -2305,18 +2434,6 @@ static int keys_equal_fn(void *key1, void *key2) + return 0 == strcmp((char *)key1, (char *)key2); + } + +- +-static char *child_name(const char *s1, const char *s2) +-{ +- if (strcmp(s1, "/")) { +- return talloc_asprintf(NULL, "%s/%s", s1, s2); +- } +- else { +- return talloc_asprintf(NULL, "/%s", s2); +- } +-} +- +- + int remember_string(struct hashtable *hash, const char *str) + { + char *k = malloc(strlen(str) + 1); +@@ -2376,7 +2493,7 @@ static int check_store_(const char *name, struct hashtable *reachable) + while (i < node->childlen && !ret) { + struct node *childnode; + size_t childlen = strlen(node->children + i); +- char * childname = child_name(node->name, ++ char * childname = child_name(NULL, node->name, + node->children + i); + + if (!childname) { +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index bfd3fc1e9df3..2d9942171d92 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -202,6 +202,7 @@ struct node { + + /* Children, each nul-terminated. */ + unsigned int childlen; ++ unsigned int childoff; /* Used by walk_node_tree() internally. */ + char *children; + + /* Allocation information for node currently in store. */ +@@ -338,6 +339,45 @@ void read_state_buffered_data(const void *ctx, struct connection *conn, + const struct xs_state_connection *sc); + void read_state_node(const void *ctx, const void *state); + ++/* ++ * Walk the node tree below root calling funcs->enter() and funcs->exit() for ++ * each node. funcs->enter() is being called when entering a node, so before ++ * any of the children of the node is processed. funcs->exit() is being ++ * called when leaving the node, so after all children have been processed. ++ * funcs->enoent() is being called when a node isn't existing. ++ * funcs->*() return values: ++ * < 0: tree walk is stopped, walk_node_tree() returns funcs->*() return value ++ * in case WALK_TREE_ERROR_STOP is returned, errno should be set ++ * WALK_TREE_OK: tree walk is continuing ++ * WALK_TREE_SKIP_CHILDREN: tree walk won't descend below current node, but ++ * walk continues ++ * WALK_TREE_RM_CHILDENTRY: Remove the child entry from its parent and write ++ * the modified parent node back to the data base, implies to not descend ++ * below the current node, but to continue the walk ++ * funcs->*() is allowed to modify the node it is called for in the data base. ++ * In case funcs->enter() is deleting the node, it must not return WALK_TREE_OK ++ * in order to avoid descending into no longer existing children. ++ */ ++/* Return values for funcs->*() and walk_node_tree(). */ ++#define WALK_TREE_SUCCESS_STOP -100 /* Stop walk early, no error. */ ++#define WALK_TREE_ERROR_STOP -1 /* Stop walk due to error. */ ++#define WALK_TREE_OK 0 /* No error. */ ++/* Return value for funcs->*() only. */ ++#define WALK_TREE_SKIP_CHILDREN 1 /* Don't recurse below current node. */ ++#define WALK_TREE_RM_CHILDENTRY 2 /* Remove child entry from parent. */ ++ ++struct walk_funcs { ++ int (*enter)(const void *ctx, struct connection *conn, ++ struct node *node, void *arg); ++ int (*exit)(const void *ctx, struct connection *conn, ++ struct node *node, void *arg); ++ int (*enoent)(const void *ctx, struct connection *conn, ++ struct node *parent, char *name, void *arg); ++}; ++ ++int walk_node_tree(const void *ctx, struct connection *conn, const char *root, ++ struct walk_funcs *funcs, void *arg); ++ + #endif /* _XENSTORED_CORE_H */ + + /* diff --git a/xsa418-4.16-04.patch b/xsa418-4.16-04.patch new file mode 100644 index 0000000..95de88f --- /dev/null +++ b/xsa418-4.16-04.patch @@ -0,0 +1,108 @@ +From bdc931fb5dcebbd8d0e44b5d8bd3fb9106ee8596 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:12 +0200 +Subject: tools/xenstore: simplify check_store() + +check_store() is using a hash table for storing all node names it has +found via walking the tree. Additionally it using another hash table +for all children of a node to detect duplicate child names. + +Simplify that by dropping the second hash table as the first one is +already holding all the needed information. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 2cda3ee375ab..760f3c16c794 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -2477,50 +2477,34 @@ static int check_store_(const char *name, struct hashtable *reachable) + if (node) { + size_t i = 0; + +- struct hashtable * children = +- create_hashtable(16, hash_from_key_fn, keys_equal_fn); +- if (!children) { +- log("check_store create table: ENOMEM"); +- return ENOMEM; +- } +- + if (!remember_string(reachable, name)) { +- hashtable_destroy(children, 0); + log("check_store: ENOMEM"); + return ENOMEM; + } + + while (i < node->childlen && !ret) { +- struct node *childnode; ++ struct node *childnode = NULL; + size_t childlen = strlen(node->children + i); +- char * childname = child_name(NULL, node->name, +- node->children + i); ++ char *childname = child_name(NULL, node->name, ++ node->children + i); + + if (!childname) { + log("check_store: ENOMEM"); + ret = ENOMEM; + break; + } ++ ++ if (hashtable_search(reachable, childname)) { ++ log("check_store: '%s' is duplicated!", ++ childname); ++ i = rm_child_entry(node, i, childlen); ++ goto next; ++ } ++ + childnode = read_node(NULL, childname, childname); +- ++ + if (childnode) { +- if (hashtable_search(children, childname)) { +- log("check_store: '%s' is duplicated!", +- childname); +- i = rm_child_entry(node, i, childlen); +- } +- else { +- if (!remember_string(children, +- childname)) { +- log("check_store: ENOMEM"); +- talloc_free(childnode); +- talloc_free(childname); +- ret = ENOMEM; +- break; +- } +- ret = check_store_(childname, +- reachable); +- } ++ ret = check_store_(childname, reachable); + } else if (errno != ENOMEM) { + log("check_store: No child '%s' found!\n", + childname); +@@ -2530,19 +2514,18 @@ static int check_store_(const char *name, struct hashtable *reachable) + ret = ENOMEM; + } + ++ next: + talloc_free(childnode); + talloc_free(childname); + i += childlen + 1; + } + +- hashtable_destroy(children, 0 /* Don't free values (they are +- all (void *)1) */); + talloc_free(node); + } else if (errno != ENOMEM) { + /* Impossible, because no database should ever be without the + root, and otherwise, we've just checked in our caller + (which made a recursive call to get here). */ +- ++ + log("check_store: No child '%s' found: impossible!", name); + } else { + log("check_store: ENOMEM"); diff --git a/xsa418-4.16-05.patch b/xsa418-4.16-05.patch new file mode 100644 index 0000000..fca551e --- /dev/null +++ b/xsa418-4.16-05.patch @@ -0,0 +1,164 @@ +From 27817f0a7d6802be04e8f43a0900b02f881b28b2 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:12 +0200 +Subject: tools/xenstore: use treewalk for check_store() + +Instead of doing an open tree walk using call recursion, use +walk_node_tree() when checking the store for inconsistencies. + +This will reduce code size and avoid many nesting levels of function +calls which could potentially exhaust the stack. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 760f3c16c794..efdd1888fd78 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -2444,18 +2444,6 @@ int remember_string(struct hashtable *hash, const char *str) + return hashtable_insert(hash, k, (void *)1); + } + +-static int rm_child_entry(struct node *node, size_t off, size_t len) +-{ +- if (!recovery) +- return off; +- +- if (remove_child_entry(NULL, node, off)) +- log("check_store: child entry could not be removed from '%s'", +- node->name); +- +- return off - len - 1; +-} +- + /** + * A node has a children field that names the children of the node, separated + * by NULs. We check whether there are entries in there that are duplicated +@@ -2469,70 +2457,29 @@ static int rm_child_entry(struct node *node, size_t off, size_t len) + * As we go, we record each node in the given reachable hashtable. These + * entries will be used later in clean_store. + */ +-static int check_store_(const char *name, struct hashtable *reachable) ++static int check_store_step(const void *ctx, struct connection *conn, ++ struct node *node, void *arg) + { +- struct node *node = read_node(NULL, name, name); +- int ret = 0; +- +- if (node) { +- size_t i = 0; +- +- if (!remember_string(reachable, name)) { +- log("check_store: ENOMEM"); +- return ENOMEM; +- } +- +- while (i < node->childlen && !ret) { +- struct node *childnode = NULL; +- size_t childlen = strlen(node->children + i); +- char *childname = child_name(NULL, node->name, +- node->children + i); +- +- if (!childname) { +- log("check_store: ENOMEM"); +- ret = ENOMEM; +- break; +- } ++ struct hashtable *reachable = arg; + +- if (hashtable_search(reachable, childname)) { +- log("check_store: '%s' is duplicated!", +- childname); +- i = rm_child_entry(node, i, childlen); +- goto next; +- } +- +- childnode = read_node(NULL, childname, childname); +- +- if (childnode) { +- ret = check_store_(childname, reachable); +- } else if (errno != ENOMEM) { +- log("check_store: No child '%s' found!\n", +- childname); +- i = rm_child_entry(node, i, childlen); +- } else { +- log("check_store: ENOMEM"); +- ret = ENOMEM; +- } ++ if (hashtable_search(reachable, (void *)node->name)) { ++ log("check_store: '%s' is duplicated!", node->name); ++ return recovery ? WALK_TREE_RM_CHILDENTRY ++ : WALK_TREE_SKIP_CHILDREN; ++ } + +- next: +- talloc_free(childnode); +- talloc_free(childname); +- i += childlen + 1; +- } ++ if (!remember_string(reachable, node->name)) ++ return WALK_TREE_ERROR_STOP; + +- talloc_free(node); +- } else if (errno != ENOMEM) { +- /* Impossible, because no database should ever be without the +- root, and otherwise, we've just checked in our caller +- (which made a recursive call to get here). */ ++ return WALK_TREE_OK; ++} + +- log("check_store: No child '%s' found: impossible!", name); +- } else { +- log("check_store: ENOMEM"); +- ret = ENOMEM; +- } ++static int check_store_enoent(const void *ctx, struct connection *conn, ++ struct node *parent, char *name, void *arg) ++{ ++ log("check_store: node '%s' not found", name); + +- return ret; ++ return recovery ? WALK_TREE_RM_CHILDENTRY : WALK_TREE_OK; + } + + +@@ -2581,24 +2528,28 @@ static void clean_store(struct hashtable *reachable) + + void check_store(void) + { +- char * root = talloc_strdup(NULL, "/"); +- struct hashtable * reachable = +- create_hashtable(16, hash_from_key_fn, keys_equal_fn); +- ++ struct hashtable *reachable; ++ struct walk_funcs walkfuncs = { ++ .enter = check_store_step, ++ .enoent = check_store_enoent, ++ }; ++ ++ reachable = create_hashtable(16, hash_from_key_fn, keys_equal_fn); + if (!reachable) { + log("check_store: ENOMEM"); + return; + } + + log("Checking store ..."); +- if (!check_store_(root, reachable) && +- !check_transactions(reachable)) ++ if (walk_node_tree(NULL, NULL, "/", &walkfuncs, reachable)) { ++ if (errno == ENOMEM) ++ log("check_store: ENOMEM"); ++ } else if (!check_transactions(reachable)) + clean_store(reachable); + log("Checking store complete."); + + hashtable_destroy(reachable, 0 /* Don't free values (they are all + (void *)1) */); +- talloc_free(root); + } + + diff --git a/xsa418-4.16-06.patch b/xsa418-4.16-06.patch new file mode 100644 index 0000000..d46c057 --- /dev/null +++ b/xsa418-4.16-06.patch @@ -0,0 +1,174 @@ +From 6ea0ffbd88b11f23779d763501ec1370b590bb2a Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:12 +0200 +Subject: tools/xenstore: use treewalk for deleting nodes + +Instead of doing an open tree walk using call recursion, use +walk_node_tree() when deleting a sub-tree of nodes. + +This will reduce code size and avoid many nesting levels of function +calls which could potentially exhaust the stack. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Acked-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index efdd1888fd78..58fb651542ec 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -1334,21 +1334,6 @@ static int do_read(const void *ctx, struct connection *conn, + return 0; + } + +-static void delete_node_single(struct connection *conn, struct node *node) +-{ +- TDB_DATA key; +- +- if (access_node(conn, node, NODE_ACCESS_DELETE, &key)) +- return; +- +- if (do_tdb_delete(conn, &key, &node->acc) != 0) { +- corrupt(conn, "Could not delete '%s'", node->name); +- return; +- } +- +- domain_entry_dec(conn, node); +-} +- + /* Must not be / */ + static char *basename(const char *name) + { +@@ -1619,69 +1604,59 @@ static int remove_child_entry(struct connection *conn, struct node *node, + return write_node(conn, node, true); + } + +-static void delete_child(struct connection *conn, +- struct node *node, const char *childname) ++static int delete_child(struct connection *conn, ++ struct node *node, const char *childname) + { + unsigned int i; + + for (i = 0; i < node->childlen; i += strlen(node->children+i) + 1) { + if (streq(node->children+i, childname)) { +- if (remove_child_entry(conn, node, i)) +- corrupt(conn, "Can't update parent node '%s'", +- node->name); +- return; ++ errno = remove_child_entry(conn, node, i) ? EIO : 0; ++ return errno; + } + } + corrupt(conn, "Can't find child '%s' in %s", childname, node->name); ++ ++ errno = EIO; ++ return errno; + } + +-static int delete_node(struct connection *conn, const void *ctx, +- struct node *parent, struct node *node, bool watch_exact) ++static int delnode_sub(const void *ctx, struct connection *conn, ++ struct node *node, void *arg) + { +- char *name; ++ const char *root = arg; ++ bool watch_exact; ++ int ret; ++ TDB_DATA key; + +- /* Delete children. */ +- while (node->childlen) { +- struct node *child; ++ /* Any error here will probably be repeated for all following calls. */ ++ ret = access_node(conn, node, NODE_ACCESS_DELETE, &key); ++ if (ret > 0) ++ return WALK_TREE_SUCCESS_STOP; + +- name = talloc_asprintf(node, "%s/%s", node->name, +- node->children); +- child = name ? read_node(conn, node, name) : NULL; +- if (child) { +- if (delete_node(conn, ctx, node, child, true)) +- return errno; +- } else { +- trace("delete_node: Error deleting child '%s/%s'!\n", +- node->name, node->children); +- /* Quit deleting. */ +- errno = ENOMEM; +- return errno; +- } +- talloc_free(name); +- } ++ /* In case of error stop the walk. */ ++ if (!ret && do_tdb_delete(conn, &key, &node->acc)) ++ return WALK_TREE_SUCCESS_STOP; + + /* + * Fire the watches now, when we can still see the node permissions. + * This fine as we are single threaded and the next possible read will + * be handled only after the node has been really removed. +- */ ++ */ ++ watch_exact = strcmp(root, node->name); + fire_watches(conn, ctx, node->name, node, watch_exact, NULL); +- delete_node_single(conn, node); +- delete_child(conn, parent, basename(node->name)); +- talloc_free(node); + +- return 0; ++ domain_entry_dec(conn, node); ++ ++ return WALK_TREE_RM_CHILDENTRY; + } + +-static int _rm(struct connection *conn, const void *ctx, struct node *node, +- const char *name) ++static int _rm(struct connection *conn, const void *ctx, const char *name) + { +- /* +- * Deleting node by node, so the result is always consistent even in +- * case of a failure. +- */ + struct node *parent; + char *parentname = get_parent(ctx, name); ++ struct walk_funcs walkfuncs = { .exit = delnode_sub }; ++ int ret; + + if (!parentname) + return errno; +@@ -1689,9 +1664,21 @@ static int _rm(struct connection *conn, const void *ctx, struct node *node, + parent = read_node(conn, ctx, parentname); + if (!parent) + return read_node_can_propagate_errno() ? errno : EINVAL; +- node->parent = parent; + +- return delete_node(conn, ctx, parent, node, false); ++ ret = walk_node_tree(ctx, conn, name, &walkfuncs, (void *)name); ++ if (ret < 0) { ++ if (ret == WALK_TREE_ERROR_STOP) { ++ corrupt(conn, "error when deleting sub-nodes of %s\n", ++ name); ++ errno = EIO; ++ } ++ return errno; ++ } ++ ++ if (delete_child(conn, parent, basename(name))) ++ return errno; ++ ++ return 0; + } + + +@@ -1728,7 +1715,7 @@ static int do_rm(const void *ctx, struct connection *conn, + if (streq(name, "/")) + return EINVAL; + +- ret = _rm(conn, ctx, node, name); ++ ret = _rm(conn, ctx, name); + if (ret) + return ret; + diff --git a/xsa418-4.16-07.patch b/xsa418-4.16-07.patch new file mode 100644 index 0000000..9600d8c --- /dev/null +++ b/xsa418-4.16-07.patch @@ -0,0 +1,163 @@ +From 1ee281b18b52bec87335ea64ee74cc159e63d036 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:12 +0200 +Subject: tools/xenstore: use treewalk for creating node records + +Instead of doing an open tree walk using call recursion, use +walk_node_tree() when creating the node records during a live update. + +This will reduce code size and avoid many nesting levels of function +calls which could potentially exhaust the stack. + +This is part of XSA-418 / CVE-2022-42321. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 58fb651542ec..05d349778bb4 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -3120,101 +3120,76 @@ const char *dump_state_node_perms(FILE *fp, const struct xs_permissions *perms, + return NULL; + } + +-static const char *dump_state_node_tree(FILE *fp, char *path, +- unsigned int path_max_len) ++struct dump_node_data { ++ FILE *fp; ++ const char *err; ++}; ++ ++static int dump_state_node_err(struct dump_node_data *data, const char *err) + { +- unsigned int pathlen, childlen, p = 0; ++ data->err = err; ++ return WALK_TREE_ERROR_STOP; ++} ++ ++static int dump_state_node(const void *ctx, struct connection *conn, ++ struct node *node, void *arg) ++{ ++ struct dump_node_data *data = arg; ++ FILE *fp = data->fp; ++ unsigned int pathlen; + struct xs_state_record_header head; + struct xs_state_node sn; +- TDB_DATA key, data; +- const struct xs_tdb_record_hdr *hdr; +- const char *child; + const char *ret; + +- pathlen = strlen(path) + 1; +- +- set_tdb_key(path, &key); +- data = tdb_fetch(tdb_ctx, key); +- if (data.dptr == NULL) +- return "Error reading node"; +- +- /* Clean up in case of failure. */ +- talloc_steal(path, data.dptr); +- +- hdr = (void *)data.dptr; ++ pathlen = strlen(node->name) + 1; + + head.type = XS_STATE_TYPE_NODE; + head.length = sizeof(sn); + sn.conn_id = 0; + sn.ta_id = 0; + sn.ta_access = 0; +- sn.perm_n = hdr->num_perms; ++ sn.perm_n = node->perms.num; + sn.path_len = pathlen; +- sn.data_len = hdr->datalen; +- head.length += hdr->num_perms * sizeof(*sn.perms); ++ sn.data_len = node->datalen; ++ head.length += node->perms.num * sizeof(*sn.perms); + head.length += pathlen; +- head.length += hdr->datalen; ++ head.length += node->datalen; + head.length = ROUNDUP(head.length, 3); + + if (fwrite(&head, sizeof(head), 1, fp) != 1) +- return "Dump node state error"; ++ return dump_state_node_err(data, "Dump node head error"); + if (fwrite(&sn, sizeof(sn), 1, fp) != 1) +- return "Dump node state error"; ++ return dump_state_node_err(data, "Dump node state error"); + +- ret = dump_state_node_perms(fp, hdr->perms, hdr->num_perms); ++ ret = dump_state_node_perms(fp, node->perms.p, node->perms.num); + if (ret) +- return ret; ++ return dump_state_node_err(data, ret); ++ ++ if (fwrite(node->name, pathlen, 1, fp) != 1) ++ return dump_state_node_err(data, "Dump node path error"); + +- if (fwrite(path, pathlen, 1, fp) != 1) +- return "Dump node path error"; +- if (hdr->datalen && +- fwrite(hdr->perms + hdr->num_perms, hdr->datalen, 1, fp) != 1) +- return "Dump node data error"; ++ if (node->datalen && fwrite(node->data, node->datalen, 1, fp) != 1) ++ return dump_state_node_err(data, "Dump node data error"); + + ret = dump_state_align(fp); + if (ret) +- return ret; ++ return dump_state_node_err(data, ret); + +- child = (char *)(hdr->perms + hdr->num_perms) + hdr->datalen; +- +- /* +- * Use path for constructing children paths. +- * As we don't write out nodes without having written their parent +- * already we will never clobber a part of the path we'll need later. +- */ +- pathlen--; +- if (path[pathlen - 1] != '/') { +- path[pathlen] = '/'; +- pathlen++; +- } +- while (p < hdr->childlen) { +- childlen = strlen(child) + 1; +- if (pathlen + childlen > path_max_len) +- return "Dump node path length error"; +- strcpy(path + pathlen, child); +- ret = dump_state_node_tree(fp, path, path_max_len); +- if (ret) +- return ret; +- p += childlen; +- child += childlen; +- } +- +- talloc_free(data.dptr); +- +- return NULL; ++ return WALK_TREE_OK; + } + + const char *dump_state_nodes(FILE *fp, const void *ctx) + { +- char *path; +- +- path = talloc_size(ctx, XENSTORE_ABS_PATH_MAX + 1); +- if (!path) +- return "Path buffer allocation error"; ++ struct dump_node_data data = { ++ .fp = fp, ++ .err = "Dump node walk error" ++ }; ++ struct walk_funcs walkfuncs = { .enter = dump_state_node }; + +- strcpy(path, "/"); ++ if (walk_node_tree(ctx, NULL, "/", &walkfuncs, &data)) ++ return data.err; + +- return dump_state_node_tree(fp, path, XENSTORE_ABS_PATH_MAX + 1); ++ return NULL; + } + + void read_state_global(const void *ctx, const void *state) diff --git a/xsa419-oxenstored.patch b/xsa419-oxenstored.patch new file mode 100644 index 0000000..0ac365d --- /dev/null +++ b/xsa419-oxenstored.patch @@ -0,0 +1,85 @@ +From 09228369a549427294febe351372d7227e624da1 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:06 +0100 +Subject: tools/ocaml/xenstored: Fix quota bypass on domain shutdown +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +XSA-322 fixed a domid reuse vulnerability by assigning Dom0 as the owner of +any nodes left after a domain is shutdown (e.g. outside its /local/domain/N +tree). + +However Dom0 has no quota on purpose, so this opened up another potential +attack vector. Avoid it by deleting these nodes instead of assigning them to +Dom0. + +This is part of XSA-419 / CVE-2022-42323. + +Reported-by: Juergen Gross +Fixes: c46eff921209 ("tools/ocaml/xenstored: clean up permissions for dead domains") +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/xenstored/perms.ml b/tools/ocaml/xenstored/perms.ml +index e8a16221f8fa..84f2503e8e29 100644 +--- a/tools/ocaml/xenstored/perms.ml ++++ b/tools/ocaml/xenstored/perms.ml +@@ -64,8 +64,7 @@ let get_owner perm = perm.owner + * *) + let remove_domid ~domid perm = + let acl = List.filter (fun (acl_domid, _) -> acl_domid <> domid) perm.acl in +- let owner = if perm.owner = domid then 0 else perm.owner in +- { perm with acl; owner } ++ if perm.owner = domid then None else Some { perm with acl; owner = perm.owner } + + let default0 = create 0 NONE [] + +diff --git a/tools/ocaml/xenstored/store.ml b/tools/ocaml/xenstored/store.ml +index 20e67b142746..70f0c83de404 100644 +--- a/tools/ocaml/xenstored/store.ml ++++ b/tools/ocaml/xenstored/store.ml +@@ -87,10 +87,21 @@ let check_owner node connection = + + let rec recurse fct node = fct node; SymbolMap.iter (fun _ -> recurse fct) node.children + +-(** [recurse_map f tree] applies [f] on each node in the tree recursively *) +-let recurse_map f = ++(** [recurse_filter_map f tree] applies [f] on each node in the tree recursively, ++ possibly removing some nodes. ++ Note that the nodes removed this way won't generate watch events. ++*) ++let recurse_filter_map f = ++ let invalid = -1 in ++ let is_valid _ node = node.perms.owner <> invalid in + let rec walk node = +- f { node with children = SymbolMap.map walk node.children } ++ (* Map.filter_map is Ocaml 4.11+ only *) ++ let node = ++ { node with children = ++ SymbolMap.map walk node.children |> SymbolMap.filter is_valid } in ++ match f node with ++ | Some keep -> keep ++ | None -> { node with perms = {node.perms with owner = invalid } } + in + walk + +@@ -444,11 +455,13 @@ let setperms store perm path nperms = + + let reset_permissions store domid = + Logging.info "store|node" "Cleaning up xenstore ACLs for domid %d" domid; +- store.root <- Node.recurse_map (fun node -> +- let perms = Perms.Node.remove_domid ~domid node.perms in +- if perms <> node.perms then +- Logging.debug "store|node" "Changed permissions for node %s" (Node.get_name node); +- { node with perms } ++ store.root <- Node.recurse_filter_map (fun node -> ++ match Perms.Node.remove_domid ~domid node.perms with ++ | None -> None ++ | Some perms -> ++ if perms <> node.perms then ++ Logging.debug "store|node" "Changed permissions for node %s" (Node.get_name node); ++ Some { node with perms } + ) store.root + + type ops = { diff --git a/xsa419-xenstored-01.patch b/xsa419-xenstored-01.patch new file mode 100644 index 0000000..3409790 --- /dev/null +++ b/xsa419-xenstored-01.patch @@ -0,0 +1,289 @@ +From e4250bf8b39ed73623c75b0f1436ac7c1d45aba7 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:12 +0200 +Subject: tools/xenstore: remove nodes owned by destroyed domain + +In case a domain is removed from Xenstore, remove all nodes owned by +it per default. + +This tackles the problem that nodes might be created by a domain +outside its home path in Xenstore, leading to Xenstore hogging more +and more memory. Domain quota don't work in this case if the guest is +rebooting in between. + +Since XSA-322 ownership of such stale nodes is transferred to dom0, +which is helping against unintended access, but not against OOM of +Xenstore. + +As a fallback for weird cases add a Xenstore start parameter for +keeping today's way to handle stale nodes, adding the risk of Xenstore +hitting an OOM situation. + +This is part of XSA-419 / CVE-2022-42322. + +Reported-by: Juergen Gross +Fixes: 496306324d8d ("tools/xenstore: revoke access rights for removed domains") +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index bdc14679adf5..13e48aaa731c 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -80,6 +80,7 @@ static bool verbose = false; + LIST_HEAD(connections); + int tracefd = -1; + static bool recovery = true; ++bool keep_orphans = false; + static int reopen_log_pipe[2]; + static int reopen_log_pipe0_pollfd_idx = -1; + char *tracefile = NULL; +@@ -753,7 +754,7 @@ struct node *read_node(struct connection *conn, const void *ctx, + node->perms.p = hdr->perms; + node->acc.domid = node->perms.p[0].id; + node->acc.memory = data.dsize; +- if (domain_adjust_node_perms(conn, node)) ++ if (domain_adjust_node_perms(node)) + goto error; + + /* If owner is gone reset currently accounted memory size. */ +@@ -796,7 +797,7 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + void *p; + struct xs_tdb_record_hdr *hdr; + +- if (domain_adjust_node_perms(conn, node)) ++ if (domain_adjust_node_perms(node)) + return errno; + + data.dsize = sizeof(*hdr) +@@ -1647,7 +1648,7 @@ static int delnode_sub(const void *ctx, struct connection *conn, + return WALK_TREE_RM_CHILDENTRY; + } + +-static int _rm(struct connection *conn, const void *ctx, const char *name) ++int rm_node(struct connection *conn, const void *ctx, const char *name) + { + struct node *parent; + char *parentname = get_parent(ctx, name); +@@ -1711,7 +1712,7 @@ static int do_rm(const void *ctx, struct connection *conn, + if (streq(name, "/")) + return EINVAL; + +- ret = _rm(conn, ctx, name); ++ ret = rm_node(conn, ctx, name); + if (ret) + return ret; + +@@ -2618,6 +2619,8 @@ static void usage(void) + " -R, --no-recovery to request that no recovery should be attempted when\n" + " the store is corrupted (debug only),\n" + " -I, --internal-db store database in memory, not on disk\n" ++" -K, --keep-orphans don't delete nodes owned by a domain when the\n" ++" domain is deleted (this is a security risk!)\n" + " -V, --verbose to request verbose execution.\n"); + } + +@@ -2642,6 +2645,7 @@ static struct option options[] = { + { "timeout", 1, NULL, 'w' }, + { "no-recovery", 0, NULL, 'R' }, + { "internal-db", 0, NULL, 'I' }, ++ { "keep-orphans", 0, NULL, 'K' }, + { "verbose", 0, NULL, 'V' }, + { "watch-nb", 1, NULL, 'W' }, + #ifndef NO_LIVE_UPDATE +@@ -2721,7 +2725,7 @@ int main(int argc, char *argv[]) + orig_argc = argc; + orig_argv = argv; + +- while ((opt = getopt_long(argc, argv, "DE:F:HNPS:t:A:M:Q:q:T:RVW:w:U", ++ while ((opt = getopt_long(argc, argv, "DE:F:HKNPS:t:A:M:Q:q:T:RVW:w:U", + options, NULL)) != -1) { + switch (opt) { + case 'D': +@@ -2757,6 +2761,9 @@ int main(int argc, char *argv[]) + case 'I': + tdb_flags = TDB_INTERNAL|TDB_NOLOCK; + break; ++ case 'K': ++ keep_orphans = true; ++ break; + case 'V': + verbose = true; + break; +diff --git a/tools/xenstore/xenstored_core.h b/tools/xenstore/xenstored_core.h +index acb00ad96914..37006d508dbf 100644 +--- a/tools/xenstore/xenstored_core.h ++++ b/tools/xenstore/xenstored_core.h +@@ -240,6 +240,9 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + struct node *read_node(struct connection *conn, const void *ctx, + const char *name); + ++/* Remove a node and its children. */ ++int rm_node(struct connection *conn, const void *ctx, const char *name); ++ + void setup_structure(bool live_update); + struct connection *new_connection(const struct interface_funcs *funcs); + struct connection *get_connection_by_id(unsigned int conn_id); +@@ -284,6 +287,7 @@ extern int quota_req_outstanding; + extern int quota_trans_nodes; + extern int quota_memory_per_domain_soft; + extern int quota_memory_per_domain_hard; ++extern bool keep_orphans; + + extern unsigned int timeout_watch_event_msec; + +diff --git a/tools/xenstore/xenstored_domain.c b/tools/xenstore/xenstored_domain.c +index 98b401fdec30..84b7817cd5e6 100644 +--- a/tools/xenstore/xenstored_domain.c ++++ b/tools/xenstore/xenstored_domain.c +@@ -227,10 +227,64 @@ static void unmap_interface(void *interface) + xengnttab_unmap(*xgt_handle, interface, 1); + } + ++static int domain_tree_remove_sub(const void *ctx, struct connection *conn, ++ struct node *node, void *arg) ++{ ++ struct domain *domain = arg; ++ TDB_DATA key; ++ int ret = WALK_TREE_OK; ++ ++ if (node->perms.p[0].id != domain->domid) ++ return WALK_TREE_OK; ++ ++ if (keep_orphans) { ++ set_tdb_key(node->name, &key); ++ domain->nbentry--; ++ node->perms.p[0].id = priv_domid; ++ node->acc.memory = 0; ++ domain_entry_inc(NULL, node); ++ if (write_node_raw(NULL, &key, node, true)) { ++ /* That's unfortunate. We only can try to continue. */ ++ syslog(LOG_ERR, ++ "error when moving orphaned node %s to dom0\n", ++ node->name); ++ } else ++ trace("orphaned node %s moved to dom0\n", node->name); ++ } else { ++ if (rm_node(NULL, ctx, node->name)) { ++ /* That's unfortunate. We only can try to continue. */ ++ syslog(LOG_ERR, ++ "error when deleting orphaned node %s\n", ++ node->name); ++ } else ++ trace("orphaned node %s deleted\n", node->name); ++ ++ /* Skip children in all cases in order to avoid more errors. */ ++ ret = WALK_TREE_SKIP_CHILDREN; ++ } ++ ++ return domain->nbentry > 0 ? ret : WALK_TREE_SUCCESS_STOP; ++} ++ ++static void domain_tree_remove(struct domain *domain) ++{ ++ int ret; ++ struct walk_funcs walkfuncs = { .enter = domain_tree_remove_sub }; ++ ++ if (domain->nbentry > 0) { ++ ret = walk_node_tree(domain, NULL, "/", &walkfuncs, domain); ++ if (ret == WALK_TREE_ERROR_STOP) ++ syslog(LOG_ERR, ++ "error when looking for orphaned nodes\n"); ++ } ++} ++ + static int destroy_domain(void *_domain) + { + struct domain *domain = _domain; + ++ domain_tree_remove(domain); ++ + list_del(&domain->list); + + if (!domain->introduced) +@@ -883,15 +937,15 @@ int domain_entry_inc(struct connection *conn, struct node *node) + struct domain *d; + unsigned int domid; + +- if (!conn) ++ if (!node->perms.p) + return 0; + +- domid = node->perms.p ? node->perms.p[0].id : conn->id; ++ domid = node->perms.p[0].id; + +- if (conn->transaction) { ++ if (conn && conn->transaction) { + transaction_entry_inc(conn->transaction, domid); + } else { +- d = (domid == conn->id && conn->domain) ? conn->domain ++ d = (conn && domid == conn->id && conn->domain) ? conn->domain + : find_or_alloc_existing_domain(domid); + if (d) + d->nbentry++; +@@ -952,23 +1006,11 @@ int domain_alloc_permrefs(struct node_perms *perms) + * Remove permissions for no longer existing domains in order to avoid a new + * domain with the same domid inheriting the permissions. + */ +-int domain_adjust_node_perms(struct connection *conn, struct node *node) ++int domain_adjust_node_perms(struct node *node) + { + unsigned int i; + int ret; + +- ret = chk_domain_generation(node->perms.p[0].id, node->generation); +- +- /* If the owner doesn't exist any longer give it to priv domain. */ +- if (!ret) { +- /* +- * In theory we'd need to update the number of dom0 nodes here, +- * but we could be called for a read of the node. So better +- * avoid the risk to overflow the node count of dom0. +- */ +- node->perms.p[0].id = priv_domid; +- } +- + for (i = 1; i < node->perms.num; i++) { + if (node->perms.p[i].perms & XS_PERM_IGNORE) + continue; +@@ -986,15 +1028,15 @@ void domain_entry_dec(struct connection *conn, struct node *node) + struct domain *d; + unsigned int domid; + +- if (!conn) ++ if (!node->perms.p) + return; + + domid = node->perms.p ? node->perms.p[0].id : conn->id; + +- if (conn->transaction) { ++ if (conn && conn->transaction) { + transaction_entry_dec(conn->transaction, domid); + } else { +- d = (domid == conn->id && conn->domain) ? conn->domain ++ d = (conn && domid == conn->id && conn->domain) ? conn->domain + : find_domain_struct(domid); + if (d) { + d->nbentry--; +@@ -1113,7 +1155,7 @@ int domain_memory_add(unsigned int domid, int mem, bool no_quota_check) + * exist, as accounting is done either for a domain related to + * the current connection, or for the domain owning a node + * (which is always existing, as the owner of the node is +- * tested to exist and replaced by domid 0 if not). ++ * tested to exist and deleted or replaced by domid 0 if not). + * So not finding the related domain MUST be an error in the + * data base. + */ +diff --git a/tools/xenstore/xenstored_domain.h b/tools/xenstore/xenstored_domain.h +index 7fe0a21d9e45..b38c82991dc6 100644 +--- a/tools/xenstore/xenstored_domain.h ++++ b/tools/xenstore/xenstored_domain.h +@@ -62,7 +62,7 @@ const char *get_implicit_path(const struct connection *conn); + bool domain_is_unprivileged(struct connection *conn); + + /* Remove node permissions for no longer existing domains. */ +-int domain_adjust_node_perms(struct connection *conn, struct node *node); ++int domain_adjust_node_perms(struct node *node); + int domain_alloc_permrefs(struct node_perms *perms); + + /* Quota manipulation */ diff --git a/xsa419-xenstored-02.patch b/xsa419-xenstored-02.patch new file mode 100644 index 0000000..e5d46a2 --- /dev/null +++ b/xsa419-xenstored-02.patch @@ -0,0 +1,93 @@ +From 929da557efea6c7d2340467d9a7fdae7fda6d2b1 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:13 +0200 +Subject: tools/xenstore: make the internal memory data base the default + +Having a file backed data base has the only advantage of being capable +to dump the contents of it while Xenstore is running, and potentially +using less swap space in case the data base can't be kept in memory. + +It has the major disadvantage of a huge performance overhead: switching +to keep the data base in memory only speeds up live update of xenstored +with 120000 nodes from 20 minutes to 11 seconds. A complete tree walk +of this configuration will be reduced from 7 seconds to 280 msecs +(measured by "xenstore-control check"). + +So make the internal memory data base the default and enhance the +"--internal-db" command line parameter to take an optional parameter +allowing to switch the internal data base back to the file based one. + +This is part of XSA-419. + +Reported-by: Juergen Gross +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall + +diff --git a/tools/helpers/init-xenstore-domain.c b/tools/helpers/init-xenstore-domain.c +index 2d9ab6f1c583..04e351ca29a8 100644 +--- a/tools/helpers/init-xenstore-domain.c ++++ b/tools/helpers/init-xenstore-domain.c +@@ -222,9 +222,9 @@ static int build(xc_interface *xch) + } + + if ( param ) +- snprintf(cmdline, 512, "--event %d --internal-db %s", rv, param); ++ snprintf(cmdline, 512, "--event %d %s", rv, param); + else +- snprintf(cmdline, 512, "--event %d --internal-db", rv); ++ snprintf(cmdline, 512, "--event %d", rv); + + dom->guest_domid = domid; + dom->cmdline = xc_dom_strdup(dom, cmdline); +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 13e48aaa731c..36fb4a832834 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -2308,7 +2308,7 @@ static void accept_connection(int sock) + } + #endif + +-static int tdb_flags; ++static int tdb_flags = TDB_INTERNAL | TDB_NOLOCK; + + /* We create initial nodes manually. */ + static void manual_node(const char *name, const char *child) +@@ -2618,7 +2618,8 @@ static void usage(void) + " watch-event: time a watch-event is kept pending\n" + " -R, --no-recovery to request that no recovery should be attempted when\n" + " the store is corrupted (debug only),\n" +-" -I, --internal-db store database in memory, not on disk\n" ++" -I, --internal-db [on|off] store database in memory, not on disk, default is\n" ++" memory, with \"--internal-db off\" it is on disk\n" + " -K, --keep-orphans don't delete nodes owned by a domain when the\n" + " domain is deleted (this is a security risk!)\n" + " -V, --verbose to request verbose execution.\n"); +@@ -2644,7 +2645,7 @@ static struct option options[] = { + { "quota-soft", 1, NULL, 'q' }, + { "timeout", 1, NULL, 'w' }, + { "no-recovery", 0, NULL, 'R' }, +- { "internal-db", 0, NULL, 'I' }, ++ { "internal-db", 2, NULL, 'I' }, + { "keep-orphans", 0, NULL, 'K' }, + { "verbose", 0, NULL, 'V' }, + { "watch-nb", 1, NULL, 'W' }, +@@ -2725,7 +2726,8 @@ int main(int argc, char *argv[]) + orig_argc = argc; + orig_argv = argv; + +- while ((opt = getopt_long(argc, argv, "DE:F:HKNPS:t:A:M:Q:q:T:RVW:w:U", ++ while ((opt = getopt_long(argc, argv, ++ "DE:F:HI::KNPS:t:A:M:Q:q:T:RVW:w:U", + options, NULL)) != -1) { + switch (opt) { + case 'D': +@@ -2759,7 +2761,8 @@ int main(int argc, char *argv[]) + tracefile = optarg; + break; + case 'I': +- tdb_flags = TDB_INTERNAL|TDB_NOLOCK; ++ if (optarg && !strcmp(optarg, "off")) ++ tdb_flags = 0; + break; + case 'K': + keep_orphans = true; diff --git a/xsa419-xenstored-03.patch b/xsa419-xenstored-03.patch new file mode 100644 index 0000000..38130c0 --- /dev/null +++ b/xsa419-xenstored-03.patch @@ -0,0 +1,44 @@ +From 54e63b7e7c42e4f975163809a01574e78552a6ab Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:13 +0200 +Subject: docs: enhance xenstore.txt with permissions description +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +The permission scheme of Xenstore nodes is not really covered by +docs/misc/xenstore.txt, other than referring to the Xen wiki. + +Add a paragraph explaining the permissions of nodes, and especially +mentioning removal of nodes when a domain has been removed from +Xenstore. + +This is part of XSA-419. + +Reported-by: Juergen Gross +Signed-off-by: Juergen Gross +Reviewed-by: Edwin Török +Acked-by: Julien Grall + +diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt +index 988ef89cba2d..44428ae3a755 100644 +--- a/docs/misc/xenstore.txt ++++ b/docs/misc/xenstore.txt +@@ -43,6 +43,17 @@ bytes are forbidden; clients specifying relative paths should keep + them to within 2048 bytes. (See XENSTORE_*_PATH_MAX in xs_wire.h.) + + ++Each node has one or multiple permission entries. Permissions are ++granted by domain-id, the first permission entry of each node specifies ++the owner of the node. Permissions of a node can be changed by the ++owner of the node, the owner can only be modified by the control ++domain (usually domain id 0). The owner always has the right to read ++and write the node, while other permissions can be setup to allow ++read and/or write access. When a domain is being removed from Xenstore ++nodes owned by that domain will be removed together with all of those ++nodes' children. ++ ++ + Communication with xenstore is via either sockets, or event channel + and shared memory, as specified in io/xs_wire.h: each message in + either direction is a header formatted as a struct xsd_sockmsg diff --git a/xsa420.patch b/xsa420.patch new file mode 100644 index 0000000..5d00dc2 --- /dev/null +++ b/xsa420.patch @@ -0,0 +1,68 @@ +From 210879456769ca211c6630f47399ca7a61a37f35 Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= +Date: Wed, 12 Oct 2022 19:13:05 +0100 +Subject: tools/ocaml: Ensure packet size is never negative +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +Integers in Ocaml have 63 or 31 bits of signed precision. + +On 64-bit builds of Ocaml, this is fine because a C uint32_t always fits +within a 63-bit signed integer. + +In 32-bit builds of Ocaml, this goes wrong. The C uint32_t is truncated +first (loses the top bit), then has a unsigned/signed mismatch. + +A "negative" value (i.e. a packet on the ring of between 1G and 2G in size) +will trigger an exception later in Bytes.make in xb.ml, and because the packet +is not removed from the ring, the exception re-triggers on every subsequent +query, creating a livelock. + +Fix both the source of the exception in Xb, and as defence in depth, mark the +domain as bad for any Invalid_argument exceptions to avoid the risk of +livelock. + +This is XSA-420 / CVE-2022-42324. + +Reported-by: Juergen Gross +Signed-off-by: Edwin Török +Acked-by: Christian Lindig + +diff --git a/tools/ocaml/libs/xb/partial.ml b/tools/ocaml/libs/xb/partial.ml +index b6e2a716e263..3aa8927eb7f0 100644 +--- a/tools/ocaml/libs/xb/partial.ml ++++ b/tools/ocaml/libs/xb/partial.ml +@@ -36,7 +36,7 @@ let of_string s = + This will leave the guest connection is a bad state and will + be hard to recover from without restarting the connection + (ie rebooting the guest) *) +- let dlen = min xenstore_payload_max dlen in ++ let dlen = max 0 (min xenstore_payload_max dlen) in + { + tid = tid; + rid = rid; +@@ -46,8 +46,8 @@ let of_string s = + } + + let append pkt s sz = +- if pkt.len > 4096 then failwith "Buffer.add: cannot grow buffer"; +- Buffer.add_string pkt.buf (String.sub s 0 sz) ++ if Buffer.length pkt.buf + sz > xenstore_payload_max then failwith "Buffer.add: cannot grow buffer"; ++ Buffer.add_substring pkt.buf s 0 sz + + let to_complete pkt = + pkt.len - (Buffer.length pkt.buf) +diff --git a/tools/ocaml/xenstored/process.ml b/tools/ocaml/xenstored/process.ml +index 5f439fe59f47..f3a71b24ad94 100644 +--- a/tools/ocaml/xenstored/process.ml ++++ b/tools/ocaml/xenstored/process.ml +@@ -722,7 +722,7 @@ let do_input store cons doms con = + History.reconnect con; + info "%s reconnection complete" (Connection.get_domstr con); + None +- | Failure exp -> ++ | Invalid_argument exp | Failure exp -> + error "caught exception %s" exp; + error "got a bad client %s" (sprintf "%-8s" (Connection.get_domstr con)); + Connection.mark_as_bad con; diff --git a/xsa421-01.patch b/xsa421-01.patch new file mode 100644 index 0000000..10960ba --- /dev/null +++ b/xsa421-01.patch @@ -0,0 +1,40 @@ +From 9166869e7e6530befddfd8bb46ff37436a38efc1 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:13 +0200 +Subject: tools/xenstore: fix deleting node in transaction + +In case a node has been created in a transaction and it is later +deleted in the same transaction, the transaction will be terminated +with an error. + +As this error is encountered only when handling the deleted node at +transaction finalization, the transaction will have been performed +partially and without updating the accounting information. This will +enable a malicious guest to create arbitrary number of nodes. + +This is part of XSA-421 / CVE-2022-42325. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Tested-by: Julien Grall +Reviewed-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 3e3eb47326cc..7ffe21bb5285 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -418,7 +418,13 @@ static int finalize_transaction(struct connection *conn, + true); + talloc_free(data.dptr); + } else { +- ret = do_tdb_delete(conn, &key, NULL); ++ /* ++ * A node having been created and later deleted ++ * in this transaction will have no generation ++ * information stored. ++ */ ++ ret = (i->generation == NO_GENERATION) ++ ? 0 : do_tdb_delete(conn, &key, NULL); + } + if (ret) + goto err; diff --git a/xsa421-02.patch b/xsa421-02.patch new file mode 100644 index 0000000..1a0b5cd --- /dev/null +++ b/xsa421-02.patch @@ -0,0 +1,401 @@ +From 09fc22fea8a4689c5e563ba4a2fa959282071792 Mon Sep 17 00:00:00 2001 +From: Juergen Gross +Date: Tue, 13 Sep 2022 07:35:14 +0200 +Subject: tools/xenstore: harden transaction finalization against errors + +When finalizing a transaction, any error occurring after checking for +conflicts will result in the transaction being performed only +partially today. Additionally accounting data will not be updated at +the end of the transaction, which might result in further problems +later. + +Avoid those problems by multiple modifications: + +- free any transaction specific nodes which don't need to be committed + as they haven't been written during the transaction as soon as their + generation count has been verified, this will reduce the risk of + out-of-memory situations + +- store the transaction specific node name in struct accessed_node in + order to avoid the need to allocate additional memory for it when + finalizing the transaction + +- don't stop the transaction finalization when hitting an error + condition, but try to continue to handle all modified nodes + +- in case of a detected error do the accounting update as needed and + call the data base checking only after that + +- if writing a node in a transaction is failing (e.g. due to a failed + quota check), fail the transaction, as prior changes to struct + accessed_node can't easily be undone in that case + +This is part of XSA-421 / CVE-2022-42326. + +Reported-by: Julien Grall +Signed-off-by: Juergen Gross +Reviewed-by: Julien Grall +Tested-by: Julien Grall + +diff --git a/tools/xenstore/xenstored_core.c b/tools/xenstore/xenstored_core.c +index 36fb4a832834..476d5c6d51bd 100644 +--- a/tools/xenstore/xenstored_core.c ++++ b/tools/xenstore/xenstored_core.c +@@ -723,8 +723,7 @@ struct node *read_node(struct connection *conn, const void *ctx, + return NULL; + } + +- if (transaction_prepend(conn, name, &key)) +- return NULL; ++ transaction_prepend(conn, name, &key); + + data = tdb_fetch(tdb_ctx, key); + +@@ -842,10 +841,21 @@ int write_node_raw(struct connection *conn, TDB_DATA *key, struct node *node, + static int write_node(struct connection *conn, struct node *node, + bool no_quota_check) + { ++ int ret; ++ + if (access_node(conn, node, NODE_ACCESS_WRITE, &node->key)) + return errno; + +- return write_node_raw(conn, &node->key, node, no_quota_check); ++ ret = write_node_raw(conn, &node->key, node, no_quota_check); ++ if (ret && conn && conn->transaction) { ++ /* ++ * Reverting access_node() is hard, so just fail the ++ * transaction. ++ */ ++ fail_transaction(conn->transaction); ++ } ++ ++ return ret; + } + + unsigned int perm_for_conn(struct connection *conn, +diff --git a/tools/xenstore/xenstored_transaction.c b/tools/xenstore/xenstored_transaction.c +index 7ffe21bb5285..ac854197cadb 100644 +--- a/tools/xenstore/xenstored_transaction.c ++++ b/tools/xenstore/xenstored_transaction.c +@@ -114,7 +114,8 @@ struct accessed_node + struct list_head list; + + /* The name of the node. */ +- char *node; ++ char *trans_name; /* Transaction specific name. */ ++ char *node; /* Main data base name. */ + + /* Generation count (or NO_GENERATION) for conflict checking. */ + uint64_t generation; +@@ -199,25 +200,20 @@ static char *transaction_get_node_name(void *ctx, struct transaction *trans, + * Prepend the transaction to name if node has been modified in the current + * transaction. + */ +-int transaction_prepend(struct connection *conn, const char *name, +- TDB_DATA *key) ++void transaction_prepend(struct connection *conn, const char *name, ++ TDB_DATA *key) + { +- char *tdb_name; ++ struct accessed_node *i; + +- if (!conn || !conn->transaction || +- !find_accessed_node(conn->transaction, name)) { +- set_tdb_key(name, key); +- return 0; ++ if (conn && conn->transaction) { ++ i = find_accessed_node(conn->transaction, name); ++ if (i) { ++ set_tdb_key(i->trans_name, key); ++ return; ++ } + } + +- tdb_name = transaction_get_node_name(conn->transaction, +- conn->transaction, name); +- if (!tdb_name) +- return errno; +- +- set_tdb_key(tdb_name, key); +- +- return 0; ++ set_tdb_key(name, key); + } + + /* +@@ -240,7 +236,6 @@ int access_node(struct connection *conn, struct node *node, + struct accessed_node *i = NULL; + struct transaction *trans; + TDB_DATA local_key; +- const char *trans_name = NULL; + int ret; + bool introduce = false; + +@@ -259,10 +254,6 @@ int access_node(struct connection *conn, struct node *node, + + trans = conn->transaction; + +- trans_name = transaction_get_node_name(node, trans, node->name); +- if (!trans_name) +- goto nomem; +- + i = find_accessed_node(trans, node->name); + if (!i) { + if (trans->nodes >= quota_trans_nodes && +@@ -273,9 +264,10 @@ int access_node(struct connection *conn, struct node *node, + i = talloc_zero(trans, struct accessed_node); + if (!i) + goto nomem; +- i->node = talloc_strdup(i, node->name); +- if (!i->node) ++ i->trans_name = transaction_get_node_name(i, trans, node->name); ++ if (!i->trans_name) + goto nomem; ++ i->node = strchr(i->trans_name, '/') + 1; + if (node->generation != NO_GENERATION && node->perms.num) { + i->perms.p = talloc_array(i, struct xs_permissions, + node->perms.num); +@@ -302,7 +294,7 @@ int access_node(struct connection *conn, struct node *node, + i->generation = node->generation; + i->check_gen = true; + if (node->generation != NO_GENERATION) { +- set_tdb_key(trans_name, &local_key); ++ set_tdb_key(i->trans_name, &local_key); + ret = write_node_raw(conn, &local_key, node, true); + if (ret) + goto err; +@@ -321,7 +313,7 @@ int access_node(struct connection *conn, struct node *node, + return -1; + + if (key) { +- set_tdb_key(trans_name, key); ++ set_tdb_key(i->trans_name, key); + if (type == NODE_ACCESS_WRITE) + i->ta_node = true; + if (type == NODE_ACCESS_DELETE) +@@ -333,7 +325,6 @@ int access_node(struct connection *conn, struct node *node, + nomem: + ret = ENOMEM; + err: +- talloc_free((void *)trans_name); + talloc_free(i); + trans->fail = true; + errno = ret; +@@ -371,100 +362,90 @@ void queue_watches(struct connection *conn, const char *name, bool watch_exact) + * base. + */ + static int finalize_transaction(struct connection *conn, +- struct transaction *trans) ++ struct transaction *trans, bool *is_corrupt) + { +- struct accessed_node *i; ++ struct accessed_node *i, *n; + TDB_DATA key, ta_key, data; + struct xs_tdb_record_hdr *hdr; + uint64_t gen; +- char *trans_name; +- int ret; + +- list_for_each_entry(i, &trans->accessed, list) { +- if (!i->check_gen) +- continue; ++ list_for_each_entry_safe(i, n, &trans->accessed, list) { ++ if (i->check_gen) { ++ set_tdb_key(i->node, &key); ++ data = tdb_fetch(tdb_ctx, key); ++ hdr = (void *)data.dptr; ++ if (!data.dptr) { ++ if (tdb_error(tdb_ctx) != TDB_ERR_NOEXIST) ++ return EIO; ++ gen = NO_GENERATION; ++ } else ++ gen = hdr->generation; ++ talloc_free(data.dptr); ++ if (i->generation != gen) ++ return EAGAIN; ++ } + +- set_tdb_key(i->node, &key); +- data = tdb_fetch(tdb_ctx, key); +- hdr = (void *)data.dptr; +- if (!data.dptr) { +- if (tdb_error(tdb_ctx) != TDB_ERR_NOEXIST) +- return EIO; +- gen = NO_GENERATION; +- } else +- gen = hdr->generation; +- talloc_free(data.dptr); +- if (i->generation != gen) +- return EAGAIN; ++ /* Entries for unmodified nodes can be removed early. */ ++ if (!i->modified) { ++ if (i->ta_node) { ++ set_tdb_key(i->trans_name, &ta_key); ++ if (do_tdb_delete(conn, &ta_key, NULL)) ++ return EIO; ++ } ++ list_del(&i->list); ++ talloc_free(i); ++ } + } + + while ((i = list_top(&trans->accessed, struct accessed_node, list))) { +- trans_name = transaction_get_node_name(i, trans, i->node); +- if (!trans_name) +- /* We are doomed: the transaction is only partial. */ +- goto err; +- +- set_tdb_key(trans_name, &ta_key); +- +- if (i->modified) { +- set_tdb_key(i->node, &key); +- if (i->ta_node) { +- data = tdb_fetch(tdb_ctx, ta_key); +- if (!data.dptr) +- goto err; ++ set_tdb_key(i->node, &key); ++ if (i->ta_node) { ++ set_tdb_key(i->trans_name, &ta_key); ++ data = tdb_fetch(tdb_ctx, ta_key); ++ if (data.dptr) { + hdr = (void *)data.dptr; + hdr->generation = ++generation; +- ret = do_tdb_write(conn, &key, &data, NULL, +- true); ++ *is_corrupt |= do_tdb_write(conn, &key, &data, ++ NULL, true); + talloc_free(data.dptr); ++ if (do_tdb_delete(conn, &ta_key, NULL)) ++ *is_corrupt = true; + } else { +- /* +- * A node having been created and later deleted +- * in this transaction will have no generation +- * information stored. +- */ +- ret = (i->generation == NO_GENERATION) +- ? 0 : do_tdb_delete(conn, &key, NULL); +- } +- if (ret) +- goto err; +- if (i->fire_watch) { +- fire_watches(conn, trans, i->node, NULL, +- i->watch_exact, +- i->perms.p ? &i->perms : NULL); ++ *is_corrupt = true; + } ++ } else { ++ /* ++ * A node having been created and later deleted ++ * in this transaction will have no generation ++ * information stored. ++ */ ++ *is_corrupt |= (i->generation == NO_GENERATION) ++ ? false ++ : do_tdb_delete(conn, &key, NULL); + } ++ if (i->fire_watch) ++ fire_watches(conn, trans, i->node, NULL, i->watch_exact, ++ i->perms.p ? &i->perms : NULL); + +- if (i->ta_node && do_tdb_delete(conn, &ta_key, NULL)) +- goto err; + list_del(&i->list); + talloc_free(i); + } + + return 0; +- +-err: +- corrupt(conn, "Partial transaction"); +- return EIO; + } + + static int destroy_transaction(void *_transaction) + { + struct transaction *trans = _transaction; + struct accessed_node *i; +- char *trans_name; + TDB_DATA key; + + wrl_ntransactions--; + trace_destroy(trans, "transaction"); + while ((i = list_top(&trans->accessed, struct accessed_node, list))) { + if (i->ta_node) { +- trans_name = transaction_get_node_name(i, trans, +- i->node); +- if (trans_name) { +- set_tdb_key(trans_name, &key); +- do_tdb_delete(trans->conn, &key, NULL); +- } ++ set_tdb_key(i->trans_name, &key); ++ do_tdb_delete(trans->conn, &key, NULL); + } + list_del(&i->list); + talloc_free(i); +@@ -556,6 +537,7 @@ int do_transaction_end(const void *ctx, struct connection *conn, + { + const char *arg = onearg(in); + struct transaction *trans; ++ bool is_corrupt = false; + int ret; + + if (!arg || (!streq(arg, "T") && !streq(arg, "F"))) +@@ -579,13 +561,17 @@ int do_transaction_end(const void *ctx, struct connection *conn, + ret = transaction_fix_domains(trans, false); + if (ret) + return ret; +- if (finalize_transaction(conn, trans)) +- return EAGAIN; ++ ret = finalize_transaction(conn, trans, &is_corrupt); ++ if (ret) ++ return ret; + + wrl_apply_debit_trans_commit(conn); + + /* fix domain entry for each changed domain */ + transaction_fix_domains(trans, true); ++ ++ if (is_corrupt) ++ corrupt(conn, "transaction inconsistency"); + } + send_ack(conn, XS_TRANSACTION_END); + +@@ -660,7 +646,7 @@ int check_transactions(struct hashtable *hash) + struct connection *conn; + struct transaction *trans; + struct accessed_node *i; +- char *tname, *tnode; ++ char *tname; + + list_for_each_entry(conn, &connections, list) { + list_for_each_entry(trans, &conn->transaction_list, list) { +@@ -672,11 +658,8 @@ int check_transactions(struct hashtable *hash) + list_for_each_entry(i, &trans->accessed, list) { + if (!i->ta_node) + continue; +- tnode = transaction_get_node_name(tname, trans, +- i->node); +- if (!tnode || !remember_string(hash, tnode)) ++ if (!remember_string(hash, i->trans_name)) + goto nomem; +- talloc_free(tnode); + } + + talloc_free(tname); +diff --git a/tools/xenstore/xenstored_transaction.h b/tools/xenstore/xenstored_transaction.h +index 39d7f81c5127..3417303f9427 100644 +--- a/tools/xenstore/xenstored_transaction.h ++++ b/tools/xenstore/xenstored_transaction.h +@@ -48,8 +48,8 @@ int __must_check access_node(struct connection *conn, struct node *node, + void queue_watches(struct connection *conn, const char *name, bool watch_exact); + + /* Prepend the transaction to name if appropriate. */ +-int transaction_prepend(struct connection *conn, const char *name, +- TDB_DATA *key); ++void transaction_prepend(struct connection *conn, const char *name, ++ TDB_DATA *key); + + /* Mark the transaction as failed. This will prevent it to be committed. */ + void fail_transaction(struct transaction *trans);