From fee19fa8d4f6f351e5a76f5801884880249d6a45 Mon Sep 17 00:00:00 2001

From: Chris Liddell <chris.liddell@artifex.com>

Date: Wed, 5 Oct 2016 09:55:55 +0100

Subject: [PATCH] Bug 697178: Add a file permissions callback

For the rare occasions when the graphics library directly opens a file

(currently for reading), this allows us to apply any restrictions on

file access normally applied in the interpteter.

---

 base/gsicc_manage.c | 10 ++++++----

 base/gslibctx.c     | 12 +++++++++++-

 base/gslibctx.h     |  7 +++++++

 psi/imain.c         |  2 ++

 psi/int.mak         |  2 +-

 psi/zfile.c         | 19 +++++++++++++++++++

 psi/zfile.h         |  7 +++++++

 7 files changed, 53 insertions(+), 6 deletions(-)

diff --git a/base/gsicc_manage.c b/base/gsicc_manage.c

index 931c2a6..e9c09c3 100644

--- a/base/gsicc_manage.c

+++ b/base/gsicc_manage.c

@@ -1124,10 +1124,12 @@ gsicc_open_search(const char* pname, int namelen, gs_memory_t *mem_gc,

     }

     /* First just try it like it is */

-    str = sfopen(pname, "r", mem_gc);

-    if (str != NULL) {

-        *strp = str;

-        return 0;

+    if (gs_check_file_permission(mem_gc, pname, namelen, "r") >= 0) {

+        str = sfopen(pname, "r", mem_gc);

+        if (str != NULL) {

+            *strp = str;

+            return 0;

+        }

     }

     /* If that fails, try %rom% */ /* FIXME: Not sure this is needed or correct */

diff --git a/base/gslibctx.c b/base/gslibctx.c

index fa4432a..f2c13e3 100644

--- a/base/gslibctx.c

+++ b/base/gslibctx.c

@@ -183,7 +183,7 @@ int gs_lib_ctx_init( gs_memory_t *mem )

         mem->gs_lib_ctx = NULL;

         return -1;

     }

-    

+    pio->client_check_file_permission = NULL;

     gp_get_realtime(pio->real_time_0);

     /* Set scanconverter to 1 (default) */

@@ -336,3 +336,13 @@ void errflush(const gs_memory_t *mem)

         fflush(mem->gs_lib_ctx->fstderr);

     /* else nothing to flush */

 }

+

+int

+gs_check_file_permission (gs_memory_t *mem, const char *fname, const int len, const char *permission)

+{

+    int code = 0;

+    if (mem->gs_lib_ctx->client_check_file_permission != NULL) {

+        code = mem->gs_lib_ctx->client_check_file_permission(mem, fname, len, permission);

+    }

+    return code;

+}

diff --git a/base/gslibctx.h b/base/gslibctx.h

index 84ec205..55eb4a6 100644

--- a/base/gslibctx.h

+++ b/base/gslibctx.h

@@ -32,6 +32,9 @@ typedef struct gs_fapi_server_s gs_fapi_server;

 #  define gs_font_dir_DEFINED

 typedef struct gs_font_dir_s gs_font_dir;

 #endif

+

+typedef int (*client_check_file_permission_t) (gs_memory_t *mem, const char *fname, const int len, const char *permission);

+

 typedef struct gs_lib_ctx_s

 {

     gs_memory_t *memory;  /* mem->gs_lib_ctx->memory == mem */

@@ -61,6 +64,7 @@ typedef struct gs_lib_ctx_s

     struct gx_io_device_s **io_device_table;

     int io_device_table_count;

     int io_device_table_size;

+    client_check_file_permission_t client_check_file_permission;

     /* Define the default value of AccurateScreens that affects setscreen

        and setcolorscreen. */

     bool screen_accurate_screens;

@@ -132,6 +136,9 @@ int

 gs_lib_ctx_get_default_device_list(const gs_memory_t *mem, char** dev_list_str,

                         int *list_str_len);

+int

+gs_check_file_permission (gs_memory_t *mem, const char *fname, const int len, const char *permission);

+

 #define IS_LIBCTX_STDOUT(mem, f) (f == mem->gs_lib_ctx->fstdout)

 #define IS_LIBCTX_STDERR(mem, f) (f == mem->gs_lib_ctx->fstderr)

diff --git a/psi/imain.c b/psi/imain.c

index 9a9bb5d..6874128 100644

--- a/psi/imain.c

+++ b/psi/imain.c

@@ -57,6 +57,7 @@

 #include "ivmspace.h"

 #include "idisp.h"              /* for setting display device callback */

 #include "iplugin.h"

+#include "zfile.h"

 #ifdef PACIFY_VALGRIND

 #include "valgrind.h"

@@ -212,6 +213,7 @@ gs_main_init1(gs_main_instance * minst)

                                            "the_gs_name_table");

             if (code < 0)

                 return code;

+            mem->gs_lib_ctx->client_check_file_permission = z_check_file_permissions;

         }

         code = obj_init(&minst->i_ctx_p, &idmem);  /* requires name_init */

         if (code < 0)

diff --git a/psi/int.mak b/psi/int.mak

index 4654afc..bb30d51 100644

--- a/psi/int.mak

+++ b/psi/int.mak

@@ -2024,7 +2024,7 @@ $(PSOBJ)imain.$(OBJ) : $(PSSRC)imain.c $(GH) $(memory__h) $(string__h)\

  $(ialloc_h) $(iconf_h) $(idebug_h) $(idict_h) $(idisp_h) $(iinit_h)\

  $(iname_h) $(interp_h) $(iplugin_h) $(isave_h) $(iscan_h) $(ivmspace_h)\

  $(iinit_h) $(main_h) $(oper_h) $(ostack_h)\

- $(sfilter_h) $(store_h) $(stream_h) $(strimpl_h)\

+ $(sfilter_h) $(store_h) $(stream_h) $(strimpl_h) $(zfile_h)\

  $(INT_MAK) $(MAKEDIRS)

 	$(PSCC) $(PSO_)imain.$(OBJ) $(C_) $(PSSRC)imain.c

diff --git a/psi/zfile.c b/psi/zfile.c

index b6caea2..fd94f67 100644

--- a/psi/zfile.c

+++ b/psi/zfile.c

@@ -197,6 +197,25 @@ check_file_permissions(i_ctx_t *i_ctx_p, const char *fname, int len,

     return check_file_permissions_reduced(i_ctx_p, fname_reduced, rlen, permitgroup);

 }

+/* z_check_file_permissions: see zfile.h for explanation

+ */

+int

+z_check_file_permissions(gs_memory_t *mem, const char *fname, const int len, const char *permission)

+{

+    i_ctx_t *i_ctx_p = get_minst_from_memory(mem)->i_ctx_p;

+    gs_parsed_file_name_t pname;

+    const char *permitgroup = permission[0] == 'r' ? "PermitFileReading" : "PermitFileWriting";

+    int code = gs_parse_file_name(&pname, fname, len, imemory);

+    if (code < 0)

+        return code;

+

+    if (pname.iodev && i_ctx_p->LockFilePermissions && strcmp(pname.iodev->dname, "%pipe%") == 0)

+        return gs_error_invalidfileaccess;

+        

+    code = check_file_permissions(i_ctx_p, fname, len, permitgroup);

+    return code;

+}

+

 /* <name_string> <access_string> file <file> */

 int                             /* exported for zsysvm.c */

 zfile(i_ctx_t *i_ctx_p)

diff --git a/psi/zfile.h b/psi/zfile.h

index fdf1373..a9399c7 100644

--- a/psi/zfile.h

+++ b/psi/zfile.h

@@ -22,4 +22,11 @@

 int zopen_file(i_ctx_t *i_ctx_p, const gs_parsed_file_name_t *pfn,

            const char *file_access, stream **ps, gs_memory_t *mem);

+/* z_check_file_permissions: a callback (via mem->gs_lib_ctx->client_check_file_permission)

+ * to allow applying the above permissions checks when opening file(s) from

+ * the graphics library

+ */

+int

+z_check_file_permissions(gs_memory_t *mem, const char *fname,

+                                 const int len, const char *permission);

 #endif

-- 

2.7.4