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From 840011af52fcdac15a749f14f19b00401a49dc51 Mon Sep 17 00:00:00 2001
From: Daniel Stenberg <daniel@haxx.se>
Date: Fri, 19 Mar 2021 12:38:49 +0100
Subject: [PATCH] vtls: add 'isproxy' argument to Curl_ssl_get/addsessionid()

To make sure we set and extract the correct session.

Reported-by: Mingtao Yang
Bug: https://curl.se/docs/CVE-2021-22890.html

CVE-2021-22890

Upstream-commit: b09c8ee15771c614c4bf3ddac893cdb12187c844
Signed-off-by: Kamil Dudka <kdudka@redhat.com>
---
 lib/vtls/openssl.c | 52 +++++++++++++++++++++++++++++++++++-----------
 lib/vtls/vtls.c    |  4 ++--
 lib/vtls/vtls.h    |  2 ++
 3 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/lib/vtls/openssl.c b/lib/vtls/openssl.c
index 5803fd1..16276f3 100644
--- a/lib/vtls/openssl.c
+++ b/lib/vtls/openssl.c
@@ -422,12 +422,23 @@ static int ossl_get_ssl_conn_index(void)
  */
 static int ossl_get_ssl_sockindex_index(void)
 {
-  static int ssl_ex_data_sockindex_index = -1;
-  if(ssl_ex_data_sockindex_index < 0) {
-    ssl_ex_data_sockindex_index = SSL_get_ex_new_index(0, NULL, NULL, NULL,
-        NULL);
+  static int sockindex_index = -1;
+  if(sockindex_index < 0) {
+    sockindex_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
   }
-  return ssl_ex_data_sockindex_index;
+  return sockindex_index;
+}
+
+/* Return an extra data index for proxy boolean.
+ * This index can be used with SSL_get_ex_data() and SSL_set_ex_data().
+ */
+static int ossl_get_proxy_index(void)
+{
+  static int proxy_index = -1;
+  if(proxy_index < 0) {
+    proxy_index = SSL_get_ex_new_index(0, NULL, NULL, NULL, NULL);
+  }
+  return proxy_index;
 }
 
 static int passwd_callback(char *buf, int num, int encrypting,
@@ -1079,7 +1090,8 @@ static int Curl_ossl_init(void)
 #endif
 
   /* Initialize the extra data indexes */
-  if(ossl_get_ssl_conn_index() < 0 || ossl_get_ssl_sockindex_index() < 0)
+  if(ossl_get_ssl_conn_index() < 0 ||
+     ossl_get_ssl_sockindex_index() < 0 || ossl_get_proxy_index() < 0)
     return 0;
 
   return 1;
@@ -2366,8 +2378,10 @@ static int ossl_new_session_cb(SSL *ssl, SSL_SESSION *ssl_sessionid)
   curl_socket_t *sockindex_ptr;
   int connectdata_idx = ossl_get_ssl_conn_index();
   int sockindex_idx = ossl_get_ssl_sockindex_index();
+  int proxy_idx = ossl_get_proxy_index();
+  bool isproxy;
 
-  if(connectdata_idx < 0 || sockindex_idx < 0)
+  if(connectdata_idx < 0 || sockindex_idx < 0 || proxy_idx < 0)
     return 0;
 
   conn = (struct connectdata*) SSL_get_ex_data(ssl, connectdata_idx);
@@ -2380,13 +2394,18 @@ static int ossl_new_session_cb(SSL *ssl, SSL_SESSION *ssl_sessionid)
   sockindex_ptr = (curl_socket_t*) SSL_get_ex_data(ssl, sockindex_idx);
   sockindex = (int)(sockindex_ptr - conn->sock);
 
+  isproxy = SSL_get_ex_data(ssl, proxy_idx) ? TRUE : FALSE;
+
   if(SSL_SET_OPTION(primary.sessionid)) {
     bool incache;
     void *old_ssl_sessionid = NULL;
 
     Curl_ssl_sessionid_lock(conn);
-    incache = !(Curl_ssl_getsessionid(conn, &old_ssl_sessionid, NULL,
-                                      sockindex));
+    if(isproxy)
+      incache = FALSE;
+    else
+      incache = !(Curl_ssl_getsessionid(conn, isproxy,
+                                        &old_ssl_sessionid, NULL, sockindex));
     if(incache) {
       if(old_ssl_sessionid != ssl_sessionid) {
         infof(data, "old SSL session ID is stale, removing\n");
@@ -2396,7 +2415,7 @@ static int ossl_new_session_cb(SSL *ssl, SSL_SESSION *ssl_sessionid)
     }
 
     if(!incache) {
-      if(!Curl_ssl_addsessionid(conn, ssl_sessionid,
+      if(!Curl_ssl_addsessionid(conn, isproxy, ssl_sessionid,
                                       0 /* unknown size */, sockindex)) {
         /* the session has been put into the session cache */
         res = 1;
@@ -2893,16 +2912,25 @@ static CURLcode ossl_connect_step1(struct connectdata *conn, int sockindex)
     void *ssl_sessionid = NULL;
     int connectdata_idx = ossl_get_ssl_conn_index();
     int sockindex_idx = ossl_get_ssl_sockindex_index();
+    int proxy_idx = ossl_get_proxy_index();
 
-    if(connectdata_idx >= 0 && sockindex_idx >= 0) {
+    if(connectdata_idx >= 0 && sockindex_idx >= 0 && proxy_idx >= 0) {
       /* Store the data needed for the "new session" callback.
        * The sockindex is stored as a pointer to an array element. */
       SSL_set_ex_data(BACKEND->handle, connectdata_idx, conn);
       SSL_set_ex_data(BACKEND->handle, sockindex_idx, conn->sock + sockindex);
+#ifndef CURL_DISABLE_PROXY
+      SSL_set_ex_data(BACKEND->handle, proxy_idx, SSL_IS_PROXY() ? (void *) 1:
+                      NULL);
+#else
+      SSL_set_ex_data(BACKEND->handle, proxy_idx, NULL);
+#endif
+
     }
 
     Curl_ssl_sessionid_lock(conn);
-    if(!Curl_ssl_getsessionid(conn, &ssl_sessionid, NULL, sockindex)) {
+    if(!Curl_ssl_getsessionid(conn, SSL_IS_PROXY() ? TRUE : FALSE,
+                              &ssl_sessionid, NULL, sockindex)) {
       /* we got a session id, use it! */
       if(!SSL_set_session(BACKEND->handle, ssl_sessionid)) {
         Curl_ssl_sessionid_unlock(conn);
diff --git a/lib/vtls/vtls.c b/lib/vtls/vtls.c
index c3a55fb..e50fdd2 100644
--- a/lib/vtls/vtls.c
+++ b/lib/vtls/vtls.c
@@ -305,6 +305,7 @@ void Curl_ssl_sessionid_unlock(struct connectdata *conn)
  * there's one suitable, it is provided. Returns TRUE when no entry matched.
  */
 bool Curl_ssl_getsessionid(struct connectdata *conn,
+                           const bool isProxy,
                            void **ssl_sessionid,
                            size_t *idsize, /* set 0 if unknown */
                            int sockindex)
@@ -315,7 +316,6 @@ bool Curl_ssl_getsessionid(struct connectdata *conn,
   long *general_age;
   bool no_match = TRUE;
 
-  const bool isProxy = CONNECT_PROXY_SSL();
   struct ssl_primary_config * const ssl_config = isProxy ?
     &conn->proxy_ssl_config :
     &conn->ssl_config;
@@ -411,6 +411,7 @@ void Curl_ssl_delsessionid(struct connectdata *conn, void *ssl_sessionid)
  * later on.
  */
 CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
+                               bool isProxy,
                                void *ssl_sessionid,
                                size_t idsize,
                                int sockindex)
@@ -423,7 +424,6 @@ CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
   char *clone_conn_to_host;
   int conn_to_port;
   long *general_age;
-  const bool isProxy = CONNECT_PROXY_SSL();
   struct ssl_primary_config * const ssl_config = isProxy ?
     &conn->proxy_ssl_config :
     &conn->ssl_config;
diff --git a/lib/vtls/vtls.h b/lib/vtls/vtls.h
index bcc8444..343cad0 100644
--- a/lib/vtls/vtls.h
+++ b/lib/vtls/vtls.h
@@ -202,6 +202,7 @@ void Curl_ssl_sessionid_unlock(struct connectdata *conn);
  * under sessionid mutex).
  */
 bool Curl_ssl_getsessionid(struct connectdata *conn,
+                           const bool isproxy,
                            void **ssl_sessionid,
                            size_t *idsize, /* set 0 if unknown */
                            int sockindex);
@@ -211,6 +212,7 @@ bool Curl_ssl_getsessionid(struct connectdata *conn,
  * object with cache (e.g. incrementing refcount on success)
  */
 CURLcode Curl_ssl_addsessionid(struct connectdata *conn,
+                               const bool isProxy,
                                void *ssl_sessionid,
                                size_t idsize,
                                int sockindex);
-- 
2.26.3