fix CVE-2010-3864

diff --git a/CHANGES b/CHANGES
index 23f145ca36d297e306df79154e7b012fafc75b7d..1b5db78d35098d36331cb4bb9f549e1b3b1409c2 100644 (file)
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 0.9.8o and 0.9.8p [xx XXX xxxx]
 
+  *) Fix extension code to avoid race conditions which can result in a buffer
+     overrun vulnerability: resumed sessions must not be modified as they can
+     be shared by multiple threads. CVE-2010-3864
+     [Steve Henson]
+
   *) Fix for double free bug in ssl/s3_clnt.c CVE-2010-2939
      [Steve Henson]
 

diff --git a/NEWS b/NEWS
index 857fb9494597a63b2c79c0321fc8a3437801fb81..65f4ef20508d0e8c39eb78cd2538edc8974af3a4 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -5,6 +5,10 @@
   This file gives a brief overview of the major changes between each OpenSSL
   release. For more details please read the CHANGES file.
 
+  Major changes between OpenSSL 0.9.8o and OpenSSL 0.9.8p:
+
+      o Fix for security issue CVE-2010-3864.
+
   Major changes between OpenSSL 0.9.8n and OpenSSL 0.9.8o:
 
       o Fix for security issue CVE-2010-0742.

diff --git a/ssl/t1_lib.c b/ssl/t1_lib.c
index d61c08c8ef424698e50dde5e8d8d09f7a759ccf5..0cc8320e1789f510ca8c500db650b47fda9caac0 100644 (file)
--- a/ssl/t1_lib.c
+++ b/ssl/t1_lib.c
@@ -432,14 +432,23 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
                                switch (servname_type)
                                        {
                                case TLSEXT_NAMETYPE_host_name:
-                                       if (s->session->tlsext_hostname == NULL)
+                                       if (!s->hit)
                                                {
-                                               if (len > TLSEXT_MAXLEN_host_name || 
-                                                       ((s->session->tlsext_hostname = OPENSSL_malloc(len+1)) == NULL))
+                                               if(s->session->tlsext_hostname)
+                                                       {
+                                                       *al = SSL_AD_DECODE_ERROR;
+                                                       return 0;
+                                                       }
+                                               if (len > TLSEXT_MAXLEN_host_name)
                                                        {
                                                        *al = TLS1_AD_UNRECOGNIZED_NAME;
                                                        return 0;
                                                        }
+                                               if ((s->session->tlsext_hostname = OPENSSL_malloc(len+1)) == NULL)
+                                                       {
+                                                       *al = TLS1_AD_INTERNAL_ERROR;
+                                                       return 0;
+                                                       }
                                                memcpy(s->session->tlsext_hostname, sdata, len);
                                                s->session->tlsext_hostname[len]='\0';
                                                if (strlen(s->session->tlsext_hostname) != len) {
@@ -452,7 +461,8 @@ int ssl_parse_clienthello_tlsext(SSL *s, unsigned char **p, unsigned char *d, in
 
                                                }
                                        else 
-                                               s->servername_done = strlen(s->session->tlsext_hostname) == len 
+                                               s->servername_done = s->session->tlsext_hostname
+                                                       && strlen(s->session->tlsext_hostname) == len 
                                                        && strncmp(s->session->tlsext_hostname, (char *)sdata, len) == 0;
                                        
                                        break;