commit e9d5510f0543bc318269a603f866f35b97cd5910
author Janos Follath <janos.follath@arm.com> Thu Apr 21 23:37:09 2016 +0100
committer Simon Butcher <simon.butcher@arm.com> Fri Apr 22 09:55:32 2016 +0100
tree 3c94d29ab812b23193c2897af41c65ead1b041bc
parent 689a6272153f44b23c1702a09b6db32b79adbd72

Fix bug in ssl_write_supported_elliptic_curves_ext

Passing invalid curves to mbedtls_ssl_conf_curves potentially could caused a
crash later in ssl_write_supported_elliptic_curves_ext. #373

ChangeLog

diff --git a/ChangeLog b/ChangeLog
index a2fae0d..ec53df4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -12,6 +12,8 @@
    * Fix issue that caused a hang when generating RSA keys of odd bitlength
    * Fix bug in mbedtls_rsa_rsaes_pkcs1_v15_encrypt that made null pointer
      dereference possible.
+   * Fix issue that caused a crash if invalid curves were passed to
+     mbedtls_ssl_conf_curves. #373
 
 Changes
    * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,

library/ssl_cli.c

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 09fc337..1d8b33f 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -269,6 +269,12 @@
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
     {
 #endif
+        if( info == NULL )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid curve in ssl configuration" ) );
+            return;
+        }
+
         elliptic_curve_len += 2;
     }
 
@@ -288,7 +294,6 @@
     for( info = mbedtls_ecp_curve_list(); info->grp_id != MBEDTLS_ECP_DP_NONE; info++ )
     {
 #endif
-
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id >> 8;
         elliptic_curve_list[elliptic_curve_len++] = info->tls_id & 0xFF;
     }