Add ecc extensions only if ecc ciphersuite is used

Fix compliancy to RFC4492. ECC extensions should be included only if ec ciphersuites are used. Interoperability issue with bouncy castle. Mbed-TLS#1157
RonEld · Jun 28, 2018 · c32b3b7 · c32b3b7
1 parent 0e342f7
commit c32b3b7
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Showing 3 changed files with 26 additions and 8 deletions.
diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
@@ -1837,7 +1837,8 @@ mbedtls_pk_type_t mbedtls_ssl_get_ciphersuite_sig_alg( const mbedtls_ssl_ciphers
 
 #endif /* MBEDTLS_PK_C */
 
-#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 int mbedtls_ssl_ciphersuite_uses_ec( const mbedtls_ssl_ciphersuite_t *info )
 {
     switch( info->key_exchange )
@@ -1847,13 +1848,14 @@ int mbedtls_ssl_ciphersuite_uses_ec( const mbedtls_ssl_ciphersuite_t *info )
         case MBEDTLS_KEY_EXCHANGE_ECDHE_PSK:
         case MBEDTLS_KEY_EXCHANGE_ECDH_RSA:
         case MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA:
+        case MBEDTLS_KEY_EXCHANGE_ECJPAKE:
             return( 1 );
 
         default:
             return( 0 );
     }
 }
-#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
+#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED*/
 
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
 int mbedtls_ssl_ciphersuite_uses_psk( const mbedtls_ssl_ciphersuite_t *info )

diff --git a/library/ssl_cli.c b/library/ssl_cli.c
@@ -769,6 +769,10 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
     unsigned char offer_compress;
     const int *ciphersuites;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+    int uses_ec = 0;
+#endif
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
 
@@ -920,6 +924,11 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x",
                                     ciphersuites[i] ) );
 
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+        uses_ec |= mbedtls_ssl_ciphersuite_uses_ec( ciphersuite_info );
+#endif
+
         n++;
         *p++ = (unsigned char)( ciphersuites[i] >> 8 );
         *p++ = (unsigned char)( ciphersuites[i]      );
@@ -1013,11 +1022,14 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-    ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+    if( uses_ec )
+    {
+        ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
 
-    ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+        ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
+    }
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)

diff --git a/library/ssl_srv.c b/library/ssl_srv.c
@@ -2570,8 +2570,12 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-    ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+    if ( mbedtls_ssl_ciphersuite_uses_ec(
+         mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
+    {
+        ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
+    }
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)