Fix non compliance SSLv3 in server extension handling.

The server code parses the client hello extensions even when the
protocol is SSLv3 and this behaviour is non compliant with rfc6101.
Also the server sends extensions in the server hello and omitting
them may prevent interoperability problems.
This commit is contained in:
Janos Follath 2016-05-06 13:57:50 +01:00
parent 00efff7469
commit 2442255f0d
2 changed files with 22 additions and 0 deletions

View file

@ -26,6 +26,7 @@ Bugfix
* Fix issue that caused a crash if invalid curves were passed to * Fix issue that caused a crash if invalid curves were passed to
mbedtls_ssl_conf_curves. #373 mbedtls_ssl_conf_curves. #373
* Fix issue in ssl_fork_server which was preventing it from functioning. #429 * Fix issue in ssl_fork_server which was preventing it from functioning. #429
* Fix non compliance SSLv3 in server extension handling.
Changes Changes
* On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5, * On ARM platforms, when compiling with -O0 with GCC, Clang or armcc5,

View file

@ -1507,6 +1507,12 @@ read_record_header:
ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL; ssl->session_negotiate->compression = MBEDTLS_SSL_COMPRESS_NULL;
#endif #endif
/* Do not parse the extensions if the protocol is SSLv3 */
#if defined(MBEDTLS_SSL_PROTO_SSL3)
if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
{
#endif
/* /*
* Check the extension length * Check the extension length
*/ */
@ -1692,8 +1698,13 @@ read_record_header:
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) ); MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO ); return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
} }
} }
#if defined(MBEDTLS_SSL_PROTO_SSL3)
}
#endif
#if defined(MBEDTLS_SSL_FALLBACK_SCSV) #if defined(MBEDTLS_SSL_FALLBACK_SCSV)
for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 ) for( i = 0, p = buf + 41 + sess_len; i < ciph_len; i += 2, p += 2 )
{ {
@ -2363,6 +2374,12 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X", MBEDTLS_SSL_DEBUG_MSG( 3, ( "server hello, compress alg.: 0x%02X",
ssl->session_negotiate->compression ) ); ssl->session_negotiate->compression ) );
/* Do not write the extensions if the protocol is SSLv3 */
#if defined(MBEDTLS_SSL_PROTO_SSL3)
if( ( ssl->major_ver != 3 ) || ( ssl->minor_ver != 0 ) )
{
#endif
/* /*
* First write extensions, then the total length * First write extensions, then the total length
*/ */
@ -2419,6 +2436,10 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
p += ext_len; p += ext_len;
} }
#if defined(MBEDTLS_SSL_PROTO_SSL3)
}
#endif
ssl->out_msglen = p - buf; ssl->out_msglen = p - buf;
ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE; ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO; ssl->out_msg[0] = MBEDTLS_SSL_HS_SERVER_HELLO;