Fix overread when verifying SERVER_HELLO in DTLS

This commit is contained in:
Andres AG 2016-09-26 14:53:05 +01:00
parent 93012e8bce
commit 5a87c9375d
2 changed files with 11 additions and 0 deletions

View File

@ -29,6 +29,8 @@ Bugfix
a contribution from Tobias Tangemann. #541
* Fixed cert_app sample program for debug output and for use when no root
certificates are provided.
* Fix potential byte overread when verifying malformed SERVER_HELLO in
ssl_parse_hello_verify_request() for DTLS. Found by Guido Vranken.
Changes
* Extended test coverage of special cases, and added new timing test suite.

View File

@ -1355,6 +1355,15 @@ static int ssl_parse_hello_verify_request( mbedtls_ssl_context *ssl )
cookie_len = *p++;
MBEDTLS_SSL_DEBUG_BUF( 3, "cookie", p, cookie_len );
if( ( ssl->in_msg + ssl->in_msglen ) - p < cookie_len )
{
MBEDTLS_SSL_DEBUG_MSG( 1,
( "cookie length does not match incoming message size" ) );
mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
}
mbedtls_free( ssl->handshake->verify_cookie );
ssl->handshake->verify_cookie = mbedtls_calloc( 1, cookie_len );