diff --git a/ChangeLog b/ChangeLog index deeaccd0c..ae3130559 100644 --- a/ChangeLog +++ b/ChangeLog @@ -19,6 +19,8 @@ Security resumption of the session). * Fix a buffer overread in ssl_parse_server_key_exchange() that could cause a crash on invalid input. + * Fix a buffer overread in ssl_parse_server_psk_hint() that could cause a + crash on invalid input. Features * Extend PKCS#8 interface by introducing support for the entire SHA @@ -55,6 +57,8 @@ Bugfix * In mbedtls_entropy_free(), properly free the message digest context. * Fix a possible arithmetic overflow in ssl_parse_server_key_exchange() that could cause a key exchange to fail on valid data. + * Fix a possible arithmetic overflow in ssl_parse_server_psk_hint() that + could cause a key exchange to fail on valid data. Changes * Clarified the documentation of mbedtls_ssl_setup. diff --git a/library/ssl_cli.c b/library/ssl_cli.c index b607fda71..c0c424bef 100644 --- a/library/ssl_cli.c +++ b/library/ssl_cli.c @@ -1850,10 +1850,16 @@ static int ssl_parse_server_psk_hint( mbedtls_ssl_context *ssl, * * opaque psk_identity_hint<0..2^16-1>; */ + if( (*p) > end - 2 ) + { + MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message " + "(psk_identity_hint length)" ) ); + return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE ); + } len = (*p)[0] << 8 | (*p)[1]; *p += 2; - if( (*p) + len > end ) + if( (*p) > end -len ) { MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message " "(psk_identity_hint length)" ) );