Add extension check for EncryptedExtensions
#include "ssl_misc.h"
#include "ssl_client.h"
#include "ssl_tls13_keys.h"
+#include "ssl_debug_helpers.h"
/* Write extensions */
@@ -1969,6 +1970,7 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
size_t extensions_len;
const unsigned char *p = buf;
const unsigned char *extensions_end;
+ uint32_t extensions_present;
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, 2 );
extensions_len = MBEDTLS_GET_UINT16_BE( p, 0 );
@@ -1978,6 +1980,8 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, end, extensions_len );
extensions_end = p + extensions_len;
+ extensions_present = MBEDTLS_SSL_EXT_NONE;
+
while( p < extensions_end )
{
unsigned int extension_type;
@@ -1996,10 +2000,27 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
MBEDTLS_SSL_CHK_BUF_READ_PTR( p, extensions_end, extension_data_len );
- /* The client MUST check EncryptedExtensions for the
- * presence of any forbidden extensions and if any are found MUST abort
- * the handshake with an "unsupported_extension" alert.
+ /* RFC 8446 page 35
+ *
+ * If an implementation receives an extension which it recognizes and which
+ * is not specified for the message in which it appears, it MUST abort the
+ * handshake with an "illegal_parameter" alert.
*/
+ extensions_present |= mbedtls_tls13_get_extension_mask( extension_type );
+ MBEDTLS_SSL_DEBUG_MSG( 3,
+ ( "encrypted extensions : received %s(%u) extension",
+ mbedtls_tls13_get_extension_name( extension_type ),
+ extension_type ) );
+ if( ( extensions_present & MBEDTLS_SSL_TLS1_3_ALLOWED_EXTS_OF_EE ) == 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG(
+ 3, ( "forbidden extension received." ) );
+ MBEDTLS_SSL_PEND_FATAL_ALERT(
+ MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER,
+ MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+ return( MBEDTLS_ERR_SSL_HANDSHAKE_FAILURE );
+ }
+
switch( extension_type )
{
case MBEDTLS_TLS_EXT_SERVERNAME:
@@ -2024,17 +2045,18 @@ static int ssl_tls13_parse_encrypted_extensions( mbedtls_ssl_context *ssl,
break;
#endif /* MBEDTLS_SSL_ALPN */
default:
- MBEDTLS_SSL_DEBUG_MSG(
- 3, ( "unsupported extension found: %u ", extension_type) );
- MBEDTLS_SSL_PEND_FATAL_ALERT(
- MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT,
- MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
- return ( MBEDTLS_ERR_SSL_UNSUPPORTED_EXTENSION );
+ MBEDTLS_SSL_DEBUG_MSG( 3,
+ ( "encrypted extensions: received %s(%u) extension ( ignored )",
+ mbedtls_tls13_get_extension_name( extension_type ),
+ extension_type ) );
+ break;
}
p += extension_data_len;
}
+ MBEDTLS_SSL_TLS1_3_PRINT_EXTS( 3, "EncrypedExtensions", extensions_present );
+
/* Check that we consumed all the message. */
if( p != end )
{
