Introduce helper to check for no-CRT notification from client
This commit introduces a server-side static helper function
`ssl_srv_check_client_no_crt_notification()`, which checks if
the message we received during the incoming certificate state
notifies the server of the lack of certificate on the client.
For SSLv3, such a notification comes as a specific alert,
while for all other TLS versions, it comes as a `Certificate`
handshake message with an empty CRT list.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index d2cb893..f89029b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5761,52 +5761,6 @@
size_t i, n;
uint8_t alert;
-#if defined(MBEDTLS_SSL_SRV_C)
-#if defined(MBEDTLS_SSL_PROTO_SSL3)
- /*
- * Check if the client sent an empty certificate
- */
- if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
- ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
- {
- if( ssl->in_msglen == 2 &&
- ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT &&
- ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING &&
- ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_NO_CERT )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
-
- /* The client was asked for a certificate but didn't send
- one. The client should know what's going on, so we
- don't send an alert. */
- ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
- return( MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE );
- }
- }
-#endif /* MBEDTLS_SSL_PROTO_SSL3 */
-
-#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
- defined(MBEDTLS_SSL_PROTO_TLS1_2)
- if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
- ssl->minor_ver != MBEDTLS_SSL_MINOR_VERSION_0 )
- {
- if( ssl->in_hslen == 3 + mbedtls_ssl_hs_hdr_len( ssl ) &&
- ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
- ssl->in_msg[0] == MBEDTLS_SSL_HS_CERTIFICATE &&
- memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
-
- /* The client was asked for a certificate but didn't send
- one. The client should know what's going on, so we
- don't send an alert. */
- ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
- return( MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE );
- }
- }
-#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
- MBEDTLS_SSL_PROTO_TLS1_2 */
-#endif /* MBEDTLS_SSL_SRV_C */
if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
{
@@ -5967,6 +5921,48 @@
return( 0 );
}
+#if defined(MBEDTLS_SSL_SRV_C)
+static int ssl_srv_check_client_no_crt_notification( mbedtls_ssl_context *ssl )
+{
+ if( ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT )
+ return( -1 );
+
+#if defined(MBEDTLS_SSL_PROTO_SSL3)
+ /*
+ * Check if the client sent an empty certificate
+ */
+ if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 )
+ {
+ if( ssl->in_msglen == 2 &&
+ ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT &&
+ ssl->in_msg[0] == MBEDTLS_SSL_ALERT_LEVEL_WARNING &&
+ ssl->in_msg[1] == MBEDTLS_SSL_ALERT_MSG_NO_CERT )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "SSLv3 client has no certificate" ) );
+ return( 0 );
+ }
+
+ return( -1 );
+ }
+#endif /* MBEDTLS_SSL_PROTO_SSL3 */
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1) || defined(MBEDTLS_SSL_PROTO_TLS1_1) || \
+ defined(MBEDTLS_SSL_PROTO_TLS1_2)
+ if( ssl->in_hslen == 3 + mbedtls_ssl_hs_hdr_len( ssl ) &&
+ ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
+ ssl->in_msg[0] == MBEDTLS_SSL_HS_CERTIFICATE &&
+ memcmp( ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl ), "\0\0\0", 3 ) == 0 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "TLSv1 client has no certificate" ) );
+ return( 0 );
+ }
+
+ return( -1 );
+#endif /* MBEDTLS_SSL_PROTO_TLS1 || MBEDTLS_SSL_PROTO_TLS1_1 || \
+ MBEDTLS_SSL_PROTO_TLS1_2 */
+}
+#endif /* MBEDTLS_SSL_SRV_C */
+
int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
{
int ret;
@@ -6029,16 +6025,21 @@
return( ret );
}
+#if defined(MBEDTLS_SSL_SRV_C)
+ if( ssl_srv_check_client_no_crt_notification( ssl ) == 0 )
+ {
+ ssl->session_negotiate->verify_result = MBEDTLS_X509_BADCERT_MISSING;
+ ssl->state++;
+
+ if( authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
+ return( 0 );
+
+ return( MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE );
+ }
+#endif /* MBEDTLS_SSL_SRV_C */
+
if( ( ret = ssl_parse_certificate_chain( ssl ) ) != 0 )
{
-#if defined(MBEDTLS_SSL_SRV_C)
- if( ret == MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE &&
- authmode == MBEDTLS_SSL_VERIFY_OPTIONAL )
- {
- ret = 0;
- }
-#endif
-
ssl->state++;
return( ret );
}