Implement parsing of CID extension in ServerHello
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index fc807be..c95782c 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -1244,6 +1244,57 @@
}
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
+#if defined(MBEDTLS_SSL_CID)
+static int ssl_parse_cid_ext( mbedtls_ssl_context *ssl,
+ const unsigned char *buf,
+ size_t len )
+{
+ size_t peer_cid_len;
+
+ if( /* CID extension only makes sense in DTLS */
+ ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM ||
+ /* The server must only send the CID extension if we have offered it. */
+ ssl->negotiate_cid == MBEDTLS_SSL_CID_DISABLED ||
+ /* CID extension must at least contain the length byte */
+ len < 1 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
+ return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+ }
+
+ peer_cid_len = *buf++;
+ len--;
+
+ if( peer_cid_len > MBEDTLS_SSL_CID_OUT_LEN_MAX )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE );
+ return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+ }
+
+ if( len != peer_cid_len )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "non-matching CID extension" ) );
+ mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
+ MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER );
+ return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO );
+ }
+
+ ssl->handshake->peer_cid_len = (uint8_t) peer_cid_len;
+ memcpy( ssl->handshake->peer_cid, buf, peer_cid_len );
+
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "Use of CID extension negotiated" ) );
+ MBEDTLS_SSL_DEBUG_BUF( 3, "Server CID", buf, peer_cid_len );
+
+ ssl->handshake->cid_in_use = MBEDTLS_SSL_CID_ENABLED;
+
+ return( 0 );
+}
+#endif /* MBEDTLS_SSL_CID */
+
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
static int ssl_parse_encrypt_then_mac_ext( mbedtls_ssl_context *ssl,
const unsigned char *buf,
@@ -1895,6 +1946,20 @@
break;
#endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
+#if defined(MBEDTLS_SSL_CID)
+ case MBEDTLS_TLS_EXT_CID:
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "found CID extension" ) );
+
+ if( ( ret = ssl_parse_cid_ext( ssl,
+ ext + 4,
+ ext_size ) ) != 0 )
+ {
+ return( ret );
+ }
+
+ break;
+#endif /* MBEDTLS_SSL_CID */
+
#if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
case MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC:
MBEDTLS_SSL_DEBUG_MSG( 3, ( "found encrypt_then_mac extension" ) );