bgpd: Ensure that bgp open message stream has enough data to read

donaldsharp · donaldsharp · commit 766eec1b7acc · 2022-11-02T13:24:48.000-04:00
If a operator receives an invalid packet that is of insufficient size
then it is possible for BGP to assert during reading of the packet
instead of gracefully resetting the connection with the peer.

Signed-off-by: Donald Sharp &lt;sharpd@nvidia.com&gt;
diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
@@ -1386,8 +1386,27 @@ static int bgp_open_receive(struct peer *peer, bgp_size_t size)
 	    || CHECK_FLAG(peer->flags, PEER_FLAG_EXTENDED_OPT_PARAMS)) {
 		uint8_t opttype;
 
+		if (STREAM_READABLE(peer->curr) < 1) {
+			flog_err(
+				EC_BGP_PKT_OPEN,
+				"%s: stream does not have enough bytes for extended optional parameters",
+				peer->host);
+			bgp_notify_send(peer, BGP_NOTIFY_OPEN_ERR,
+					BGP_NOTIFY_OPEN_MALFORMED_ATTR);
+			return BGP_Stop;
+		}
+
 		opttype = stream_getc(peer->curr);
 		if (opttype == BGP_OPEN_NON_EXT_OPT_TYPE_EXTENDED_LENGTH) {
+			if (STREAM_READABLE(peer->curr) < 2) {
+				flog_err(
+					EC_BGP_PKT_OPEN,
+					"%s: stream does not have enough bytes to read the extended optional parameters optlen",
+					peer->host);
+				bgp_notify_send(peer, BGP_NOTIFY_OPEN_ERR,
+						BGP_NOTIFY_OPEN_MALFORMED_ATTR);
+				return BGP_Stop;
+			}
 			optlen = stream_getw(peer->curr);
 			SET_FLAG(peer->sflags,
 				 PEER_STATUS_EXT_OPT_PARAMS_LENGTH);
