bgpd: Check if cluster list attribute is not received via eBGP session

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index b5cdcfd2df..63705fb155 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2183,6 +2183,15 @@ bgp_attr_cluster_list(struct bgp_attr_parser_args *args)
 	struct attr *const attr = args->attr;
 	const bgp_size_t length = args->length;
 
+	/* if the CLUSTER_LIST attribute is received from an external
+	 * neighbor, it SHALL be discarded using the approach of "attribute
+	 * discard".
+	 */
+	if (peer->sort == BGP_PEER_EBGP) {
+		stream_forward_getp(peer->curr, length);
+		return BGP_ATTR_PARSE_PROCEED;
+	}
+
 	/* if received from an internal neighbor, it SHALL be considered
 	 * malformed if its length is not a non-zero multiple of 4.  If
 	 * malformed, the UPDATE message SHALL be handled using the approach