From: claudio <claudio@openbsd.org>
Date: Mon, 9 Sep 2024 15:00:45 +0000 (+0000)
Subject: Handle the CLUSTER_LIST attribute as described in RFC7606
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=457c3e2447edb817f924bc78ed8765a7f3c9f09c;p=openbsd

Handle the CLUSTER_LIST attribute as described in RFC7606

Just drop the attribute if received from an external peer.
Treat as withdraw if the len is 0 or not % 4.
OK tb@
---

diff --git a/usr.sbin/bgpd/rde.c b/usr.sbin/bgpd/rde.c
index a855f27a799..fb58c5ec54d 100644
--- a/usr.sbin/bgpd/rde.c
+++ b/usr.sbin/bgpd/rde.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde.c,v 1.631 2024/09/09 14:58:47 claudio Exp $ */
+/*	$OpenBSD: rde.c,v 1.632 2024/09/09 15:00:45 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -2192,8 +2192,22 @@ rde_attr_parse(struct ibuf *buf, struct rde_peer *peer,
 	case ATTR_CLUSTER_LIST:
 		if (!CHECK_FLAGS(flags, ATTR_OPTIONAL, 0))
 			goto bad_flags;
-		if (ibuf_size(&attrbuf) % 4 != 0)
-			goto bad_len;
+		if (peer->conf.ebgp) {
+			/* As per RFC7606 use "attribute discard" here. */
+			log_peer_warnx(&peer->conf, "bad CLUSTER_LIST, "
+			    "received from external peer, attribute discarded");
+			break;
+		}
+		if (ibuf_size(&attrbuf) % 4 != 0 || ibuf_size(&attrbuf) == 0) {
+			/*
+			 * mark update as bad and withdraw all routes as per
+			 * RFC 7606
+			 */
+			a->flags |= F_ATTR_PARSE_ERR;
+			log_peer_warnx(&peer->conf, "bad CLUSTER_LIST, "
+			    "path invalidated and prefix withdrawn");
+			break;
+		}
 		goto optattr;
 	case ATTR_MP_REACH_NLRI:
 		if (!CHECK_FLAGS(flags, ATTR_OPTIONAL, 0))