From 168204de6371f594c4f1ebac30ca3e181a851e39 Mon Sep 17 00:00:00 2001
From: Donald Sharp <sharpd@nvidia.com>
Date: Wed, 5 Apr 2023 14:57:05 -0400
Subject: [PATCH] bgpd: Limit flowspec to no attribute means a implicit
 withdrawal
Upsteam: yes
References: CVE-2023-41909,bsc#1215065,https://github.com/FRRouting/frr/pull/13222/commits/cfd04dcb3e689754a72507d086ba3b9709fc5ed8

All other parsing functions done from bgp_nlri_parse() assume
no attributes == an implicit withdrawal.  Let's move
bgp_nlri_parse_flowspec() into the same alignment.

Reported-by: Matteo Memelli <mmemelli@amazon.it>
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
Signed-off-by: Marius Tomaschewski <mt@suse.com>

diff --git a/bgpd/bgp_flowspec.c b/bgpd/bgp_flowspec.c
index 39c0cfe514..fe1f0d50f8 100644
--- a/bgpd/bgp_flowspec.c
+++ b/bgpd/bgp_flowspec.c
@@ -112,6 +112,13 @@ int bgp_nlri_parse_flowspec(struct peer *peer, struct attr *attr,
 	afi = packet->afi;
 	safi = packet->safi;
 
+	/*
+	 * All other AFI/SAFI's treat no attribute as a implicit
+	 * withdraw.  Flowspec should as well.
+	 */
+	if (!attr)
+		withdraw = 1;
+
 	if (packet->length >= FLOWSPEC_NLRI_SIZELIMIT_EXTENDED) {
 		flog_err(EC_BGP_FLOWSPEC_PACKET,
 			 "BGP flowspec nlri length maximum reached (%u)",
-- 
2.35.3