From: Claudio Jeker <cjeker@diehard.n-r-g.com>
Subject: bgpd: fix l3vpn error on withdraws
To: tech@openbsd.org
Date: Mon, 28 Oct 2024 11:19:49 +0100

When withdrawing a L3VPN route (AID_VPN_IPv{4,6}) the labelstack is
actually unused. Right now this triggers a check in pt_fill() that I added
because of memcpy UB but here both labelstack pointers are never NULL and
all of this is just wrong. Therefor just remove the checks.
 
-- 
:wq Claudio

Index: rde_prefix.c
===================================================================
RCS file: /cvs/src/usr.sbin/bgpd/rde_prefix.c,v
diff -u -p -r1.52 rde_prefix.c
--- rde_prefix.c	10 Sep 2024 08:47:51 -0000	1.52
+++ rde_prefix.c	28 Oct 2024 10:11:32 -0000
@@ -225,8 +225,6 @@ pt_fill(struct bgpd_addr *prefix, int pr
 		pte_vpn4.prefixlen = prefixlen;
 		pte_vpn4.rd = prefix->rd;
 		pte_vpn4.labellen = prefix->labellen;
-		if (prefix->labellen == 0)
-			fatalx("pt_fill: no MPLS label in VPN addr");
 		memcpy(pte_vpn4.labelstack, prefix->labelstack,
 		    prefix->labellen);
 		return ((struct pt_entry *)&pte_vpn4);
@@ -241,8 +239,6 @@ pt_fill(struct bgpd_addr *prefix, int pr
 		pte_vpn6.prefixlen = prefixlen;
 		pte_vpn6.rd = prefix->rd;
 		pte_vpn6.labellen = prefix->labellen;
-		if (prefix->labellen == 0)
-			fatalx("pt_fill: no MPLS label in VPN addr");
 		memcpy(pte_vpn6.labelstack, prefix->labelstack,
 		    prefix->labellen);
 		return ((struct pt_entry *)&pte_vpn6);