From: claudio <claudio@openbsd.org>
Date: Mon, 11 Jul 2022 16:58:58 +0000 (+0000)
Subject: Properly roll back in the add-path send case in up_dump_prefix()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=513afc985d020741736cc4ca5c0d91272be801c2;p=openbsd

Properly roll back in the add-path send case in up_dump_prefix()

When up_dump_prefix() runs out of space while filling out prefixes
a possible path_id needs to be removed from the buf or else a corrupted
UPDATE is sent out.
OK tb@
---

diff --git a/usr.sbin/bgpd/rde_update.c b/usr.sbin/bgpd/rde_update.c
index 9332136f757..49253b30e18 100644
--- a/usr.sbin/bgpd/rde_update.c
+++ b/usr.sbin/bgpd/rde_update.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rde_update.c,v 1.143 2022/07/11 16:55:21 claudio Exp $ */
+/*	$OpenBSD: rde_update.c,v 1.144 2022/07/11 16:58:58 claudio Exp $ */
 
 /*
  * Copyright (c) 2004 Claudio Jeker <claudio@openbsd.org>
@@ -675,8 +675,11 @@ up_dump_prefix(u_char *buf, int len, struct prefix_tree *prefix_head,
 		}
 		pt_getaddr(p->pt, &addr);
 		if ((r = prefix_write(buf + wpos, len - wpos,
-		    &addr, p->pt->prefixlen, withdraw)) == -1)
+		    &addr, p->pt->prefixlen, withdraw)) == -1) {
+			if (peer_has_add_path(peer, p->pt->aid, CAPA_AP_SEND))
+				wpos -= sizeof(pathid);
 			break;
+		}
 		wpos += r;
 
 		/* make sure we only dump prefixes which belong together */
@@ -688,7 +691,6 @@ up_dump_prefix(u_char *buf, int len, struct prefix_tree *prefix_head,
 		    (np->flags & PREFIX_FLAG_EOR))
 			done = 1;
 
-
 		if (withdraw) {
 			/* prefix no longer needed, remove it */
 			prefix_adjout_destroy(p);
@@ -700,6 +702,7 @@ up_dump_prefix(u_char *buf, int len, struct prefix_tree *prefix_head,
 			peer->up_nlricnt--;
 			peer->prefix_sent_update++;
 		}
+
 		if (done)
 			break;
 	}