From 7f893e0cbaa30667b9cacb947cb5fc65fedd29ae Mon Sep 17 00:00:00 2001
From: claudio <claudio@openbsd.org>
Date: Wed, 4 Sep 2024 13:30:10 +0000
Subject: [PATCH] Call pfkey_remove() only after the Session Engine finished
 reloading its configuration. Doing so before could result in some messages
 being sent out without proper TCP-MD5 signature.

Fix for: https://github.com/openbgpd-portable/openbgpd-portable/issues/82
OK tb@
---
 usr.sbin/bgpd/bgpd.c    | 14 +++++++++-----
 usr.sbin/bgpd/config.c  | 29 +++++++++++++++++++++--------
 usr.sbin/bgpd/session.h |  3 ++-
 3 files changed, 32 insertions(+), 14 deletions(-)

diff --git a/usr.sbin/bgpd/bgpd.c b/usr.sbin/bgpd/bgpd.c
index 8b6e1bc70ce..e997d680259 100644
--- a/usr.sbin/bgpd/bgpd.c
+++ b/usr.sbin/bgpd/bgpd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: bgpd.c,v 1.265 2024/08/12 09:04:23 claudio Exp $ */
+/*	$OpenBSD: bgpd.c,v 1.266 2024/09/04 13:30:10 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -575,13 +575,11 @@ reconfigure(char *conffile, struct bgpd_config *conf)
 
 	merge_config(conf, new_conf);
 
-	if (prepare_listeners(conf) == -1) {
+	if (prepare_listeners(conf) == -1)
 		return (1);
-	}
 
-	if (control_setup(conf) == -1) {
+	if (control_setup(conf) == -1)
 		return (1);
-	}
 
 	return send_config(conf);
 }
@@ -647,6 +645,9 @@ send_config(struct bgpd_config *conf)
 
 	/* send peer list to the SE */
 	RB_FOREACH(p, peer_head, &conf->peers) {
+		if (p->reconf_action == RECONF_DELETE)
+			continue;
+
 		if (imsg_compose(ibuf_se, IMSG_RECONF_PEER, p->conf.id, 0, -1,
 		    &p->conf, sizeof(p->conf)) == -1)
 			return (-1);
@@ -1025,6 +1026,9 @@ dispatch_imsg(struct imsgbuf *imsgbuf, int idx, struct bgpd_config *conf)
 
 				/* redistribute list needs to be reloaded too */
 				kr_reload();
+
+				/* also remove old peers */
+				free_deleted_peers(conf);
 			}
 			reconfpending--;
 			break;
diff --git a/usr.sbin/bgpd/config.c b/usr.sbin/bgpd/config.c
index bf93a521beb..94efad738b8 100644
--- a/usr.sbin/bgpd/config.c
+++ b/usr.sbin/bgpd/config.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.110 2024/08/14 19:09:51 claudio Exp $ */
+/*	$OpenBSD: config.c,v 1.111 2024/09/04 13:30:10 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004, 2005 Henning Brauer <henning@openbsd.org>
@@ -434,8 +434,7 @@ merge_config(struct bgpd_config *xconf, struct bgpd_config *conf)
 	 * merge peers:
 	 * - need to know which peers are new, replaced and removed
 	 * - walk over old peers and check if there is a corresponding new
-	 *   peer if so mark it RECONF_KEEP. Remove all old peers.
-	 * - swap lists (old peer list is actually empty).
+	 *   peer if so mark it RECONF_KEEP. Mark all old peers RECONF_DELETE.
 	 */
 	RB_FOREACH_SAFE(p, peer_head, &xconf->peers, nextp) {
 		np = getpeerbyid(conf, p->conf.id);
@@ -443,13 +442,12 @@ merge_config(struct bgpd_config *xconf, struct bgpd_config *conf)
 			np->reconf_action = RECONF_KEEP;
 			/* copy the auth state since parent uses it */
 			np->auth = p->auth;
+
+			RB_REMOVE(peer_head, &xconf->peers, p);
+			free(p);
 		} else {
-			/* peer no longer exists, clear pfkey state */
-			pfkey_remove(p);
+			p->reconf_action = RECONF_DELETE;
 		}
-
-		RB_REMOVE(peer_head, &xconf->peers, p);
-		free(p);
 	}
 	RB_FOREACH_SAFE(np, peer_head, &conf->peers, nextp) {
 		RB_REMOVE(peer_head, &conf->peers, np);
@@ -461,6 +459,21 @@ merge_config(struct bgpd_config *xconf, struct bgpd_config *conf)
 	free_config(conf);
 }
 
+void
+free_deleted_peers(struct bgpd_config *conf)
+{
+	struct peer *p, *nextp;
+
+	RB_FOREACH_SAFE(p, peer_head, &conf->peers, nextp) {
+		if (p->reconf_action == RECONF_DELETE) {
+			/* peer no longer exists, clear pfkey state */
+			pfkey_remove(p);
+			RB_REMOVE(peer_head, &conf->peers, p);
+			free(p);
+		}
+	}
+}
+
 uint32_t
 get_bgpid(void)
 {
diff --git a/usr.sbin/bgpd/session.h b/usr.sbin/bgpd/session.h
index cd008c0ae77..12e871eef4d 100644
--- a/usr.sbin/bgpd/session.h
+++ b/usr.sbin/bgpd/session.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: session.h,v 1.172 2024/08/20 11:59:39 claudio Exp $ */
+/*	$OpenBSD: session.h,v 1.173 2024/09/04 13:30:10 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -247,6 +247,7 @@ int	 carp_demote_set(char *, int);
 
 /* config.c */
 void	 merge_config(struct bgpd_config *, struct bgpd_config *);
+void	 free_deleted_peers(struct bgpd_config *);
 int	 prepare_listeners(struct bgpd_config *);
 
 /* control.c */
-- 
2.20.1