From 46c03dec08cc0b2ba97a70ace8666a47d93944e5 Mon Sep 17 00:00:00 2001
From: florian <florian@openbsd.org>
Date: Sat, 24 Aug 2024 16:34:23 +0000
Subject: [PATCH] Stop peeking into struct imsg when relaying control messages.

pointed out by & OK tb
---
 sbin/slaacd/control.c |  7 +++----
 sbin/slaacd/slaacd.c  | 12 +++++++++++-
 sbin/slaacd/slaacd.h  |  5 ++---
 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/sbin/slaacd/control.c b/sbin/slaacd/control.c
index a5fb37fb4bc..2cdf0568d4c 100644
--- a/sbin/slaacd/control.c
+++ b/sbin/slaacd/control.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: control.c,v 1.10 2024/08/24 09:44:41 florian Exp $	*/
+/*	$OpenBSD: control.c,v 1.11 2024/08/24 16:34:23 florian Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -296,10 +296,9 @@ control_imsg_relay(struct imsg *imsg)
 {
 	struct ctl_conn	*c;
 
-	if ((c = control_connbypid(imsg->hdr.pid)) == NULL)
+	if ((c = control_connbypid(imsg_get_pid(imsg))) == NULL)
 		return (0);
 
-	return (imsg_compose_event(&c->iev, imsg->hdr.type, 0, imsg->hdr.pid,
-	    -1, imsg->data, IMSG_DATA_SIZE(*imsg)));
+	return (imsg_forward_event(&c->iev, imsg));
 }
 #endif	/* SMALL */
diff --git a/sbin/slaacd/slaacd.c b/sbin/slaacd/slaacd.c
index c76bae07ed3..da9a98ecff6 100644
--- a/sbin/slaacd/slaacd.c
+++ b/sbin/slaacd/slaacd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: slaacd.c,v 1.71 2024/08/24 09:44:41 florian Exp $	*/
+/*	$OpenBSD: slaacd.c,v 1.72 2024/08/24 16:34:23 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -587,6 +587,16 @@ imsg_compose_event(struct imsgev *iev, uint16_t type, uint32_t peerid,
 	return (ret);
 }
 
+int
+imsg_forward_event(struct imsgev *iev, struct imsg *imsg)
+{
+	int	ret;
+
+	if ((ret = imsg_forward(&iev->ibuf, imsg)) != -1)
+		imsg_event_add(iev);
+
+	return (ret);
+}
 static int
 main_imsg_send_ipc_sockets(struct imsgbuf *frontend_buf,
     struct imsgbuf *engine_buf)
diff --git a/sbin/slaacd/slaacd.h b/sbin/slaacd/slaacd.h
index 77087c3c56a..9f7ba45749d 100644
--- a/sbin/slaacd/slaacd.h
+++ b/sbin/slaacd/slaacd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: slaacd.h,v 1.39 2024/08/24 09:42:40 florian Exp $	*/
+/*	$OpenBSD: slaacd.h,v 1.40 2024/08/24 16:34:23 florian Exp $	*/
 
 /*
  * Copyright (c) 2017 Florian Obser <florian@openbsd.org>
@@ -27,8 +27,6 @@
 
 #define	MAX_RDNS_COUNT		8 /* max nameserver in a RTM_PROPOSAL */
 
-#define	IMSG_DATA_SIZE(imsg)	((imsg).hdr.len - IMSG_HEADER_SIZE)
-
 struct imsgev {
 	struct imsgbuf	 ibuf;
 	void		(*handler)(int, short, void *);
@@ -204,6 +202,7 @@ struct imsg_dup_addr {
 void		imsg_event_add(struct imsgev *);
 int		imsg_compose_event(struct imsgev *, uint16_t, uint32_t, pid_t,
 		    int, void *, uint16_t);
+int		imsg_forward_event(struct imsgev *, struct imsg *);
 #ifndef	SMALL
 const char	*sin6_to_str(struct sockaddr_in6 *);
 const char	*i2s(uint32_t);
-- 
2.20.1