From 151af94ebac619594e1f4599e395b8946cb47d32 Mon Sep 17 00:00:00 2001
From: Omar Polo <op@omarpolo.com>
Date: Fri, 28 Jan 2022 12:34:42 +0000
Subject: only memcpy into imsg->data if datalen is not zero

Passing a NULL pointer to memcpy is UB no matter if len is 0 (commit by
claudio@, backporting for gmid.)
---
 compat/imsg.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'compat')

diff --git a/compat/imsg.c b/compat/imsg.c
index 3d36a40..74aead2 100644
--- a/compat/imsg.c
+++ b/compat/imsg.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: imsg.c,v 1.16 2017/12/14 09:27:44 kettenis Exp $	*/
+/*	$OpenBSD: imsg.c,v 1.17 2022/01/28 10:41:44 claudio Exp $	*/
 
 /*
  * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
@@ -151,7 +151,8 @@ imsg_get(struct imsgbuf *ibuf, struct imsg *imsg)
 	else
 		imsg->fd = -1;
 
-	memcpy(imsg->data, ibuf->r.rptr, datalen);
+	if (datalen != 0)
+		memcpy(imsg->data, ibuf->r.rptr, datalen);
 
 	if (imsg->hdr.len < av) {
 		left = av - imsg->hdr.len;
-- 
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