From 802c227e3a1d7fd4bb043494b5840376a5592cb7 Mon Sep 17 00:00:00 2001
From: dv <dv@openbsd.org>
Date: Sun, 29 Aug 2021 11:41:27 +0000
Subject: [PATCH] check for null vioblk info

If {c,m}alloc fail, info could be NULL and result in NULL deref.

Reported by Ilja van Sprundel.

ok mlarkin@
---
 usr.sbin/vmd/virtio.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/vmd/virtio.c b/usr.sbin/vmd/virtio.c
index 30580c0f5bc..8150047b13f 100644
--- a/usr.sbin/vmd/virtio.c
+++ b/usr.sbin/vmd/virtio.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: virtio.c,v 1.94 2021/08/29 11:14:27 dv Exp $	*/
+/*	$OpenBSD: virtio.c,v 1.95 2021/08/29 11:41:27 dv Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
@@ -521,6 +521,11 @@ vioblk_notifyq(struct vioblk_dev *dev)
 				info = vioblk_start_read(dev,
 				    cmd.sector + secbias, secdata_desc->len);
 
+				if (info == NULL) {
+					log_warnx("vioblk: can't start read");
+					goto out;
+				}
+
 				/* read the data, use current data descriptor */
 				secdata = vioblk_finish_read(info);
 				if (secdata == NULL) {
-- 
2.20.1