linux-kernel - [PATCH RESEND net] vhost: fix vhost_vq_access

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 9 Apr 2018 22:40:02 +0300
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
        virtualization@...ts.linux-foundation.org
Cc:     linux-kernel@...r.kernel.org, jasowang@...hat.com,
        kvm@...r.kernel.org, mst@...hat.com,
        syzkaller-bugs@...glegroups.com,
        Stefan Hajnoczi <stefanha@...hat.com>
Subject: [PATCH RESEND net] vhost: fix vhost_vq_access_ok() log check

From: Stefan Hajnoczi <stefanha@...hat.com>

Commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ("vhost: validate log
when IOTLB is enabled") introduced a regression.  The logic was
originally:

  if (vq->iotlb)
      return 1;
  return A && B;

After the patch the short-circuit logic for A was inverted:

  if (A || vq->iotlb)
      return A;
  return B;

The correct logic is:

  if (!A || vq->iotlb)
      return A;
  return B;

Reported-by: syzbot+65a84dde0214b0387ccd@...kaller.appspotmail.com
Cc: Jason Wang <jasowang@...hat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@...hat.com>
Acked-by: Michael S. Tsirkin <mst@...hat.com>

---
 drivers/vhost/vhost.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5320039671b7..f6af4210679a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1246,7 +1246,7 @@ int vhost_vq_access_ok(struct vhost_virtqueue *vq)
 {
 	int ret = vq_log_access_ok(vq, vq->log_base);
 
-	if (ret || vq->iotlb)
+	if (!ret || vq->iotlb)
 		return ret;
 
 	return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
-- 
2.14.3