UPSTREAM: vhost/vsock: fix vhost virtio_vsock_pkt use-after-free

Stash the packet length in a local variable before handing over
ownership of the packet to virtio_transport_recv_pkt() or
virtio_transport_free_pkt().

This patch solves the use-after-free since pkt is no longer guaranteed
to be alive.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 3fda5d6e58)
Bug: 121166534
Test: Ran cuttlefish with android-4.4 + vsock adb tunnel
Signed-off-by: Cody Schuffelen <schuffelen@google.com>
Change-Id: I2a6a8b2eb1b647645ff7c76a37f61dce3b0fab9f
This commit is contained in:
Stefan Hajnoczi
2016-08-04 14:52:53 +01:00
committed by Alistair Strachan
parent b09cc234f3
commit 613ffe1838

View File

@@ -307,6 +307,8 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
vhost_disable_notify(&vsock->dev, vq);
for (;;) {
u32 len;
if (!vhost_vsock_more_replies(vsock)) {
/* Stop tx until the device processes already
* pending replies. Leave tx virtqueue
@@ -334,13 +336,15 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work)
continue;
}
len = pkt->len;
/* Only accept correctly addressed packets */
if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid)
virtio_transport_recv_pkt(pkt);
else
virtio_transport_free_pkt(pkt);
vhost_add_used(vq, head, sizeof(pkt->hdr) + pkt->len);
vhost_add_used(vq, head, sizeof(pkt->hdr) + len);
added = true;
}