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>
diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 0ddf3a2..e3b30ea 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -307,6 +307,8 @@
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 @@
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;
}