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Commit 3fda5d6e authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Michael S. Tsirkin
Browse files

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: default avatarDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 1b8553c0

drivers/vhost/vsock.c

+5 −1
Original line number Diff line number Diff line
@@ -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;

	}