On Thu, 27 Nov 2014, Jason Wang wrote:
> virtio_net_handle_ctrl() and other functions that process control vq
> request call iov_discard_front() which will shorten the iov. This will
> lead unmapping in virtqueue_push() leaks mapping.
>
> Fixes this by keeping the original iov untouched and using a temp variable
> in those functions.
>
> Cc: Wen Congyang <we...@cn.fujitsu.com>
> Cc: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> Cc: qemu-sta...@nongnu.org
> Signed-off-by: Jason Wang <jasow...@redhat.com>
Reviewed-by: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> Changes from V1:
> - Use g_memdup() to simplify codes
> ---
> hw/net/virtio-net.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 9b88775..e574bd4 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -798,7 +798,7 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev,
> VirtQueue *vq)
> virtio_net_ctrl_ack status = VIRTIO_NET_ERR;
> VirtQueueElement elem;
> size_t s;
> - struct iovec *iov;
> + struct iovec *iov, *iov2;
> unsigned int iov_cnt;
>
> while (virtqueue_pop(vq, &elem)) {
> @@ -808,8 +808,8 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev,
> VirtQueue *vq)
> exit(1);
> }
>
> - iov = elem.out_sg;
> iov_cnt = elem.out_num;
> + iov2 = iov = g_memdup(elem.out_sg, sizeof(struct iovec) *
> elem.out_num);
> s = iov_to_buf(iov, iov_cnt, 0, &ctrl, sizeof(ctrl));
> iov_discard_front(&iov, &iov_cnt, sizeof(ctrl));
> if (s != sizeof(ctrl)) {
> @@ -833,6 +833,7 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev,
> VirtQueue *vq)
>
> virtqueue_push(vq, &elem, sizeof(status));
> virtio_notify(vdev, vq);
> + g_free(iov2);
> }
> }
>
> --
> 1.9.1
>
