virtio-net: fix unmap leak

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.

upstream-commit-id: 771b6ed37e3aa188a7485560b949a41c6cf174dc

Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Message-id: 1417082643-23907-1-git-send-email-jasowang@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 2ac6ce5c25f5bef19ff6d8bd8ea9c168941445c5..d5e8ecb72fc21c3353c6311121bc0f3b5cc8f6eb 100644 (file)
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -772,7 +772,7 @@ 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)) {
@@ -782,8 +782,8 @@ 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)) {
@@ -805,6 +805,7 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
 
         virtqueue_push(vq, &elem, sizeof(status));
         virtio_notify(vdev, vq);
+        g_free(iov2);
     }
 }