[PULL 40/45] vhost-vsock: detach the virqueue element in case of error

[Michael S. Tsirkin]

From: Stefano Garzarella <sgarzare@redhat.com>

In vhost_vsock_common_send_transport_reset(), if an element popped from
the virtqueue is invalid, we should call virtqueue_detach_element() to
detach it from the virtqueue before freeing its memory.

Fixes: fc0b9b0e1c ("vhost-vsock: add virtio sockets device")
Fixes: CVE-2022-26354
Cc: qemu-stable@nongnu.org
Reported-by: VictorV <vv474172261@gmail.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-Id: <20220228095058.27899-1-sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/virtio/vhost-vsock-common.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost-vsock-common.c b/hw/virtio/vhost-vsock-common.c
index 3f3771274e..ed706681ac 100644
--- a/hw/virtio/vhost-vsock-common.c
+++ b/hw/virtio/vhost-vsock-common.c
@@ -153,19 +153,23 @@ static void 
vhost_vsock_common_send_transport_reset(VHostVSockCommon *vvc)
     if (elem->out_num) {
         error_report("invalid vhost-vsock event virtqueue element with "
                      "out buffers");
-        goto out;
+        goto err;
     }
 
     if (iov_from_buf(elem->in_sg, elem->in_num, 0,
                      &event, sizeof(event)) != sizeof(event)) {
         error_report("vhost-vsock event virtqueue element is too short");
-        goto out;
+        goto err;
     }
 
     virtqueue_push(vq, elem, sizeof(event));
     virtio_notify(VIRTIO_DEVICE(vvc), vq);
 
-out:
+    g_free(elem);
+    return;
+
+err:
+    virtqueue_detach_element(vq, elem, 0);
     g_free(elem);
 }
 
-- 
MST