vhost-net: fix use-after-free in vhost_net_flush
authorMichael S. Tsirkin <mst@redhat.com>
Tue, 25 Jun 2013 14:29:46 +0000 (17:29 +0300)
committerMichael S. Tsirkin <mst@redhat.com>
Sun, 7 Jul 2013 11:06:22 +0000 (14:06 +0300)
commitc38e39c378f46f00ce922dd40a91043a9925c28d
treea5286110beeea3f5fef0c86fb44535d91402ea3b
parent8bb495e3f02401ee6f76d1b1d77f3ac9f079e376
vhost-net: fix use-after-free in vhost_net_flush

vhost_net_ubuf_put_and_wait has a confusing name:
it will actually also free it's argument.
Thus since commit 1280c27f8e29acf4af2da914e80ec27c3dbd5c01
    "vhost-net: flush outstanding DMAs on memory change"
vhost_net_flush tries to use the argument after passing it
to vhost_net_ubuf_put_and_wait, this results
in use after free.
To fix, don't free the argument in vhost_net_ubuf_put_and_wait,
add an new API for callers that want to free ubufs.

Acked-by: Asias He <asias@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
drivers/vhost/net.c