vhost-net: fix use-after-free in vhost_net_flush
authorMichael S. Tsirkin <mst@redhat.com>
Sun, 7 Jul 2013 11:26:53 +0000 (14:26 +0300)
committerDavid S. Miller <davem@davemloft.net>
Tue, 9 Jul 2013 19:55:48 +0000 (12:55 -0700)
commitdd7633ecd553a5e304d349aa6f8eb8a0417098c5
treeb78a356c1a5bef54e7ce20ca440e9c9159d818ac
parent785bf6f7904352242d187ff6087d523a4ce1b3ac
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/vhost/net.c