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| author | Michael S. Tsirkin <mst@redhat.com> | 2013-07-07 14:26:53 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-07-09 12:55:48 -0700 |
| commit | dd7633ecd553a5e304d349aa6f8eb8a0417098c5 (patch) | |
| tree | b78a356c1a5bef54e7ce20ca440e9c9159d818ac /drivers | |
| parent | 785bf6f7904352242d187ff6087d523a4ce1b3ac (diff) | |
| download | linux-dd7633ecd553a5e304d349aa6f8eb8a0417098c5.tar.bz2 | |
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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/vhost/net.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index f80d3dd41d8c..8ca5ac71b845 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -150,6 +150,11 @@ static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) { kref_put(&ubufs->kref, vhost_net_zerocopy_done_signal); wait_event(ubufs->wait, !atomic_read(&ubufs->kref.refcount)); +} + +static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) +{ + vhost_net_ubuf_put_and_wait(ubufs); kfree(ubufs); } @@ -948,7 +953,7 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) mutex_unlock(&vq->mutex); if (oldubufs) { - vhost_net_ubuf_put_and_wait(oldubufs); + vhost_net_ubuf_put_wait_and_free(oldubufs); mutex_lock(&vq->mutex); vhost_zerocopy_signal_used(n, vq); mutex_unlock(&vq->mutex); @@ -966,7 +971,7 @@ err_used: rcu_assign_pointer(vq->private_data, oldsock); vhost_net_enable_vq(n, vq); if (ubufs) - vhost_net_ubuf_put_and_wait(ubufs); + vhost_net_ubuf_put_wait_and_free(ubufs); err_ubufs: fput(sock->file); err_vq: |