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vhost/vsock: don't check owner in vhost_vsock_stop() while releasing 

commit a58da53ffd70294ebea8ecd0eb45fd0d74add9f9 upstream.

vhost_vsock_stop() calls vhost_dev_check_owner() to check the device
ownership. It expects current->mm to be valid.

vhost_vsock_stop() is also called by vhost_vsock_dev_release() when
the user has not done close(), so when we are in do_exit(). In this
case current->mm is invalid and we're releasing the device, so we
should clean it anyway.

Let's check the owner only when vhost_vsock_stop() is called
by an ioctl.

When invoked from release we can not fail so we don't check return
code of vhost_vsock_stop(). We need to stop vsock even if it's not
the owner.

Fixes: 433fc58e6b ("VSOCK: Introduce vhost_vsock.ko")
Cc: stable@vger.kernel.org
Reported-by: syzbot+1e3ea63db39f2b4440e0@syzkaller.appspotmail.com
Reported-and-tested-by: syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Stefano Garzarella 2022-02-22 10:47:42 +01:00 committed by Greg Kroah-Hartman
parent dd0de35102
commit 0b608b3392
1 changed files with 14 additions and 7 deletions
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21
drivers/vhost/vsock.c
View File

@ -570,16 +570,18 @@ err:
return ret;
}
static int vhost_vsock_stop(struct vhost_vsock *vsock)
static int vhost_vsock_stop(struct vhost_vsock *vsock, bool check_owner)
{
size_t i;
int ret;
int ret = 0;
mutex_lock(&vsock->dev.mutex);
ret = vhost_dev_check_owner(&vsock->dev);
if (ret)
goto err;
if (check_owner) {
ret = vhost_dev_check_owner(&vsock->dev);
if (ret)
goto err;
}
for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) {
struct vhost_virtqueue *vq = &vsock->vqs[i];
@ -694,7 +696,12 @@ static int vhost_vsock_dev_release(struct inode *inode, struct file *file)
* inefficient. Room for improvement here. */
vsock_for_each_connected_socket(vhost_vsock_reset_orphans);
vhost_vsock_stop(vsock);
/* Don't check the owner, because we are in the release path, so we
* need to stop the vsock device in any case.
* vhost_vsock_stop() can not fail in this case, so we don't need to
* check the return code.
*/
vhost_vsock_stop(vsock, false);
vhost_vsock_flush(vsock);
vhost_dev_stop(&vsock->dev);
@ -792,7 +799,7 @@ static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl,
if (start)
return vhost_vsock_start(vsock);
else
return vhost_vsock_stop(vsock);
return vhost_vsock_stop(vsock, true);
case VHOST_GET_FEATURES:
features = VHOST_VSOCK_FEATURES;
if (copy_to_user(argp, &features, sizeof(features)))