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Commit d65026c6 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

vhost: validate log when IOTLB is enabled 



Vq log_base is the userspace address of bitmap which has nothing to do
with IOTLB. So it needs to be validated unconditionally otherwise we
may try use 0 as log_base which may lead to pin pages that will lead
unexpected result (e.g trigger BUG_ON() in set_bit_to_user()).

Fixes: 6b1e6cc7 ("vhost: new device IOTLB API")
Reported-by: default avatar <syzbot+6304bf97ef436580fede@syzkaller.appspotmail.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 58f101bf

drivers/vhost/vhost.c

+6 −8
Original line number Diff line number Diff line
@@ -1244,14 +1244,12 @@ static int vq_log_access_ok(struct vhost_virtqueue *vq, 
/* Caller should have vq mutex and device mutex */

int vhost_vq_access_ok(struct vhost_virtqueue *vq)

{

	if (vq->iotlb) {

		/* When device IOTLB was used, the access validation

		 * will be validated during prefetching.

		 */

		return 1;

	}

	return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used) &&

		vq_log_access_ok(vq, vq->log_base);

	int ret = vq_log_access_ok(vq, vq->log_base);



	if (ret || vq->iotlb)

		return ret;



	return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);

}

EXPORT_SYMBOL_GPL(vhost_vq_access_ok);