On Wed, Apr 11, 2018 at 12:25:24AM +0200, Greg Kroah-Hartman wrote:
4.14-stable review patch. If anyone has any objections, please let me know.
From: Jason Wang jasowang@redhat.com
[ Upstream commit d65026c6c62e7d9616c8ceb5a53b68bcdc050525 ]
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: 6b1e6cc7855b0 ("vhost: new device IOTLB API") Reported-by: syzbot+6304bf97ef436580fede@syzkaller.appspotmail.com Signed-off-by: Jason Wang jasowang@redhat.com Acked-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
drivers/vhost/vhost.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
--- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -1252,14 +1252,12 @@ static int vq_log_access_ok(struct vhost /* 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)
That's a bug, davem just queued a patch to fix this upstream.
return ret;- return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
} EXPORT_SYMBOL_GPL(vhost_vq_access_ok);