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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 5d5a9d9..5320039 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -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);
--
2.7.4
