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UPSTREAM: vhost: validate log when IOTLB is enabled

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[ Upstream commit d65026c6c6 ]

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: 6b1e6cc785 ("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>
(cherry picked from commit 992dbb1d5a)
Bug: 121166534
Test: Ran cuttlefish with android-4.4 + VSOCKETS, VMWARE_VMCI_VSOCKETS
Signed-off-by: Alistair Strachan <astrachan@google.com>

Change-Id: I64ef687ec8f55800ce300d0a0eac5473853bf6fd
This commit is contained in:
Jason Wang
2018-03-29 16:00:04 +08:00
committed by Alistair Strachan
parent 579cd6fe1e
commit 167925fc0e
1 changed files with 6 additions and 8 deletions
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14
drivers/vhost/vhost.c
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@@ -1176,14 +1176,12 @@ 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);