This is a note to let you know that I've just added the patch titled

vhost: validate log when IOTLB is enabled

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: vhost-validate-log-when-iotlb-is-enabled.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Tue Apr 10 23:20:08 CEST 2018

From: Jason Wang jasowang@redhat.com Date: Thu, 29 Mar 2018 16:00:04 +0800 Subject: vhost: validate log when IOTLB is enabled

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) + return ret; + + return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); } EXPORT_SYMBOL_GPL(vhost_vq_access_ok);

Patches currently in stable-queue which might be from jasowang@redhat.com are

queue-4.14/vhost-validate-log-when-iotlb-is-enabled.patch queue-4.14/vhost_net-add-missing-lock-nesting-notation.patch queue-4.14/vhost-correctly-remove-wait-queue-during-poll-failure.patch