vhost: Fix Spectre V1 vulnerability

[ Upstream commit ff002269a4ee9c769dbf9365acef633ebcbd6cbe ]

The idx in vhost_vring_ioctl() was controlled by userspace, hence a
potential exploitation of the Spectre variant 1 vulnerability.

Fixing this by sanitizing idx before using it to index d->vqs.

Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jason Wang 2018-10-30 14:10:49 +08:00 committed by Greg Kroah-Hartman
parent 8de8589c09
commit 628a149b00

View file

@ -27,6 +27,7 @@
#include <linux/cgroup.h>
#include <linux/module.h>
#include <linux/sort.h>
#include <linux/nospec.h>
#include "vhost.h"
@ -748,6 +749,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
if (idx >= d->nvqs)
return -ENOBUFS;
idx = array_index_nospec(idx, d->nvqs);
vq = d->vqs[idx];
mutex_lock(&vq->mutex);