From: Jason Wang <jasowang@redhat.com>
Date: Tue, 30 Oct 2018 06:10:49 +0000 (+0800)
Subject: vhost: Fix Spectre V1 vulnerability
X-Git-Tag: v4.9.136~26
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=242e6f52a0cd1b5526a093e6bb39cec2b76b0284;p=platform%2Fkernel%2Flinux-amlogic.git

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>
---

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index c569b6454a9d..4c5625cb540c 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -28,6 +28,7 @@
 #include <linux/module.h>
 #include <linux/sort.h>
 #include <linux/interval_tree_generic.h>
+#include <linux/nospec.h>
 
 #include "vhost.h"
 
@@ -1289,6 +1290,7 @@ 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);