[PATCH 1/2] vhost-vdpa: Fix integer overflow in vhost_vdpa_process_iotlb_update()

From: Xie Yongji <xieyongji@bytedance.com>
To: mst@redhat.com, jasowang@redhat.com, dan.carpenter@oracle.com
Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] vhost-vdpa: Fix integer overflow in vhost_vdpa_process_iotlb_update()
Date: Fri, 16 Jul 2021 18:22:38 +0800	[thread overview]
Message-ID: <20210716102239.96-1-xieyongji@bytedance.com> (raw)

The "msg->iova + msg->size" addition can have an integer overflow
if the iotlb message is from a malicious user space application.
So let's fix it.

Fixes: 1b48dc03e575 ("vhost: vdpa: report iova range")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/vhost/vdpa.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 210ab35a7ebf..8e3c8790d493 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -615,6 +615,7 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	int ret = 0;
 
 	if (msg->iova < v->range.first ||
+	    msg->iova - 1 > U64_MAX - msg->size ||
 	    msg->iova + msg->size - 1 > v->range.last)
 		return -EINVAL;
 
-- 
2.11.0

