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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Xie Yongji <xieyongji@bytedance.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Jason Wang <jasowang@redhat.com>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 41/98] vhost-vdpa: Fix integer overflow in vhost_vdpa_process_iotlb_update()
Date:   Tue, 24 Aug 2021 12:58:11 -0400
Message-Id: <20210824165908.709932-42-sashal@kernel.org>
In-Reply-To: <20210824165908.709932-1-sashal@kernel.org>
References: <20210824165908.709932-1-sashal@kernel.org>
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From: Xie Yongji <xieyongji@bytedance.com>

[ Upstream commit 0e398290cff997610b66e73573faaee70c9a700e ]

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>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210728130756.97-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/vhost/vdpa.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 80184153ac7d..c4d53ff06bf8 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -623,7 +623,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	long pinned;
 	int ret = 0;
 
-	if (msg->iova < v->range.first ||
+	if (msg->iova < v->range.first || !msg->size ||
+	    msg->iova > U64_MAX - msg->size + 1 ||
 	    msg->iova + msg->size - 1 > v->range.last)
 		return -EINVAL;
 
-- 
2.30.2