linux-kernel - [PATCH RFC v4 5/5] vhost: last descriptor must have NEXT clear

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Date:   Sun, 13 Oct 2019 07:42:22 -0400
From:   "Michael S. Tsirkin" <mst@...hat.com>
To:     linux-kernel@...r.kernel.org
Cc:     kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org,
        netdev@...r.kernel.org, Jason Wang <jasowang@...hat.com>
Subject: [PATCH RFC v4 5/5] vhost: last descriptor must have NEXT clear

fetch_buf already guarantees we exit on a descriptor without a NEXT
flag.  Add a BUG_ON statement to make sure we don't overflow the buffer
in case of a bug.

Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
---
 drivers/vhost/vhost.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index d46c28149f6f..09f594bb069a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2656,6 +2656,8 @@ int vhost_get_vq_desc_batch(struct vhost_virtqueue *vq,
 			break;
 	}
 
+	BUG_ON(i >= vq->ndescs);
+
 	vq->first_desc = i + 1;
 
 	return ret;
-- 
MST