[PATCH 1/1] vhost: fix missing descriptor chains length checks

[Yunjian Wang <wangyunjian@huawei.com>]

The descriptor chains length must be greater than the Virtio-net
header size. Otherwise, such descriptor chains sizes implies no
packet data.

Fixes: fe8477ebbd94 ("vhost: support async packed ring dequeue")
Cc: stable@dpdk.org

Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
---
 lib/vhost/virtio_net.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 69901ab3b5..8fc9bfa056 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -3962,6 +3962,16 @@ virtio_dev_tx_async_single_packed(struct virtio_net *dev,
 					 VHOST_ACCESS_RO) < 0))
 		return -1;
 
+	if (unlikely(buf_len <= dev->vhost_hlen)) {
+		if (!allocerr_warned) {
+			VHOST_DATA_LOG(dev->ifname, ERR, "Invalid buffer length.");
+			allocerr_warned = true;
+		}
+		return -1;
+	}
+
+	buf_len -= dev->vhost_hlen;
+
 	if (unlikely(virtio_dev_pktmbuf_prep(dev, pkts, buf_len))) {
 		if (!allocerr_warned) {
 			VHOST_DATA_LOG(dev->ifname, ERR, "Failed mbuf alloc of size %d from %s.",
-- 
2.33.0