virtio_net: Add hash_key_length check

Add hash_key_length check in virtnet_probe() to avoid possible out of
bound errors when setting/reading the hash key.

Fixes: c7114b1 ("drivers/net/virtio_net: Added basic RSS support.")
Signed-off-by: Philo Lu <lulie@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Joe Damato <jdamato@fastly.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: LPhgh

drivers/net/virtio_net.c

@@ -6451,6 +6451,12 @@ static int virtnet_probe(struct virtio_device *vdev)
 	if (vi->has_rss || vi->has_rss_hash_report) {
 		vi->rss_key_size =
 			virtio_cread8(vdev, offsetof(struct virtio_net_config, rss_max_key_size));
+		if (vi->rss_key_size > VIRTIO_NET_RSS_MAX_KEY_SIZE) {
+			dev_err(&vdev->dev, "rss_max_key_size=%u exceeds the limit %u.\n",
+				vi->rss_key_size, VIRTIO_NET_RSS_MAX_KEY_SIZE);
+			err = -EINVAL;
+			goto free;
+		}
 
 		vi->rss_hash_types_supported =
 		    virtio_cread32(vdev, offsetof(struct virtio_net_config, supported_hash_types));