virtio-net: Verify page list size before fitting into skb

This patch verifies that the length of a buffer stored in a linked list
of pages is small enough to fit into a skb.

If the size is larger than a max size of a skb, it means that we shouldn't
go ahead building skbs anyway since we won't be able to send the buffer as
the user requested.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
Cc: kvm@vger.kernel.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sasha Levin 2011-09-28 04:40:54 +00:00 коммит произвёл David S. Miller
Родитель 515853ccec
Коммит e878d78b9a
1 изменённых файлов: 13 добавлений и 0 удалений

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@ -195,6 +195,19 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
len -= copy;
offset += copy;
/*
* Verify that we can indeed put this data into a skb.
* This is here to handle cases when the device erroneously
* tries to receive more than is possible. This is usually
* the case of a broken device.
*/
if (unlikely(len > MAX_SKB_FRAGS * PAGE_SIZE)) {
if (net_ratelimit())
pr_debug("%s: too much data\n", skb->dev->name);
dev_kfree_skb(skb);
return NULL;
}
while (len) {
set_skb_frag(skb, page, offset, &len);
page = (struct page *)page->private;