From e878d78b9a7403fabc89ecc93c56928b74d14f01 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Wed, 28 Sep 2011 04:40:54 +0000 Subject: [PATCH] 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 Cc: "Michael S. Tsirkin" Cc: virtualization@lists.linux-foundation.org Cc: netdev@vger.kernel.org Cc: kvm@vger.kernel.org Signed-off-by: Sasha Levin Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index d6e93ba9ff47..b8225f3b31d1 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -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; -- 2.20.1