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SubjectRe: [PATCH 2/2] virtio-net: Prevent NULL dereference
On Mon, Sep 26, 2011 at 08:41:09PM +0300, Sasha Levin wrote:
> This patch prevents a NULL dereference when the user has passed a length
> longer than an actual buffer to virtio-net.
>
> 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>

Hmm, another protection against a buggy device, right?
No problem with that, but let's discard the packet
and print a disgnostic, so that the user can discover
what happened.

> ---
> drivers/net/virtio_net.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 64e0717..8d32c1e 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -198,7 +198,7 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
> len -= copy;
> offset += copy;
>
> - while (len) {
> + while (len && page) {
> set_skb_frag(skb, page, offset, &len);
> page = (struct page *)page->private;
> offset = 0;
> --
> 1.7.6.1


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