Messages in this thread | | | Date | Mon, 3 Oct 2011 21:04:16 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v2 1/2] virtio-net: Verify page list size before fitting into skb |
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On Wed, Sep 28, 2011 at 05:40:54PM +0300, Sasha Levin wrote: > 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> > --- > drivers/net/virtio_net.c | 13 +++++++++++++ > 1 files changed, 13 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 0c7321c..bde0dec 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; > + } > +
BTW, receive_mergeable does pr_debug("%s: packet too long\n", skb->dev->name); skb->dev->stats.rx_length_errors++;
which makes sense.
> while (len) { > set_skb_frag(skb, page, offset, &len); > page = (struct page *)page->private; > -- > 1.7.6.1
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