Messages in this thread | | | Subject | Re: [PATCH] virtio-net: Add validation for used length | From | Jason Wang <> | Date | Tue, 25 May 2021 14:30:27 +0800 |
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在 2021/5/25 下午12:58, Xie Yongji 写道: > This adds validation for used length (might come > from an untrusted device) to avoid data corruption > or loss. > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com> > --- > drivers/net/virtio_net.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index c4711e23af88..2dcdc1a3c7e8 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -668,6 +668,13 @@ static struct sk_buff *receive_small(struct net_device *dev, > void *orig_data; > u32 act; > > + if (unlikely(len > GOOD_PACKET_LEN)) { > + pr_debug("%s: rx error: len %u exceeds max size %lu\n", > + dev->name, len, GOOD_PACKET_LEN); > + dev->stats.rx_length_errors++; > + goto err_xdp; > + }
Need to count vi->hdr_len here?
> + > if (unlikely(hdr->hdr.gso_type)) > goto err_xdp; > > @@ -739,6 +746,14 @@ static struct sk_buff *receive_small(struct net_device *dev, > } > rcu_read_unlock(); > > + if (unlikely(len > GOOD_PACKET_LEN)) { > + pr_debug("%s: rx error: len %u exceeds max size %lu\n", > + dev->name, len, GOOD_PACKET_LEN); > + dev->stats.rx_length_errors++; > + put_page(page); > + return NULL; > + } > + > skb = build_skb(buf, buflen); > if (!skb) { > put_page(page); > @@ -822,6 +837,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev, > void *data; > u32 act; > > + if (unlikely(len > truesize)) { > + pr_debug("%s: rx error: len %u exceeds truesize %lu\n", > + dev->name, len, (unsigned long)ctx); > + dev->stats.rx_length_errors++; > + goto err_xdp; > + }
There's a similar check after the XDP, let's simply move it here?
And do we need similar check in receive_big()?
Thanks
> + > /* Transient failure which in theory could occur if > * in-flight packets from before XDP was enabled reach > * the receive path after XDP is loaded.
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