Messages in this thread | | | From | Yongji Xie <> | Date | Tue, 25 May 2021 16:45:56 +0800 | Subject | Re: Re: [PATCH] virtio-net: Add validation for used length |
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On Tue, May 25, 2021 at 2:30 PM Jason Wang <jasowang@redhat.com> wrote: > > > 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? >
We did len -= vi->hdr_len before.
> > > + > > 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?
Do we still need that in non-XDP cases?
> > And do we need similar check in receive_big()? >
It seems that the check in page_to_skb() can do similar things.
Thanks, Yongji
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