netdev - Re: [3/3] gso: Handle malicious GRO packets without crashing

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Date:	Tue, 12 Nov 2013 02:55:03 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	Ben Hutchings <bhutchings@...arflare.com>,
	David Miller <davem@...emloft.net>,
	christoph.paasch@...ouvain.be, netdev@...r.kernel.org,
	hkchu@...gle.com, mwdalton@...gle.com
Subject: Re: [3/3] gso: Handle malicious GRO packets without crashing

On Thu, Nov 07, 2013 at 10:13:29PM +0300, Sergei Shtylyov wrote:
> Hello.
> 
> On 11/07/2013 10:08 AM, Herbert Xu wrote:
> 
> >As virtio_net can now generate GRO frag_list packets without
> >sufficient verification, we need to handle malicious GRO packets
> >thrown at us.
> 
> >This patch converts to affected BUG_ONs in skb_segment to rate-
> >limited warnings.
> 
> >Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
> 
> >diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> >index bcc3f1c..fb1106d 100644
> >--- a/net/core/skbuff.c
> >+++ b/net/core/skbuff.c
> >@@ -2881,7 +2881,15 @@ struct sk_buff *skb_segment(struct sk_buff *skb, netdev_features_t features)
> >  			while (tail->next)
> >  				tail = tail->next;
> >
> >-			BUG_ON(fskb && tail->len != len + doffset);
> >+			if (fskb && tail->len != len + doffset) {
> >+				net_warn_ratelimited(
> >+					"skb_segment: "
> >+					"illegal GSO fragment: %u %u\n",
> 
>    Don't break up the message -- chekpatch.pl should allow that...

Thanks for the comment.  In the latest version of this patch
this should no longer be an issue.
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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