netdev - Re: [PATCH 5/6] dccp: Fix incorrect length check for ICMPv4 packets

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Message-ID: <20080725102558.GB21357@gerrit.erg.abdn.ac.uk>
Date:	Fri, 25 Jul 2008 11:25:58 +0100
From:	Gerrit Renker <gerrit@....abdn.ac.uk>
To:	David Miller <davem@...emloft.net>
Cc:	dccp@...r.kernel.org, netdev@...r.kernel.org, yjwei@...fujitsu.com
Subject: Re: [PATCH 5/6] dccp: Fix incorrect length check for ICMPv4 packets

| > -	if (skb->len < (iph->ihl << 2) + 8) {
| > +	if (skb->len < (iph->ihl << 2) + __dccp_basic_hdr_len(dh)) {
| >  		ICMP_INC_STATS_BH(net, ICMP_MIB_INERRORS);
| >  		return;
| >  	}
| 
| You can't dereference "dh" before you know there is even
| space past offset "iph->ihl << 2".  Yet that is what doing
| an unconditional __dccp_basic_hdr_len() call here is going
| to do.
| 
Oh that was my fault. Thanks a lot for pointing this out.

Will work out a fixed/improved version for both patches,
test and then resubmit.

Gerrit
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