netdev - Re: [PATCH net 2/2] IPv6: reply ICMP error if the first fragment don't include all headers

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Date:   Thu, 8 Oct 2020 16:36:39 +0800
From:   Hangbin Liu <liuhangbin@...il.com>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org, "David S . Miller" <davem@...emloft.net>,
        Alexey Kuznetsov <kuznet@....inr.ac.ru>,
        Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH net 2/2] IPv6: reply ICMP error if the first fragment
 don't include all headers

On Wed, Oct 07, 2020 at 07:58:07AM -0700, Jakub Kicinski wrote:
> On Wed,  7 Oct 2020 11:55:02 +0800 Hangbin Liu wrote:
> > Based on RFC 8200, Section 4.5 Fragment Header:
> > 
> >   -  If the first fragment does not include all headers through an
> >      Upper-Layer header, then that fragment should be discarded and
> >      an ICMP Parameter Problem, Code 3, message should be sent to
> >      the source of the fragment, with the Pointer field set to zero.
> > 
> > As the packet may be any kind of L4 protocol, I only checked if there
> > has Upper-Layer header by pskb_may_pull(skb, offset + 1).
> > 
> > As the 1st truncated fragment may also be ICMP message, I also add
> > a check in ICMP code is_ineligible() to let fragment packet with nexthdr
> > ICMP but no ICMP header return false.
> > 
> > Signed-off-by: Hangbin Liu <liuhangbin@...il.com>
> 
> net/ipv6/icmp.c:159:65: warning: incorrect type in argument 4 (different base types)
> net/ipv6/icmp.c:159:65:    expected unsigned short *fragoff
> net/ipv6/icmp.c:159:65:    got restricted __be16 *

Ah, Thanks for pointing out this error, I will fix it.

Regards
Hangbin