netdev - Re: [PATCH net] sit: Set skb->protocol properly in ipip6_tunnel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 28 Nov 2016 10:17:23 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     David Miller <davem@...emloft.net>
Cc:     alexander.duyck@...il.com, sfr@...b.auug.org.au, elicooper@....com,
        netdev@...r.kernel.org
Subject: Re: [PATCH net] sit: Set skb->protocol properly in
 ipip6_tunnel_xmit()

On Mon, 2016-11-28 at 13:01 -0500, David Miller wrote:

> Hmmm, ip6_finish_output2() also does a proper assignment of skb->protocol,
> therefore why was commit ae148b085876fa771d9ef2c05f85d4b4bf09ce0d
> ("ip6_tunnel: Update skb->protocol to ETH_P_IPV6 in ip6_tnl_xmit()")
> necessary at all?
I was referring to Stephen bug report.

It appears that Eli changelog was not very precise, because his bug was
because of XFRM being involved.

xfrm_output() -> xfrm_output_gso() -> skb_gso_segment()

So XFRM calls skb_gso_segment() before ip_output() or
ip6_finish_output2() had a chance to change skb->protocol