netdev - Re: [RESEND net v3] net: ip_tunnel: fix mtu calculation

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:   Fri, 29 Jan 2021 16:28:52 -0800
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     Vadim Fedorenko <vfedorenko@...ek.ru>
Cc:     Jakub Kicinski <kuba@...nel.org>,
        Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        Slava Bacherikov <mail@...va.cc>,
        Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [RESEND net v3] net: ip_tunnel: fix mtu calculation

On Fri, Jan 29, 2021 at 2:30 PM Vadim Fedorenko <vfedorenko@...ek.ru> wrote:
>
> dev->hard_header_len for tunnel interface is set only when header_ops
> are set too and already contains full overhead of any tunnel encapsulation.
> That's why there is not need to use this overhead twice in mtu calc.
>
> Fixes: fdafed459998 ("ip_gre: set dev->hard_header_len and dev->needed_headroom properly")
> Reported-by: Slava Bacherikov <mail@...va.cc>
> Signed-off-by: Vadim Fedorenko <vfedorenko@...ek.ru>

I have no objection, just please double check this does not break
other IP tunnels as you touch the core ip tunnel code, especially
those using ip_tunnel_header_ops.

Thanks.