linux-kernel - Re: [PATCH net-next v4 4/4] net: gro: move L3 flush checks to tcp_gro

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: Tue, 26 Mar 2024 15:43:42 +0100
From: Richard Gobert <richardbgobert@...il.com>
To: Eric Dumazet <edumazet@...gle.com>
Cc: davem@...emloft.net, kuba@...nel.org, pabeni@...hat.com,
 willemdebruijn.kernel@...il.com, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH net-next v4 4/4] net: gro: move L3 flush checks to
 tcp_gro_receive

Eric Dumazet wrote:
> On Mon, Mar 25, 2024 at 7:27 PM Richard Gobert <richardbgobert@...il.com> wrote:
>>
>> {inet,ipv6}_gro_receive functions perform flush checks (ttl, flags,
>> iph->id, ...) against all packets in a loop. These flush checks are used
>> currently only in tcp flows in GRO.
> 
> I think this is a bug.
> 
> GRO should not aggregate packets if their ttl/tos fields do not match.

AFAIU, the only UDP flow where ttl/flush_id need to be checked is when
udp_gro_receive_segment calls skb_gro_receive - could you confirm / point
out if there are any other flows to which these flush checks may be
relevant?

As I've discussed with Willem in v3 I prefer to fix this bug in a separate
series.