From: Daniel Axtens <dja@axtens.net>
To: Daniel Borkmann <daniel@iogearbox.net>,
David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, alexei.starovoitov@gmail.com
Subject: Re: [PATCH 5/6] net: add and use helpers when adjusting gso_size
Date: Thu, 01 Mar 2018 11:17:44 +1100 [thread overview]
Message-ID: <878tbcejiv.fsf@linkitivity.dja.id.au> (raw)
In-Reply-To: <f4684aae-10e4-6e64-08b5-3995f19d9b8d@iogearbox.net>
Hi Daniel,
>> It means that a user loaded eBPF program can trigger logs full of
>> warnings merely by using this eBPF helper and generating GSO'd SCTP
>> traffic.
>>
>> Daniel and Alexei, this is a serious problem. The eBPF helpers
>> mentioned here cannot handle SCTP GSO packets properly, and in fact
>> corrupt them if they adjust the gso_size.
>>
>> SCTP GSO packets use the GSO_BY_FRAGS scheme and cannot be treated
>> the same way we treat normal GSO packets.
>
> Thanks for Cc, I would have missed it. This patch in combination with
> patch 6/6 seems okay since we reject it in these cases, which is fine
> (although it could be a warn_once), but patch 6/6 is definitely buggy
> in that we leave the skb in a half edited state when leaving the helper.
> Daniel, want me to fix this up from bpf side and route 5/6 and actual
> fix via bpf tree? Otherwise please respin with fixed 6/6.
I'm happy for you to take these two via the bpf tree with whatever
fixes/changes are appropriate - I'm no eBPF expert so my fix was a 'best
guess' only. Let me know if you would like anything respun on my end.
Regards,
Daniel
PS. apologies for missing you on Cc - will make sure you're cced on any
future bpf-related work!
>
> Thanks,
> Daniel
next prev parent reply other threads:[~2018-03-01 0:17 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-27 13:04 [PATCH 0/6]GSO_BY_FRAGS correctness improvements Daniel Axtens
2018-02-27 13:04 ` [PATCH 1/6] net: rename skb_gso_validate_mtu -> skb_gso_validate_network_len Daniel Axtens
2018-02-27 13:04 ` [PATCH 2/6] net: sched: tbf: handle GSO_BY_FRAGS case in enqueue Daniel Axtens
2018-02-27 13:04 ` [PATCH 3/6] net: xfrm: use skb_gso_validate_network_len() to check gso sizes Daniel Axtens
2018-02-27 13:04 ` [PATCH 4/6] net: make skb_gso_*_seglen functions private Daniel Axtens
2018-02-28 15:53 ` David Miller
2018-02-27 13:04 ` [PATCH 5/6] net: add and use helpers when adjusting gso_size Daniel Axtens
2018-02-28 15:56 ` David Miller
2018-02-28 16:21 ` Daniel Borkmann
2018-03-01 0:17 ` Daniel Axtens [this message]
2018-03-01 0:47 ` Daniel Borkmann
2018-02-27 13:04 ` [PATCH 6/6] net: filter: refuse to change gso_size of SCTP packets Daniel Axtens
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=878tbcejiv.fsf@linkitivity.dja.id.au \
--to=dja@axtens.net \
--cc=alexei.starovoitov@gmail.com \
--cc=daniel@iogearbox.net \
--cc=davem@davemloft.net \
--cc=netdev@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox