netdev - Re: [PATCH bpf-next 02/11] bpfilter: Add logging facility

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]

Message-ID: <681F9A5A-63F0-432A-B188-CF4FC11AF2A8@fb.com>
Date:   Thu, 20 May 2021 16:35:45 +0000
From:   Song Liu <songliubraving@...com>
To:     Dmitrii Banshchikov <me@...que.spb.ru>
CC:     Song Liu <song@...nel.org>, bpf <bpf@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        "David S . Miller" <davem@...emloft.net>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, Martin Lau <kafai@...com>,
        Yonghong Song <yhs@...com>,
        John Fastabend <john.fastabend@...il.com>,
        KP Singh <kpsingh@...nel.org>,
        Networking <netdev@...r.kernel.org>, Andrey Ignatov <rdna@...com>
Subject: Re: [PATCH bpf-next 02/11] bpfilter: Add logging facility



> On May 20, 2021, at 12:08 AM, Dmitrii Banshchikov <me@...que.spb.ru> wrote:
> 
> On Wed, May 19, 2021 at 10:32:25AM -0700, Song Liu wrote:
>> On Tue, May 18, 2021 at 11:05 PM Dmitrii Banshchikov <me@...que.spb.ru> wrote:
>>> 
>>> There are three logging levels for messages: FATAL, NOTICE and DEBUG.
>>> When a message is logged with FATAL level it results in bpfilter
>>> usermode helper termination.
>> 
>> Could you please explain why we choose to have 3 levels? Will we need
>> more levels,
>> like WARNING, ERROR, etc.?
> 
> 
> I found that I need one level for development - to trace what
> goes rignt and wrong. At the same time as those messages go to
> dmesg this level is too verbose to be used under normal
> circumstances. That is why another level is introduced. And the
> last one exists to verify invariants or error condintions from
> which there is no right way to recover and they result in
> bpfilter termination.

/dev/kmsg supports specifying priority of the message. Like:

   echo '<4> This message have priority of 4' > /dev/kmsg

Therefore, with proper priority settings, we can have more levels safely.
Does this make sense?

Thanks,
Song

[...]