From: "Mickaël Salaün" <mic@digikod.net>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Casey Schaufler <casey@schaufler-ca.com>,
linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>
Cc: james.l.morris@oracle.com, serge@hallyn.com,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH v1] LSM: Enable multiple calls to security_add_hooks() for the same LSM
Date: Sun, 30 Apr 2017 11:35:26 +0200 [thread overview]
Message-ID: <46eeb13f-db7f-68c4-0bf7-fddaaed5460c@digikod.net> (raw)
In-Reply-To: <201704301111.CFC52113.LFVFQJtFOOMHOS@I-love.SAKURA.ne.jp>
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On 30/04/2017 04:11, Tetsuo Handa wrote:
> Casey Schaufler wrote:
>> On 4/29/2017 12:02 PM, Mickael Salaun wrote:
>>> Check if the registering LSM already registered hooks just before. This
>>> enable to split hook declarations into multiple files without
>>> registering multiple time the same LSM name, starting from commit
>>> d69dece5f5b6 ("LSM: Add /sys/kernel/security/lsm").
>>
>> What's special about the previous registration? Keep it
>> simple and check it the name is already anywhere on the
>> list and only add it if it's not already there. I don't
>> see advantage to:
>>
>> % cat /sys/kernel/security/lsm
>> capability,yama,spiffy,selinux,spiffy
>>
>> over
>> % cat /sys/kernel/security/lsm
>> capability,yama,spiffy,selinux
>>
That was my first though, but then I realized that I don't see any use
case where an LSM would register hooks interleaved with other LSM. I
find the current approach simpler because we only search from the end of
the string and we do not handle special cases (e.g. matching only a
sub-name). Moreover, this approach respects the semantic describe in
Documentation/security/LSM.txt: "The list reflects the order in which
checks are made".
>
> - if (lsm_append(lsm, &lsm_names) < 0)
> + if (lsm && lsm_append(lsm, &lsm_names) < 0)
>
> in security_add_hooks()?
>
That was considered
[https://lkml.kernel.org/r/CAGXu5jJCvJ6-uZ=Kfhh3xD7UvaY+G99e9NXFMzvi=9OQzA6Ecg@mail.gmail.com]
but Kees and Casey seem to prefer the current approach.
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next prev parent reply other threads:[~2017-04-30 9:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-29 19:02 [PATCH v1] LSM: Enable multiple calls to security_add_hooks() for the same LSM Mickaël Salaün
2017-04-29 20:00 ` Casey Schaufler
2017-04-30 2:11 ` Tetsuo Handa
2017-04-30 9:35 ` Mickaël Salaün [this message]
2017-04-30 23:28 ` James Morris
2017-05-08 19:24 ` Mickaël Salaün
2017-05-08 20:07 ` Casey Schaufler
2017-05-08 20:12 ` Mickaël Salaün
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