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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
	serue@us.ibm.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org,
	linux-kernel@vger.kernel.org, takedakn@nttdata.co.jp,
	haradats@nttdata.co.jp
Subject: Re: [PATCH (mmotm-2008-12-02-17-08)] Introduce security_path_set/clear() hooks.
Date: Sat, 6 Dec 2008 06:16:42 +0000	[thread overview]
Message-ID: <20081206061642.GM28946@ZenIV.linux.org.uk> (raw)
In-Reply-To: <1228513998.21715.75.camel@localhost.localdomain>

On Fri, Dec 05, 2008 at 04:53:18PM -0500, Stephen Smalley wrote:
> > Right. Locations of inserting security_path_set()/security_path_clear() pairs
> > are subset of mnt_want_write()/mnt_drop_write() pairs. Thus, we can insert
> > security_path_set()/security_path_clear() pairs into
> > mnt_want_write()/mnt_drop_write() pairs, if we can tolerate performance
> > regression. According to our rough measurement, there is about 8 - 22% of
> > performance regression. But this approach needs minimum modification to the
> > existing kernel (only two hooks to be inserted).
> 
> I assume you also need separate hooks to cover the read-only open case?
> As for your performance, your implementation of mp_* is clearly
> non-optimal, so I'd expect there is plenty of room for improvement
> there.

And just what will happen if you end up with foo_mkdir() calling something
that does e.g. pathname resolution in fs-controlled private namespace and
creates/removes some files there?

      parent reply	other threads:[~2008-12-06  6:16 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20081120112543.799450455@I-love.SAKURA.ne.jp>
     [not found] ` <20081120112727.557697893@I-love.SAKURA.ne.jp>
     [not found]   ` <1228161612.18720.211.camel@moss-spartans.epoch.ncsc.mil>
     [not found]     ` <200812021939.FFC05200.OVQJSOMtFFHLFO@I-love.SAKURA.ne.jp>
     [not found]       ` <1228225719.26101.52.camel@moss-spartans.epoch.ncsc.mil>
     [not found]         ` <49364808.1070907@nttdata.co.jp>
2008-12-03  8:56           ` [PATCH (mmotm-2008-12-02-17-08)] Introduce security_path_set/clear() hooks Kentaro Takeda
2008-12-03 14:13             ` Stephen Smalley
2008-12-04 12:00               ` Tetsuo Handa
2008-12-04 18:20                 ` Serge E. Hallyn
2008-12-04 21:41                   ` [PATCH (mmotm-2008-12-02-17-08)] Introducesecurity_path_set/clear() hooks Tetsuo Handa
2008-12-05 21:53                 ` [PATCH (mmotm-2008-12-02-17-08)] Introduce security_path_set/clear() hooks Stephen Smalley
2008-12-05 23:27                   ` Tetsuo Handa
2008-12-06  5:25                     ` [RFC] Add "reason" parameter to mnt_want_write() Tetsuo Handa
2008-12-06  5:53                       ` Al Viro
2008-12-06  6:16                   ` Al Viro [this message]

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