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Date: Tue, 16 Nov 2010 09:58:37 +1100 (EST)
From: James Morris <jmorris@namei.org>
To: Eric Paris <eparis@redhat.com>
cc: Eric Paris <eparis@parisplace.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Joe Perches <joe@perches.com>,
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        Andrew Morton <akpm@linux-foundation.org>,
        LSM List <linux-security-module@vger.kernel.org>
Subject: Re: [PATCH] Fix dmesg_restrict build failure with CONFIG_EMBEDDED=y
 and CONFIG_PRINTK=n
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On Mon, 15 Nov 2010, Eric Paris wrote:

> Not sure how that's possible.  I mean, I guess it's possible if the
> fabled LSM reimplements the cap call, but I'm not sure how you can
> remove a restrictive only security check without 'weakening' the system
> in some way.

If generic security logic is mixed into a capability call, then not 
implementing the cap call also loses the generic security logic.

e.g. dmesg_restrict should always be verified, regardless of whether 
cap_security() is called or not.

If cap_syslog() should always be called, then it should not be possible 
not not call it :-)


- James
-- 
James Morris
<jmorris@namei.org>