Re: [PATCH try #2] security: Convert LSM into a static interface

From: "Serge E. Hallyn" <serue@us.ibm.com>
To: Greg KH <greg@kroah.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>,
	Adrian Bunk <bunk@stusta.de>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	James Morris <jmorris@namei.org>,
	Andreas Gruenbacher <agruen@suse.de>,
	Chris Wright <chrisw@sous-sol.org>,
	linux-security-module@vger.kernel.org,
	Andrew Morgan <agm@google.com>, Andrew Morton <akpm@google.com>,
	Stephen Smalley <sds@tycho.nsa.gov>,
	lkml <linux-kernel@vger.kernel.org>,
	Arjan van de Ven <arjan@infradead.org>,
	Eric Paris <eparis@redhat.com>
Subject: Re: [PATCH try #2] security: Convert LSM into a static interface
Date: Tue, 26 Jun 2007 13:40:48 -0500	[thread overview]
Message-ID: <20070626184048.GA12109@sergelap.austin.ibm.com> (raw)
In-Reply-To: <20070626181823.GA5602@kroah.com>

Quoting Greg KH (greg@kroah.com):
> On Tue, Jun 26, 2007 at 09:06:44AM -0500, Serge E. Hallyn wrote:
> > Quoting Adrian Bunk (bunk@stusta.de):
> > > On Mon, Jun 25, 2007 at 10:57:31PM -0500, Serge E. Hallyn wrote:
> > > > Quoting James Morris (jmorris@namei.org):
> > > > > On Mon, 25 Jun 2007, Andreas Gruenbacher wrote:
> > > > > 
> > > > > > It's useful for some LSMs to be modular, and LSMs which are y/n options won't 
> > > > > > have any security architecture issues with unloading at all. 
> > > > > 
> > > > > Which LSMs?  Upstream, there are SELinux and capabilty, and they're not 
> > > > > safe as loadable modules.
> > > > > 
> > > > > > The mere fact 
> > > > > > that SELinux cannot be built as a module is a rather weak argument for 
> > > > > > disabling LSM modules as a whole, so  please don't.
> > > > > 
> > > > > That's not the argument.  Please review the thread.
> > > > 
> > > > The argument is 'abuse', right?
> > > > 
> > > > Abuse is defined as using the LSM hooks for non-security applications,
> > > > right?
> > > > 
> > > > It seems to me that the community is doing a good job of discouraging
> > > > such abuse - by redirecting the "wrong-doers" to implement proper
> > > > upstream solutions, i.e. taskstats, the audit subsystem, etc.
> > > > 
> > > > Such encouragement seems a far better response than taking away freedoms
> > > > and flexibility from everyone.
> > > 
> > > We are not living in a world where everyone had good intentions...
> > 
> > Oh no, i took a wrong turn somewhere  :)
> > 
> > > For _some_ "wrong-doers" your approach works.
> > > 
> > > But how do you convince the "wrong-doers" who do things like putting 
> > > MODULE_LICENSE("GPL") into their binary-only modules and who ignore you 
> > > and get away because noone sues them?
> > 
> > Do these really exist?
> 
> Yes they do.
> 
> > Maybe noone sues them because noone knows who they are...
> 
> Maybe no one knows because the people doing the legal action against
> them are trying to be nice and do it quietly.

So they're being nice to the violaters, and then clamping down on
everyone...

> And legal action takes time, it is quite slow going unfortunatly.
> 
> Heck, I've seen code that is even properly licensed under the GPL abuse
> this security layer for things it was not ment to do at all, and that
> stuff comes from _very_ big companies that really should know better...

But that's back to the other type of 'abuse' which i was originally
talking about, and which IMO is being well addressed through education.

As for the others, I have no better suggestions.  I wish I did.

> So I agree that we should unexport it.  It will make people who want to
> abuse the interface at least think twice about it.

And those who don't abuse it too.

> thanks,
> 
> greg "I want to mark structures read-only" k-h

And I know I'm not the one who's going to stop you...

-serge