In-Reply-To: <20080813065401.1bbdcb07@infradead.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: "Adrian Bunk" <bunk@kernel.org>, davecb@sun.com,
       "Greg KH" <greg@kroah.com>, "Press, Jonathan" <Jonathan.Press@ca.com>,
       linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org,
       malware-list@lists.printk.net, "Mihai Don??u" <mdontu@bitdefender.com>,
       "Pavel Machek" <pavel@suse.cz>
Subject: Re: [malware-list] [RFC 0/5] [TALPA] Intro to a linuxinterfaceforon access
 scanning
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From: tvrtko.ursulin@sophos.com
Date: Wed, 13 Aug 2008 15:16:12 +0100
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Arjan van de Ven <arjan@infradead.org> wrote on 13/08/2008 14:54:01:

> > I am not sure what you are suggesting, and I may have missed the
> > libmalware proposal (I don't see any mention of that specific idea in
> > any other message).  However, just to be clear...  At no point did we
> > suggest that the kernel would do any scanning.  What we have been
> > interested in is a mechanism that can allow a scanning application to
> > be notified by the kernel of specific i/o events, for those events to
> > be blocked by the kernel until a user-space scan is done, and then the
> > user-space scan sends back allow or deny, at which point the i/o event
> > returns to the caller -- either success or error.  This is the only
> > way that malware can be guaranteed of being detected when it is used
> > (for local application purposes or for transmission to another
> > platform) or created. 
> 
> this is a very broad statement that ignores the LD_PRELOAD approach,
> and thus not true.

LD_PRELOAD does not solve at least knfsd and suid binaries. But we are 
going in circles. :)
 
> > Also, a solution that requires applications to be modified will not
> > work, because there is no way that we would be able to get ALL
> > applications on the machines to be modified in the required ways.  If
> > ANY applications are not so modified, then you have an unacceptable
> 
> you don't need to modify applications to make them use a library...

Same is true for a kernel solution. Plus, it also works for those who make 
system calls directly, knfsd and suid binaries, and we can have cheap and 
ultra-efficient caching. Not much kernel code, even less complex kernel 
code and unmeasurable impact when not used and compiled in. What are the 
big technical objections to that?

--
Tvrtko A. Ursulin
Senior Software Engineer, Sophos

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