Date: Fri, 20 May 2011 20:42:54 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Dan Rosenberg <drosenberg@vsecurity.com>
Cc: Kees Cook <kees.cook@canonical.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-kernel@vger.kernel.org, davej@redhat.com, davem@davemloft.net,
        eranian@google.com, adobriyan@gmail.com, penberg@kernel.org
Subject: Re: [BUG] perf: bogus correlation of kernel symbols
Message-ID: <20110520184254.GB18322@elte.hu>
References: <1305293345.1949.22.camel@dan>
 <20110516153527.GC21107@elte.hu>
 <1305852966.3005.19.camel@dan>
 <20110520120750.GJ14745@elte.hu>
 <1305896093.3005.24.camel@dan>
 <20110520131108.GA17699@elte.hu>
 <1305913261.20623.12.camel@dan>
 <BANLkTinCnqrzMyoSzS04fCAqks1bd9Y8=g@mail.gmail.com>
 <20110520182705.GU25448@outflux.net>
 <1305916484.20623.23.camel@dan>
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* Dan Rosenberg <drosenberg@vsecurity.com> wrote:

> At least one distro (Red Hat) ships with panic_on_oops enabled by default, so 
> attackers don't get more than one chance.  Likewise, vulnerabilities in 
> interrupt context will only have one chance, as will any issue where failed 
> exploitation prevents subsequent attempts, as is frequently the case due to 
> failures to clean up locking primitives on an OOPS.

So it's basically a last line of defense: the attacker has to assume the risk 
of the attack being detected.

That has a chilling effect on some types of attacks: especially those where the 
attacker goes against a high value target with a zero day kernel exploit. 
Risking a crash does not just mean possibly alerting the target, but also means 
possibly losing the zero-day exploit - if that oops log gets to a kernel 
developer who starts wondering about the weird backtrace.

Thanks,

	Ingo
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