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Open Source and information security mailing list archives
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Date: Thu, 03 Mar 2011 14:58:02 -0600 From: Matt Mackall <mpm@...enic.com> To: Dan Rosenberg <drosenberg@...curity.com> Cc: cl@...ux-foundation.org, penberg@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] Make /proc/slabinfo 0400 On Thu, 2011-03-03 at 12:50 -0500, Dan Rosenberg wrote: > Allowing unprivileged users to read /proc/slabinfo represents a security > risk, since revealing details of slab allocations can expose information > that is useful when exploiting kernel heap corruption issues. This is > evidenced by observing that nearly all recent public exploits for heap > issues rely on feedback from /proc/slabinfo to manipulate heap layout > into an exploitable state. Looking at a couple of these exploits, my suspicion is that looking at slabinfo simply improves the odds of success by a small factor (ie 10x or so) and doesn't present a real obstacle to attackers. All that appears to be required is to arrange that an overrunnable object be allocated next to one that is exploitable when overrun. And that can be arranged with fairly high probability on SLUB's merged caches. On the other hand, I'm not convinced the contents of this file are of much use to people without admin access. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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