From: Dan Rosenberg <drosenberg@vsecurity.com>
Subject: [CRYPTO] obfuscating kernel pointers
Date: Fri, 12 Nov 2010 08:32:01 -0500
Message-ID: <1289568721.3090.267.camel@Dan>
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To: linux-crypto@vger.kernel.org
Sender: linux-crypto-owner@vger.kernel.org

Hi Crypto people,

I'm planning on submitting a patch that introduces a new %p format
specifier that obfuscates kernel pointers depending on privileges.  This
change is for security reasons - many networking protocols expose
pointers to socket structures in their /proc interfaces, which are
attractive targets when exploiting other issues.

It's been suggested that I initialize a secret value at boot, and use
that as the key to a crypto hash function.  I should use a function that
is relatively fast (ideally), produces a unique output based on its
input of a pointer, and produces consistent output when given the same
input.  It should be difficult to infer the input given only the output.

I have two questions:

1. What is a proper, safe way of initializing a random value at boot?
Are there any existing examples that do this?

2. Can you recommend a crypto algorithm that would be well suited for
this pointer obfuscation?

Thanks,
Dan