[CRYPTO] obfuscating kernel pointers

[Dan Rosenberg <drosenberg@xxxxxxxxxxxxx>]

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

--
To unsubscribe from this list: send the line "unsubscribe linux-crypto" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html