Re: crypto: zeroization of sensitive data in af_alg

[Sandy Harris]

On Sun, Nov 9, 2014 at 5:33 PM, Stephan Mueller <smueller@xxxxxxxxxx> wrote:

> while working on the AF_ALG interface, I saw no active zeroizations of memory
> that may hold sensitive data that is maintained outside the kernel crypto API
> cipher handles. ...

> I think I found the location for the first one: hash_sock_destruct that should
> be enhanced with a memset(0) of ctx->result.

See also a thread titled "memset() in crypto code?" on the linux
crypto list. The claim is that gcc can optimise memset() away so you
need a different function to guarantee the intended results. There's a
patch to the random driver that uses a new function
memzero_explicit(), and one of the newer C standards has a different
function name for the purpose.
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