Re: [PATCH v2 1/3] Add the latent_entropy gcc plugin

Andrew Morton
2016-06-01T19:42:31Z

On Tue, 31 May 2016 01:31:45 +0200 Emese Revfy <re.emese@gmail.com> wrote:

> This plugin mitigates the problem of the kernel having too little entropy during
> and after boot for generating crypto keys.
>
> It creates a local variable in every marked function. The value of this variable is
> modified by randomly chosen operations (add, xor and rol) and
> random values (gcc generates them at compile time and the stack pointer at runtime).
> It depends on the control flow (e.g., loops, conditions).
>
> Before the function returns the plugin writes this local variable
> into the latent_entropy global variable. The value of this global variable is
> added to the kernel entropy pool in do_one_initcall() and _do_fork().

I don't think I'm really understanding. Won't this produce the same
value on each and every boot?