Re: [PATCH v2 8/9] random: use hash function for crng_slow_load()

Eric Biggers
2022-02-21T03:40:30Z

On Wed, Feb 09, 2022 at 02:19:18AM +0100, Jason A. Donenfeld wrote:
> Since we have a hash function that's really fast, and the goal of
> crng_slow_load() is reportedly to "touch all of the crng's state", we
> can just hash the old state together with the new state and call it a
> day. This way we dont need to reason about another LFSR or worry about
> various attacks there. This code is only ever used at early boot and
> then never again.
>
> Cc: Theodore Ts'o <tytso@mit.edu>
> Cc: Dominik Brodowski <linux@dominikbrodowski.net>
> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
> ---
> drivers/char/random.c | 42 +++++++++++++++---------------------------
> 1 file changed, 15 insertions(+), 27 deletions(-)

Reviewed-by: Eric Biggers <ebiggers@google.com>

- Eric