Re: [PATCH v2 05/10] random: group crng functions

From: Dominik Brodowski <linux@dominikbrodowski.net>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: linux-kernel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>
Subject: Re: [PATCH v2 05/10] random: group crng functions
Date: Sun, 13 Feb 2022 07:54:37 +0100	[thread overview]
Message-ID: <YgirLX70xHFXTMDf@owl.dominikbrodowski.net> (raw)
In-Reply-To: <20220212122318.623435-6-Jason@zx2c4.com>

> @@ -724,54 +563,433 @@ static void crng_make_state(u32 chacha_state[CHACHA_STATE_WORDS],
>  	local_unlock_irqrestore(&crngs.lock, flags);
>  }
>  
> -static ssize_t get_random_bytes_user(void __user *buf, size_t nbytes)
> +/*
> + * This function is for crng_init < 2 only.

No, it's for crng_init == 0 only.

> +/*
> + * This function is for crng_init < 2 only.

Same here.

> + * Batched entropy returns random integers. The quality of the random
> + * number is good as /dev/urandom. In order to ensure that the randomness

/dev/random

> +size_t __must_check get_random_bytes_arch(void *buf, size_t nbytes)

Sidenote: We should get rid of the sole caller of that function, and then of
this function. AFAICS, using get_random_bytes() (once rand_initialize() has
been called) should never be less secure than get_random_bytes_arch() IFF
arch_get_random_long() exists -- which is what the sole caller seems to be
interested in.

Otherwise, all looks good. Thanks,

	Dominik