Commit 77fc95f8 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld
Browse files

random: account for arch randomness in bits 



Rather than accounting in bytes and multiplying (shifting), we can just
account in bits and avoid the shift. The main motivation for this is
there are other patches in flux that expand this code a bit, and
avoiding the duplication of "* 8" everywhere makes things a bit clearer.

Cc: stable@vger.kernel.org
Fixes: 12e45a2a ("random: credit architectural init the exact amount")
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
parent 39e0f991

drivers/char/random.c

+5 −5
Original line number Original line Diff line number Diff line
@@ -776,7 +776,7 @@ static struct notifier_block pm_notifier = { .notifier_call = random_pm_notifica 
int __init random_init(const char *command_line)

int __init random_init(const char *command_line)

{

{

	ktime_t now = ktime_get_real();

	ktime_t now = ktime_get_real();

	unsigned int i, arch_bytes;

	unsigned int i, arch_bits;

	unsigned long entropy;

	unsigned long entropy;





#if defined(LATENT_ENTROPY_PLUGIN)

#if defined(LATENT_ENTROPY_PLUGIN)
@@ -784,12 +784,12 @@ int __init random_init(const char *command_line) 
	_mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed));

	_mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed));

#endif

#endif





	for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE;

	for (i = 0, arch_bits = BLAKE2S_BLOCK_SIZE * 8;

	     i < BLAKE2S_BLOCK_SIZE; i += sizeof(entropy)) {

	     i < BLAKE2S_BLOCK_SIZE; i += sizeof(entropy)) {

		if (!arch_get_random_seed_long_early(&entropy) &&

		if (!arch_get_random_seed_long_early(&entropy) &&

		    !arch_get_random_long_early(&entropy)) {

		    !arch_get_random_long_early(&entropy)) {

			entropy = random_get_entropy();

			entropy = random_get_entropy();

			arch_bytes -= sizeof(entropy);

			arch_bits -= sizeof(entropy) * 8;

		}

		}

		_mix_pool_bytes(&entropy, sizeof(entropy));

		_mix_pool_bytes(&entropy, sizeof(entropy));

	}

	}
@@ -801,8 +801,8 @@ int __init random_init(const char *command_line) 
	if (crng_ready())

	if (crng_ready())

		crng_reseed();

		crng_reseed();

	else if (trust_cpu)

	else if (trust_cpu)

		_credit_init_bits(arch_bytes * 8);

		_credit_init_bits(arch_bits);

	used_arch_random = arch_bytes * 8 >= POOL_READY_BITS;

	used_arch_random = arch_bits >= POOL_READY_BITS;





	WARN_ON(register_pm_notifier(&pm_notifier));

	WARN_ON(register_pm_notifier(&pm_notifier));