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authorJason A. Donenfeld2022-05-12 15:32:26 +0200
committerJason A. Donenfeld2022-05-18 15:53:53 +0200
commit12e45a2a6308105469968951e6d563e8f4fea187 (patch)
tree30bed7b967450540055573e2be8162489b64cde5 /drivers/char
parent2f14062bb14b0fcfcc21e6dc7d5b5c0d25966164 (diff)
random: credit architectural init the exact amount
RDRAND and RDSEED can fail sometimes, which is fine. We currently initialize the RNG with 512 bits of RDRAND/RDSEED. We only need 256 bits of those to succeed in order to initialize the RNG. Instead of the current "all or nothing" approach, actually credit these contributions the amount that is actually contributed. Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/random.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 95982dc08669..29062595b610 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -927,9 +927,8 @@ static struct notifier_block pm_notifier = { .notifier_call = random_pm_notifica
*/
int __init random_init(const char *command_line)
{
- size_t i;
ktime_t now = ktime_get_real();
- bool arch_init = true;
+ unsigned int i, arch_bytes;
unsigned long rv;
#if defined(LATENT_ENTROPY_PLUGIN)
@@ -937,11 +936,12 @@ int __init random_init(const char *command_line)
_mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed));
#endif
- for (i = 0; i < BLAKE2S_BLOCK_SIZE; i += sizeof(rv)) {
+ for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE;
+ i < BLAKE2S_BLOCK_SIZE; i += sizeof(rv)) {
if (!arch_get_random_seed_long_early(&rv) &&
!arch_get_random_long_early(&rv)) {
rv = random_get_entropy();
- arch_init = false;
+ arch_bytes -= sizeof(rv);
}
_mix_pool_bytes(&rv, sizeof(rv));
}
@@ -952,8 +952,8 @@ int __init random_init(const char *command_line)
if (crng_ready())
crng_reseed();
- else if (arch_init && trust_cpu)
- credit_init_bits(BLAKE2S_BLOCK_SIZE * 8);
+ else if (trust_cpu)
+ credit_init_bits(arch_bytes * 8);
WARN_ON(register_pm_notifier(&pm_notifier));