diff options
Diffstat (limited to 'crypto')
| -rw-r--r-- | crypto/drbg.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/crypto/drbg.c b/crypto/drbg.c index 9f6485962ecc..5977a72afb03 100644 --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -100,6 +100,7 @@ #include <crypto/drbg.h> #include <crypto/internal/cipher.h> #include <linux/kernel.h> +#include <linux/jiffies.h> /*************************************************************** * Backend cipher definitions available to DRBG @@ -1044,6 +1045,7 @@ static inline int __drbg_seed(struct drbg_state *drbg, struct list_head *seed, return ret; drbg->seeded = new_seed_state; + drbg->last_seed_time = jiffies; /* 10.1.1.2 / 10.1.1.3 step 5 */ drbg->reseed_ctr = 1; @@ -1112,6 +1114,26 @@ out: return ret; } +static bool drbg_nopr_reseed_interval_elapsed(struct drbg_state *drbg) +{ + unsigned long next_reseed; + + /* Don't ever reseed from get_random_bytes() in test mode. */ + if (list_empty(&drbg->test_data.list)) + return false; + + /* + * Obtain fresh entropy for the nopr DRBGs after 300s have + * elapsed in order to still achieve sort of partial + * prediction resistance over the time domain at least. Note + * that the period of 300s has been chosen to match the + * CRNG_RESEED_INTERVAL of the get_random_bytes()' chacha + * rngs. + */ + next_reseed = drbg->last_seed_time + 300 * HZ; + return time_after(jiffies, next_reseed); +} + /* * Seeding or reseeding of the DRBG * @@ -1413,7 +1435,8 @@ static int drbg_generate(struct drbg_state *drbg, /* 9.3.1 step 7.4 */ addtl = NULL; } else if (rng_is_initialized() && - drbg->seeded == DRBG_SEED_STATE_PARTIAL) { + (drbg->seeded == DRBG_SEED_STATE_PARTIAL || + drbg_nopr_reseed_interval_elapsed(drbg))) { len = drbg_seed_from_random(drbg); if (len) goto err; @@ -1569,6 +1592,7 @@ static int drbg_instantiate(struct drbg_state *drbg, struct drbg_string *pers, drbg->core = &drbg_cores[coreref]; drbg->pr = pr; drbg->seeded = DRBG_SEED_STATE_UNSEEDED; + drbg->last_seed_time = 0; drbg->reseed_threshold = drbg_max_requests(drbg); ret = drbg_alloc_state(drbg); |