diff options
| -rw-r--r-- | crypto/Kconfig | 17 | ||||
| -rw-r--r-- | crypto/jitterentropy-kcapi.c | 6 |
2 files changed, 21 insertions, 2 deletions
diff --git a/crypto/Kconfig b/crypto/Kconfig index 00c827d9f0d2d..ed931ddea644d 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -1339,6 +1339,23 @@ config CRYPTO_JITTERENTROPY_MEMORY_BLOCKSIZE default 1024 if CRYPTO_JITTERENTROPY_MEMSIZE_1024 default 2048 if CRYPTO_JITTERENTROPY_MEMSIZE_8192 +config CRYPTO_JITTERENTROPY_OSR + int "CPU Jitter RNG Oversampling Rate" + range 1 15 + default 1 + depends on CRYPTO_JITTERENTROPY + help + The Jitter RNG allows the specification of an oversampling rate (OSR). + The Jitter RNG operation requires a fixed amount of timing + measurements to produce one output block of random numbers. The + OSR value is multiplied with the amount of timing measurements to + generate one output block. Thus, the timing measurement is oversampled + by the OSR factor. The oversampling allows the Jitter RNG to operate + on hardware whose timers deliver limited amount of entropy (e.g. + the timer is coarse) by setting the OSR to a higher value. The + trade-off, however, is that the Jitter RNG now requires more time + to generate random numbers. + config CRYPTO_JITTERENTROPY_TESTINTERFACE bool "CPU Jitter RNG Test Interface" depends on CRYPTO_JITTERENTROPY diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c index a8e7bbd28c6eb..0c6752221451b 100644 --- a/crypto/jitterentropy-kcapi.c +++ b/crypto/jitterentropy-kcapi.c @@ -256,7 +256,9 @@ static int jent_kcapi_init(struct crypto_tfm *tfm) crypto_shash_init(sdesc); rng->sdesc = sdesc; - rng->entropy_collector = jent_entropy_collector_alloc(0, 0, sdesc); + rng->entropy_collector = + jent_entropy_collector_alloc(CONFIG_CRYPTO_JITTERENTROPY_OSR, 0, + sdesc); if (!rng->entropy_collector) { ret = -ENOMEM; goto err; @@ -345,7 +347,7 @@ static int __init jent_mod_init(void) desc->tfm = tfm; crypto_shash_init(desc); - ret = jent_entropy_init(0, 0, desc); + ret = jent_entropy_init(CONFIG_CRYPTO_JITTERENTROPY_OSR, 0, desc); shash_desc_zero(desc); crypto_free_shash(tfm); if (ret) { |