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authorStephan Müller <smueller@chronox.de>2020-04-17 22:33:33 +0300
committerHerbert Xu <herbert@gondor.apana.org.au>2020-04-24 10:42:17 +0300
commit764428fe99e82ce9a57ca22fb8adc3370922348d (patch)
treef9addb875204120d19674575e23fc7c6bf0dfb59 /crypto/jitterentropy-kcapi.c
parent63e05f3275172283fd0020dba678ef8eca869ef7 (diff)
downloadlinux-764428fe99e82ce9a57ca22fb8adc3370922348d.tar.xz
crypto: jitter - SP800-90B compliance
SP800-90B specifies various requirements for the noise source(s) that may seed any DRNG including SP800-90A DRBGs. In November 2020, SP800-90B will be mandated for all noise sources that provide entropy to DRBGs as part of a FIPS 140-[2|3] validation or other evaluation types. Without SP800-90B compliance, a noise source is defined to always deliver zero bits of entropy. This patch ports the SP800-90B compliance from the user space Jitter RNG version 2.2.0. The following changes are applied: - addition of (an enhanced version of) the repetitive count test (RCT) from SP800-90B section 4.4.1 - the enhancement is due to the fact of using the stuck test as input to the RCT. - addition of the adaptive proportion test (APT) from SP800-90B section 4.4.2 - update of the power-on self test to perform a test measurement of 1024 noise samples compliant to SP800-90B section 4.3 - remove of the continuous random number generator test which is replaced by APT and RCT Health test failures due to the SP800-90B operation are only enforced in FIPS mode. If a runtime health test failure is detected, the Jitter RNG is reset. If more than 1024 resets in a row are performed, a permanent error is returned to the caller. Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/jitterentropy-kcapi.c')
-rw-r--r--crypto/jitterentropy-kcapi.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c
index a5ce8f96790f..b43684c0dade 100644
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -108,6 +108,7 @@ void jent_get_nstime(__u64 *out)
struct jitterentropy {
spinlock_t jent_lock;
struct rand_data *entropy_collector;
+ unsigned int reset_cnt;
};
static int jent_kcapi_init(struct crypto_tfm *tfm)
@@ -142,7 +143,33 @@ static int jent_kcapi_random(struct crypto_rng *tfm,
int ret = 0;
spin_lock(&rng->jent_lock);
+
+ /* Return a permanent error in case we had too many resets in a row. */
+ if (rng->reset_cnt > (1<<10)) {
+ ret = -EFAULT;
+ goto out;
+ }
+
ret = jent_read_entropy(rng->entropy_collector, rdata, dlen);
+
+ /* Reset RNG in case of health failures */
+ if (ret < -1) {
+ pr_warn_ratelimited("Reset Jitter RNG due to health test failure: %s failure\n",
+ (ret == -2) ? "Repetition Count Test" :
+ "Adaptive Proportion Test");
+
+ rng->reset_cnt++;
+
+ ret = -EAGAIN;
+ } else {
+ rng->reset_cnt = 0;
+
+ /* Convert the Jitter RNG error into a usable error code */
+ if (ret == -1)
+ ret = -EINVAL;
+ }
+
+out:
spin_unlock(&rng->jent_lock);
return ret;