From 04597c8dd6c4b55e946fec50dc3b14a5d9d54501 Mon Sep 17 00:00:00 2001 From: Stephan Müller Date: Thu, 21 Sep 2023 13:48:11 +0200 Subject: crypto: jitter - add RCT/APT support for different OSRs The oversampling rate (OSR) value specifies the heuristically implied entropy in the recorded data - H_submitter = 1/osr. A different entropy estimate implies a different APT/RCT cutoff value. This change adds support for OSRs 1 through 15. This OSR can be selected by the caller of the Jitter RNG. For this patch, the caller still uses one hard-coded OSR. A subsequent patch allows this value to be configured. In addition, the power-up self test is adjusted as follows: * It allows the caller to provide an oversampling rate that should be tested with - commonly it should be the same as used for the actual runtime operation. This makes the power-up testing therefore consistent with the runtime operation. * It calls now jent_measure_jitter (i.e. collects the full entropy that can possibly be harvested by the Jitter RNG) instead of only jent_condition_data (which only returns the entropy harvested from the conditioning component). This should now alleviate reports where the Jitter RNG initialization thinks there is too little entropy. * The power-up test now solely relies on the (enhanced) APT and RCT test that is used as a health test at runtime. The code allowing the different OSRs as well as the power-up test changes are present in the user space version of the Jitter RNG 3.4.1 and thus was already in production use for some time. Reported-by "Ospan, Abylay" Signed-off-by: Stephan Mueller Signed-off-by: Herbert Xu --- crypto/jitterentropy-kcapi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'crypto/jitterentropy-kcapi.c') diff --git a/crypto/jitterentropy-kcapi.c b/crypto/jitterentropy-kcapi.c index 7d1463a1562a..1de730f94683 100644 --- a/crypto/jitterentropy-kcapi.c +++ b/crypto/jitterentropy-kcapi.c @@ -245,7 +245,7 @@ static int jent_kcapi_init(struct crypto_tfm *tfm) crypto_shash_init(sdesc); rng->sdesc = sdesc; - rng->entropy_collector = jent_entropy_collector_alloc(1, 0, sdesc); + rng->entropy_collector = jent_entropy_collector_alloc(0, 0, sdesc); if (!rng->entropy_collector) { ret = -ENOMEM; goto err; @@ -334,7 +334,7 @@ static int __init jent_mod_init(void) desc->tfm = tfm; crypto_shash_init(desc); - ret = jent_entropy_init(desc); + ret = jent_entropy_init(0, 0, desc); shash_desc_zero(desc); crypto_free_shash(tfm); if (ret) { -- cgit