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author | 2022-01-11 10:21:35 -0800 | |
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committer | 2022-01-11 10:21:35 -0800 | |
commit | 5c947d0dbae8038ec1c8b538891f6475350542ee (patch) | |
tree | bd81b14e0cd2212bf885b835d9da39db51a33d43 /crypto/jitterentropy.c | |
parent | Merge tag 'docs-5.17' of git://git.lwn.net/linux (diff) | |
parent | crypto: af_alg - rewrite NULL pointer check (diff) | |
download | linux-dev-5c947d0dbae8038ec1c8b538891f6475350542ee.tar.xz linux-dev-5c947d0dbae8038ec1c8b538891f6475350542ee.zip |
Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
"Algorithms:
- Drop alignment requirement for data in aesni
- Use synchronous seeding from the /dev/random in DRBG
- Reseed nopr DRBGs every 5 minutes from /dev/random
- Add KDF algorithms currently used by security/DH
- Fix lack of entropy on some AMD CPUs with jitter RNG
Drivers:
- Add support for the D1 variant in sun8i-ce
- Add SEV_INIT_EX support in ccp
- PFVF support for GEN4 host driver in qat
- Compression support for GEN4 devices in qat
- Add cn10k random number generator support"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (145 commits)
crypto: af_alg - rewrite NULL pointer check
lib/mpi: Add the return value check of kcalloc()
crypto: qat - fix definition of ring reset results
crypto: hisilicon - cleanup warning in qm_get_qos_value()
crypto: kdf - select SHA-256 required for self-test
crypto: x86/aesni - don't require alignment of data
crypto: ccp - remove unneeded semicolon
crypto: stm32/crc32 - Fix kernel BUG triggered in probe()
crypto: s390/sha512 - Use macros instead of direct IV numbers
crypto: sparc/sha - remove duplicate hash init function
crypto: powerpc/sha - remove duplicate hash init function
crypto: mips/sha - remove duplicate hash init function
crypto: sha256 - remove duplicate generic hash init function
crypto: jitter - add oversampling of noise source
MAINTAINERS: update SEC2 driver maintainers list
crypto: ux500 - Use platform_get_irq() to get the interrupt
crypto: hisilicon/qm - disable qm clock-gating
crypto: omap-aes - Fix broken pm_runtime_and_get() usage
MAINTAINERS: update caam crypto driver maintainers list
crypto: octeontx2 - prevent underflow in get_cores_bmap()
...
Diffstat (limited to 'crypto/jitterentropy.c')
-rw-r--r-- | crypto/jitterentropy.c | 32 |
1 files changed, 23 insertions, 9 deletions
diff --git a/crypto/jitterentropy.c b/crypto/jitterentropy.c index 4dc2261cdeef..93bff3213823 100644 --- a/crypto/jitterentropy.c +++ b/crypto/jitterentropy.c @@ -117,6 +117,22 @@ struct rand_data { #define JENT_EHEALTH 9 /* Health test failed during initialization */ #define JENT_ERCT 10 /* RCT failed during initialization */ +/* + * The output n bits can receive more than n bits of min entropy, of course, + * but the fixed output of the conditioning function can only asymptotically + * approach the output size bits of min entropy, not attain that bound. Random + * maps will tend to have output collisions, which reduces the creditable + * output entropy (that is what SP 800-90B Section 3.1.5.1.2 attempts to bound). + * + * The value "64" is justified in Appendix A.4 of the current 90C draft, + * and aligns with NIST's in "epsilon" definition in this document, which is + * that a string can be considered "full entropy" if you can bound the min + * entropy in each bit of output to at least 1-epsilon, where epsilon is + * required to be <= 2^(-32). + */ +#define JENT_ENTROPY_SAFETY_FACTOR 64 + +#include <linux/fips.h> #include "jitterentropy.h" /*************************************************************************** @@ -265,7 +281,6 @@ static int jent_stuck(struct rand_data *ec, __u64 current_delta) { __u64 delta2 = jent_delta(ec->last_delta, current_delta); __u64 delta3 = jent_delta(ec->last_delta2, delta2); - unsigned int delta_masked = current_delta & JENT_APT_WORD_MASK; ec->last_delta = current_delta; ec->last_delta2 = delta2; @@ -274,7 +289,7 @@ static int jent_stuck(struct rand_data *ec, __u64 current_delta) * Insert the result of the comparison of two back-to-back time * deltas. */ - jent_apt_insert(ec, delta_masked); + jent_apt_insert(ec, current_delta); if (!current_delta || !delta2 || !delta3) { /* RCT with a stuck bit */ @@ -299,10 +314,6 @@ static int jent_stuck(struct rand_data *ec, __u64 current_delta) */ static int jent_health_failure(struct rand_data *ec) { - /* Test is only enabled in FIPS mode */ - if (!jent_fips_enabled()) - return 0; - return ec->health_failure; } @@ -547,12 +558,15 @@ static int jent_measure_jitter(struct rand_data *ec) */ static void jent_gen_entropy(struct rand_data *ec) { - unsigned int k = 0; + unsigned int k = 0, safety_factor = 0; + + if (fips_enabled) + safety_factor = JENT_ENTROPY_SAFETY_FACTOR; /* priming of the ->prev_time value */ jent_measure_jitter(ec); - while (1) { + while (!jent_health_failure(ec)) { /* If a stuck measurement is received, repeat measurement */ if (jent_measure_jitter(ec)) continue; @@ -561,7 +575,7 @@ static void jent_gen_entropy(struct rand_data *ec) * We multiply the loop value with ->osr to obtain the * oversampling rate requested by the caller */ - if (++k >= (DATA_SIZE_BITS * ec->osr)) + if (++k >= ((DATA_SIZE_BITS + safety_factor) * ec->osr)) break; } } |