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Commit 505172e11f5a0d9916e20e40d3b0a6f87d3a59b6

Authored by Jarod Wilson
Committed by Herbert Xu
1 parent bae6d3038b
Exists in master and in 6 other branches imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

crypto: ansi_cprng - enforce key != seed in fips mode 

Apparently, NIST is tightening up its requirements for FIPS validation
with respect to RNGs. Its always been required that in fips mode, the
ansi cprng not be fed key and seed material that was identical, but
they're now interpreting FIPS 140-2, section AS07.09 as requiring that
the implementation itself must enforce the requirement. Easy fix, we
just do a memcmp of key and seed in fips_cprng_reset and call it a day.

v2: Per Neil's advice, ensure slen is sufficiently long before we
compare key and seed to avoid looking at potentially unallocated mem.

CC: Stephan Mueller <smueller@atsec.com>
CC: Steve Grubb <sgrubb@redhat.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Showing 1 changed file with 8 additions and 0 deletions Side-by-side Diff

... ... @@ -414,9 +414,17 @@
414 414 static int fips_cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
415 415 {
416 416 u8 rdata[DEFAULT_BLK_SZ];
  417 + u8 *key = seed + DEFAULT_BLK_SZ;
417 418 int rc;
418 419  
419 420 struct prng_context *prng = crypto_rng_ctx(tfm);
  421 +
  422 + if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ)
  423 + return -EINVAL;
  424 +
  425 + /* fips strictly requires seed != key */
  426 + if (!memcmp(seed, key, DEFAULT_PRNG_KSZ))
  427 + return -EINVAL;
420 428  
421 429 rc = cprng_reset(tfm, seed, slen);
422 430