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authorNeil Horman <nhorman@tuxdriver.com>2008-11-04 23:13:14 -0500
committerHerbert Xu <herbert@gondor.apana.org.au>2008-12-24 19:01:21 -0500
commit2566578a6feb9d9e39da41326afe8ed6022db3c5 (patch)
tree4fb341d8912afbf5b1c47e0938f251210843ef2d /crypto
parent420a4b20c504e4674bf253601f793bdb254f99fa (diff)
crypto: ansi_cprng - Allow resetting of DT value
This is a patch that was sent to me by Jarod Wilson, marking off my outstanding todo to allow the ansi cprng to set/reset the DT counter value in a cprng instance. Currently crytpo_rng_reset accepts a seed byte array which is interpreted by the ansi_cprng as a {V key} tuple. This patch extends that tuple to now be {V key DT}, with DT an optional value during reset. This patch also fixes a bug we noticed in which the offset of the key area of the seed is started at DEFAULT_PRNG_KSZ rather than DEFAULT_BLK_SZ as it should be. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Jarod Wilson <jarod@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/ansi_cprng.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c
index 72db0fd763cc..486aa93646f7 100644
--- a/crypto/ansi_cprng.c
+++ b/crypto/ansi_cprng.c
@@ -349,15 +349,25 @@ static int cprng_get_random(struct crypto_rng *tfm, u8 *rdata,
349 return get_prng_bytes(rdata, dlen, prng); 349 return get_prng_bytes(rdata, dlen, prng);
350} 350}
351 351
352/*
353 * This is the cprng_registered reset method the seed value is
354 * interpreted as the tuple { V KEY DT}
355 * V and KEY are required during reset, and DT is optional, detected
356 * as being present by testing the length of the seed
357 */
352static int cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen) 358static int cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen)
353{ 359{
354 struct prng_context *prng = crypto_rng_ctx(tfm); 360 struct prng_context *prng = crypto_rng_ctx(tfm);
355 u8 *key = seed + DEFAULT_PRNG_KSZ; 361 u8 *key = seed + DEFAULT_BLK_SZ;
362 u8 *dt = NULL;
356 363
357 if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) 364 if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ)
358 return -EINVAL; 365 return -EINVAL;
359 366
360 reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, NULL); 367 if (slen >= (2 * DEFAULT_BLK_SZ + DEFAULT_PRNG_KSZ))
368 dt = key + DEFAULT_PRNG_KSZ;
369
370 reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, dt);
361 371
362 if (prng->flags & PRNG_NEED_RESET) 372 if (prng->flags & PRNG_NEED_RESET)
363 return -EINVAL; 373 return -EINVAL;
@@ -379,7 +389,7 @@ static struct crypto_alg rng_alg = {
379 .rng = { 389 .rng = {
380 .rng_make_random = cprng_get_random, 390 .rng_make_random = cprng_get_random,
381 .rng_reset = cprng_reset, 391 .rng_reset = cprng_reset,
382 .seedsize = DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ, 392 .seedsize = DEFAULT_PRNG_KSZ + 2*DEFAULT_BLK_SZ,
383 } 393 }
384 } 394 }
385}; 395};