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| author | Neil Horman <nhorman@tuxdriver.com> | 2008-11-05 12:13:14 +0800 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2008-12-25 11:01:21 +1100 |
| commit | 2566578a6feb9d9e39da41326afe8ed6022db3c5 (patch) | |
| tree | 4fb341d8912afbf5b1c47e0938f251210843ef2d /crypto/ansi_cprng.c | |
| parent | 420a4b20c504e4674bf253601f793bdb254f99fa (diff) | |
| download | lwn-2566578a6feb9d9e39da41326afe8ed6022db3c5.tar.gz lwn-2566578a6feb9d9e39da41326afe8ed6022db3c5.zip | |
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/ansi_cprng.c')
| -rw-r--r-- | crypto/ansi_cprng.c | 16 |
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, return get_prng_bytes(rdata, dlen, prng); } +/* + * This is the cprng_registered reset method the seed value is + * interpreted as the tuple { V KEY DT} + * V and KEY are required during reset, and DT is optional, detected + * as being present by testing the length of the seed + */ static int cprng_reset(struct crypto_rng *tfm, u8 *seed, unsigned int slen) { struct prng_context *prng = crypto_rng_ctx(tfm); - u8 *key = seed + DEFAULT_PRNG_KSZ; + u8 *key = seed + DEFAULT_BLK_SZ; + u8 *dt = NULL; if (slen < DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ) return -EINVAL; - reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, NULL); + if (slen >= (2 * DEFAULT_BLK_SZ + DEFAULT_PRNG_KSZ)) + dt = key + DEFAULT_PRNG_KSZ; + + reset_prng_context(prng, key, DEFAULT_PRNG_KSZ, seed, dt); if (prng->flags & PRNG_NEED_RESET) return -EINVAL; @@ -379,7 +389,7 @@ static struct crypto_alg rng_alg = { .rng = { .rng_make_random = cprng_get_random, .rng_reset = cprng_reset, - .seedsize = DEFAULT_PRNG_KSZ + DEFAULT_BLK_SZ, + .seedsize = DEFAULT_PRNG_KSZ + 2*DEFAULT_BLK_SZ, } } }; |