On Monday 03 November 2008 16:22:40 Neil Horman wrote:
> Hey all-
>       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.
>
> Regards
> Neil
>
> Signed-off-by: Neil Horman <[EMAIL PROTECTED]>

Even better than my original version, since it lets providing a DT value be 
optional. Go ahead and slap this on there too:

Signed-off-by: Jarod Wilson <[EMAIL PROTECTED]>


>  ansi_cprng.c |   16 +++++++++++++---
>  1 file changed, 13 insertions(+), 3 deletions(-)
>
>
> diff --git a/crypto/ansi_cprng.c b/crypto/ansi_cprng.c
> index 72db0fd..486aa93 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,
>               }
>       }
>  };

-- 
Jarod Wilson
[EMAIL PROTECTED]

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