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 <nhorman@xxxxxxxxxxxxx>
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 <jarod@xxxxxxxxxx>
> 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
jarod@xxxxxxxxxx
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