crypto: ansi_cprng - Allow resetting of DT value (2566578a) · Commits · 戴 / test

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>

crypto/ansi_cprng.c

+13 −3

Original line number	Diff line number	Diff line
		@@ -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,
		}
		}
		};

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