From: Mathieu Malaterre Subject: [RFC PATCH] crypto: make the seed() function optional Date: Wed, 13 Sep 2017 22:09:15 +0200 Message-ID: <20170913200915.20738-1-malat@debian.org> Cc: PrasannaKumar Muralidharan , Mathieu Malaterre , Neil Horman , Herbert Xu , "David S. Miller" , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org To: unlisted-recipients:; (no To-header on input) Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org This makes it simplier for driver author to not provide the seed() function in case of a pseudo RNG where the seed operation is a no-op. Document that the seed() function pointer is optional in header. Signed-off-by: Mathieu Malaterre --- The PRNG as found on Ingenic JZ4780 is one such example. This is found on a MIPS Creator CI20 SoC. crypto/rng.c | 7 ++++++- include/crypto/rng.h | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/crypto/rng.c b/crypto/rng.c index 5e8469244960..ed08581901a9 100644 --- a/crypto/rng.c +++ b/crypto/rng.c @@ -35,9 +35,14 @@ static int crypto_default_rng_refcnt; int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) { + struct rng_alg *ralg = crypto_rng_alg(tfm); u8 *buf = NULL; int err; + /* In case of PRNG, no need to seed */ + if (!ralg->seed) + return 0; + if (!seed && slen) { buf = kmalloc(slen, GFP_KERNEL); if (!buf) @@ -47,7 +52,7 @@ int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) seed = buf; } - err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); + err = ralg->seed(tfm, seed, slen); kzfree(buf); return err; diff --git a/include/crypto/rng.h b/include/crypto/rng.h index b95ede354a66..ac5d061d0297 100644 --- a/include/crypto/rng.h +++ b/include/crypto/rng.h @@ -32,7 +32,7 @@ struct crypto_rng; * random number generator requires a seed for setting * up a new state, the seed must be provided by the * consumer while invoking this function. The required - * size of the seed is defined with @seedsize . + * size of the seed is defined with @seedsize. Optional. * @set_ent: Set entropy that would otherwise be obtained from * entropy source. Internal use only. * @seedsize: The seed size required for a random number generator -- 2.11.0