[PATCH 29/38] crypto: drbg - Put rng_alg methods in logical order

[Eric Biggers]

Put the DRBG implementation of the rng_alg methods in the order in which
they're called (cra_init => set_ent => seed => generate => cra_exit) so
that it's easier to understand the flow.

Also rename drbg_kcapi_random to drbg_kcapi_generate, and
drbg_kcapi_cleanup to drbg_kcapi_exit, so they match the method names.

Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
 crypto/drbg.c | 82 ++++++++++++++++++++++-----------------------------
 1 file changed, 36 insertions(+), 46 deletions(-)

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 9ff1a0e1b129..ef9c3e9fdf6e 100644
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -607,17 +607,24 @@ static int drbg_uninstantiate(struct drbg_state *drbg)
 	drbg_dealloc_state(drbg);
 	/* no scrubbing of test_data -- this shall survive an uninstantiate */
 	return 0;
 }
 
-/*
- * Helper function for setting the test data in the DRBG
- *
- * @drbg DRBG state handle
- * @data test data
- * @len test data length
- */
+/***************************************************************
+ * Kernel crypto API interface to DRBG
+ ***************************************************************/
+
+static int drbg_kcapi_init(struct crypto_tfm *tfm)
+{
+	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
+
+	mutex_init(&drbg->drbg_mutex);
+
+	return 0;
+}
+
+/* Set test entropy in the DRBG. */
 static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
 				   const u8 *data, unsigned int len)
 {
 	struct drbg_state *drbg = crypto_rng_ctx(tfm);
 
@@ -625,39 +632,42 @@ static void drbg_kcapi_set_entropy(struct crypto_rng *tfm,
 	drbg->test_entropy = data;
 	drbg->test_entropylen = len;
 	mutex_unlock(&drbg->drbg_mutex);
 }
 
-/***************************************************************
- * Kernel crypto API interface to register DRBG
- ***************************************************************/
-
-static int drbg_kcapi_init(struct crypto_tfm *tfm)
+/* Seed (i.e. instantiate) or re-seed the DRBG. */
+static int drbg_kcapi_seed(struct crypto_rng *tfm,
+			   const u8 *seed, unsigned int slen, bool pr)
 {
-	struct drbg_state *drbg = crypto_tfm_ctx(tfm);
+	struct drbg_state *drbg = crypto_rng_ctx(tfm);
 
-	mutex_init(&drbg->drbg_mutex);
+	return drbg_instantiate(drbg, seed, slen, pr);
+}
 
-	return 0;
+static int drbg_kcapi_seed_pr(struct crypto_rng *tfm,
+			      const u8 *seed, unsigned int slen)
+{
+	return drbg_kcapi_seed(tfm, seed, slen, /* pr= */ true);
 }
 
-static void drbg_kcapi_cleanup(struct crypto_tfm *tfm)
+static int drbg_kcapi_seed_nopr(struct crypto_rng *tfm,
+				const u8 *seed, unsigned int slen)
 {
-	drbg_uninstantiate(crypto_tfm_ctx(tfm));
+	return drbg_kcapi_seed(tfm, seed, slen, /* pr= */ false);
 }
 
 /*
  * Generate random numbers invoked by the kernel crypto API:
  *
  * src is additional input supplied to the RNG.
  * slen is the length of src.
  * dst is the output buffer where random data is to be stored.
  * dlen is the length of dst.
  */
-static int drbg_kcapi_random(struct crypto_rng *tfm,
-			     const u8 *src, unsigned int slen,
-			     u8 *dst, unsigned int dlen)
+static int drbg_kcapi_generate(struct crypto_rng *tfm,
+			       const u8 *src, unsigned int slen,
+			       u8 *dst, unsigned int dlen)
 {
 	struct drbg_state *drbg = crypto_rng_ctx(tfm);
 
 	/*
 	 * Break the request into multiple requests if needed, to avoid
@@ -676,35 +686,15 @@ static int drbg_kcapi_random(struct crypto_rng *tfm,
 		dlen -= n;
 	} while (dlen);
 	return 0;
 }
 
-/* Seed (i.e. instantiate) or re-seed the DRBG. */
-static int drbg_kcapi_seed(struct crypto_rng *tfm,
-			   const u8 *seed, unsigned int slen, bool pr)
+static void drbg_kcapi_exit(struct crypto_tfm *tfm)
 {
-	struct drbg_state *drbg = crypto_rng_ctx(tfm);
-
-	return drbg_instantiate(drbg, seed, slen, pr);
-}
-
-static int drbg_kcapi_seed_pr(struct crypto_rng *tfm,
-			      const u8 *seed, unsigned int slen)
-{
-	return drbg_kcapi_seed(tfm, seed, slen, /* pr= */ true);
-}
-
-static int drbg_kcapi_seed_nopr(struct crypto_rng *tfm,
-				const u8 *seed, unsigned int slen)
-{
-	return drbg_kcapi_seed(tfm, seed, slen, /* pr= */ false);
+	drbg_uninstantiate(crypto_tfm_ctx(tfm));
 }
 
-/***************************************************************
- * Kernel module: code to load the module
- ***************************************************************/
-
 /*
  * Tests as defined in 11.3.2 in addition to the cipher tests: testing
  * of the error handling.
  *
  * Note: testing of failing seed source as defined in 11.3.2 is not applicable
@@ -767,24 +757,24 @@ static struct rng_alg drbg_algs[] = {
 		.base.cra_ctxsize	= sizeof(struct drbg_state),
 		.base.cra_module	= THIS_MODULE,
 		.base.cra_init		= drbg_kcapi_init,
 		.set_ent		= drbg_kcapi_set_entropy,
 		.seed			= drbg_kcapi_seed_pr,
-		.generate		= drbg_kcapi_random,
-		.base.cra_exit		= drbg_kcapi_cleanup,
+		.generate		= drbg_kcapi_generate,
+		.base.cra_exit		= drbg_kcapi_exit,
 	},
 	{
 		.base.cra_name		= "stdrng",
 		.base.cra_driver_name	= "drbg_nopr_hmac_sha512",
 		.base.cra_priority	= 201,
 		.base.cra_ctxsize	= sizeof(struct drbg_state),
 		.base.cra_module	= THIS_MODULE,
 		.base.cra_init		= drbg_kcapi_init,
 		.set_ent		= drbg_kcapi_set_entropy,
 		.seed			= drbg_kcapi_seed_nopr,
-		.generate		= drbg_kcapi_random,
-		.base.cra_exit		= drbg_kcapi_cleanup,
+		.generate		= drbg_kcapi_generate,
+		.base.cra_exit		= drbg_kcapi_exit,
 	},
 };
 
 static int __init drbg_init(void)
 {
-- 
2.53.0