crypto: hash - introduce crypto_hash_alg_has_setkey()

Templates that use an shash spawn can use crypto_shash_alg_has_setkey()
to determine whether the underlying algorithm requires a key or not.
But there was no corresponding function for ahash spawns.  Add it.

Note that the new function actually has to support both shash and ahash
algorithms, since the ahash API can be used with either.

Cc: stable@vger.kernel.org
Signed-off-by: NEric Biggers <ebiggers@google.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

crypto/ahash.c

@@ -649,5 +649,16 @@ struct hash_alg_common *ahash_attr_alg(struct rtattr *rta, u32 type, u32 mask)
 }
 EXPORT_SYMBOL_GPL(ahash_attr_alg);
 
+bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
+{
+	struct crypto_alg *alg = &halg->base;
+
+	if (alg->cra_type != &crypto_ahash_type)
+		return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
+
+	return __crypto_ahash_alg(alg)->setkey != NULL;
+}
+EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("Asynchronous cryptographic hash type");

include/crypto/internal/hash.h

@@ -90,6 +90,8 @@ static inline bool crypto_shash_alg_has_setkey(struct shash_alg *alg)
 	return alg->setkey != shash_no_setkey;
 }
 
+bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg);
+
 int crypto_init_ahash_spawn(struct crypto_ahash_spawn *spawn,
 			    struct hash_alg_common *alg,
 			    struct crypto_instance *inst);