crypto: shash - Add shash_register_instance

This patch adds shash_register_instance so that shash instances
can be registered without bypassing the shash checks applied to
normal algorithms.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/shash.c

@@ -480,7 +480,7 @@ struct crypto_shash *crypto_alloc_shash(const char *alg_name, u32 type,
 }
 EXPORT_SYMBOL_GPL(crypto_alloc_shash);
 
-int crypto_register_shash(struct shash_alg *alg)
+static int shash_prepare_alg(struct shash_alg *alg)
 {
 	struct crypto_alg *base = &alg->base;
 
@@ -491,6 +491,17 @@ int crypto_register_shash(struct shash_alg *alg)
 	base->cra_type = &crypto_shash_type;
 	base->cra_flags &= ~CRYPTO_ALG_TYPE_MASK;
 	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
+	return 0;
+}
+
+int crypto_register_shash(struct shash_alg *alg)
+{
+	struct crypto_alg *base = &alg->base;
+	int err;
+
+	err = shash_prepare_alg(alg);
+	if (err)
+		return err;
 
 	return crypto_register_alg(base);
 }
@@ -502,6 +513,19 @@ int crypto_unregister_shash(struct shash_alg *alg)
 }
 EXPORT_SYMBOL_GPL(crypto_unregister_shash);
 
+int shash_register_instance(struct crypto_template *tmpl,
+			    struct shash_instance *inst)
+{
+	int err;
+
+	err = shash_prepare_alg(&inst->alg);
+	if (err)
+		return err;
+
+	return crypto_register_instance(tmpl, shash_crypto_instance(inst));
+}
+EXPORT_SYMBOL_GPL(shash_register_instance);
+
 void shash_free_instance(struct crypto_instance *inst)
 {
 	crypto_drop_spawn(crypto_instance_ctx(inst));

include/crypto/internal/hash.h

@@ -53,7 +53,8 @@ int crypto_hash_walk_first_compat(struct hash_desc *hdesc,
 
 int crypto_register_shash(struct shash_alg *alg);
 int crypto_unregister_shash(struct shash_alg *alg);
-
+int shash_register_instance(struct crypto_template *tmpl,
+			    struct shash_instance *inst);
 void shash_free_instance(struct crypto_instance *inst);
 
 int crypto_init_shash_spawn(struct crypto_shash_spawn *spawn,