crypto: hmac - use crypto_grab_shash() and simplify error paths

Make the hmac template use the new function crypto_grab_shash() to
initialize its shash spawn.

This is needed to make all spawns be initialized in a consistent way.

This required making hmac_create() allocate the instance directly rather
than use shash_alloc_instance().

Also simplify the error handling by taking advantage of crypto_drop_*()
now accepting (as a no-op) spawns that haven't been initialized yet, and
by taking advantage of crypto_grab_*() now handling ERR_PTR() names.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/hmac.c b/crypto/hmac.c
index 685e499..0a42b70 100644 (file)
--- a/crypto/hmac.c
+++ b/crypto/hmac.c
@@ -165,6 +165,7 @@ static void hmac_exit_tfm(struct crypto_shash *parent)
 static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 {
        struct shash_instance *inst;
+       struct crypto_shash_spawn *spawn;
        struct crypto_alg *alg;
        struct shash_alg *salg;
        int err;
@@ -175,31 +176,32 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
        if (err)
                return err;
 
-       salg = shash_attr_alg(tb[1], 0, 0);
-       if (IS_ERR(salg))
-               return PTR_ERR(salg);
+       inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
+       if (!inst)
+               return -ENOMEM;
+       spawn = shash_instance_ctx(inst);
+
+       err = crypto_grab_shash(spawn, shash_crypto_instance(inst),
+                               crypto_attr_alg_name(tb[1]), 0, 0);
+       if (err)
+               goto err_free_inst;
+       salg = crypto_spawn_shash_alg(spawn);
        alg = &salg->base;
 
        /* The underlying hash algorithm must not require a key */
        err = -EINVAL;
        if (crypto_shash_alg_needs_key(salg))
-               goto out_put_alg;
+               goto err_free_inst;
 
        ds = salg->digestsize;
        ss = salg->statesize;
        if (ds > alg->cra_blocksize ||
            ss < alg->cra_blocksize)
-               goto out_put_alg;
+               goto err_free_inst;
 
-       inst = shash_alloc_instance("hmac", alg);
-       err = PTR_ERR(inst);
-       if (IS_ERR(inst))
-               goto out_put_alg;
-
-       err = crypto_init_shash_spawn(shash_instance_ctx(inst), salg,
-                                     shash_crypto_instance(inst));
+       err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
        if (err)
-               goto out_free_inst;
+               goto err_free_inst;
 
        inst->alg.base.cra_priority = alg->cra_priority;
        inst->alg.base.cra_blocksize = alg->cra_blocksize;
@@ -224,12 +226,9 @@ static int hmac_create(struct crypto_template *tmpl, struct rtattr **tb)
 
        err = shash_register_instance(tmpl, inst);
        if (err) {
-out_free_inst:
+err_free_inst:
                shash_free_instance(shash_crypto_instance(inst));
        }
-
-out_put_alg:
-       crypto_mod_put(alg);
        return err;
 }