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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>
This commit is contained in:
Eric Biggers 2020-01-02 19:58:54 -08:00 committed by Herbert Xu
parent 218c5035fe
commit 39e7a283b3
1 changed files with 16 additions and 17 deletions
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33
crypto/hmac.c
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@ -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;
}