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crypto: ctr - Propagate NEED_FALLBACK bit

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When requesting a fallback algorithm, we should propagate the
NEED_FALLBACK bit when search for the underlying algorithm.

This will prevents drivers from allocating unnecessary fallbacks that
are never called. For instance, currently the vmx-crypto driver will use
the following chain of calls when calling the fallback implementation:

p8_aes_ctr -> ctr(p8_aes) -> aes-generic

However p8_aes will always delegate its calls to aes-generic. With this
patch, p8_aes_ctr will be able to use ctr(aes-generic) directly as its
fallback. The same applies to aes_s390.

Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Marcelo Cerri 2017-02-27 09:38:26 -03:00 committed by Herbert Xu
parent e6c2e65c70
commit d2c2a85cfe
1 changed files with 18 additions and 5 deletions
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23
crypto/ctr.c
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@ -181,15 +181,24 @@ static void crypto_ctr_exit_tfm(struct crypto_tfm *tfm)
static struct crypto_instance *crypto_ctr_alloc(struct rtattr **tb)
{
struct crypto_instance *inst;
struct crypto_attr_type *algt;
struct crypto_alg *alg;
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
if (err)
return ERR_PTR(err);
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return ERR_CAST(algt);
mask = CRYPTO_ALG_TYPE_MASK |
crypto_requires_off(algt->type, algt->mask,
CRYPTO_ALG_NEED_FALLBACK);
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, mask);
if (IS_ERR(alg))
return ERR_CAST(alg);
@ -350,6 +359,8 @@ static int crypto_rfc3686_create(struct crypto_template *tmpl,
struct skcipher_alg *alg;
struct crypto_skcipher_spawn *spawn;
const char *cipher_name;
u32 mask;
int err;
algt = crypto_get_attr_type(tb);
@ -367,12 +378,14 @@ static int crypto_rfc3686_create(struct crypto_template *tmpl,
if (!inst)
return -ENOMEM;
mask = crypto_requires_sync(algt->type, algt->mask) |
crypto_requires_off(algt->type, algt->mask,
CRYPTO_ALG_NEED_FALLBACK);
spawn = skcipher_instance_ctx(inst);
crypto_set_skcipher_spawn(spawn, skcipher_crypto_instance(inst));
err = crypto_grab_skcipher(spawn, cipher_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
err = crypto_grab_skcipher(spawn, cipher_name, 0, mask);
if (err)
goto err_free_inst;