Commit d2c2a85c authored by Marcelo Cerri's avatar Marcelo Cerri Committed by Herbert Xu
Browse files

crypto: ctr - Propagate NEED_FALLBACK bit 



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: default avatarMarcelo Henrique Cerri <marcelo.cerri@canonical.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent e6c2e65c

crypto/ctr.c

+18 −5
Original line number Diff line number Diff line
@@ -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;

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