From 0872da16dd632e5d1d3f80388f7ae6fbeb17ad53 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Thu, 3 Jan 2019 20:16:14 -0800 Subject: [PATCH] crypto: skcipher - add helper for simple block cipher modes The majority of skcipher templates (including both the existing ones and the ones remaining to be converted from the "blkcipher" API) just wrap a single block cipher algorithm. This includes cbc, cfb, ctr, ecb, kw, ofb, and pcbc. Add a helper function skcipher_alloc_instance_simple() that handles allocating an skcipher instance for this common case. Signed-off-by: Eric Biggers Reviewed-by: Stephan Mueller Signed-off-by: Herbert Xu --- crypto/skcipher.c | 131 +++++++++++++++++++++++++++++ include/crypto/internal/skcipher.h | 15 ++++ 2 files changed, 146 insertions(+) diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 2a969296bc24..040ae6377b32 100644 --- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -1058,5 +1058,136 @@ int skcipher_register_instance(struct crypto_template *tmpl, } EXPORT_SYMBOL_GPL(skcipher_register_instance); +static int skcipher_setkey_simple(struct crypto_skcipher *tfm, const u8 *key, + unsigned int keylen) +{ + struct crypto_cipher *cipher = skcipher_cipher_simple(tfm); + int err; + + crypto_cipher_clear_flags(cipher, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(cipher, crypto_skcipher_get_flags(tfm) & + CRYPTO_TFM_REQ_MASK); + err = crypto_cipher_setkey(cipher, key, keylen); + crypto_skcipher_set_flags(tfm, crypto_cipher_get_flags(cipher) & + CRYPTO_TFM_RES_MASK); + return err; +} + +static int skcipher_init_tfm_simple(struct crypto_skcipher *tfm) +{ + struct skcipher_instance *inst = skcipher_alg_instance(tfm); + struct crypto_spawn *spawn = skcipher_instance_ctx(inst); + struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm); + struct crypto_cipher *cipher; + + cipher = crypto_spawn_cipher(spawn); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + ctx->cipher = cipher; + return 0; +} + +static void skcipher_exit_tfm_simple(struct crypto_skcipher *tfm) +{ + struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm); + + crypto_free_cipher(ctx->cipher); +} + +static void skcipher_free_instance_simple(struct skcipher_instance *inst) +{ + crypto_drop_spawn(skcipher_instance_ctx(inst)); + kfree(inst); +} + +/** + * skcipher_alloc_instance_simple - allocate instance of simple block cipher mode + * + * Allocate an skcipher_instance for a simple block cipher mode of operation, + * e.g. cbc or ecb. The instance context will have just a single crypto_spawn, + * that for the underlying cipher. The {min,max}_keysize, ivsize, blocksize, + * alignmask, and priority are set from the underlying cipher but can be + * overridden if needed. The tfm context defaults to skcipher_ctx_simple, and + * default ->setkey(), ->init(), and ->exit() methods are installed. + * + * @tmpl: the template being instantiated + * @tb: the template parameters + * @cipher_alg_ret: on success, a pointer to the underlying cipher algorithm is + * returned here. It must be dropped with crypto_mod_put(). + * + * Return: a pointer to the new instance, or an ERR_PTR(). The caller still + * needs to register the instance. + */ +struct skcipher_instance * +skcipher_alloc_instance_simple(struct crypto_template *tmpl, struct rtattr **tb, + struct crypto_alg **cipher_alg_ret) +{ + struct crypto_attr_type *algt; + struct crypto_alg *cipher_alg; + struct skcipher_instance *inst; + struct crypto_spawn *spawn; + u32 mask; + int err; + + algt = crypto_get_attr_type(tb); + if (IS_ERR(algt)) + return ERR_CAST(algt); + + if ((algt->type ^ CRYPTO_ALG_TYPE_SKCIPHER) & algt->mask) + return ERR_PTR(-EINVAL); + + mask = CRYPTO_ALG_TYPE_MASK | + crypto_requires_off(algt->type, algt->mask, + CRYPTO_ALG_NEED_FALLBACK); + + cipher_alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask); + if (IS_ERR(cipher_alg)) + return ERR_CAST(cipher_alg); + + inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); + if (!inst) { + err = -ENOMEM; + goto err_put_cipher_alg; + } + spawn = skcipher_instance_ctx(inst); + + err = crypto_inst_setname(skcipher_crypto_instance(inst), tmpl->name, + cipher_alg); + if (err) + goto err_free_inst; + + err = crypto_init_spawn(spawn, cipher_alg, + skcipher_crypto_instance(inst), + CRYPTO_ALG_TYPE_MASK); + if (err) + goto err_free_inst; + inst->free = skcipher_free_instance_simple; + + /* Default algorithm properties, can be overridden */ + inst->alg.base.cra_blocksize = cipher_alg->cra_blocksize; + inst->alg.base.cra_alignmask = cipher_alg->cra_alignmask; + inst->alg.base.cra_priority = cipher_alg->cra_priority; + inst->alg.min_keysize = cipher_alg->cra_cipher.cia_min_keysize; + inst->alg.max_keysize = cipher_alg->cra_cipher.cia_max_keysize; + inst->alg.ivsize = cipher_alg->cra_blocksize; + + /* Use skcipher_ctx_simple by default, can be overridden */ + inst->alg.base.cra_ctxsize = sizeof(struct skcipher_ctx_simple); + inst->alg.setkey = skcipher_setkey_simple; + inst->alg.init = skcipher_init_tfm_simple; + inst->alg.exit = skcipher_exit_tfm_simple; + + *cipher_alg_ret = cipher_alg; + return inst; + +err_free_inst: + kfree(inst); +err_put_cipher_alg: + crypto_mod_put(cipher_alg); + return ERR_PTR(err); +} +EXPORT_SYMBOL_GPL(skcipher_alloc_instance_simple); + MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("Symmetric key cipher type"); diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h index 453e867b4bd9..9de6032209cb 100644 --- a/include/crypto/internal/skcipher.h +++ b/include/crypto/internal/skcipher.h @@ -205,5 +205,20 @@ static inline unsigned int crypto_skcipher_alg_max_keysize( return alg->max_keysize; } +/* Helpers for simple block cipher modes of operation */ +struct skcipher_ctx_simple { + struct crypto_cipher *cipher; /* underlying block cipher */ +}; +static inline struct crypto_cipher * +skcipher_cipher_simple(struct crypto_skcipher *tfm) +{ + struct skcipher_ctx_simple *ctx = crypto_skcipher_ctx(tfm); + + return ctx->cipher; +} +struct skcipher_instance * +skcipher_alloc_instance_simple(struct crypto_template *tmpl, struct rtattr **tb, + struct crypto_alg **cipher_alg_ret); + #endif /* _CRYPTO_INTERNAL_SKCIPHER_H */ -- 2.30.2