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Diffstat (limited to '')
| -rw-r--r-- | crypto/cbc.c | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/crypto/cbc.c b/crypto/cbc.c new file mode 100644 index 000000000..dd5f332fd --- /dev/null +++ b/crypto/cbc.c @@ -0,0 +1,211 @@ +/* + * CBC: Cipher Block Chaining mode + * + * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or (at your option) + * any later version. + * + */ + +#include <crypto/algapi.h> +#include <crypto/cbc.h> +#include <crypto/internal/skcipher.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/log2.h> +#include <linux/module.h> +#include <linux/slab.h> + +struct crypto_cbc_ctx { + struct crypto_cipher *child; +}; + +static int crypto_cbc_setkey(struct crypto_skcipher *parent, const u8 *key, + unsigned int keylen) +{ + struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(parent); + struct crypto_cipher *child = ctx->child; + int err; + + crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); + crypto_cipher_set_flags(child, crypto_skcipher_get_flags(parent) & + CRYPTO_TFM_REQ_MASK); + err = crypto_cipher_setkey(child, key, keylen); + crypto_skcipher_set_flags(parent, crypto_cipher_get_flags(child) & + CRYPTO_TFM_RES_MASK); + return err; +} + +static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm, + const u8 *src, u8 *dst) +{ + struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); + + crypto_cipher_encrypt_one(ctx->child, dst, src); +} + +static int crypto_cbc_encrypt(struct skcipher_request *req) +{ + return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one); +} + +static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm, + const u8 *src, u8 *dst) +{ + struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); + + crypto_cipher_decrypt_one(ctx->child, dst, src); +} + +static int crypto_cbc_decrypt(struct skcipher_request *req) +{ + struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + struct skcipher_walk walk; + int err; + + err = skcipher_walk_virt(&walk, req, false); + + while (walk.nbytes) { + err = crypto_cbc_decrypt_blocks(&walk, tfm, + crypto_cbc_decrypt_one); + err = skcipher_walk_done(&walk, err); + } + + return err; +} + +static int crypto_cbc_init_tfm(struct crypto_skcipher *tfm) +{ + struct skcipher_instance *inst = skcipher_alg_instance(tfm); + struct crypto_spawn *spawn = skcipher_instance_ctx(inst); + struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); + struct crypto_cipher *cipher; + + cipher = crypto_spawn_cipher(spawn); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + ctx->child = cipher; + return 0; +} + +static void crypto_cbc_exit_tfm(struct crypto_skcipher *tfm) +{ + struct crypto_cbc_ctx *ctx = crypto_skcipher_ctx(tfm); + + crypto_free_cipher(ctx->child); +} + +static void crypto_cbc_free(struct skcipher_instance *inst) +{ + crypto_drop_skcipher(skcipher_instance_ctx(inst)); + kfree(inst); +} + +static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb) +{ + struct skcipher_instance *inst; + struct crypto_attr_type *algt; + struct crypto_spawn *spawn; + struct crypto_alg *alg; + u32 mask; + int err; + + err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER); + if (err) + return err; + + inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); + if (!inst) + return -ENOMEM; + + algt = crypto_get_attr_type(tb); + err = PTR_ERR(algt); + if (IS_ERR(algt)) + goto err_free_inst; + + mask = CRYPTO_ALG_TYPE_MASK | + crypto_requires_off(algt->type, algt->mask, + CRYPTO_ALG_NEED_FALLBACK); + + alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, mask); + err = PTR_ERR(alg); + if (IS_ERR(alg)) + goto err_free_inst; + + spawn = skcipher_instance_ctx(inst); + err = crypto_init_spawn(spawn, alg, skcipher_crypto_instance(inst), + CRYPTO_ALG_TYPE_MASK); + if (err) + goto err_put_alg; + + err = crypto_inst_setname(skcipher_crypto_instance(inst), "cbc", alg); + if (err) + goto err_drop_spawn; + + err = -EINVAL; + if (!is_power_of_2(alg->cra_blocksize)) + goto err_drop_spawn; + + inst->alg.base.cra_priority = alg->cra_priority; + inst->alg.base.cra_blocksize = alg->cra_blocksize; + inst->alg.base.cra_alignmask = alg->cra_alignmask; + + inst->alg.ivsize = alg->cra_blocksize; + inst->alg.min_keysize = alg->cra_cipher.cia_min_keysize; + inst->alg.max_keysize = alg->cra_cipher.cia_max_keysize; + + inst->alg.base.cra_ctxsize = sizeof(struct crypto_cbc_ctx); + + inst->alg.init = crypto_cbc_init_tfm; + inst->alg.exit = crypto_cbc_exit_tfm; + + inst->alg.setkey = crypto_cbc_setkey; + inst->alg.encrypt = crypto_cbc_encrypt; + inst->alg.decrypt = crypto_cbc_decrypt; + + inst->free = crypto_cbc_free; + + err = skcipher_register_instance(tmpl, inst); + if (err) + goto err_drop_spawn; + crypto_mod_put(alg); + +out: + return err; + +err_drop_spawn: + crypto_drop_spawn(spawn); +err_put_alg: + crypto_mod_put(alg); +err_free_inst: + kfree(inst); + goto out; +} + +static struct crypto_template crypto_cbc_tmpl = { + .name = "cbc", + .create = crypto_cbc_create, + .module = THIS_MODULE, +}; + +static int __init crypto_cbc_module_init(void) +{ + return crypto_register_template(&crypto_cbc_tmpl); +} + +static void __exit crypto_cbc_module_exit(void) +{ + crypto_unregister_template(&crypto_cbc_tmpl); +} + +module_init(crypto_cbc_module_init); +module_exit(crypto_cbc_module_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("CBC block cipher algorithm"); +MODULE_ALIAS_CRYPTO("cbc"); |