/* * 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/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_spawn *spawn; struct crypto_alg *alg; 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; alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, CRYPTO_ALG_TYPE_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); crypto_mod_put(alg); if (err) goto err_free_inst; 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; out: return err; err_drop_spawn: crypto_drop_spawn(spawn); 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");