/* * 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);	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");