LXR linux/crypto/cbc.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * CBC: Cipher Block Chaining mode
   4 *
   5 * Copyright (c) 2006-2016 Herbert Xu <herbert@gondor.apana.org.au>
   6 */
   7
   8#include <crypto/algapi.h>
   9#include <crypto/cbc.h>
  10#include <crypto/internal/skcipher.h>
  11#include <linux/err.h>
  12#include <linux/init.h>
  13#include <linux/kernel.h>
  14#include <linux/log2.h>
  15#include <linux/module.h>
  16
  17static inline void crypto_cbc_encrypt_one(struct crypto_skcipher *tfm,
  18                                          const u8 *src, u8 *dst)
  19{
  20        crypto_cipher_encrypt_one(skcipher_cipher_simple(tfm), dst, src);
  21}
  22
  23static int crypto_cbc_encrypt(struct skcipher_request *req)
  24{
  25        return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
  26}
  27
  28static inline void crypto_cbc_decrypt_one(struct crypto_skcipher *tfm,
  29                                          const u8 *src, u8 *dst)
  30{
  31        crypto_cipher_decrypt_one(skcipher_cipher_simple(tfm), dst, src);
  32}
  33
  34static int crypto_cbc_decrypt(struct skcipher_request *req)
  35{
  36        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  37        struct skcipher_walk walk;
  38        int err;
  39
  40        err = skcipher_walk_virt(&walk, req, false);
  41
  42        while (walk.nbytes) {
  43                err = crypto_cbc_decrypt_blocks(&walk, tfm,
  44                                                crypto_cbc_decrypt_one);
  45                err = skcipher_walk_done(&walk, err);
  46        }
  47
  48        return err;
  49}
  50
  51static int crypto_cbc_create(struct crypto_template *tmpl, struct rtattr **tb)
  52{
  53        struct skcipher_instance *inst;
  54        struct crypto_alg *alg;
  55        int err;
  56
  57        inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
  58        if (IS_ERR(inst))
  59                return PTR_ERR(inst);
  60
  61        err = -EINVAL;
  62        if (!is_power_of_2(alg->cra_blocksize))
  63                goto out_free_inst;
  64
  65        inst->alg.encrypt = crypto_cbc_encrypt;
  66        inst->alg.decrypt = crypto_cbc_decrypt;
  67
  68        err = skcipher_register_instance(tmpl, inst);
  69        if (err)
  70                goto out_free_inst;
  71        goto out_put_alg;
  72
  73out_free_inst:
  74        inst->free(inst);
  75out_put_alg:
  76        crypto_mod_put(alg);
  77        return err;
  78}
  79
  80static struct crypto_template crypto_cbc_tmpl = {
  81        .name = "cbc",
  82        .create = crypto_cbc_create,
  83        .module = THIS_MODULE,
  84};
  85
  86static int __init crypto_cbc_module_init(void)
  87{
  88        return crypto_register_template(&crypto_cbc_tmpl);
  89}
  90
  91static void __exit crypto_cbc_module_exit(void)
  92{
  93        crypto_unregister_template(&crypto_cbc_tmpl);
  94}
  95
  96subsys_initcall(crypto_cbc_module_init);
  97module_exit(crypto_cbc_module_exit);
  98
  99MODULE_LICENSE("GPL");
 100MODULE_DESCRIPTION("CBC block cipher mode of operation");
 101MODULE_ALIAS_CRYPTO("cbc");
 102