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
  17 static 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
  23 static int crypto_cbc_encrypt(struct skcipher_request *req)
  24 {
  25         return crypto_cbc_encrypt_walk(req, crypto_cbc_encrypt_one);
  26 }
  27
  28 static 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
  34 static 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
  51 static 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);
  58         if (IS_ERR(inst))
  59                 return PTR_ERR(inst);
  60
  61         alg = skcipher_ialg_simple(inst);
  62
  63         err = -EINVAL;
  64         if (!is_power_of_2(alg->cra_blocksize))
  65                 goto out_free_inst;
  66
  67         inst->alg.encrypt = crypto_cbc_encrypt;
  68         inst->alg.decrypt = crypto_cbc_decrypt;
  69
  70         err = skcipher_register_instance(tmpl, inst);
  71         if (err) {
  72 out_free_inst:
  73                 inst->free(inst);
  74         }
  75
  76         return err;
  77 }
  78
  79 static struct crypto_template crypto_cbc_tmpl = {
  80         .name = "cbc",
  81         .create = crypto_cbc_create,
  82         .module = THIS_MODULE,
  83 };
  84
  85 static int __init crypto_cbc_module_init(void)
  86 {
  87         return crypto_register_template(&crypto_cbc_tmpl);
  88 }
  89
  90 static void __exit crypto_cbc_module_exit(void)
  91 {
  92         crypto_unregister_template(&crypto_cbc_tmpl);
  93 }
  94
  95 subsys_initcall(crypto_cbc_module_init);
  96 module_exit(crypto_cbc_module_exit);
  97
  98 MODULE_LICENSE("GPL");
  99 MODULE_DESCRIPTION("CBC block cipher mode of operation");
 100 MODULE_ALIAS_CRYPTO("cbc");