crypto/ecb.c

   1 /*
   2  * ECB: Electronic CodeBook mode
   3  *
   4  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  */
  12
  13 #include <crypto/algapi.h>
  14 #include <crypto/internal/skcipher.h>
  15 #include <linux/err.h>
  16 #include <linux/init.h>
  17 #include <linux/kernel.h>
  18 #include <linux/module.h>
  19
  20 static int crypto_ecb_crypt(struct skcipher_request *req,
  21                             struct crypto_cipher *cipher,
  22                             void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
  23 {
  24         const unsigned int bsize = crypto_cipher_blocksize(cipher);
  25         struct skcipher_walk walk;
  26         unsigned int nbytes;
  27         int err;
  28
  29         err = skcipher_walk_virt(&walk, req, false);
  30
  31         while ((nbytes = walk.nbytes) != 0) {
  32                 const u8 *src = walk.src.virt.addr;
  33                 u8 *dst = walk.dst.virt.addr;
  34
  35                 do {
  36                         fn(crypto_cipher_tfm(cipher), dst, src);
  37
  38                         src += bsize;
  39                         dst += bsize;
  40                 } while ((nbytes -= bsize) >= bsize);
  41
  42                 err = skcipher_walk_done(&walk, nbytes);
  43         }
  44
  45         return err;
  46 }
  47
  48 static int crypto_ecb_encrypt(struct skcipher_request *req)
  49 {
  50         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  51         struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
  52
  53         return crypto_ecb_crypt(req, cipher,
  54                                 crypto_cipher_alg(cipher)->cia_encrypt);
  55 }
  56
  57 static int crypto_ecb_decrypt(struct skcipher_request *req)
  58 {
  59         struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
  60         struct crypto_cipher *cipher = skcipher_cipher_simple(tfm);
  61
  62         return crypto_ecb_crypt(req, cipher,
  63                                 crypto_cipher_alg(cipher)->cia_decrypt);
  64 }
  65
  66 static int crypto_ecb_create(struct crypto_template *tmpl, struct rtattr **tb)
  67 {
  68         struct skcipher_instance *inst;
  69         struct crypto_alg *alg;
  70         int err;
  71
  72         inst = skcipher_alloc_instance_simple(tmpl, tb, &alg);
  73         if (IS_ERR(inst))
  74                 return PTR_ERR(inst);
  75
  76         inst->alg.ivsize = 0; /* ECB mode doesn't take an IV */
  77
  78         inst->alg.encrypt = crypto_ecb_encrypt;
  79         inst->alg.decrypt = crypto_ecb_decrypt;
  80
  81         err = skcipher_register_instance(tmpl, inst);
  82         if (err)
  83                 inst->free(inst);
  84         crypto_mod_put(alg);
  85         return err;
  86 }
  87
  88 static struct crypto_template crypto_ecb_tmpl = {
  89         .name = "ecb",
  90         .create = crypto_ecb_create,
  91         .module = THIS_MODULE,
  92 };
  93
  94 static int __init crypto_ecb_module_init(void)
  95 {
  96         return crypto_register_template(&crypto_ecb_tmpl);
  97 }
  98
  99 static void __exit crypto_ecb_module_exit(void)
 100 {
 101         crypto_unregister_template(&crypto_ecb_tmpl);
 102 }
 103
 104 subsys_initcall(crypto_ecb_module_init);
 105 module_exit(crypto_ecb_module_exit);
 106
 107 MODULE_LICENSE("GPL");
 108 MODULE_DESCRIPTION("ECB block cipher mode of operation");
 109 MODULE_ALIAS_CRYPTO("ecb");