LXR linux/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
  20static 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
  48static 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
  57static 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
  66static 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
  88static struct crypto_template crypto_ecb_tmpl = {
  89        .name = "ecb",
  90        .create = crypto_ecb_create,
  91        .module = THIS_MODULE,
  92};
  93
  94static int __init crypto_ecb_module_init(void)
  95{
  96        return crypto_register_template(&crypto_ecb_tmpl);
  97}
  98
  99static void __exit crypto_ecb_module_exit(void)
 100{
 101        crypto_unregister_template(&crypto_ecb_tmpl);
 102}
 103
 104module_init(crypto_ecb_module_init);
 105module_exit(crypto_ecb_module_exit);
 106
 107MODULE_LICENSE("GPL");
 108MODULE_DESCRIPTION("ECB block cipher mode of operation");
 109MODULE_ALIAS_CRYPTO("ecb");
 110