LXR linux/crypto/crypto

   1/* 
   2 * Cryptographic API.
   3 *
   4 * Null algorithms, aka Much Ado About Nothing.
   5 *
   6 * These are needed for IPsec, and may be useful in general for
   7 * testing & debugging.
   8 * 
   9 * The null cipher is compliant with RFC2410.
  10 *
  11 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  12 *
  13 * This program is free software; you can redistribute it and/or modify
  14 * it under the terms of the GNU General Public License as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 */
  19#include <linux/init.h>
  20#include <linux/module.h>
  21#include <linux/mm.h>
  22#include <linux/crypto.h>
  23#include <linux/string.h>
  24
  25#define NULL_KEY_SIZE           0
  26#define NULL_BLOCK_SIZE         1
  27#define NULL_DIGEST_SIZE        0
  28
  29static int null_compress(struct crypto_tfm *tfm, const u8 *src,
  30                         unsigned int slen, u8 *dst, unsigned int *dlen)
  31{
  32        if (slen > *dlen)
  33                return -EINVAL;
  34        memcpy(dst, src, slen);
  35        *dlen = slen;
  36        return 0;
  37}
  38
  39static void null_init(struct crypto_tfm *tfm)
  40{ }
  41
  42static void null_update(struct crypto_tfm *tfm, const u8 *data,
  43                        unsigned int len)
  44{ }
  45
  46static void null_final(struct crypto_tfm *tfm, u8 *out)
  47{ }
  48
  49static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
  50                       unsigned int keylen)
  51{ return 0; }
  52
  53static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  54{
  55        memcpy(dst, src, NULL_BLOCK_SIZE);
  56}
  57
  58static struct crypto_alg compress_null = {
  59        .cra_name               =       "compress_null",
  60        .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
  61        .cra_blocksize          =       NULL_BLOCK_SIZE,
  62        .cra_ctxsize            =       0,
  63        .cra_module             =       THIS_MODULE,
  64        .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),
  65        .cra_u                  =       { .compress = {
  66        .coa_compress           =       null_compress,
  67        .coa_decompress         =       null_compress } }
  68};
  69
  70static struct crypto_alg digest_null = {
  71        .cra_name               =       "digest_null",
  72        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
  73        .cra_blocksize          =       NULL_BLOCK_SIZE,
  74        .cra_ctxsize            =       0,
  75        .cra_module             =       THIS_MODULE,
  76        .cra_list               =       LIST_HEAD_INIT(digest_null.cra_list),   
  77        .cra_u                  =       { .digest = {
  78        .dia_digestsize         =       NULL_DIGEST_SIZE,
  79        .dia_init               =       null_init,
  80        .dia_update             =       null_update,
  81        .dia_final              =       null_final } }
  82};
  83
  84static struct crypto_alg cipher_null = {
  85        .cra_name               =       "cipher_null",
  86        .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
  87        .cra_blocksize          =       NULL_BLOCK_SIZE,
  88        .cra_ctxsize            =       0,
  89        .cra_module             =       THIS_MODULE,
  90        .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),
  91        .cra_u                  =       { .cipher = {
  92        .cia_min_keysize        =       NULL_KEY_SIZE,
  93        .cia_max_keysize        =       NULL_KEY_SIZE,
  94        .cia_setkey             =       null_setkey,
  95        .cia_encrypt            =       null_crypt,
  96        .cia_decrypt            =       null_crypt } }
  97};
  98
  99MODULE_ALIAS("compress_null");
 100MODULE_ALIAS("digest_null");
 101MODULE_ALIAS("cipher_null");
 102
 103static int __init init(void)
 104{
 105        int ret = 0;
 106        
 107        ret = crypto_register_alg(&cipher_null);
 108        if (ret < 0)
 109                goto out;
 110
 111        ret = crypto_register_alg(&digest_null);
 112        if (ret < 0) {
 113                crypto_unregister_alg(&cipher_null);
 114                goto out;
 115        }
 116
 117        ret = crypto_register_alg(&compress_null);
 118        if (ret < 0) {
 119                crypto_unregister_alg(&digest_null);
 120                crypto_unregister_alg(&cipher_null);
 121                goto out;
 122        }
 123
 124out:    
 125        return ret;
 126}
 127
 128static void __exit fini(void)
 129{
 130        crypto_unregister_alg(&compress_null);
 131        crypto_unregister_alg(&digest_null);
 132        crypto_unregister_alg(&cipher_null);
 133}
 134
 135module_init(init);
 136module_exit(fini);
 137
 138MODULE_LICENSE("GPL");
 139MODULE_DESCRIPTION("Null Cryptographic Algorithms");
 140