crypto/crypto_null.c

   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 <asm/scatterlist.h>
  23 #include <linux/crypto.h>
  24
  25 #define NULL_KEY_SIZE           0
  26 #define NULL_BLOCK_SIZE         1
  27 #define NULL_DIGEST_SIZE        0
  28
  29 static int null_compress(void *ctx, const u8 *src, unsigned int slen,
  30                          u8 *dst, unsigned int *dlen)
  31 { return 0; }
  32
  33 static int null_decompress(void *ctx, const u8 *src, unsigned int slen,
  34                            u8 *dst, unsigned int *dlen)
  35 { return 0; }
  36
  37 static void null_init(void *ctx)
  38 { }
  39
  40 static void null_update(void *ctx, const u8 *data, unsigned int len)
  41 { }
  42
  43 static void null_final(void *ctx, u8 *out)
  44 { }
  45
  46 static int null_setkey(void *ctx, const u8 *key,
  47                        unsigned int keylen, u32 *flags)
  48 { return 0; }
  49
  50 static void null_encrypt(void *ctx, u8 *dst, const u8 *src)
  51 { }
  52
  53 static void null_decrypt(void *ctx, u8 *dst, const u8 *src)
  54 { }
  55
  56 static struct crypto_alg compress_null = {
  57         .cra_name               =       "compress_null",
  58         .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
  59         .cra_blocksize          =       NULL_BLOCK_SIZE,
  60         .cra_ctxsize            =       0,
  61         .cra_module             =       THIS_MODULE,
  62         .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),
  63         .cra_u                  =       { .compress = {
  64         .coa_compress           =       null_compress,
  65         .coa_decompress         =       null_decompress } }
  66 };
  67
  68 static struct crypto_alg digest_null = {
  69         .cra_name               =       "digest_null",
  70         .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
  71         .cra_blocksize          =       NULL_BLOCK_SIZE,
  72         .cra_ctxsize            =       0,
  73         .cra_module             =       THIS_MODULE,
  74         .cra_list               =       LIST_HEAD_INIT(digest_null.cra_list),
  75         .cra_u                  =       { .digest = {
  76         .dia_digestsize         =       NULL_DIGEST_SIZE,
  77         .dia_init               =       null_init,
  78         .dia_update             =       null_update,
  79         .dia_final              =       null_final } }
  80 };
  81
  82 static struct crypto_alg cipher_null = {
  83         .cra_name               =       "cipher_null",
  84         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
  85         .cra_blocksize          =       NULL_BLOCK_SIZE,
  86         .cra_ctxsize            =       0,
  87         .cra_module             =       THIS_MODULE,
  88         .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),
  89         .cra_u                  =       { .cipher = {
  90         .cia_min_keysize        =       NULL_KEY_SIZE,
  91         .cia_max_keysize        =       NULL_KEY_SIZE,
  92         .cia_setkey             =       null_setkey,
  93         .cia_encrypt            =       null_encrypt,
  94         .cia_decrypt            =       null_decrypt } }
  95 };
  96
  97 static int __init init(void)
  98 {
  99         int ret = 0;
 100
 101         ret = crypto_register_alg(&cipher_null);
 102         if (ret < 0)
 103                 goto out;
 104
 105         ret = crypto_register_alg(&digest_null);
 106         if (ret < 0) {
 107                 crypto_unregister_alg(&cipher_null);
 108                 goto out;
 109         }
 110
 111         ret = crypto_register_alg(&compress_null);
 112         if (ret < 0) {
 113                 crypto_unregister_alg(&digest_null);
 114                 crypto_unregister_alg(&cipher_null);
 115                 goto out;
 116         }
 117
 118 out:
 119         return ret;
 120 }
 121
 122 static void __exit fini(void)
 123 {
 124         crypto_unregister_alg(&compress_null);
 125         crypto_unregister_alg(&digest_null);
 126         crypto_unregister_alg(&cipher_null);
 127 }
 128
 129 module_init(init);
 130 module_exit(fini);
 131
 132 MODULE_LICENSE("GPL");
 133 MODULE_DESCRIPTION("Null Cryptographic Algorithms");