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
  20 #include <crypto/internal/hash.h>
  21 #include <crypto/internal/skcipher.h>
  22 #include <linux/init.h>
  23 #include <linux/module.h>
  24 #include <linux/mm.h>
  25 #include <linux/string.h>
  26
  27 #define NULL_KEY_SIZE           0
  28 #define NULL_BLOCK_SIZE         1
  29 #define NULL_DIGEST_SIZE        0
  30 #define NULL_IV_SIZE            0
  31
  32 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
  33                          unsigned int slen, u8 *dst, unsigned int *dlen)
  34 {
  35         if (slen > *dlen)
  36                 return -EINVAL;
  37         memcpy(dst, src, slen);
  38         *dlen = slen;
  39         return 0;
  40 }
  41
  42 static int null_init(struct shash_desc *desc)
  43 {
  44         return 0;
  45 }
  46
  47 static int null_update(struct shash_desc *desc, const u8 *data,
  48                        unsigned int len)
  49 {
  50         return 0;
  51 }
  52
  53 static int null_final(struct shash_desc *desc, u8 *out)
  54 {
  55         return 0;
  56 }
  57
  58 static int null_digest(struct shash_desc *desc, const u8 *data,
  59                        unsigned int len, u8 *out)
  60 {
  61         return 0;
  62 }
  63
  64 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
  65                             unsigned int keylen)
  66 { return 0; }
  67
  68 static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
  69                        unsigned int keylen)
  70 { return 0; }
  71
  72 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  73 {
  74         memcpy(dst, src, NULL_BLOCK_SIZE);
  75 }
  76
  77 static int skcipher_null_crypt(struct blkcipher_desc *desc,
  78                                struct scatterlist *dst,
  79                                struct scatterlist *src, unsigned int nbytes)
  80 {
  81         struct blkcipher_walk walk;
  82         int err;
  83
  84         blkcipher_walk_init(&walk, dst, src, nbytes);
  85         err = blkcipher_walk_virt(desc, &walk);
  86
  87         while (walk.nbytes) {
  88                 if (walk.src.virt.addr != walk.dst.virt.addr)
  89                         memcpy(walk.dst.virt.addr, walk.src.virt.addr,
  90                                walk.nbytes);
  91                 err = blkcipher_walk_done(desc, &walk, 0);
  92         }
  93
  94         return err;
  95 }
  96
  97 static struct crypto_alg compress_null = {
  98         .cra_name               =       "compress_null",
  99         .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
 100         .cra_blocksize          =       NULL_BLOCK_SIZE,
 101         .cra_ctxsize            =       0,
 102         .cra_module             =       THIS_MODULE,
 103         .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),
 104         .cra_u                  =       { .compress = {
 105         .coa_compress           =       null_compress,
 106         .coa_decompress         =       null_compress } }
 107 };
 108
 109 static struct shash_alg digest_null = {
 110         .digestsize             =       NULL_DIGEST_SIZE,
 111         .setkey                 =       null_hash_setkey,
 112         .init                   =       null_init,
 113         .update                 =       null_update,
 114         .finup                  =       null_digest,
 115         .digest                 =       null_digest,
 116         .final                  =       null_final,
 117         .base                   =       {
 118                 .cra_name               =       "digest_null",
 119                 .cra_flags              =       CRYPTO_ALG_TYPE_SHASH,
 120                 .cra_blocksize          =       NULL_BLOCK_SIZE,
 121                 .cra_module             =       THIS_MODULE,
 122         }
 123 };
 124
 125 static struct crypto_alg cipher_null = {
 126         .cra_name               =       "cipher_null",
 127         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 128         .cra_blocksize          =       NULL_BLOCK_SIZE,
 129         .cra_ctxsize            =       0,
 130         .cra_module             =       THIS_MODULE,
 131         .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),
 132         .cra_u                  =       { .cipher = {
 133         .cia_min_keysize        =       NULL_KEY_SIZE,
 134         .cia_max_keysize        =       NULL_KEY_SIZE,
 135         .cia_setkey             =       null_setkey,
 136         .cia_encrypt            =       null_crypt,
 137         .cia_decrypt            =       null_crypt } }
 138 };
 139
 140 static struct crypto_alg skcipher_null = {
 141         .cra_name               =       "ecb(cipher_null)",
 142         .cra_driver_name        =       "ecb-cipher_null",
 143         .cra_priority           =       100,
 144         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 145         .cra_blocksize          =       NULL_BLOCK_SIZE,
 146         .cra_type               =       &crypto_blkcipher_type,
 147         .cra_ctxsize            =       0,
 148         .cra_module             =       THIS_MODULE,
 149         .cra_list               =       LIST_HEAD_INIT(skcipher_null.cra_list),
 150         .cra_u                  =       { .blkcipher = {
 151         .min_keysize            =       NULL_KEY_SIZE,
 152         .max_keysize            =       NULL_KEY_SIZE,
 153         .ivsize                 =       NULL_IV_SIZE,
 154         .setkey                 =       null_setkey,
 155         .encrypt                =       skcipher_null_crypt,
 156         .decrypt                =       skcipher_null_crypt } }
 157 };
 158
 159 MODULE_ALIAS("compress_null");
 160 MODULE_ALIAS("digest_null");
 161 MODULE_ALIAS("cipher_null");
 162
 163 static int __init crypto_null_mod_init(void)
 164 {
 165         int ret = 0;
 166
 167         ret = crypto_register_alg(&cipher_null);
 168         if (ret < 0)
 169                 goto out;
 170
 171         ret = crypto_register_alg(&skcipher_null);
 172         if (ret < 0)
 173                 goto out_unregister_cipher;
 174
 175         ret = crypto_register_shash(&digest_null);
 176         if (ret < 0)
 177                 goto out_unregister_skcipher;
 178
 179         ret = crypto_register_alg(&compress_null);
 180         if (ret < 0)
 181                 goto out_unregister_digest;
 182
 183 out:
 184         return ret;
 185
 186 out_unregister_digest:
 187         crypto_unregister_shash(&digest_null);
 188 out_unregister_skcipher:
 189         crypto_unregister_alg(&skcipher_null);
 190 out_unregister_cipher:
 191         crypto_unregister_alg(&cipher_null);
 192         goto out;
 193 }
 194
 195 static void __exit crypto_null_mod_fini(void)
 196 {
 197         crypto_unregister_alg(&compress_null);
 198         crypto_unregister_shash(&digest_null);
 199         crypto_unregister_alg(&skcipher_null);
 200         crypto_unregister_alg(&cipher_null);
 201 }
 202
 203 module_init(crypto_null_mod_init);
 204 module_exit(crypto_null_mod_fini);
 205
 206 MODULE_LICENSE("GPL");
 207 MODULE_DESCRIPTION("Null Cryptographic Algorithms");