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