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/null.h>
  21 #include <crypto/internal/hash.h>
  22 #include <crypto/internal/skcipher.h>
  23 #include <linux/init.h>
  24 #include <linux/module.h>
  25 #include <linux/mm.h>
  26 #include <linux/string.h>
  27
  28 static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
  29 static struct crypto_blkcipher *crypto_default_null_skcipher;
  30 static int crypto_default_null_skcipher_refcnt;
  31 static struct crypto_skcipher *crypto_default_null_skcipher2;
  32 static int crypto_default_null_skcipher2_refcnt;
  33
  34 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
  35                          unsigned int slen, u8 *dst, unsigned int *dlen)
  36 {
  37         if (slen > *dlen)
  38                 return -EINVAL;
  39         memcpy(dst, src, slen);
  40         *dlen = slen;
  41         return 0;
  42 }
  43
  44 static int null_init(struct shash_desc *desc)
  45 {
  46         return 0;
  47 }
  48
  49 static int null_update(struct shash_desc *desc, const u8 *data,
  50                        unsigned int len)
  51 {
  52         return 0;
  53 }
  54
  55 static int null_final(struct shash_desc *desc, u8 *out)
  56 {
  57         return 0;
  58 }
  59
  60 static int null_digest(struct shash_desc *desc, const u8 *data,
  61                        unsigned int len, u8 *out)
  62 {
  63         return 0;
  64 }
  65
  66 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
  67                             unsigned int keylen)
  68 { return 0; }
  69
  70 static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
  71                        unsigned int keylen)
  72 { return 0; }
  73
  74 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  75 {
  76         memcpy(dst, src, NULL_BLOCK_SIZE);
  77 }
  78
  79 static int skcipher_null_crypt(struct blkcipher_desc *desc,
  80                                struct scatterlist *dst,
  81                                struct scatterlist *src, unsigned int nbytes)
  82 {
  83         struct blkcipher_walk walk;
  84         int err;
  85
  86         blkcipher_walk_init(&walk, dst, src, nbytes);
  87         err = blkcipher_walk_virt(desc, &walk);
  88
  89         while (walk.nbytes) {
  90                 if (walk.src.virt.addr != walk.dst.virt.addr)
  91                         memcpy(walk.dst.virt.addr, walk.src.virt.addr,
  92                                walk.nbytes);
  93                 err = blkcipher_walk_done(desc, &walk, 0);
  94         }
  95
  96         return err;
  97 }
  98
  99 static struct shash_alg digest_null = {
 100         .digestsize             =       NULL_DIGEST_SIZE,
 101         .setkey                 =       null_hash_setkey,
 102         .init                   =       null_init,
 103         .update                 =       null_update,
 104         .finup                  =       null_digest,
 105         .digest                 =       null_digest,
 106         .final                  =       null_final,
 107         .base                   =       {
 108                 .cra_name               =       "digest_null",
 109                 .cra_flags              =       CRYPTO_ALG_TYPE_SHASH,
 110                 .cra_blocksize          =       NULL_BLOCK_SIZE,
 111                 .cra_module             =       THIS_MODULE,
 112         }
 113 };
 114
 115 static struct crypto_alg null_algs[3] = { {
 116         .cra_name               =       "cipher_null",
 117         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 118         .cra_blocksize          =       NULL_BLOCK_SIZE,
 119         .cra_ctxsize            =       0,
 120         .cra_module             =       THIS_MODULE,
 121         .cra_u                  =       { .cipher = {
 122         .cia_min_keysize        =       NULL_KEY_SIZE,
 123         .cia_max_keysize        =       NULL_KEY_SIZE,
 124         .cia_setkey             =       null_setkey,
 125         .cia_encrypt            =       null_crypt,
 126         .cia_decrypt            =       null_crypt } }
 127 }, {
 128         .cra_name               =       "ecb(cipher_null)",
 129         .cra_driver_name        =       "ecb-cipher_null",
 130         .cra_priority           =       100,
 131         .cra_flags              =       CRYPTO_ALG_TYPE_BLKCIPHER,
 132         .cra_blocksize          =       NULL_BLOCK_SIZE,
 133         .cra_type               =       &crypto_blkcipher_type,
 134         .cra_ctxsize            =       0,
 135         .cra_module             =       THIS_MODULE,
 136         .cra_u                  =       { .blkcipher = {
 137         .min_keysize            =       NULL_KEY_SIZE,
 138         .max_keysize            =       NULL_KEY_SIZE,
 139         .ivsize                 =       NULL_IV_SIZE,
 140         .setkey                 =       null_setkey,
 141         .encrypt                =       skcipher_null_crypt,
 142         .decrypt                =       skcipher_null_crypt } }
 143 }, {
 144         .cra_name               =       "compress_null",
 145         .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
 146         .cra_blocksize          =       NULL_BLOCK_SIZE,
 147         .cra_ctxsize            =       0,
 148         .cra_module             =       THIS_MODULE,
 149         .cra_u                  =       { .compress = {
 150         .coa_compress           =       null_compress,
 151         .coa_decompress         =       null_compress } }
 152 } };
 153
 154 MODULE_ALIAS_CRYPTO("compress_null");
 155 MODULE_ALIAS_CRYPTO("digest_null");
 156 MODULE_ALIAS_CRYPTO("cipher_null");
 157
 158 struct crypto_blkcipher *crypto_get_default_null_skcipher(void)
 159 {
 160         struct crypto_blkcipher *tfm;
 161
 162         mutex_lock(&crypto_default_null_skcipher_lock);
 163         tfm = crypto_default_null_skcipher;
 164
 165         if (!tfm) {
 166                 tfm = crypto_alloc_blkcipher("ecb(cipher_null)", 0, 0);
 167                 if (IS_ERR(tfm))
 168                         goto unlock;
 169
 170                 crypto_default_null_skcipher = tfm;
 171         }
 172
 173         crypto_default_null_skcipher_refcnt++;
 174
 175 unlock:
 176         mutex_unlock(&crypto_default_null_skcipher_lock);
 177
 178         return tfm;
 179 }
 180 EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
 181
 182 void crypto_put_default_null_skcipher(void)
 183 {
 184         mutex_lock(&crypto_default_null_skcipher_lock);
 185         if (!--crypto_default_null_skcipher_refcnt) {
 186                 crypto_free_blkcipher(crypto_default_null_skcipher);
 187                 crypto_default_null_skcipher = NULL;
 188         }
 189         mutex_unlock(&crypto_default_null_skcipher_lock);
 190 }
 191 EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
 192
 193 struct crypto_skcipher *crypto_get_default_null_skcipher2(void)
 194 {
 195         struct crypto_skcipher *tfm;
 196
 197         mutex_lock(&crypto_default_null_skcipher_lock);
 198         tfm = crypto_default_null_skcipher2;
 199
 200         if (!tfm) {
 201                 tfm = crypto_alloc_skcipher("ecb(cipher_null)",
 202                                             0, CRYPTO_ALG_ASYNC);
 203                 if (IS_ERR(tfm))
 204                         goto unlock;
 205
 206                 crypto_default_null_skcipher2 = tfm;
 207         }
 208
 209         crypto_default_null_skcipher2_refcnt++;
 210
 211 unlock:
 212         mutex_unlock(&crypto_default_null_skcipher_lock);
 213
 214         return tfm;
 215 }
 216 EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher2);
 217
 218 void crypto_put_default_null_skcipher2(void)
 219 {
 220         mutex_lock(&crypto_default_null_skcipher_lock);
 221         if (!--crypto_default_null_skcipher2_refcnt) {
 222                 crypto_free_skcipher(crypto_default_null_skcipher2);
 223                 crypto_default_null_skcipher2 = NULL;
 224         }
 225         mutex_unlock(&crypto_default_null_skcipher_lock);
 226 }
 227 EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher2);
 228
 229 static int __init crypto_null_mod_init(void)
 230 {
 231         int ret = 0;
 232
 233         ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
 234         if (ret < 0)
 235                 goto out;
 236
 237         ret = crypto_register_shash(&digest_null);
 238         if (ret < 0)
 239                 goto out_unregister_algs;
 240
 241         return 0;
 242
 243 out_unregister_algs:
 244         crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
 245 out:
 246         return ret;
 247 }
 248
 249 static void __exit crypto_null_mod_fini(void)
 250 {
 251         crypto_unregister_shash(&digest_null);
 252         crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
 253 }
 254
 255 module_init(crypto_null_mod_init);
 256 module_exit(crypto_null_mod_fini);
 257
 258 MODULE_LICENSE("GPL");
 259 MODULE_DESCRIPTION("Null Cryptographic Algorithms");