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"); 208