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 <linux/crypto.h> 23 #include <linux/string.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(struct crypto_tfm *tfm, const u8 *src, 30 unsigned int slen, u8 *dst, unsigned int *dlen) 31 { 32 if (slen > *dlen) 33 return -EINVAL; 34 memcpy(dst, src, slen); 35 *dlen = slen; 36 return 0; 37 } 38 39 static void null_init(struct crypto_tfm *tfm) 40 { } 41 42 static void null_update(struct crypto_tfm *tfm, const u8 *data, 43 unsigned int len) 44 { } 45 46 static void null_final(struct crypto_tfm *tfm, u8 *out) 47 { } 48 49 static int null_setkey(struct crypto_tfm *tfm, const u8 *key, 50 unsigned int keylen) 51 { return 0; } 52 53 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 54 { 55 memcpy(dst, src, NULL_BLOCK_SIZE); 56 } 57 58 static struct crypto_alg compress_null = { 59 .cra_name = "compress_null", 60 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, 61 .cra_blocksize = NULL_BLOCK_SIZE, 62 .cra_ctxsize = 0, 63 .cra_module = THIS_MODULE, 64 .cra_list = LIST_HEAD_INIT(compress_null.cra_list), 65 .cra_u = { .compress = { 66 .coa_compress = null_compress, 67 .coa_decompress = null_compress } } 68 }; 69 70 static struct crypto_alg digest_null = { 71 .cra_name = "digest_null", 72 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 73 .cra_blocksize = NULL_BLOCK_SIZE, 74 .cra_ctxsize = 0, 75 .cra_module = THIS_MODULE, 76 .cra_list = LIST_HEAD_INIT(digest_null.cra_list), 77 .cra_u = { .digest = { 78 .dia_digestsize = NULL_DIGEST_SIZE, 79 .dia_init = null_init, 80 .dia_update = null_update, 81 .dia_final = null_final } } 82 }; 83 84 static struct crypto_alg cipher_null = { 85 .cra_name = "cipher_null", 86 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 87 .cra_blocksize = NULL_BLOCK_SIZE, 88 .cra_ctxsize = 0, 89 .cra_module = THIS_MODULE, 90 .cra_list = LIST_HEAD_INIT(cipher_null.cra_list), 91 .cra_u = { .cipher = { 92 .cia_min_keysize = NULL_KEY_SIZE, 93 .cia_max_keysize = NULL_KEY_SIZE, 94 .cia_setkey = null_setkey, 95 .cia_encrypt = null_crypt, 96 .cia_decrypt = null_crypt } } 97 }; 98 99 MODULE_ALIAS("compress_null"); 100 MODULE_ALIAS("digest_null"); 101 MODULE_ALIAS("cipher_null"); 102 103 static int __init init(void) 104 { 105 int ret = 0; 106 107 ret = crypto_register_alg(&cipher_null); 108 if (ret < 0) 109 goto out; 110 111 ret = crypto_register_alg(&digest_null); 112 if (ret < 0) { 113 crypto_unregister_alg(&cipher_null); 114 goto out; 115 } 116 117 ret = crypto_register_alg(&compress_null); 118 if (ret < 0) { 119 crypto_unregister_alg(&digest_null); 120 crypto_unregister_alg(&cipher_null); 121 goto out; 122 } 123 124 out: 125 return ret; 126 } 127 128 static void __exit fini(void) 129 { 130 crypto_unregister_alg(&compress_null); 131 crypto_unregister_alg(&digest_null); 132 crypto_unregister_alg(&cipher_null); 133 } 134 135 module_init(init); 136 module_exit(fini); 137 138 MODULE_LICENSE("GPL"); 139 MODULE_DESCRIPTION("Null Cryptographic Algorithms"); 140