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 <asm/scatterlist.h> 23 #include <linux/crypto.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(void *ctx, const u8 *src, unsigned int slen, 30 u8 *dst, unsigned int *dlen) 31 { return 0; } 32 33 static int null_decompress(void *ctx, const u8 *src, unsigned int slen, 34 u8 *dst, unsigned int *dlen) 35 { return 0; } 36 37 static void null_init(void *ctx) 38 { } 39 40 static void null_update(void *ctx, const u8 *data, unsigned int len) 41 { } 42 43 static void null_final(void *ctx, u8 *out) 44 { } 45 46 static int null_setkey(void *ctx, const u8 *key, 47 unsigned int keylen, u32 *flags) 48 { return 0; } 49 50 static void null_encrypt(void *ctx, u8 *dst, const u8 *src) 51 { } 52 53 static void null_decrypt(void *ctx, u8 *dst, const u8 *src) 54 { } 55 56 static struct crypto_alg compress_null = { 57 .cra_name = "compress_null", 58 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, 59 .cra_blocksize = NULL_BLOCK_SIZE, 60 .cra_ctxsize = 0, 61 .cra_module = THIS_MODULE, 62 .cra_list = LIST_HEAD_INIT(compress_null.cra_list), 63 .cra_u = { .compress = { 64 .coa_compress = null_compress, 65 .coa_decompress = null_decompress } } 66 }; 67 68 static struct crypto_alg digest_null = { 69 .cra_name = "digest_null", 70 .cra_flags = CRYPTO_ALG_TYPE_DIGEST, 71 .cra_blocksize = NULL_BLOCK_SIZE, 72 .cra_ctxsize = 0, 73 .cra_module = THIS_MODULE, 74 .cra_list = LIST_HEAD_INIT(digest_null.cra_list), 75 .cra_u = { .digest = { 76 .dia_digestsize = NULL_DIGEST_SIZE, 77 .dia_init = null_init, 78 .dia_update = null_update, 79 .dia_final = null_final } } 80 }; 81 82 static struct crypto_alg cipher_null = { 83 .cra_name = "cipher_null", 84 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 85 .cra_blocksize = NULL_BLOCK_SIZE, 86 .cra_ctxsize = 0, 87 .cra_module = THIS_MODULE, 88 .cra_list = LIST_HEAD_INIT(cipher_null.cra_list), 89 .cra_u = { .cipher = { 90 .cia_min_keysize = NULL_KEY_SIZE, 91 .cia_max_keysize = NULL_KEY_SIZE, 92 .cia_setkey = null_setkey, 93 .cia_encrypt = null_encrypt, 94 .cia_decrypt = null_decrypt } } 95 }; 96 97 MODULE_ALIAS("compress_null"); 98 MODULE_ALIAS("digest_null"); 99 MODULE_ALIAS("cipher_null"); 100 101 static int __init init(void) 102 { 103 int ret = 0; 104 105 ret = crypto_register_alg(&cipher_null); 106 if (ret < 0) 107 goto out; 108 109 ret = crypto_register_alg(&digest_null); 110 if (ret < 0) { 111 crypto_unregister_alg(&cipher_null); 112 goto out; 113 } 114 115 ret = crypto_register_alg(&compress_null); 116 if (ret < 0) { 117 crypto_unregister_alg(&digest_null); 118 crypto_unregister_alg(&cipher_null); 119 goto out; 120 } 121 122 out: 123 return ret; 124 } 125 126 static void __exit fini(void) 127 { 128 crypto_unregister_alg(&compress_null); 129 crypto_unregister_alg(&digest_null); 130 crypto_unregister_alg(&cipher_null); 131 } 132 133 module_init(init); 134 module_exit(fini); 135 136 MODULE_LICENSE("GPL"); 137 MODULE_DESCRIPTION("Null Cryptographic Algorithms"); 138