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 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 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(init); 186 module_exit(fini); 187 188 MODULE_LICENSE("GPL"); 189 MODULE_DESCRIPTION("Null Cryptographic Algorithms"); 190