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 int null_compress(struct crypto_tfm *tfm, const u8 *src, 29 unsigned int slen, u8 *dst, unsigned int *dlen) 30 { 31 if (slen > *dlen) 32 return -EINVAL; 33 memcpy(dst, src, slen); 34 *dlen = slen; 35 return 0; 36 } 37 38 static int null_init(struct shash_desc *desc) 39 { 40 return 0; 41 } 42 43 static int null_update(struct shash_desc *desc, const u8 *data, 44 unsigned int len) 45 { 46 return 0; 47 } 48 49 static int null_final(struct shash_desc *desc, u8 *out) 50 { 51 return 0; 52 } 53 54 static int null_digest(struct shash_desc *desc, const u8 *data, 55 unsigned int len, u8 *out) 56 { 57 return 0; 58 } 59 60 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key, 61 unsigned int keylen) 62 { return 0; } 63 64 static int null_setkey(struct crypto_tfm *tfm, const u8 *key, 65 unsigned int keylen) 66 { return 0; } 67 68 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) 69 { 70 memcpy(dst, src, NULL_BLOCK_SIZE); 71 } 72 73 static int skcipher_null_crypt(struct blkcipher_desc *desc, 74 struct scatterlist *dst, 75 struct scatterlist *src, unsigned int nbytes) 76 { 77 struct blkcipher_walk walk; 78 int err; 79 80 blkcipher_walk_init(&walk, dst, src, nbytes); 81 err = blkcipher_walk_virt(desc, &walk); 82 83 while (walk.nbytes) { 84 if (walk.src.virt.addr != walk.dst.virt.addr) 85 memcpy(walk.dst.virt.addr, walk.src.virt.addr, 86 walk.nbytes); 87 err = blkcipher_walk_done(desc, &walk, 0); 88 } 89 90 return err; 91 } 92 93 static struct shash_alg digest_null = { 94 .digestsize = NULL_DIGEST_SIZE, 95 .setkey = null_hash_setkey, 96 .init = null_init, 97 .update = null_update, 98 .finup = null_digest, 99 .digest = null_digest, 100 .final = null_final, 101 .base = { 102 .cra_name = "digest_null", 103 .cra_flags = CRYPTO_ALG_TYPE_SHASH, 104 .cra_blocksize = NULL_BLOCK_SIZE, 105 .cra_module = THIS_MODULE, 106 } 107 }; 108 109 static struct crypto_alg null_algs[3] = { { 110 .cra_name = "cipher_null", 111 .cra_flags = CRYPTO_ALG_TYPE_CIPHER, 112 .cra_blocksize = NULL_BLOCK_SIZE, 113 .cra_ctxsize = 0, 114 .cra_module = THIS_MODULE, 115 .cra_u = { .cipher = { 116 .cia_min_keysize = NULL_KEY_SIZE, 117 .cia_max_keysize = NULL_KEY_SIZE, 118 .cia_setkey = null_setkey, 119 .cia_encrypt = null_crypt, 120 .cia_decrypt = null_crypt } } 121 }, { 122 .cra_name = "ecb(cipher_null)", 123 .cra_driver_name = "ecb-cipher_null", 124 .cra_priority = 100, 125 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, 126 .cra_blocksize = NULL_BLOCK_SIZE, 127 .cra_type = &crypto_blkcipher_type, 128 .cra_ctxsize = 0, 129 .cra_module = THIS_MODULE, 130 .cra_u = { .blkcipher = { 131 .min_keysize = NULL_KEY_SIZE, 132 .max_keysize = NULL_KEY_SIZE, 133 .ivsize = NULL_IV_SIZE, 134 .setkey = null_setkey, 135 .encrypt = skcipher_null_crypt, 136 .decrypt = skcipher_null_crypt } } 137 }, { 138 .cra_name = "compress_null", 139 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, 140 .cra_blocksize = NULL_BLOCK_SIZE, 141 .cra_ctxsize = 0, 142 .cra_module = THIS_MODULE, 143 .cra_u = { .compress = { 144 .coa_compress = null_compress, 145 .coa_decompress = null_compress } } 146 } }; 147 148 MODULE_ALIAS("compress_null"); 149 MODULE_ALIAS("digest_null"); 150 MODULE_ALIAS("cipher_null"); 151 152 static int __init crypto_null_mod_init(void) 153 { 154 int ret = 0; 155 156 ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs)); 157 if (ret < 0) 158 goto out; 159 160 ret = crypto_register_shash(&digest_null); 161 if (ret < 0) 162 goto out_unregister_algs; 163 164 return 0; 165 166 out_unregister_algs: 167 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); 168 out: 169 return ret; 170 } 171 172 static void __exit crypto_null_mod_fini(void) 173 { 174 crypto_unregister_shash(&digest_null); 175 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); 176 } 177 178 module_init(crypto_null_mod_init); 179 module_exit(crypto_null_mod_fini); 180 181 MODULE_LICENSE("GPL"); 182 MODULE_DESCRIPTION("Null Cryptographic Algorithms"); 183