| 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | /* |
| 3 | * Cryptographic API. |
| 4 | * |
| 5 | * Null algorithms, aka Much Ado About Nothing. |
| 6 | * |
| 7 | * These are needed for IPsec, and may be useful in general for |
| 8 | * testing & debugging. |
| 9 | * |
| 10 | * The null cipher is compliant with RFC2410. |
| 11 | * |
| 12 | * Copyright (c) 2002 James Morris <jmorris@intercode.com.au> |
| 13 | */ |
| 14 | |
| 15 | #include <crypto/null.h> |
| 16 | #include <crypto/internal/hash.h> |
| 17 | #include <crypto/internal/skcipher.h> |
| 18 | #include <linux/init.h> |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/mm.h> |
| 21 | #include <linux/string.h> |
| 22 | |
| 23 | static DEFINE_MUTEX(crypto_default_null_skcipher_lock); |
| 24 | static struct crypto_sync_skcipher *crypto_default_null_skcipher; |
| 25 | static int crypto_default_null_skcipher_refcnt; |
| 26 | |
| 27 | static int null_compress(struct crypto_tfm *tfm, const u8 *src, |
| 28 | unsigned int slen, u8 *dst, unsigned int *dlen) |
| 29 | { |
| 30 | if (slen > *dlen) |
| 31 | return -EINVAL; |
| 32 | memcpy(dst, src, slen); |
| 33 | *dlen = slen; |
| 34 | return 0; |
| 35 | } |
| 36 | |
| 37 | static int null_init(struct shash_desc *desc) |
| 38 | { |
| 39 | return 0; |
| 40 | } |
| 41 | |
| 42 | static int null_update(struct shash_desc *desc, const u8 *data, |
| 43 | unsigned int len) |
| 44 | { |
| 45 | return 0; |
| 46 | } |
| 47 | |
| 48 | static int null_final(struct shash_desc *desc, u8 *out) |
| 49 | { |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | static int null_digest(struct shash_desc *desc, const u8 *data, |
| 54 | unsigned int len, u8 *out) |
| 55 | { |
| 56 | return 0; |
| 57 | } |
| 58 | |
| 59 | static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key, |
| 60 | unsigned int keylen) |
| 61 | { return 0; } |
| 62 | |
| 63 | static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key, |
| 64 | unsigned int keylen) |
| 65 | { return 0; } |
| 66 | |
| 67 | static int null_setkey(struct crypto_tfm *tfm, const u8 *key, |
| 68 | unsigned int keylen) |
| 69 | { return 0; } |
| 70 | |
| 71 | static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
| 72 | { |
| 73 | memcpy(dst, src, NULL_BLOCK_SIZE); |
| 74 | } |
| 75 | |
| 76 | static int null_skcipher_crypt(struct skcipher_request *req) |
| 77 | { |
| 78 | struct skcipher_walk walk; |
| 79 | int err; |
| 80 | |
| 81 | err = skcipher_walk_virt(&walk, req, false); |
| 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 = skcipher_walk_done(&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_driver_name = "digest_null-generic", |
| 104 | .cra_blocksize = NULL_BLOCK_SIZE, |
| 105 | .cra_module = THIS_MODULE, |
| 106 | } |
| 107 | }; |
| 108 | |
| 109 | static struct skcipher_alg skcipher_null = { |
| 110 | .base.cra_name = "ecb(cipher_null)", |
| 111 | .base.cra_driver_name = "ecb-cipher_null", |
| 112 | .base.cra_priority = 100, |
| 113 | .base.cra_blocksize = NULL_BLOCK_SIZE, |
| 114 | .base.cra_ctxsize = 0, |
| 115 | .base.cra_module = THIS_MODULE, |
| 116 | .min_keysize = NULL_KEY_SIZE, |
| 117 | .max_keysize = NULL_KEY_SIZE, |
| 118 | .ivsize = NULL_IV_SIZE, |
| 119 | .setkey = null_skcipher_setkey, |
| 120 | .encrypt = null_skcipher_crypt, |
| 121 | .decrypt = null_skcipher_crypt, |
| 122 | }; |
| 123 | |
| 124 | static struct crypto_alg null_algs[] = { { |
| 125 | .cra_name = "cipher_null", |
| 126 | .cra_driver_name = "cipher_null-generic", |
| 127 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
| 128 | .cra_blocksize = NULL_BLOCK_SIZE, |
| 129 | .cra_ctxsize = 0, |
| 130 | .cra_module = THIS_MODULE, |
| 131 | .cra_u = { .cipher = { |
| 132 | .cia_min_keysize = NULL_KEY_SIZE, |
| 133 | .cia_max_keysize = NULL_KEY_SIZE, |
| 134 | .cia_setkey = null_setkey, |
| 135 | .cia_encrypt = null_crypt, |
| 136 | .cia_decrypt = null_crypt } } |
| 137 | }, { |
| 138 | .cra_name = "compress_null", |
| 139 | .cra_driver_name = "compress_null-generic", |
| 140 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, |
| 141 | .cra_blocksize = NULL_BLOCK_SIZE, |
| 142 | .cra_ctxsize = 0, |
| 143 | .cra_module = THIS_MODULE, |
| 144 | .cra_u = { .compress = { |
| 145 | .coa_compress = null_compress, |
| 146 | .coa_decompress = null_compress } } |
| 147 | } }; |
| 148 | |
| 149 | MODULE_ALIAS_CRYPTO("compress_null"); |
| 150 | MODULE_ALIAS_CRYPTO("digest_null"); |
| 151 | MODULE_ALIAS_CRYPTO("cipher_null"); |
| 152 | |
| 153 | struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void) |
| 154 | { |
| 155 | struct crypto_sync_skcipher *tfm; |
| 156 | |
| 157 | mutex_lock(&crypto_default_null_skcipher_lock); |
| 158 | tfm = crypto_default_null_skcipher; |
| 159 | |
| 160 | if (!tfm) { |
| 161 | tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0); |
| 162 | if (IS_ERR(tfm)) |
| 163 | goto unlock; |
| 164 | |
| 165 | crypto_default_null_skcipher = tfm; |
| 166 | } |
| 167 | |
| 168 | crypto_default_null_skcipher_refcnt++; |
| 169 | |
| 170 | unlock: |
| 171 | mutex_unlock(&crypto_default_null_skcipher_lock); |
| 172 | |
| 173 | return tfm; |
| 174 | } |
| 175 | EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher); |
| 176 | |
| 177 | void crypto_put_default_null_skcipher(void) |
| 178 | { |
| 179 | mutex_lock(&crypto_default_null_skcipher_lock); |
| 180 | if (!--crypto_default_null_skcipher_refcnt) { |
| 181 | crypto_free_sync_skcipher(crypto_default_null_skcipher); |
| 182 | crypto_default_null_skcipher = NULL; |
| 183 | } |
| 184 | mutex_unlock(&crypto_default_null_skcipher_lock); |
| 185 | } |
| 186 | EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher); |
| 187 | |
| 188 | static int __init crypto_null_mod_init(void) |
| 189 | { |
| 190 | int ret = 0; |
| 191 | |
| 192 | ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs)); |
| 193 | if (ret < 0) |
| 194 | goto out; |
| 195 | |
| 196 | ret = crypto_register_shash(&digest_null); |
| 197 | if (ret < 0) |
| 198 | goto out_unregister_algs; |
| 199 | |
| 200 | ret = crypto_register_skcipher(&skcipher_null); |
| 201 | if (ret < 0) |
| 202 | goto out_unregister_shash; |
| 203 | |
| 204 | return 0; |
| 205 | |
| 206 | out_unregister_shash: |
| 207 | crypto_unregister_shash(&digest_null); |
| 208 | out_unregister_algs: |
| 209 | crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); |
| 210 | out: |
| 211 | return ret; |
| 212 | } |
| 213 | |
| 214 | static void __exit crypto_null_mod_fini(void) |
| 215 | { |
| 216 | crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); |
| 217 | crypto_unregister_shash(&digest_null); |
| 218 | crypto_unregister_skcipher(&skcipher_null); |
| 219 | } |
| 220 | |
| 221 | subsys_initcall(crypto_null_mod_init); |
| 222 | module_exit(crypto_null_mod_fini); |
| 223 | |
| 224 | MODULE_LICENSE("GPL"); |
| 225 | MODULE_DESCRIPTION("Null Cryptographic Algorithms"); |