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1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 for8 * 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 23static DEFINE_MUTEX(crypto_default_null_skcipher_lock);24static struct crypto_sync_skcipher *crypto_default_null_skcipher;25static int crypto_default_null_skcipher_refcnt;26 27static 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 37static int null_init(struct shash_desc *desc)38{39 return 0;40}41 42static int null_update(struct shash_desc *desc, const u8 *data,43 unsigned int len)44{45 return 0;46}47 48static int null_final(struct shash_desc *desc, u8 *out)49{50 return 0;51}52 53static int null_digest(struct shash_desc *desc, const u8 *data,54 unsigned int len, u8 *out)55{56 return 0;57}58 59static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,60 unsigned int keylen)61{ return 0; }62 63static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,64 unsigned int keylen)65{ return 0; }66 67static int null_setkey(struct crypto_tfm *tfm, const u8 *key,68 unsigned int keylen)69{ return 0; }70 71static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)72{73 memcpy(dst, src, NULL_BLOCK_SIZE);74}75 76static 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 93static 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 109static 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 124static 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 149MODULE_ALIAS_CRYPTO("compress_null");150MODULE_ALIAS_CRYPTO("digest_null");151MODULE_ALIAS_CRYPTO("cipher_null");152 153struct 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 170unlock:171 mutex_unlock(&crypto_default_null_skcipher_lock);172 173 return tfm;174}175EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);176 177void 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}186EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);187 188static 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 206out_unregister_shash:207 crypto_unregister_shash(&digest_null);208out_unregister_algs:209 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));210out:211 return ret;212}213 214static 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 221subsys_initcall(crypto_null_mod_init);222module_exit(crypto_null_mod_fini);223 224MODULE_LICENSE("GPL");225MODULE_DESCRIPTION("Null Cryptographic Algorithms");226