crypto_null.c

  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 <crypto/scatterwalk.h>
 19#include <linux/init.h>
 20#include <linux/module.h>
 21#include <linux/string.h>
 22
 23static int null_init(struct shash_desc *desc)
 24{
 25	return 0;
 26}
 27
 28static int null_update(struct shash_desc *desc, const u8 *data,
 29		       unsigned int len)
 30{
 31	return 0;
 32}
 33
 34static int null_final(struct shash_desc *desc, u8 *out)
 35{
 36	return 0;
 37}
 38
 39static int null_digest(struct shash_desc *desc, const u8 *data,
 40		       unsigned int len, u8 *out)
 41{
 42	return 0;
 43}
 44
 45static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
 46			    unsigned int keylen)
 47{ return 0; }
 48
 49static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
 50				unsigned int keylen)
 51{ return 0; }
 52
 53static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
 54		       unsigned int keylen)
 55{ return 0; }
 56
 57static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 58{
 59	memcpy(dst, src, NULL_BLOCK_SIZE);
 60}
 61
 62static int null_skcipher_crypt(struct skcipher_request *req)
 63{
 64	if (req->src != req->dst)
 65		memcpy_sglist(req->dst, req->src, req->cryptlen);
 66	return 0;
 67}
 68
 69static struct shash_alg digest_null = {
 70	.digestsize		=	NULL_DIGEST_SIZE,
 71	.setkey   		=	null_hash_setkey,
 72	.init   		=	null_init,
 73	.update 		=	null_update,
 74	.finup 			=	null_digest,
 75	.digest 		=	null_digest,
 76	.final  		=	null_final,
 77	.base			=	{
 78		.cra_name		=	"digest_null",
 79		.cra_driver_name	=	"digest_null-generic",
 80		.cra_blocksize		=	NULL_BLOCK_SIZE,
 81		.cra_module		=	THIS_MODULE,
 82	}
 83};
 84
 85static struct skcipher_alg skcipher_null = {
 86	.base.cra_name		=	"ecb(cipher_null)",
 87	.base.cra_driver_name	=	"ecb-cipher_null",
 88	.base.cra_priority	=	100,
 89	.base.cra_blocksize	=	NULL_BLOCK_SIZE,
 90	.base.cra_ctxsize	=	0,
 91	.base.cra_module	=	THIS_MODULE,
 92	.min_keysize		=	NULL_KEY_SIZE,
 93	.max_keysize		=	NULL_KEY_SIZE,
 94	.ivsize			=	NULL_IV_SIZE,
 95	.setkey			=	null_skcipher_setkey,
 96	.encrypt		=	null_skcipher_crypt,
 97	.decrypt		=	null_skcipher_crypt,
 98};
 99
100static struct crypto_alg cipher_null = {
101	.cra_name		=	"cipher_null",
102	.cra_driver_name	=	"cipher_null-generic",
103	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
104	.cra_blocksize		=	NULL_BLOCK_SIZE,
105	.cra_ctxsize		=	0,
106	.cra_module		=	THIS_MODULE,
107	.cra_u			=	{ .cipher = {
108	.cia_min_keysize	=	NULL_KEY_SIZE,
109	.cia_max_keysize	=	NULL_KEY_SIZE,
110	.cia_setkey		= 	null_setkey,
111	.cia_encrypt		=	null_crypt,
112	.cia_decrypt		=	null_crypt } }
113};
114
115MODULE_ALIAS_CRYPTO("digest_null");
116MODULE_ALIAS_CRYPTO("cipher_null");
117
118static int __init crypto_null_mod_init(void)
119{
120	int ret = 0;
121
122	ret = crypto_register_alg(&cipher_null);
123	if (ret < 0)
124		goto out;
125
126	ret = crypto_register_shash(&digest_null);
127	if (ret < 0)
128		goto out_unregister_algs;
129
130	ret = crypto_register_skcipher(&skcipher_null);
131	if (ret < 0)
132		goto out_unregister_shash;
133
134	return 0;
135
136out_unregister_shash:
137	crypto_unregister_shash(&digest_null);
138out_unregister_algs:
139	crypto_unregister_alg(&cipher_null);
140out:
141	return ret;
142}
143
144static void __exit crypto_null_mod_fini(void)
145{
146	crypto_unregister_alg(&cipher_null);
147	crypto_unregister_shash(&digest_null);
148	crypto_unregister_skcipher(&skcipher_null);
149}
150
151module_init(crypto_null_mod_init);
152module_exit(crypto_null_mod_fini);
153
154MODULE_LICENSE("GPL");
155MODULE_DESCRIPTION("Null Cryptographic Algorithms");