linux - crypto/crypto

140 lines · 3.3 KiB

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 <[email protected]>
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	#include <linux/init.h>
20	#include <linux/module.h>
21	#include <linux/mm.h>
22	#include <asm/scatterlist.h>
23	#include <linux/crypto.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
30	static int null_compress(struct crypto_tfm tfm, const u8 src,
31	unsigned int slen, u8 dst, unsigned int dlen)
32	{
33	if (slen > *dlen)
34	return -EINVAL;
35	memcpy(dst, src, slen);
36	*dlen = slen;
37	return 0;
38	}
39
40	static void null_init(struct crypto_tfm *tfm)
41	{ }
42
43	static void null_update(struct crypto_tfm tfm, const u8 data,
44	unsigned int len)
45	{ }
46
47	static void null_final(struct crypto_tfm tfm, u8 out)
48	{ }
49
50	static int null_setkey(struct crypto_tfm tfm, const u8 key,
51	unsigned int keylen, u32 *flags)
52	{ return 0; }
53
54	static void null_crypt(struct crypto_tfm tfm, u8 dst, const u8 *src)
55	{
56	memcpy(dst, src, NULL_BLOCK_SIZE);
57	}
58
59	static struct crypto_alg compress_null = {
60	.cra_name = "compress_null",
61	.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
62	.cra_blocksize = NULL_BLOCK_SIZE,
63	.cra_ctxsize = 0,
64	.cra_module = THIS_MODULE,
65	.cra_list = LIST_HEAD_INIT(compress_null.cra_list),
66	.cra_u = { .compress = {
67	.coa_compress = null_compress,
68	.coa_decompress = null_compress } }
69	};
70
71	static struct crypto_alg digest_null = {
72	.cra_name = "digest_null",
73	.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
74	.cra_blocksize = NULL_BLOCK_SIZE,
75	.cra_ctxsize = 0,
76	.cra_module = THIS_MODULE,
77	.cra_list = LIST_HEAD_INIT(digest_null.cra_list),
78	.cra_u = { .digest = {
79	.dia_digestsize = NULL_DIGEST_SIZE,
80	.dia_init = null_init,
81	.dia_update = null_update,
82	.dia_final = null_final } }
83	};
84
85	static struct crypto_alg cipher_null = {
86	.cra_name = "cipher_null",
87	.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
88	.cra_blocksize = NULL_BLOCK_SIZE,
89	.cra_ctxsize = 0,
90	.cra_module = THIS_MODULE,
91	.cra_list = LIST_HEAD_INIT(cipher_null.cra_list),
92	.cra_u = { .cipher = {
93	.cia_min_keysize = NULL_KEY_SIZE,
94	.cia_max_keysize = NULL_KEY_SIZE,
95	.cia_setkey = null_setkey,
96	.cia_encrypt = null_crypt,
97	.cia_decrypt = null_crypt } }
98	};
99
100	MODULE_ALIAS("compress_null");
101	MODULE_ALIAS("digest_null");
102	MODULE_ALIAS("cipher_null");
103
104	static int __init init(void)
105	{
106	int ret = 0;
107
108	ret = crypto_register_alg(&cipher_null);
109	if (ret < 0)
110	goto out;
111
112	ret = crypto_register_alg(&digest_null);
113	if (ret < 0) {
114	crypto_unregister_alg(&cipher_null);
115	goto out;
116	}
117
118	ret = crypto_register_alg(&compress_null);
119	if (ret < 0) {
120	crypto_unregister_alg(&digest_null);
121	crypto_unregister_alg(&cipher_null);
122	goto out;
123	}
124
125	out:
126	return ret;
127	}
128
129	static void __exit fini(void)
130	{
131	crypto_unregister_alg(&compress_null);
132	crypto_unregister_alg(&digest_null);
133	crypto_unregister_alg(&cipher_null);
134	}
135
136	module_init(init);
137	module_exit(fini);
138
139	MODULE_LICENSE("GPL");
140	MODULE_DESCRIPTION("Null Cryptographic Algorithms");