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 #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_setkey = null_setkey,
81 .dia_init = null_init,
82 .dia_update = null_update,
83 .dia_final = null_final } }
84 };
85
86 static struct crypto_alg cipher_null = {
87 .cra_name = "cipher_null",
88 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
89 .cra_blocksize = NULL_BLOCK_SIZE,
90 .cra_ctxsize = 0,
91 .cra_module = THIS_MODULE,
92 .cra_list = LIST_HEAD_INIT(cipher_null.cra_list),
93 .cra_u = { .cipher = {
94 .cia_min_keysize = NULL_KEY_SIZE,
95 .cia_max_keysize = NULL_KEY_SIZE,
96 .cia_setkey = null_setkey,
97 .cia_encrypt = null_crypt,
98 .cia_decrypt = null_crypt } }
99 };
100
101 MODULE_ALIAS("compress_null");
102 MODULE_ALIAS("digest_null");
103 MODULE_ALIAS("cipher_null");
104
105 static int __init init(void)
106 {
107 int ret = 0;
108
109 ret = crypto_register_alg(&cipher_null);
110 if (ret < 0)
111 goto out;
112
113 ret = crypto_register_alg(&digest_null);
114 if (ret < 0) {
115 crypto_unregister_alg(&cipher_null);
116 goto out;
117 }
118
119 ret = crypto_register_alg(&compress_null);
120 if (ret < 0) {
121 crypto_unregister_alg(&digest_null);
122 crypto_unregister_alg(&cipher_null);
123 goto out;
124 }
125
126 out:
127 return ret;
128 }
129
130 static void __exit fini(void)
131 {
132 crypto_unregister_alg(&compress_null);
133 crypto_unregister_alg(&digest_null);
134 crypto_unregister_alg(&cipher_null);
135 }
136
137 module_init(init);
138 module_exit(fini);
139
140 MODULE_LICENSE("GPL");
141 MODULE_DESCRIPTION("Null Cryptographic Algorithms");
142
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