[PATCH] crypto: fix null encryption/compression
[linux-2.6.git] / crypto / crypto_null.c
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(void *ctx, const u8 *src, unsigned int slen,
31                          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(void *ctx)
41 { }
42
43 static void null_update(void *ctx, const u8 *data, unsigned int len)
44 { }
45
46 static void null_final(void *ctx, u8 *out)
47 { }
48
49 static int null_setkey(void *ctx, const u8 *key,
50                        unsigned int keylen, u32 *flags)
51 { return 0; }
52
53 static void null_crypt(void *ctx, u8 *dst, const u8 *src)
54 {
55         memcpy(dst, src, NULL_BLOCK_SIZE);
56 }
57
58 static struct crypto_alg compress_null = {
59         .cra_name               =       "compress_null",
60         .cra_flags              =       CRYPTO_ALG_TYPE_COMPRESS,
61         .cra_blocksize          =       NULL_BLOCK_SIZE,
62         .cra_ctxsize            =       0,
63         .cra_module             =       THIS_MODULE,
64         .cra_list               =       LIST_HEAD_INIT(compress_null.cra_list),
65         .cra_u                  =       { .compress = {
66         .coa_compress           =       null_compress,
67         .coa_decompress         =       null_compress } }
68 };
69
70 static struct crypto_alg digest_null = {
71         .cra_name               =       "digest_null",
72         .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
73         .cra_blocksize          =       NULL_BLOCK_SIZE,
74         .cra_ctxsize            =       0,
75         .cra_module             =       THIS_MODULE,
76         .cra_list               =       LIST_HEAD_INIT(digest_null.cra_list),   
77         .cra_u                  =       { .digest = {
78         .dia_digestsize         =       NULL_DIGEST_SIZE,
79         .dia_init               =       null_init,
80         .dia_update             =       null_update,
81         .dia_final              =       null_final } }
82 };
83
84 static struct crypto_alg cipher_null = {
85         .cra_name               =       "cipher_null",
86         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
87         .cra_blocksize          =       NULL_BLOCK_SIZE,
88         .cra_ctxsize            =       0,
89         .cra_module             =       THIS_MODULE,
90         .cra_list               =       LIST_HEAD_INIT(cipher_null.cra_list),
91         .cra_u                  =       { .cipher = {
92         .cia_min_keysize        =       NULL_KEY_SIZE,
93         .cia_max_keysize        =       NULL_KEY_SIZE,
94         .cia_setkey             =       null_setkey,
95         .cia_encrypt            =       null_crypt,
96         .cia_decrypt            =       null_crypt } }
97 };
98
99 MODULE_ALIAS("compress_null");
100 MODULE_ALIAS("digest_null");
101 MODULE_ALIAS("cipher_null");
102
103 static int __init init(void)
104 {
105         int ret = 0;
106         
107         ret = crypto_register_alg(&cipher_null);
108         if (ret < 0)
109                 goto out;
110
111         ret = crypto_register_alg(&digest_null);
112         if (ret < 0) {
113                 crypto_unregister_alg(&cipher_null);
114                 goto out;
115         }
116
117         ret = crypto_register_alg(&compress_null);
118         if (ret < 0) {
119                 crypto_unregister_alg(&digest_null);
120                 crypto_unregister_alg(&cipher_null);
121                 goto out;
122         }
123
124 out:    
125         return ret;
126 }
127
128 static void __exit fini(void)
129 {
130         crypto_unregister_alg(&compress_null);
131         crypto_unregister_alg(&digest_null);
132         crypto_unregister_alg(&cipher_null);
133 }
134
135 module_init(init);
136 module_exit(fini);
137
138 MODULE_LICENSE("GPL");
139 MODULE_DESCRIPTION("Null Cryptographic Algorithms");