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
20 #include <crypto/internal/hash.h>
21 #include <crypto/internal/skcipher.h>
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/mm.h>
25 #include <linux/string.h>
26
27 #define NULL_KEY_SIZE 0
28 #define NULL_BLOCK_SIZE 1
29 #define NULL_DIGEST_SIZE 0
30 #define NULL_IV_SIZE 0
31
32 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
33 unsigned int slen, u8 *dst, unsigned int *dlen)
34 {
35 if (slen > *dlen)
36 return -EINVAL;
37 memcpy(dst, src, slen);
38 *dlen = slen;
39 return 0;
40 }
41
42 static int null_init(struct shash_desc *desc)
43 {
44 return 0;
45 }
46
47 static int null_update(struct shash_desc *desc, const u8 *data,
48 unsigned int len)
49 {
50 return 0;
51 }
52
53 static int null_final(struct shash_desc *desc, u8 *out)
54 {
55 return 0;
56 }
57
58 static int null_digest(struct shash_desc *desc, const u8 *data,
59 unsigned int len, u8 *out)
60 {
61 return 0;
62 }
63
64 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
65 unsigned int keylen)
66 { return 0; }
67
68 static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
69 unsigned int keylen)
70 { return 0; }
71
72 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
73 {
74 memcpy(dst, src, NULL_BLOCK_SIZE);
75 }
76
77 static int skcipher_null_crypt(struct blkcipher_desc *desc,
78 struct scatterlist *dst,
79 struct scatterlist *src, unsigned int nbytes)
80 {
81 struct blkcipher_walk walk;
82 int err;
83
84 blkcipher_walk_init(&walk, dst, src, nbytes);
85 err = blkcipher_walk_virt(desc, &walk);
86
87 while (walk.nbytes) {
88 if (walk.src.virt.addr != walk.dst.virt.addr)
89 memcpy(walk.dst.virt.addr, walk.src.virt.addr,
90 walk.nbytes);
91 err = blkcipher_walk_done(desc, &walk, 0);
92 }
93
94 return err;
95 }
96
97 static struct crypto_alg compress_null = {
98 .cra_name = "compress_null",
99 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
100 .cra_blocksize = NULL_BLOCK_SIZE,
101 .cra_ctxsize = 0,
102 .cra_module = THIS_MODULE,
103 .cra_list = LIST_HEAD_INIT(compress_null.cra_list),
104 .cra_u = { .compress = {
105 .coa_compress = null_compress,
106 .coa_decompress = null_compress } }
107 };
108
109 static struct shash_alg digest_null = {
110 .digestsize = NULL_DIGEST_SIZE,
111 .setkey = null_hash_setkey,
112 .init = null_init,
113 .update = null_update,
114 .finup = null_digest,
115 .digest = null_digest,
116 .final = null_final,
117 .base = {
118 .cra_name = "digest_null",
119 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
120 .cra_blocksize = NULL_BLOCK_SIZE,
121 .cra_module = THIS_MODULE,
122 }
123 };
124
125 static struct crypto_alg cipher_null = {
126 .cra_name = "cipher_null",
127 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
128 .cra_blocksize = NULL_BLOCK_SIZE,
129 .cra_ctxsize = 0,
130 .cra_module = THIS_MODULE,
131 .cra_list = LIST_HEAD_INIT(cipher_null.cra_list),
132 .cra_u = { .cipher = {
133 .cia_min_keysize = NULL_KEY_SIZE,
134 .cia_max_keysize = NULL_KEY_SIZE,
135 .cia_setkey = null_setkey,
136 .cia_encrypt = null_crypt,
137 .cia_decrypt = null_crypt } }
138 };
139
140 static struct crypto_alg skcipher_null = {
141 .cra_name = "ecb(cipher_null)",
142 .cra_driver_name = "ecb-cipher_null",
143 .cra_priority = 100,
144 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
145 .cra_blocksize = NULL_BLOCK_SIZE,
146 .cra_type = &crypto_blkcipher_type,
147 .cra_ctxsize = 0,
148 .cra_module = THIS_MODULE,
149 .cra_list = LIST_HEAD_INIT(skcipher_null.cra_list),
150 .cra_u = { .blkcipher = {
151 .min_keysize = NULL_KEY_SIZE,
152 .max_keysize = NULL_KEY_SIZE,
153 .ivsize = NULL_IV_SIZE,
154 .setkey = null_setkey,
155 .encrypt = skcipher_null_crypt,
156 .decrypt = skcipher_null_crypt } }
157 };
158
159 MODULE_ALIAS("compress_null");
160 MODULE_ALIAS("digest_null");
161 MODULE_ALIAS("cipher_null");
162
163 static int __init crypto_null_mod_init(void)
164 {
165 int ret = 0;
166
167 ret = crypto_register_alg(&cipher_null);
168 if (ret < 0)
169 goto out;
170
171 ret = crypto_register_alg(&skcipher_null);
172 if (ret < 0)
173 goto out_unregister_cipher;
174
175 ret = crypto_register_shash(&digest_null);
176 if (ret < 0)
177 goto out_unregister_skcipher;
178
179 ret = crypto_register_alg(&compress_null);
180 if (ret < 0)
181 goto out_unregister_digest;
182
183 out:
184 return ret;
185
186 out_unregister_digest:
187 crypto_unregister_shash(&digest_null);
188 out_unregister_skcipher:
189 crypto_unregister_alg(&skcipher_null);
190 out_unregister_cipher:
191 crypto_unregister_alg(&cipher_null);
192 goto out;
193 }
194
195 static void __exit crypto_null_mod_fini(void)
196 {
197 crypto_unregister_alg(&compress_null);
198 crypto_unregister_shash(&digest_null);
199 crypto_unregister_alg(&skcipher_null);
200 crypto_unregister_alg(&cipher_null);
201 }
202
203 module_init(crypto_null_mod_init);
204 module_exit(crypto_null_mod_fini);
205
206 MODULE_LICENSE("GPL");
207 MODULE_DESCRIPTION("Null Cryptographic Algorithms");
208
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