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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/null.h> | |
21 | #include <crypto/internal/hash.h> | |
22 | #include <crypto/internal/skcipher.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/mm.h> | |
26 | #include <linux/string.h> | |
27 | ||
28 | static DEFINE_MUTEX(crypto_default_null_skcipher_lock); | |
29 | static struct crypto_skcipher *crypto_default_null_skcipher; | |
30 | static int crypto_default_null_skcipher_refcnt; | |
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 shash_alg digest_null = { | |
98 | .digestsize = NULL_DIGEST_SIZE, | |
99 | .setkey = null_hash_setkey, | |
100 | .init = null_init, | |
101 | .update = null_update, | |
102 | .finup = null_digest, | |
103 | .digest = null_digest, | |
104 | .final = null_final, | |
105 | .base = { | |
106 | .cra_name = "digest_null", | |
107 | .cra_flags = CRYPTO_ALG_TYPE_SHASH, | |
108 | .cra_blocksize = NULL_BLOCK_SIZE, | |
109 | .cra_module = THIS_MODULE, | |
110 | } | |
111 | }; | |
112 | ||
113 | static struct crypto_alg null_algs[3] = { { | |
114 | .cra_name = "cipher_null", | |
115 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, | |
116 | .cra_blocksize = NULL_BLOCK_SIZE, | |
117 | .cra_ctxsize = 0, | |
118 | .cra_module = THIS_MODULE, | |
119 | .cra_u = { .cipher = { | |
120 | .cia_min_keysize = NULL_KEY_SIZE, | |
121 | .cia_max_keysize = NULL_KEY_SIZE, | |
122 | .cia_setkey = null_setkey, | |
123 | .cia_encrypt = null_crypt, | |
124 | .cia_decrypt = null_crypt } } | |
125 | }, { | |
126 | .cra_name = "ecb(cipher_null)", | |
127 | .cra_driver_name = "ecb-cipher_null", | |
128 | .cra_priority = 100, | |
129 | .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, | |
130 | .cra_blocksize = NULL_BLOCK_SIZE, | |
131 | .cra_type = &crypto_blkcipher_type, | |
132 | .cra_ctxsize = 0, | |
133 | .cra_module = THIS_MODULE, | |
134 | .cra_u = { .blkcipher = { | |
135 | .min_keysize = NULL_KEY_SIZE, | |
136 | .max_keysize = NULL_KEY_SIZE, | |
137 | .ivsize = NULL_IV_SIZE, | |
138 | .setkey = null_setkey, | |
139 | .encrypt = skcipher_null_crypt, | |
140 | .decrypt = skcipher_null_crypt } } | |
141 | }, { | |
142 | .cra_name = "compress_null", | |
143 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, | |
144 | .cra_blocksize = NULL_BLOCK_SIZE, | |
145 | .cra_ctxsize = 0, | |
146 | .cra_module = THIS_MODULE, | |
147 | .cra_u = { .compress = { | |
148 | .coa_compress = null_compress, | |
149 | .coa_decompress = null_compress } } | |
150 | } }; | |
151 | ||
152 | MODULE_ALIAS_CRYPTO("compress_null"); | |
153 | MODULE_ALIAS_CRYPTO("digest_null"); | |
154 | MODULE_ALIAS_CRYPTO("cipher_null"); | |
155 | ||
156 | struct crypto_skcipher *crypto_get_default_null_skcipher(void) | |
157 | { | |
158 | struct crypto_skcipher *tfm; | |
159 | ||
160 | mutex_lock(&crypto_default_null_skcipher_lock); | |
161 | tfm = crypto_default_null_skcipher; | |
162 | ||
163 | if (!tfm) { | |
164 | tfm = crypto_alloc_skcipher("ecb(cipher_null)", | |
165 | 0, CRYPTO_ALG_ASYNC); | |
166 | if (IS_ERR(tfm)) | |
167 | goto unlock; | |
168 | ||
169 | crypto_default_null_skcipher = tfm; | |
170 | } | |
171 | ||
172 | crypto_default_null_skcipher_refcnt++; | |
173 | ||
174 | unlock: | |
175 | mutex_unlock(&crypto_default_null_skcipher_lock); | |
176 | ||
177 | return tfm; | |
178 | } | |
179 | EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher); | |
180 | ||
181 | void crypto_put_default_null_skcipher(void) | |
182 | { | |
183 | mutex_lock(&crypto_default_null_skcipher_lock); | |
184 | if (!--crypto_default_null_skcipher_refcnt) { | |
185 | crypto_free_skcipher(crypto_default_null_skcipher); | |
186 | crypto_default_null_skcipher = NULL; | |
187 | } | |
188 | mutex_unlock(&crypto_default_null_skcipher_lock); | |
189 | } | |
190 | EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher); | |
191 | ||
192 | static int __init crypto_null_mod_init(void) | |
193 | { | |
194 | int ret = 0; | |
195 | ||
196 | ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs)); | |
197 | if (ret < 0) | |
198 | goto out; | |
199 | ||
200 | ret = crypto_register_shash(&digest_null); | |
201 | if (ret < 0) | |
202 | goto out_unregister_algs; | |
203 | ||
204 | return 0; | |
205 | ||
206 | out_unregister_algs: | |
207 | crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); | |
208 | out: | |
209 | return ret; | |
210 | } | |
211 | ||
212 | static void __exit crypto_null_mod_fini(void) | |
213 | { | |
214 | crypto_unregister_shash(&digest_null); | |
215 | crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs)); | |
216 | } | |
217 | ||
218 | module_init(crypto_null_mod_init); | |
219 | module_exit(crypto_null_mod_fini); | |
220 | ||
221 | MODULE_LICENSE("GPL"); | |
222 | MODULE_DESCRIPTION("Null Cryptographic Algorithms"); |