blob: 20ff2c746e0ba220a192dc460194b97de0cc0702
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"); |
223 |