Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Cryptographic API.
4 *
5 * Null algorithms, aka Much Ado About Nothing.
6 *
7 * These are needed for IPsec, and may be useful in general for
8 * testing & debugging.
9 *
10 * The null cipher is compliant with RFC2410.
11 *
12 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
13 */
14
15#include <crypto/null.h>
16#include <crypto/internal/hash.h>
17#include <crypto/internal/skcipher.h>
18#include <linux/init.h>
19#include <linux/module.h>
20#include <linux/mm.h>
21#include <linux/string.h>
22
23static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
24static struct crypto_sync_skcipher *crypto_default_null_skcipher;
25static int crypto_default_null_skcipher_refcnt;
26
27static int null_compress(struct crypto_tfm *tfm, const u8 *src,
28 unsigned int slen, u8 *dst, unsigned int *dlen)
29{
30 if (slen > *dlen)
31 return -EINVAL;
32 memcpy(dst, src, slen);
33 *dlen = slen;
34 return 0;
35}
36
37static int null_init(struct shash_desc *desc)
38{
39 return 0;
40}
41
42static int null_update(struct shash_desc *desc, const u8 *data,
43 unsigned int len)
44{
45 return 0;
46}
47
48static int null_final(struct shash_desc *desc, u8 *out)
49{
50 return 0;
51}
52
53static int null_digest(struct shash_desc *desc, const u8 *data,
54 unsigned int len, u8 *out)
55{
56 return 0;
57}
58
59static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
60 unsigned int keylen)
61{ return 0; }
62
63static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
64 unsigned int keylen)
65{ return 0; }
66
67static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
68 unsigned int keylen)
69{ return 0; }
70
71static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
72{
73 memcpy(dst, src, NULL_BLOCK_SIZE);
74}
75
76static int null_skcipher_crypt(struct skcipher_request *req)
77{
78 struct skcipher_walk walk;
79 int err;
80
81 err = skcipher_walk_virt(&walk, req, false);
82
83 while (walk.nbytes) {
84 if (walk.src.virt.addr != walk.dst.virt.addr)
85 memcpy(walk.dst.virt.addr, walk.src.virt.addr,
86 walk.nbytes);
87 err = skcipher_walk_done(&walk, 0);
88 }
89
90 return err;
91}
92
93static struct shash_alg digest_null = {
94 .digestsize = NULL_DIGEST_SIZE,
95 .setkey = null_hash_setkey,
96 .init = null_init,
97 .update = null_update,
98 .finup = null_digest,
99 .digest = null_digest,
100 .final = null_final,
101 .base = {
102 .cra_name = "digest_null",
103 .cra_blocksize = NULL_BLOCK_SIZE,
104 .cra_module = THIS_MODULE,
105 }
106};
107
108static struct skcipher_alg skcipher_null = {
109 .base.cra_name = "ecb(cipher_null)",
110 .base.cra_driver_name = "ecb-cipher_null",
111 .base.cra_priority = 100,
112 .base.cra_blocksize = NULL_BLOCK_SIZE,
113 .base.cra_ctxsize = 0,
114 .base.cra_module = THIS_MODULE,
115 .min_keysize = NULL_KEY_SIZE,
116 .max_keysize = NULL_KEY_SIZE,
117 .ivsize = NULL_IV_SIZE,
118 .setkey = null_skcipher_setkey,
119 .encrypt = null_skcipher_crypt,
120 .decrypt = null_skcipher_crypt,
121};
122
123static struct crypto_alg null_algs[] = { {
124 .cra_name = "cipher_null",
125 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
126 .cra_blocksize = NULL_BLOCK_SIZE,
127 .cra_ctxsize = 0,
128 .cra_module = THIS_MODULE,
129 .cra_u = { .cipher = {
130 .cia_min_keysize = NULL_KEY_SIZE,
131 .cia_max_keysize = NULL_KEY_SIZE,
132 .cia_setkey = null_setkey,
133 .cia_encrypt = null_crypt,
134 .cia_decrypt = null_crypt } }
135}, {
136 .cra_name = "compress_null",
137 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
138 .cra_blocksize = NULL_BLOCK_SIZE,
139 .cra_ctxsize = 0,
140 .cra_module = THIS_MODULE,
141 .cra_u = { .compress = {
142 .coa_compress = null_compress,
143 .coa_decompress = null_compress } }
144} };
145
146MODULE_ALIAS_CRYPTO("compress_null");
147MODULE_ALIAS_CRYPTO("digest_null");
148MODULE_ALIAS_CRYPTO("cipher_null");
149
150struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
151{
152 struct crypto_sync_skcipher *tfm;
153
154 mutex_lock(&crypto_default_null_skcipher_lock);
155 tfm = crypto_default_null_skcipher;
156
157 if (!tfm) {
158 tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
159 if (IS_ERR(tfm))
160 goto unlock;
161
162 crypto_default_null_skcipher = tfm;
163 }
164
165 crypto_default_null_skcipher_refcnt++;
166
167unlock:
168 mutex_unlock(&crypto_default_null_skcipher_lock);
169
170 return tfm;
171}
172EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
173
174void crypto_put_default_null_skcipher(void)
175{
176 mutex_lock(&crypto_default_null_skcipher_lock);
177 if (!--crypto_default_null_skcipher_refcnt) {
178 crypto_free_sync_skcipher(crypto_default_null_skcipher);
179 crypto_default_null_skcipher = NULL;
180 }
181 mutex_unlock(&crypto_default_null_skcipher_lock);
182}
183EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
184
185static int __init crypto_null_mod_init(void)
186{
187 int ret = 0;
188
189 ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
190 if (ret < 0)
191 goto out;
192
193 ret = crypto_register_shash(&digest_null);
194 if (ret < 0)
195 goto out_unregister_algs;
196
197 ret = crypto_register_skcipher(&skcipher_null);
198 if (ret < 0)
199 goto out_unregister_shash;
200
201 return 0;
202
203out_unregister_shash:
204 crypto_unregister_shash(&digest_null);
205out_unregister_algs:
206 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
207out:
208 return ret;
209}
210
211static void __exit crypto_null_mod_fini(void)
212{
213 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
214 crypto_unregister_shash(&digest_null);
215 crypto_unregister_skcipher(&skcipher_null);
216}
217
218subsys_initcall(crypto_null_mod_init);
219module_exit(crypto_null_mod_fini);
220
221MODULE_LICENSE("GPL");
222MODULE_DESCRIPTION("Null Cryptographic Algorithms");