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 | |
23 | static DEFINE_MUTEX(crypto_default_null_skcipher_lock); |
24 | static struct crypto_sync_skcipher *crypto_default_null_skcipher; |
25 | static int crypto_default_null_skcipher_refcnt; |
26 | |
27 | static 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 | |
37 | static int null_init(struct shash_desc *desc) |
38 | { |
39 | return 0; |
40 | } |
41 | |
42 | static int null_update(struct shash_desc *desc, const u8 *data, |
43 | unsigned int len) |
44 | { |
45 | return 0; |
46 | } |
47 | |
48 | static int null_final(struct shash_desc *desc, u8 *out) |
49 | { |
50 | return 0; |
51 | } |
52 | |
53 | static int null_digest(struct shash_desc *desc, const u8 *data, |
54 | unsigned int len, u8 *out) |
55 | { |
56 | return 0; |
57 | } |
58 | |
59 | static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key, |
60 | unsigned int keylen) |
61 | { return 0; } |
62 | |
63 | static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key, |
64 | unsigned int keylen) |
65 | { return 0; } |
66 | |
67 | static int null_setkey(struct crypto_tfm *tfm, const u8 *key, |
68 | unsigned int keylen) |
69 | { return 0; } |
70 | |
71 | static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) |
72 | { |
73 | memcpy(dst, src, NULL_BLOCK_SIZE); |
74 | } |
75 | |
76 | static int null_skcipher_crypt(struct skcipher_request *req) |
77 | { |
78 | struct skcipher_walk walk; |
79 | int err; |
80 | |
81 | err = skcipher_walk_virt(walk: &walk, req, atomic: 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: &walk, err: 0); |
88 | } |
89 | |
90 | return err; |
91 | } |
92 | |
93 | static 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_driver_name = "digest_null-generic" , |
104 | .cra_blocksize = NULL_BLOCK_SIZE, |
105 | .cra_module = THIS_MODULE, |
106 | } |
107 | }; |
108 | |
109 | static struct skcipher_alg skcipher_null = { |
110 | .base.cra_name = "ecb(cipher_null)" , |
111 | .base.cra_driver_name = "ecb-cipher_null" , |
112 | .base.cra_priority = 100, |
113 | .base.cra_blocksize = NULL_BLOCK_SIZE, |
114 | .base.cra_ctxsize = 0, |
115 | .base.cra_module = THIS_MODULE, |
116 | .min_keysize = NULL_KEY_SIZE, |
117 | .max_keysize = NULL_KEY_SIZE, |
118 | .ivsize = NULL_IV_SIZE, |
119 | .setkey = null_skcipher_setkey, |
120 | .encrypt = null_skcipher_crypt, |
121 | .decrypt = null_skcipher_crypt, |
122 | }; |
123 | |
124 | static struct crypto_alg null_algs[] = { { |
125 | .cra_name = "cipher_null" , |
126 | .cra_driver_name = "cipher_null-generic" , |
127 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
128 | .cra_blocksize = NULL_BLOCK_SIZE, |
129 | .cra_ctxsize = 0, |
130 | .cra_module = THIS_MODULE, |
131 | .cra_u = { .cipher = { |
132 | .cia_min_keysize = NULL_KEY_SIZE, |
133 | .cia_max_keysize = NULL_KEY_SIZE, |
134 | .cia_setkey = null_setkey, |
135 | .cia_encrypt = null_crypt, |
136 | .cia_decrypt = null_crypt } } |
137 | }, { |
138 | .cra_name = "compress_null" , |
139 | .cra_driver_name = "compress_null-generic" , |
140 | .cra_flags = CRYPTO_ALG_TYPE_COMPRESS, |
141 | .cra_blocksize = NULL_BLOCK_SIZE, |
142 | .cra_ctxsize = 0, |
143 | .cra_module = THIS_MODULE, |
144 | .cra_u = { .compress = { |
145 | .coa_compress = null_compress, |
146 | .coa_decompress = null_compress } } |
147 | } }; |
148 | |
149 | MODULE_ALIAS_CRYPTO("compress_null" ); |
150 | MODULE_ALIAS_CRYPTO("digest_null" ); |
151 | MODULE_ALIAS_CRYPTO("cipher_null" ); |
152 | |
153 | struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void) |
154 | { |
155 | struct crypto_sync_skcipher *tfm; |
156 | |
157 | mutex_lock(&crypto_default_null_skcipher_lock); |
158 | tfm = crypto_default_null_skcipher; |
159 | |
160 | if (!tfm) { |
161 | tfm = crypto_alloc_sync_skcipher(alg_name: "ecb(cipher_null)" , type: 0, mask: 0); |
162 | if (IS_ERR(ptr: tfm)) |
163 | goto unlock; |
164 | |
165 | crypto_default_null_skcipher = tfm; |
166 | } |
167 | |
168 | crypto_default_null_skcipher_refcnt++; |
169 | |
170 | unlock: |
171 | mutex_unlock(lock: &crypto_default_null_skcipher_lock); |
172 | |
173 | return tfm; |
174 | } |
175 | EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher); |
176 | |
177 | void crypto_put_default_null_skcipher(void) |
178 | { |
179 | mutex_lock(&crypto_default_null_skcipher_lock); |
180 | if (!--crypto_default_null_skcipher_refcnt) { |
181 | crypto_free_sync_skcipher(tfm: crypto_default_null_skcipher); |
182 | crypto_default_null_skcipher = NULL; |
183 | } |
184 | mutex_unlock(lock: &crypto_default_null_skcipher_lock); |
185 | } |
186 | EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher); |
187 | |
188 | static int __init crypto_null_mod_init(void) |
189 | { |
190 | int ret = 0; |
191 | |
192 | ret = crypto_register_algs(algs: null_algs, ARRAY_SIZE(null_algs)); |
193 | if (ret < 0) |
194 | goto out; |
195 | |
196 | ret = crypto_register_shash(alg: &digest_null); |
197 | if (ret < 0) |
198 | goto out_unregister_algs; |
199 | |
200 | ret = crypto_register_skcipher(alg: &skcipher_null); |
201 | if (ret < 0) |
202 | goto out_unregister_shash; |
203 | |
204 | return 0; |
205 | |
206 | out_unregister_shash: |
207 | crypto_unregister_shash(alg: &digest_null); |
208 | out_unregister_algs: |
209 | crypto_unregister_algs(algs: null_algs, ARRAY_SIZE(null_algs)); |
210 | out: |
211 | return ret; |
212 | } |
213 | |
214 | static void __exit crypto_null_mod_fini(void) |
215 | { |
216 | crypto_unregister_algs(algs: null_algs, ARRAY_SIZE(null_algs)); |
217 | crypto_unregister_shash(alg: &digest_null); |
218 | crypto_unregister_skcipher(alg: &skcipher_null); |
219 | } |
220 | |
221 | subsys_initcall(crypto_null_mod_init); |
222 | module_exit(crypto_null_mod_fini); |
223 | |
224 | MODULE_LICENSE("GPL" ); |
225 | MODULE_DESCRIPTION("Null Cryptographic Algorithms" ); |
226 | |