1 // SPDX-License-Identifier: GPL-2.0-or-later
5 * Null algorithms, aka Much Ado About Nothing.
7 * These are needed for IPsec, and may be useful in general for
10 * The null cipher is compliant with RFC2410.
12 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
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>
21 #include <linux/string.h>
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;
27 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
28 unsigned int slen, u8 *dst, unsigned int *dlen)
32 memcpy(dst, src, slen);
37 static int null_init(struct shash_desc *desc)
42 static int null_update(struct shash_desc *desc, const u8 *data,
48 static int null_final(struct shash_desc *desc, u8 *out)
53 static int null_digest(struct shash_desc *desc, const u8 *data,
54 unsigned int len, u8 *out)
59 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
63 static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
67 static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
71 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
73 memcpy(dst, src, NULL_BLOCK_SIZE);
76 static int null_skcipher_crypt(struct skcipher_request *req)
78 struct skcipher_walk walk;
81 err = skcipher_walk_virt(&walk, req, false);
84 if (walk.src.virt.addr != walk.dst.virt.addr)
85 memcpy(walk.dst.virt.addr, walk.src.virt.addr,
87 err = skcipher_walk_done(&walk, 0);
93 static struct shash_alg digest_null = {
94 .digestsize = NULL_DIGEST_SIZE,
95 .setkey = null_hash_setkey,
97 .update = null_update,
99 .digest = null_digest,
102 .cra_name = "digest_null",
103 .cra_blocksize = NULL_BLOCK_SIZE,
104 .cra_module = THIS_MODULE,
108 static 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,
123 static struct crypto_alg null_algs[] = { {
124 .cra_name = "cipher_null",
125 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
126 .cra_blocksize = NULL_BLOCK_SIZE,
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 } }
136 .cra_name = "compress_null",
137 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
138 .cra_blocksize = NULL_BLOCK_SIZE,
140 .cra_module = THIS_MODULE,
141 .cra_u = { .compress = {
142 .coa_compress = null_compress,
143 .coa_decompress = null_compress } }
146 MODULE_ALIAS_CRYPTO("compress_null");
147 MODULE_ALIAS_CRYPTO("digest_null");
148 MODULE_ALIAS_CRYPTO("cipher_null");
150 struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
152 struct crypto_sync_skcipher *tfm;
154 mutex_lock(&crypto_default_null_skcipher_lock);
155 tfm = crypto_default_null_skcipher;
158 tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
162 crypto_default_null_skcipher = tfm;
165 crypto_default_null_skcipher_refcnt++;
168 mutex_unlock(&crypto_default_null_skcipher_lock);
172 EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
174 void crypto_put_default_null_skcipher(void)
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;
181 mutex_unlock(&crypto_default_null_skcipher_lock);
183 EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
185 static int __init crypto_null_mod_init(void)
189 ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
193 ret = crypto_register_shash(&digest_null);
195 goto out_unregister_algs;
197 ret = crypto_register_skcipher(&skcipher_null);
199 goto out_unregister_shash;
203 out_unregister_shash:
204 crypto_unregister_shash(&digest_null);
206 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
211 static void __exit crypto_null_mod_fini(void)
213 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
214 crypto_unregister_shash(&digest_null);
215 crypto_unregister_skcipher(&skcipher_null);
218 subsys_initcall(crypto_null_mod_init);
219 module_exit(crypto_null_mod_fini);
221 MODULE_LICENSE("GPL");
222 MODULE_DESCRIPTION("Null Cryptographic Algorithms");