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");