11da177e4SLinus Torvalds // SPDX-License-Identifier: GPL-2.0-or-later
21da177e4SLinus Torvalds /*
31da177e4SLinus Torvalds * Cryptographic API.
41da177e4SLinus Torvalds *
51da177e4SLinus Torvalds * Null algorithms, aka Much Ado About Nothing.
61da177e4SLinus Torvalds *
71da177e4SLinus Torvalds * These are needed for IPsec, and may be useful in general for
81da177e4SLinus Torvalds * testing & debugging.
91da177e4SLinus Torvalds *
101da177e4SLinus Torvalds * The null cipher is compliant with RFC2410.
111da177e4SLinus Torvalds *
121da177e4SLinus Torvalds * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
131da177e4SLinus Torvalds */
141da177e4SLinus Torvalds
151da177e4SLinus Torvalds #include <crypto/null.h>
161da177e4SLinus Torvalds #include <crypto/internal/hash.h>
171da177e4SLinus Torvalds #include <crypto/internal/skcipher.h>
181da177e4SLinus Torvalds #include <linux/init.h>
193631c650SHerbert Xu #include <linux/module.h>
2072567258SHoria Geanta #include <linux/mm.h>
21d35d2454SHerbert Xu #include <linux/string.h>
223631c650SHerbert Xu
231da177e4SLinus Torvalds static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
241da177e4SLinus Torvalds static struct crypto_sync_skcipher *crypto_default_null_skcipher;
251da177e4SLinus Torvalds static int crypto_default_null_skcipher_refcnt;
26d0856009SPatrick McHardy
null_compress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)271da177e4SLinus Torvalds static int null_compress(struct crypto_tfm *tfm, const u8 *src,
2833023463SHerbert Xu unsigned int slen, u8 *dst, unsigned int *dlen)
298d605398SKees Cook {
3033023463SHerbert Xu if (slen > *dlen)
3133023463SHerbert Xu return -EINVAL;
326c2bb98bSHerbert Xu memcpy(dst, src, slen);
336c2bb98bSHerbert Xu *dlen = slen;
34d0856009SPatrick McHardy return 0;
35d0856009SPatrick McHardy }
36d0856009SPatrick McHardy
null_init(struct shash_desc * desc)37d0856009SPatrick McHardy static int null_init(struct shash_desc *desc)
38d0856009SPatrick McHardy {
39d0856009SPatrick McHardy return 0;
40d0856009SPatrick McHardy }
411da177e4SLinus Torvalds
null_update(struct shash_desc * desc,const u8 * data,unsigned int len)42d35d2454SHerbert Xu static int null_update(struct shash_desc *desc, const u8 *data,
43d35d2454SHerbert Xu unsigned int len)
44d35d2454SHerbert Xu {
45d35d2454SHerbert Xu return 0;
461da177e4SLinus Torvalds }
47d35d2454SHerbert Xu
null_final(struct shash_desc * desc,u8 * out)486c2bb98bSHerbert Xu static int null_final(struct shash_desc *desc, u8 *out)
49d35d2454SHerbert Xu {
50d35d2454SHerbert Xu return 0;
51d35d2454SHerbert Xu }
521da177e4SLinus Torvalds
null_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)53d35d2454SHerbert Xu static int null_digest(struct shash_desc *desc, const u8 *data,
54d35d2454SHerbert Xu unsigned int len, u8 *out)
55d35d2454SHerbert Xu {
56d35d2454SHerbert Xu return 0;
57d35d2454SHerbert Xu }
58d35d2454SHerbert Xu
null_hash_setkey(struct crypto_shash * tfm,const u8 * key,unsigned int keylen)59d35d2454SHerbert Xu static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
60d35d2454SHerbert Xu unsigned int keylen)
61d35d2454SHerbert Xu { return 0; }
62d35d2454SHerbert Xu
null_skcipher_setkey(struct crypto_skcipher * tfm,const u8 * key,unsigned int keylen)63d35d2454SHerbert Xu static int null_skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key,
64d35d2454SHerbert Xu unsigned int keylen)
65d35d2454SHerbert Xu { return 0; }
66d35d2454SHerbert Xu
null_setkey(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)671da177e4SLinus Torvalds static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
6831d40c20SEric Biggers unsigned int keylen)
6931d40c20SEric Biggers { return 0; }
7031d40c20SEric Biggers
null_crypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)7131d40c20SEric Biggers static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
726c2bb98bSHerbert Xu {
73560c06aeSHerbert Xu memcpy(dst, src, NULL_BLOCK_SIZE);
741da177e4SLinus Torvalds }
751da177e4SLinus Torvalds
null_skcipher_crypt(struct skcipher_request * req)766c2bb98bSHerbert Xu static int null_skcipher_crypt(struct skcipher_request *req)
77d0856009SPatrick McHardy {
78d0856009SPatrick McHardy struct skcipher_walk walk;
79d0856009SPatrick McHardy int err;
801da177e4SLinus Torvalds
8131d40c20SEric Biggers err = skcipher_walk_virt(&walk, req, false);
823631c650SHerbert Xu
8331d40c20SEric Biggers while (walk.nbytes) {
843631c650SHerbert Xu if (walk.src.virt.addr != walk.dst.virt.addr)
853631c650SHerbert Xu memcpy(walk.dst.virt.addr, walk.src.virt.addr,
8631d40c20SEric Biggers walk.nbytes);
873631c650SHerbert Xu err = skcipher_walk_done(&walk, 0);
883631c650SHerbert Xu }
893631c650SHerbert Xu
903631c650SHerbert Xu return err;
913631c650SHerbert Xu }
9231d40c20SEric Biggers
933631c650SHerbert Xu static struct shash_alg digest_null = {
943631c650SHerbert Xu .digestsize = NULL_DIGEST_SIZE,
953631c650SHerbert Xu .setkey = null_hash_setkey,
963631c650SHerbert Xu .init = null_init,
973631c650SHerbert Xu .update = null_update,
98d35d2454SHerbert Xu .finup = null_digest,
99d35d2454SHerbert Xu .digest = null_digest,
100d35d2454SHerbert Xu .final = null_final,
101d35d2454SHerbert Xu .base = {
102d35d2454SHerbert Xu .cra_name = "digest_null",
103d35d2454SHerbert Xu .cra_driver_name = "digest_null-generic",
104d35d2454SHerbert Xu .cra_blocksize = NULL_BLOCK_SIZE,
105d35d2454SHerbert Xu .cra_module = THIS_MODULE,
106d35d2454SHerbert Xu }
1071da177e4SLinus Torvalds };
108d6ebf528SEric Biggers
1091da177e4SLinus Torvalds static struct skcipher_alg skcipher_null = {
1101da177e4SLinus Torvalds .base.cra_name = "ecb(cipher_null)",
111d35d2454SHerbert Xu .base.cra_driver_name = "ecb-cipher_null",
1121da177e4SLinus Torvalds .base.cra_priority = 100,
1131da177e4SLinus Torvalds .base.cra_blocksize = NULL_BLOCK_SIZE,
11431d40c20SEric Biggers .base.cra_ctxsize = 0,
11531d40c20SEric Biggers .base.cra_module = THIS_MODULE,
11631d40c20SEric Biggers .min_keysize = NULL_KEY_SIZE,
11731d40c20SEric Biggers .max_keysize = NULL_KEY_SIZE,
11831d40c20SEric Biggers .ivsize = NULL_IV_SIZE,
11931d40c20SEric Biggers .setkey = null_skcipher_setkey,
12031d40c20SEric Biggers .encrypt = null_skcipher_crypt,
12131d40c20SEric Biggers .decrypt = null_skcipher_crypt,
12231d40c20SEric Biggers };
12331d40c20SEric Biggers
12431d40c20SEric Biggers static struct crypto_alg null_algs[] = { {
12531d40c20SEric Biggers .cra_name = "cipher_null",
12631d40c20SEric Biggers .cra_driver_name = "cipher_null-generic",
12731d40c20SEric Biggers .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
12831d40c20SEric Biggers .cra_blocksize = NULL_BLOCK_SIZE,
12931d40c20SEric Biggers .cra_ctxsize = 0,
1301da177e4SLinus Torvalds .cra_module = THIS_MODULE,
131d6ebf528SEric Biggers .cra_u = { .cipher = {
1321da177e4SLinus Torvalds .cia_min_keysize = NULL_KEY_SIZE,
1331da177e4SLinus Torvalds .cia_max_keysize = NULL_KEY_SIZE,
1341da177e4SLinus Torvalds .cia_setkey = null_setkey,
1351da177e4SLinus Torvalds .cia_encrypt = null_crypt,
1361da177e4SLinus Torvalds .cia_decrypt = null_crypt } }
1371da177e4SLinus Torvalds }, {
1381da177e4SLinus Torvalds .cra_name = "compress_null",
1391da177e4SLinus Torvalds .cra_driver_name = "compress_null-generic",
140d0856009SPatrick McHardy .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
141d0856009SPatrick McHardy .cra_blocksize = NULL_BLOCK_SIZE,
14270a03bffSJussi Kivilinna .cra_ctxsize = 0,
14370a03bffSJussi Kivilinna .cra_module = THIS_MODULE,
144d6ebf528SEric Biggers .cra_u = { .compress = {
14570a03bffSJussi Kivilinna .coa_compress = null_compress,
14670a03bffSJussi Kivilinna .coa_decompress = null_compress } }
14770a03bffSJussi Kivilinna } };
14870a03bffSJussi Kivilinna
14970a03bffSJussi Kivilinna MODULE_ALIAS_CRYPTO("compress_null");
15070a03bffSJussi Kivilinna MODULE_ALIAS_CRYPTO("digest_null");
15170a03bffSJussi Kivilinna MODULE_ALIAS_CRYPTO("cipher_null");
15270a03bffSJussi Kivilinna
crypto_get_default_null_skcipher(void)1533631c650SHerbert Xu struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
1545d26a105SKees Cook {
1555d26a105SKees Cook struct crypto_sync_skcipher *tfm;
1565d26a105SKees Cook
1571da177e4SLinus Torvalds mutex_lock(&crypto_default_null_skcipher_lock);
1588d605398SKees Cook tfm = crypto_default_null_skcipher;
15933023463SHerbert Xu
1608d605398SKees Cook if (!tfm) {
16133023463SHerbert Xu tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
16233023463SHerbert Xu if (IS_ERR(tfm))
16333023463SHerbert Xu goto unlock;
16433023463SHerbert Xu
16533023463SHerbert Xu crypto_default_null_skcipher = tfm;
1668d605398SKees Cook }
16733023463SHerbert Xu
16833023463SHerbert Xu crypto_default_null_skcipher_refcnt++;
16933023463SHerbert Xu
17033023463SHerbert Xu unlock:
17133023463SHerbert Xu mutex_unlock(&crypto_default_null_skcipher_lock);
17233023463SHerbert Xu
17333023463SHerbert Xu return tfm;
17433023463SHerbert Xu }
17533023463SHerbert Xu EXPORT_SYMBOL_GPL(crypto_get_default_null_skcipher);
17633023463SHerbert Xu
crypto_put_default_null_skcipher(void)17733023463SHerbert Xu void crypto_put_default_null_skcipher(void)
17833023463SHerbert Xu {
17933023463SHerbert Xu mutex_lock(&crypto_default_null_skcipher_lock);
18033023463SHerbert Xu if (!--crypto_default_null_skcipher_refcnt) {
18133023463SHerbert Xu crypto_free_sync_skcipher(crypto_default_null_skcipher);
18233023463SHerbert Xu crypto_default_null_skcipher = NULL;
18333023463SHerbert Xu }
18433023463SHerbert Xu mutex_unlock(&crypto_default_null_skcipher_lock);
18533023463SHerbert Xu }
1868d605398SKees Cook EXPORT_SYMBOL_GPL(crypto_put_default_null_skcipher);
18733023463SHerbert Xu
crypto_null_mod_init(void)18833023463SHerbert Xu static int __init crypto_null_mod_init(void)
18933023463SHerbert Xu {
19033023463SHerbert Xu int ret = 0;
19133023463SHerbert Xu
19233023463SHerbert Xu ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
1933af5b90bSKamalesh Babulal if (ret < 0)
1941da177e4SLinus Torvalds goto out;
1951da177e4SLinus Torvalds
1961da177e4SLinus Torvalds ret = crypto_register_shash(&digest_null);
19770a03bffSJussi Kivilinna if (ret < 0)
1981da177e4SLinus Torvalds goto out_unregister_algs;
1991da177e4SLinus Torvalds
2001da177e4SLinus Torvalds ret = crypto_register_skcipher(&skcipher_null);
201d35d2454SHerbert Xu if (ret < 0)
2023631c650SHerbert Xu goto out_unregister_shash;
20370a03bffSJussi Kivilinna
2041da177e4SLinus Torvalds return 0;
20531d40c20SEric Biggers
20631d40c20SEric Biggers out_unregister_shash:
20731d40c20SEric Biggers crypto_unregister_shash(&digest_null);
20831d40c20SEric Biggers out_unregister_algs:
20970a03bffSJussi Kivilinna crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
2101da177e4SLinus Torvalds out:
21131d40c20SEric Biggers return ret;
21231d40c20SEric Biggers }
21370a03bffSJussi Kivilinna
crypto_null_mod_fini(void)21470a03bffSJussi Kivilinna static void __exit crypto_null_mod_fini(void)
2151da177e4SLinus Torvalds {
2161da177e4SLinus Torvalds crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
2171da177e4SLinus Torvalds crypto_unregister_shash(&digest_null);
2181da177e4SLinus Torvalds crypto_unregister_skcipher(&skcipher_null);
2193af5b90bSKamalesh Babulal }
2201da177e4SLinus Torvalds
22170a03bffSJussi Kivilinna subsys_initcall(crypto_null_mod_init);
22231d40c20SEric Biggers module_exit(crypto_null_mod_fini);
22331d40c20SEric Biggers
2241da177e4SLinus Torvalds MODULE_LICENSE("GPL");
2251da177e4SLinus Torvalds MODULE_DESCRIPTION("Null Cryptographic Algorithms");
226c4741b23SEric Biggers