1 /*
2 * Cryptographic API.
3 *
4 * Null algorithms, aka Much Ado About Nothing.
5 *
6 * These are needed for IPsec, and may be useful in general for
7 * testing & debugging.
8 *
9 * The null cipher is compliant with RFC2410.
10 *
11 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 */
19
20 #include <crypto/null.h>
21 #include <crypto/internal/hash.h>
22 #include <crypto/internal/skcipher.h>
23 #include <linux/init.h>
24 #include <linux/module.h>
25 #include <linux/mm.h>
26 #include <linux/string.h>
27
null_compress(struct crypto_tfm * tfm,const u8 * src,unsigned int slen,u8 * dst,unsigned int * dlen)28 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
29 unsigned int slen, u8 *dst, unsigned int *dlen)
30 {
31 if (slen > *dlen)
32 return -EINVAL;
33 memcpy(dst, src, slen);
34 *dlen = slen;
35 return 0;
36 }
37
null_init(struct shash_desc * desc)38 static int null_init(struct shash_desc *desc)
39 {
40 return 0;
41 }
42
null_update(struct shash_desc * desc,const u8 * data,unsigned int len)43 static int null_update(struct shash_desc *desc, const u8 *data,
44 unsigned int len)
45 {
46 return 0;
47 }
48
null_final(struct shash_desc * desc,u8 * out)49 static int null_final(struct shash_desc *desc, u8 *out)
50 {
51 return 0;
52 }
53
null_digest(struct shash_desc * desc,const u8 * data,unsigned int len,u8 * out)54 static int null_digest(struct shash_desc *desc, const u8 *data,
55 unsigned int len, u8 *out)
56 {
57 return 0;
58 }
59
null_hash_setkey(struct crypto_shash * tfm,const u8 * key,unsigned int keylen)60 static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
61 unsigned int keylen)
62 { return 0; }
63
null_setkey(struct crypto_tfm * tfm,const u8 * key,unsigned int keylen)64 static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
65 unsigned int keylen)
66 { return 0; }
67
null_crypt(struct crypto_tfm * tfm,u8 * dst,const u8 * src)68 static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
69 {
70 memcpy(dst, src, NULL_BLOCK_SIZE);
71 }
72
skcipher_null_crypt(struct blkcipher_desc * desc,struct scatterlist * dst,struct scatterlist * src,unsigned int nbytes)73 static int skcipher_null_crypt(struct blkcipher_desc *desc,
74 struct scatterlist *dst,
75 struct scatterlist *src, unsigned int nbytes)
76 {
77 struct blkcipher_walk walk;
78 int err;
79
80 blkcipher_walk_init(&walk, dst, src, nbytes);
81 err = blkcipher_walk_virt(desc, &walk);
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 = blkcipher_walk_done(desc, &walk, 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_flags = CRYPTO_ALG_TYPE_SHASH,
104 .cra_blocksize = NULL_BLOCK_SIZE,
105 .cra_module = THIS_MODULE,
106 }
107 };
108
109 static struct crypto_alg null_algs[3] = { {
110 .cra_name = "cipher_null",
111 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
112 .cra_blocksize = NULL_BLOCK_SIZE,
113 .cra_ctxsize = 0,
114 .cra_module = THIS_MODULE,
115 .cra_u = { .cipher = {
116 .cia_min_keysize = NULL_KEY_SIZE,
117 .cia_max_keysize = NULL_KEY_SIZE,
118 .cia_setkey = null_setkey,
119 .cia_encrypt = null_crypt,
120 .cia_decrypt = null_crypt } }
121 }, {
122 .cra_name = "ecb(cipher_null)",
123 .cra_driver_name = "ecb-cipher_null",
124 .cra_priority = 100,
125 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
126 .cra_blocksize = NULL_BLOCK_SIZE,
127 .cra_type = &crypto_blkcipher_type,
128 .cra_ctxsize = 0,
129 .cra_module = THIS_MODULE,
130 .cra_u = { .blkcipher = {
131 .min_keysize = NULL_KEY_SIZE,
132 .max_keysize = NULL_KEY_SIZE,
133 .ivsize = NULL_IV_SIZE,
134 .setkey = null_setkey,
135 .encrypt = skcipher_null_crypt,
136 .decrypt = skcipher_null_crypt } }
137 }, {
138 .cra_name = "compress_null",
139 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
140 .cra_blocksize = NULL_BLOCK_SIZE,
141 .cra_ctxsize = 0,
142 .cra_module = THIS_MODULE,
143 .cra_u = { .compress = {
144 .coa_compress = null_compress,
145 .coa_decompress = null_compress } }
146 } };
147
148 MODULE_ALIAS_CRYPTO("compress_null");
149 MODULE_ALIAS_CRYPTO("digest_null");
150 MODULE_ALIAS_CRYPTO("cipher_null");
151
crypto_null_mod_init(void)152 static int __init crypto_null_mod_init(void)
153 {
154 int ret = 0;
155
156 ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
157 if (ret < 0)
158 goto out;
159
160 ret = crypto_register_shash(&digest_null);
161 if (ret < 0)
162 goto out_unregister_algs;
163
164 return 0;
165
166 out_unregister_algs:
167 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
168 out:
169 return ret;
170 }
171
crypto_null_mod_fini(void)172 static void __exit crypto_null_mod_fini(void)
173 {
174 crypto_unregister_shash(&digest_null);
175 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
176 }
177
178 module_init(crypto_null_mod_init);
179 module_exit(crypto_null_mod_fini);
180
181 MODULE_LICENSE("GPL");
182 MODULE_DESCRIPTION("Null Cryptographic Algorithms");
183