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20#include <crypto/internal/hash.h>
21#include <crypto/internal/skcipher.h>
22#include <linux/init.h>
23#include <linux/module.h>
24#include <linux/mm.h>
25#include <linux/string.h>
26
27#define NULL_KEY_SIZE 0
28#define NULL_BLOCK_SIZE 1
29#define NULL_DIGEST_SIZE 0
30#define NULL_IV_SIZE 0
31
32static int null_compress(struct crypto_tfm *tfm, const u8 *src,
33 unsigned int slen, u8 *dst, unsigned int *dlen)
34{
35 if (slen > *dlen)
36 return -EINVAL;
37 memcpy(dst, src, slen);
38 *dlen = slen;
39 return 0;
40}
41
42static int null_init(struct shash_desc *desc)
43{
44 return 0;
45}
46
47static int null_update(struct shash_desc *desc, const u8 *data,
48 unsigned int len)
49{
50 return 0;
51}
52
53static int null_final(struct shash_desc *desc, u8 *out)
54{
55 return 0;
56}
57
58static int null_digest(struct shash_desc *desc, const u8 *data,
59 unsigned int len, u8 *out)
60{
61 return 0;
62}
63
64static int null_hash_setkey(struct crypto_shash *tfm, const u8 *key,
65 unsigned int keylen)
66{ return 0; }
67
68static int null_setkey(struct crypto_tfm *tfm, const u8 *key,
69 unsigned int keylen)
70{ return 0; }
71
72static void null_crypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
73{
74 memcpy(dst, src, NULL_BLOCK_SIZE);
75}
76
77static int skcipher_null_crypt(struct blkcipher_desc *desc,
78 struct scatterlist *dst,
79 struct scatterlist *src, unsigned int nbytes)
80{
81 struct blkcipher_walk walk;
82 int err;
83
84 blkcipher_walk_init(&walk, dst, src, nbytes);
85 err = blkcipher_walk_virt(desc, &walk);
86
87 while (walk.nbytes) {
88 if (walk.src.virt.addr != walk.dst.virt.addr)
89 memcpy(walk.dst.virt.addr, walk.src.virt.addr,
90 walk.nbytes);
91 err = blkcipher_walk_done(desc, &walk, 0);
92 }
93
94 return err;
95}
96
97static struct shash_alg digest_null = {
98 .digestsize = NULL_DIGEST_SIZE,
99 .setkey = null_hash_setkey,
100 .init = null_init,
101 .update = null_update,
102 .finup = null_digest,
103 .digest = null_digest,
104 .final = null_final,
105 .base = {
106 .cra_name = "digest_null",
107 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
108 .cra_blocksize = NULL_BLOCK_SIZE,
109 .cra_module = THIS_MODULE,
110 }
111};
112
113static struct crypto_alg null_algs[3] = { {
114 .cra_name = "cipher_null",
115 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
116 .cra_blocksize = NULL_BLOCK_SIZE,
117 .cra_ctxsize = 0,
118 .cra_module = THIS_MODULE,
119 .cra_u = { .cipher = {
120 .cia_min_keysize = NULL_KEY_SIZE,
121 .cia_max_keysize = NULL_KEY_SIZE,
122 .cia_setkey = null_setkey,
123 .cia_encrypt = null_crypt,
124 .cia_decrypt = null_crypt } }
125}, {
126 .cra_name = "ecb(cipher_null)",
127 .cra_driver_name = "ecb-cipher_null",
128 .cra_priority = 100,
129 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
130 .cra_blocksize = NULL_BLOCK_SIZE,
131 .cra_type = &crypto_blkcipher_type,
132 .cra_ctxsize = 0,
133 .cra_module = THIS_MODULE,
134 .cra_u = { .blkcipher = {
135 .min_keysize = NULL_KEY_SIZE,
136 .max_keysize = NULL_KEY_SIZE,
137 .ivsize = NULL_IV_SIZE,
138 .setkey = null_setkey,
139 .encrypt = skcipher_null_crypt,
140 .decrypt = skcipher_null_crypt } }
141}, {
142 .cra_name = "compress_null",
143 .cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
144 .cra_blocksize = NULL_BLOCK_SIZE,
145 .cra_ctxsize = 0,
146 .cra_module = THIS_MODULE,
147 .cra_u = { .compress = {
148 .coa_compress = null_compress,
149 .coa_decompress = null_compress } }
150} };
151
152MODULE_ALIAS("compress_null");
153MODULE_ALIAS("digest_null");
154MODULE_ALIAS("cipher_null");
155
156static int __init crypto_null_mod_init(void)
157{
158 int ret = 0;
159
160 ret = crypto_register_algs(null_algs, ARRAY_SIZE(null_algs));
161 if (ret < 0)
162 goto out;
163
164 ret = crypto_register_shash(&digest_null);
165 if (ret < 0)
166 goto out_unregister_algs;
167
168 return 0;
169
170out_unregister_algs:
171 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
172out:
173 return ret;
174}
175
176static void __exit crypto_null_mod_fini(void)
177{
178 crypto_unregister_shash(&digest_null);
179 crypto_unregister_algs(null_algs, ARRAY_SIZE(null_algs));
180}
181
182module_init(crypto_null_mod_init);
183module_exit(crypto_null_mod_fini);
184
185MODULE_LICENSE("GPL");
186MODULE_DESCRIPTION("Null Cryptographic Algorithms");
187
