1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C)2006 USAGI/WIDE Project
4 *
5 * Author:
6 * Kazunori Miyazawa <miyazawa@linux-ipv6.org>
7 */
8
9 #include <crypto/internal/cipher.h>
10 #include <crypto/internal/hash.h>
11 #include <linux/err.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14
15 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
16 0x02020202, 0x02020202, 0x02020202, 0x02020202,
17 0x03030303, 0x03030303, 0x03030303, 0x03030303};
18
19 /*
20 * +------------------------
21 * | <parent tfm>
22 * +------------------------
23 * | xcbc_tfm_ctx
24 * +------------------------
25 * | consts (block size * 2)
26 * +------------------------
27 */
28 struct xcbc_tfm_ctx {
29 struct crypto_cipher *child;
30 u8 consts[];
31 };
32
33 /*
34 * +------------------------
35 * | <shash desc>
36 * +------------------------
37 * | xcbc_desc_ctx
38 * +------------------------
39 * | odds (block size)
40 * +------------------------
41 * | prev (block size)
42 * +------------------------
43 */
44 struct xcbc_desc_ctx {
45 unsigned int len;
46 u8 odds[];
47 };
48
49 #define XCBC_BLOCKSIZE 16
50
51 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
52 const u8 *inkey, unsigned int keylen)
53 {
54 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
55 u8 *consts = ctx->consts;
56 int err = 0;
57 u8 key1[XCBC_BLOCKSIZE];
58 int bs = sizeof(key1);
59
60 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
61 return err;
62
63 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
64 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
65 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
66
67 return crypto_cipher_setkey(ctx->child, key1, bs);
68
69 }
70
71 static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
72 {
73 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
74 int bs = crypto_shash_blocksize(pdesc->tfm);
75 u8 *prev = &ctx->odds[bs];
76
77 ctx->len = 0;
78 memset(prev, 0, bs);
79
80 return 0;
81 }
82
83 static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
84 unsigned int len)
85 {
86 struct crypto_shash *parent = pdesc->tfm;
87 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
88 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
89 struct crypto_cipher *tfm = tctx->child;
90 int bs = crypto_shash_blocksize(parent);
91 u8 *odds = ctx->odds;
92 u8 *prev = odds + bs;
93
94 /* checking the data can fill the block */
95 if ((ctx->len + len) <= bs) {
96 memcpy(odds + ctx->len, p, len);
97 ctx->len += len;
98 return 0;
99 }
100
101 /* filling odds with new data and encrypting it */
102 memcpy(odds + ctx->len, p, bs - ctx->len);
103 len -= bs - ctx->len;
104 p += bs - ctx->len;
105
106 crypto_xor(prev, odds, bs);
107 crypto_cipher_encrypt_one(tfm, prev, prev);
108
109 /* clearing the length */
110 ctx->len = 0;
111
112 /* encrypting the rest of data */
113 while (len > bs) {
114 crypto_xor(prev, p, bs);
115 crypto_cipher_encrypt_one(tfm, prev, prev);
116 p += bs;
117 len -= bs;
118 }
119
120 /* keeping the surplus of blocksize */
121 if (len) {
122 memcpy(odds, p, len);
123 ctx->len = len;
124 }
125
126 return 0;
127 }
128
129 static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
130 {
131 struct crypto_shash *parent = pdesc->tfm;
132 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
133 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
134 struct crypto_cipher *tfm = tctx->child;
135 int bs = crypto_shash_blocksize(parent);
136 u8 *odds = ctx->odds;
137 u8 *prev = odds + bs;
138 unsigned int offset = 0;
139
140 if (ctx->len != bs) {
141 unsigned int rlen;
142 u8 *p = odds + ctx->len;
143
144 *p = 0x80;
145 p++;
146
147 rlen = bs - ctx->len -1;
148 if (rlen)
149 memset(p, 0, rlen);
150
151 offset += bs;
152 }
153
154 crypto_xor(prev, odds, bs);
155 crypto_xor(prev, &tctx->consts[offset], bs);
156
157 crypto_cipher_encrypt_one(tfm, out, prev);
158
159 return 0;
160 }
161
162 static int xcbc_init_tfm(struct crypto_tfm *tfm)
163 {
164 struct crypto_cipher *cipher;
165 struct crypto_instance *inst = (void *)tfm->__crt_alg;
166 struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
167 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
168
169 cipher = crypto_spawn_cipher(spawn);
170 if (IS_ERR(cipher))
171 return PTR_ERR(cipher);
172
173 ctx->child = cipher;
174
175 return 0;
176 };
177
178 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
179 {
180 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
181 crypto_free_cipher(ctx->child);
182 }
183
184 static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
185 {
186 struct shash_instance *inst;
187 struct crypto_cipher_spawn *spawn;
188 struct crypto_alg *alg;
189 u32 mask;
190 int err;
191
192 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
193 if (err)
194 return err;
195
196 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
197 if (!inst)
198 return -ENOMEM;
199 spawn = shash_instance_ctx(inst);
200
201 err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
202 crypto_attr_alg_name(tb[1]), 0, mask);
203 if (err)
204 goto err_free_inst;
205 alg = crypto_spawn_cipher_alg(spawn);
206
207 err = -EINVAL;
208 if (alg->cra_blocksize != XCBC_BLOCKSIZE)
209 goto err_free_inst;
210
211 err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
212 if (err)
213 goto err_free_inst;
214
215 inst->alg.base.cra_priority = alg->cra_priority;
216 inst->alg.base.cra_blocksize = alg->cra_blocksize;
217 inst->alg.base.cra_ctxsize = sizeof(struct xcbc_tfm_ctx) +
218 alg->cra_blocksize * 2;
219
220 inst->alg.digestsize = alg->cra_blocksize;
221 inst->alg.descsize = sizeof(struct xcbc_desc_ctx) +
222 alg->cra_blocksize * 2;
223
224 inst->alg.base.cra_init = xcbc_init_tfm;
225 inst->alg.base.cra_exit = xcbc_exit_tfm;
226
227 inst->alg.init = crypto_xcbc_digest_init;
228 inst->alg.update = crypto_xcbc_digest_update;
229 inst->alg.final = crypto_xcbc_digest_final;
230 inst->alg.setkey = crypto_xcbc_digest_setkey;
231
232 inst->free = shash_free_singlespawn_instance;
233
234 err = shash_register_instance(tmpl, inst);
235 if (err) {
236 err_free_inst:
237 shash_free_singlespawn_instance(inst);
238 }
239 return err;
240 }
241
242 static struct crypto_template crypto_xcbc_tmpl = {
243 .name = "xcbc",
244 .create = xcbc_create,
245 .module = THIS_MODULE,
246 };
247
248 static int __init crypto_xcbc_module_init(void)
249 {
250 return crypto_register_template(&crypto_xcbc_tmpl);
251 }
252
253 static void __exit crypto_xcbc_module_exit(void)
254 {
255 crypto_unregister_template(&crypto_xcbc_tmpl);
256 }
257
258 subsys_initcall(crypto_xcbc_module_init);
259 module_exit(crypto_xcbc_module_exit);
260
261 MODULE_LICENSE("GPL");
262 MODULE_DESCRIPTION("XCBC keyed hash algorithm");
263 MODULE_ALIAS_CRYPTO("xcbc");
264 MODULE_IMPORT_NS(CRYPTO_INTERNAL);
265
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