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/hash.h>
10 #include <linux/err.h>
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13
14 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
15 0x02020202, 0x02020202, 0x02020202, 0x02020202,
16 0x03030303, 0x03030303, 0x03030303, 0x03030303};
17
18 /*
19 * +------------------------
20 * | <parent tfm>
21 * +------------------------
22 * | xcbc_tfm_ctx
23 * +------------------------
24 * | consts (block size * 2)
25 * +------------------------
26 */
27 struct xcbc_tfm_ctx {
28 struct crypto_cipher *child;
29 u8 ctx[];
30 };
31
32 /*
33 * +------------------------
34 * | <shash desc>
35 * +------------------------
36 * | xcbc_desc_ctx
37 * +------------------------
38 * | odds (block size)
39 * +------------------------
40 * | prev (block size)
41 * +------------------------
42 */
43 struct xcbc_desc_ctx {
44 unsigned int len;
45 u8 ctx[];
46 };
47
48 #define XCBC_BLOCKSIZE 16
49
crypto_xcbc_digest_setkey(struct crypto_shash * parent,const u8 * inkey,unsigned int keylen)50 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
51 const u8 *inkey, unsigned int keylen)
52 {
53 unsigned long alignmask = crypto_shash_alignmask(parent);
54 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
55 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
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
crypto_xcbc_digest_init(struct shash_desc * pdesc)71 static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
72 {
73 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm);
74 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
75 int bs = crypto_shash_blocksize(pdesc->tfm);
76 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs;
77
78 ctx->len = 0;
79 memset(prev, 0, bs);
80
81 return 0;
82 }
83
crypto_xcbc_digest_update(struct shash_desc * pdesc,const u8 * p,unsigned int len)84 static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
85 unsigned int len)
86 {
87 struct crypto_shash *parent = pdesc->tfm;
88 unsigned long alignmask = crypto_shash_alignmask(parent);
89 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
90 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
91 struct crypto_cipher *tfm = tctx->child;
92 int bs = crypto_shash_blocksize(parent);
93 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
94 u8 *prev = odds + bs;
95
96 /* checking the data can fill the block */
97 if ((ctx->len + len) <= bs) {
98 memcpy(odds + ctx->len, p, len);
99 ctx->len += len;
100 return 0;
101 }
102
103 /* filling odds with new data and encrypting it */
104 memcpy(odds + ctx->len, p, bs - ctx->len);
105 len -= bs - ctx->len;
106 p += bs - ctx->len;
107
108 crypto_xor(prev, odds, bs);
109 crypto_cipher_encrypt_one(tfm, prev, prev);
110
111 /* clearing the length */
112 ctx->len = 0;
113
114 /* encrypting the rest of data */
115 while (len > bs) {
116 crypto_xor(prev, p, bs);
117 crypto_cipher_encrypt_one(tfm, prev, prev);
118 p += bs;
119 len -= bs;
120 }
121
122 /* keeping the surplus of blocksize */
123 if (len) {
124 memcpy(odds, p, len);
125 ctx->len = len;
126 }
127
128 return 0;
129 }
130
crypto_xcbc_digest_final(struct shash_desc * pdesc,u8 * out)131 static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out)
132 {
133 struct crypto_shash *parent = pdesc->tfm;
134 unsigned long alignmask = crypto_shash_alignmask(parent);
135 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
136 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc);
137 struct crypto_cipher *tfm = tctx->child;
138 int bs = crypto_shash_blocksize(parent);
139 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1);
140 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1);
141 u8 *prev = odds + bs;
142 unsigned int offset = 0;
143
144 if (ctx->len != bs) {
145 unsigned int rlen;
146 u8 *p = odds + ctx->len;
147
148 *p = 0x80;
149 p++;
150
151 rlen = bs - ctx->len -1;
152 if (rlen)
153 memset(p, 0, rlen);
154
155 offset += bs;
156 }
157
158 crypto_xor(prev, odds, bs);
159 crypto_xor(prev, consts + offset, bs);
160
161 crypto_cipher_encrypt_one(tfm, out, prev);
162
163 return 0;
164 }
165
xcbc_init_tfm(struct crypto_tfm * tfm)166 static int xcbc_init_tfm(struct crypto_tfm *tfm)
167 {
168 struct crypto_cipher *cipher;
169 struct crypto_instance *inst = (void *)tfm->__crt_alg;
170 struct crypto_spawn *spawn = crypto_instance_ctx(inst);
171 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
172
173 cipher = crypto_spawn_cipher(spawn);
174 if (IS_ERR(cipher))
175 return PTR_ERR(cipher);
176
177 ctx->child = cipher;
178
179 return 0;
180 };
181
xcbc_exit_tfm(struct crypto_tfm * tfm)182 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
183 {
184 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
185 crypto_free_cipher(ctx->child);
186 }
187
xcbc_create(struct crypto_template * tmpl,struct rtattr ** tb)188 static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
189 {
190 struct shash_instance *inst;
191 struct crypto_alg *alg;
192 unsigned long alignmask;
193 int err;
194
195 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH);
196 if (err)
197 return err;
198
199 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
200 CRYPTO_ALG_TYPE_MASK);
201 if (IS_ERR(alg))
202 return PTR_ERR(alg);
203
204 switch(alg->cra_blocksize) {
205 case XCBC_BLOCKSIZE:
206 break;
207 default:
208 goto out_put_alg;
209 }
210
211 inst = shash_alloc_instance("xcbc", alg);
212 err = PTR_ERR(inst);
213 if (IS_ERR(inst))
214 goto out_put_alg;
215
216 err = crypto_init_spawn(shash_instance_ctx(inst), alg,
217 shash_crypto_instance(inst),
218 CRYPTO_ALG_TYPE_MASK);
219 if (err)
220 goto out_free_inst;
221
222 alignmask = alg->cra_alignmask | 3;
223 inst->alg.base.cra_alignmask = alignmask;
224 inst->alg.base.cra_priority = alg->cra_priority;
225 inst->alg.base.cra_blocksize = alg->cra_blocksize;
226
227 inst->alg.digestsize = alg->cra_blocksize;
228 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx),
229 crypto_tfm_ctx_alignment()) +
230 (alignmask &
231 ~(crypto_tfm_ctx_alignment() - 1)) +
232 alg->cra_blocksize * 2;
233
234 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx),
235 alignmask + 1) +
236 alg->cra_blocksize * 2;
237 inst->alg.base.cra_init = xcbc_init_tfm;
238 inst->alg.base.cra_exit = xcbc_exit_tfm;
239
240 inst->alg.init = crypto_xcbc_digest_init;
241 inst->alg.update = crypto_xcbc_digest_update;
242 inst->alg.final = crypto_xcbc_digest_final;
243 inst->alg.setkey = crypto_xcbc_digest_setkey;
244
245 err = shash_register_instance(tmpl, inst);
246 if (err) {
247 out_free_inst:
248 shash_free_instance(shash_crypto_instance(inst));
249 }
250
251 out_put_alg:
252 crypto_mod_put(alg);
253 return err;
254 }
255
256 static struct crypto_template crypto_xcbc_tmpl = {
257 .name = "xcbc",
258 .create = xcbc_create,
259 .free = shash_free_instance,
260 .module = THIS_MODULE,
261 };
262
crypto_xcbc_module_init(void)263 static int __init crypto_xcbc_module_init(void)
264 {
265 return crypto_register_template(&crypto_xcbc_tmpl);
266 }
267
crypto_xcbc_module_exit(void)268 static void __exit crypto_xcbc_module_exit(void)
269 {
270 crypto_unregister_template(&crypto_xcbc_tmpl);
271 }
272
273 subsys_initcall(crypto_xcbc_module_init);
274 module_exit(crypto_xcbc_module_exit);
275
276 MODULE_LICENSE("GPL");
277 MODULE_DESCRIPTION("XCBC keyed hash algorithm");
278 MODULE_ALIAS_CRYPTO("xcbc");
279