Root/
1 | /* |
2 | * CMAC: Cipher Block Mode for Authentication |
3 | * |
4 | * Copyright © 2013 Jussi Kivilinna <jussi.kivilinna@iki.fi> |
5 | * |
6 | * Based on work by: |
7 | * Copyright © 2013 Tom St Denis <tstdenis@elliptictech.com> |
8 | * Based on crypto/xcbc.c: |
9 | * Copyright © 2006 USAGI/WIDE Project, |
10 | * Author: Kazunori Miyazawa <miyazawa@linux-ipv6.org> |
11 | * |
12 | * This program is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU General Public License as published by |
14 | * the Free Software Foundation; either version 2 of the License, or |
15 | * (at your option) any later version. |
16 | * |
17 | */ |
18 | |
19 | #include <crypto/internal/hash.h> |
20 | #include <linux/err.h> |
21 | #include <linux/kernel.h> |
22 | #include <linux/module.h> |
23 | |
24 | /* |
25 | * +------------------------ |
26 | * | <parent tfm> |
27 | * +------------------------ |
28 | * | cmac_tfm_ctx |
29 | * +------------------------ |
30 | * | consts (block size * 2) |
31 | * +------------------------ |
32 | */ |
33 | struct cmac_tfm_ctx { |
34 | struct crypto_cipher *child; |
35 | u8 ctx[]; |
36 | }; |
37 | |
38 | /* |
39 | * +------------------------ |
40 | * | <shash desc> |
41 | * +------------------------ |
42 | * | cmac_desc_ctx |
43 | * +------------------------ |
44 | * | odds (block size) |
45 | * +------------------------ |
46 | * | prev (block size) |
47 | * +------------------------ |
48 | */ |
49 | struct cmac_desc_ctx { |
50 | unsigned int len; |
51 | u8 ctx[]; |
52 | }; |
53 | |
54 | static int crypto_cmac_digest_setkey(struct crypto_shash *parent, |
55 | const u8 *inkey, unsigned int keylen) |
56 | { |
57 | unsigned long alignmask = crypto_shash_alignmask(parent); |
58 | struct cmac_tfm_ctx *ctx = crypto_shash_ctx(parent); |
59 | unsigned int bs = crypto_shash_blocksize(parent); |
60 | __be64 *consts = PTR_ALIGN((void *)ctx->ctx, alignmask + 1); |
61 | u64 _const[2]; |
62 | int i, err = 0; |
63 | u8 msb_mask, gfmask; |
64 | |
65 | err = crypto_cipher_setkey(ctx->child, inkey, keylen); |
66 | if (err) |
67 | return err; |
68 | |
69 | /* encrypt the zero block */ |
70 | memset(consts, 0, bs); |
71 | crypto_cipher_encrypt_one(ctx->child, (u8 *)consts, (u8 *)consts); |
72 | |
73 | switch (bs) { |
74 | case 16: |
75 | gfmask = 0x87; |
76 | _const[0] = be64_to_cpu(consts[1]); |
77 | _const[1] = be64_to_cpu(consts[0]); |
78 | |
79 | /* gf(2^128) multiply zero-ciphertext with u and u^2 */ |
80 | for (i = 0; i < 4; i += 2) { |
81 | msb_mask = ((s64)_const[1] >> 63) & gfmask; |
82 | _const[1] = (_const[1] << 1) | (_const[0] >> 63); |
83 | _const[0] = (_const[0] << 1) ^ msb_mask; |
84 | |
85 | consts[i + 0] = cpu_to_be64(_const[1]); |
86 | consts[i + 1] = cpu_to_be64(_const[0]); |
87 | } |
88 | |
89 | break; |
90 | case 8: |
91 | gfmask = 0x1B; |
92 | _const[0] = be64_to_cpu(consts[0]); |
93 | |
94 | /* gf(2^64) multiply zero-ciphertext with u and u^2 */ |
95 | for (i = 0; i < 2; i++) { |
96 | msb_mask = ((s64)_const[0] >> 63) & gfmask; |
97 | _const[0] = (_const[0] << 1) ^ msb_mask; |
98 | |
99 | consts[i] = cpu_to_be64(_const[0]); |
100 | } |
101 | |
102 | break; |
103 | } |
104 | |
105 | return 0; |
106 | } |
107 | |
108 | static int crypto_cmac_digest_init(struct shash_desc *pdesc) |
109 | { |
110 | unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm); |
111 | struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc); |
112 | int bs = crypto_shash_blocksize(pdesc->tfm); |
113 | u8 *prev = PTR_ALIGN((void *)ctx->ctx, alignmask + 1) + bs; |
114 | |
115 | ctx->len = 0; |
116 | memset(prev, 0, bs); |
117 | |
118 | return 0; |
119 | } |
120 | |
121 | static int crypto_cmac_digest_update(struct shash_desc *pdesc, const u8 *p, |
122 | unsigned int len) |
123 | { |
124 | struct crypto_shash *parent = pdesc->tfm; |
125 | unsigned long alignmask = crypto_shash_alignmask(parent); |
126 | struct cmac_tfm_ctx *tctx = crypto_shash_ctx(parent); |
127 | struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc); |
128 | struct crypto_cipher *tfm = tctx->child; |
129 | int bs = crypto_shash_blocksize(parent); |
130 | u8 *odds = PTR_ALIGN((void *)ctx->ctx, alignmask + 1); |
131 | u8 *prev = odds + bs; |
132 | |
133 | /* checking the data can fill the block */ |
134 | if ((ctx->len + len) <= bs) { |
135 | memcpy(odds + ctx->len, p, len); |
136 | ctx->len += len; |
137 | return 0; |
138 | } |
139 | |
140 | /* filling odds with new data and encrypting it */ |
141 | memcpy(odds + ctx->len, p, bs - ctx->len); |
142 | len -= bs - ctx->len; |
143 | p += bs - ctx->len; |
144 | |
145 | crypto_xor(prev, odds, bs); |
146 | crypto_cipher_encrypt_one(tfm, prev, prev); |
147 | |
148 | /* clearing the length */ |
149 | ctx->len = 0; |
150 | |
151 | /* encrypting the rest of data */ |
152 | while (len > bs) { |
153 | crypto_xor(prev, p, bs); |
154 | crypto_cipher_encrypt_one(tfm, prev, prev); |
155 | p += bs; |
156 | len -= bs; |
157 | } |
158 | |
159 | /* keeping the surplus of blocksize */ |
160 | if (len) { |
161 | memcpy(odds, p, len); |
162 | ctx->len = len; |
163 | } |
164 | |
165 | return 0; |
166 | } |
167 | |
168 | static int crypto_cmac_digest_final(struct shash_desc *pdesc, u8 *out) |
169 | { |
170 | struct crypto_shash *parent = pdesc->tfm; |
171 | unsigned long alignmask = crypto_shash_alignmask(parent); |
172 | struct cmac_tfm_ctx *tctx = crypto_shash_ctx(parent); |
173 | struct cmac_desc_ctx *ctx = shash_desc_ctx(pdesc); |
174 | struct crypto_cipher *tfm = tctx->child; |
175 | int bs = crypto_shash_blocksize(parent); |
176 | u8 *consts = PTR_ALIGN((void *)tctx->ctx, alignmask + 1); |
177 | u8 *odds = PTR_ALIGN((void *)ctx->ctx, alignmask + 1); |
178 | u8 *prev = odds + bs; |
179 | unsigned int offset = 0; |
180 | |
181 | if (ctx->len != bs) { |
182 | unsigned int rlen; |
183 | u8 *p = odds + ctx->len; |
184 | |
185 | *p = 0x80; |
186 | p++; |
187 | |
188 | rlen = bs - ctx->len - 1; |
189 | if (rlen) |
190 | memset(p, 0, rlen); |
191 | |
192 | offset += bs; |
193 | } |
194 | |
195 | crypto_xor(prev, odds, bs); |
196 | crypto_xor(prev, consts + offset, bs); |
197 | |
198 | crypto_cipher_encrypt_one(tfm, out, prev); |
199 | |
200 | return 0; |
201 | } |
202 | |
203 | static int cmac_init_tfm(struct crypto_tfm *tfm) |
204 | { |
205 | struct crypto_cipher *cipher; |
206 | struct crypto_instance *inst = (void *)tfm->__crt_alg; |
207 | struct crypto_spawn *spawn = crypto_instance_ctx(inst); |
208 | struct cmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm); |
209 | |
210 | cipher = crypto_spawn_cipher(spawn); |
211 | if (IS_ERR(cipher)) |
212 | return PTR_ERR(cipher); |
213 | |
214 | ctx->child = cipher; |
215 | |
216 | return 0; |
217 | }; |
218 | |
219 | static void cmac_exit_tfm(struct crypto_tfm *tfm) |
220 | { |
221 | struct cmac_tfm_ctx *ctx = crypto_tfm_ctx(tfm); |
222 | crypto_free_cipher(ctx->child); |
223 | } |
224 | |
225 | static int cmac_create(struct crypto_template *tmpl, struct rtattr **tb) |
226 | { |
227 | struct shash_instance *inst; |
228 | struct crypto_alg *alg; |
229 | unsigned long alignmask; |
230 | int err; |
231 | |
232 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); |
233 | if (err) |
234 | return err; |
235 | |
236 | alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, |
237 | CRYPTO_ALG_TYPE_MASK); |
238 | if (IS_ERR(alg)) |
239 | return PTR_ERR(alg); |
240 | |
241 | switch (alg->cra_blocksize) { |
242 | case 16: |
243 | case 8: |
244 | break; |
245 | default: |
246 | goto out_put_alg; |
247 | } |
248 | |
249 | inst = shash_alloc_instance("cmac", alg); |
250 | err = PTR_ERR(inst); |
251 | if (IS_ERR(inst)) |
252 | goto out_put_alg; |
253 | |
254 | err = crypto_init_spawn(shash_instance_ctx(inst), alg, |
255 | shash_crypto_instance(inst), |
256 | CRYPTO_ALG_TYPE_MASK); |
257 | if (err) |
258 | goto out_free_inst; |
259 | |
260 | alignmask = alg->cra_alignmask | (sizeof(long) - 1); |
261 | inst->alg.base.cra_alignmask = alignmask; |
262 | inst->alg.base.cra_priority = alg->cra_priority; |
263 | inst->alg.base.cra_blocksize = alg->cra_blocksize; |
264 | |
265 | inst->alg.digestsize = alg->cra_blocksize; |
266 | inst->alg.descsize = |
267 | ALIGN(sizeof(struct cmac_desc_ctx), crypto_tfm_ctx_alignment()) |
268 | + (alignmask & ~(crypto_tfm_ctx_alignment() - 1)) |
269 | + alg->cra_blocksize * 2; |
270 | |
271 | inst->alg.base.cra_ctxsize = |
272 | ALIGN(sizeof(struct cmac_tfm_ctx), alignmask + 1) |
273 | + alg->cra_blocksize * 2; |
274 | |
275 | inst->alg.base.cra_init = cmac_init_tfm; |
276 | inst->alg.base.cra_exit = cmac_exit_tfm; |
277 | |
278 | inst->alg.init = crypto_cmac_digest_init; |
279 | inst->alg.update = crypto_cmac_digest_update; |
280 | inst->alg.final = crypto_cmac_digest_final; |
281 | inst->alg.setkey = crypto_cmac_digest_setkey; |
282 | |
283 | err = shash_register_instance(tmpl, inst); |
284 | if (err) { |
285 | out_free_inst: |
286 | shash_free_instance(shash_crypto_instance(inst)); |
287 | } |
288 | |
289 | out_put_alg: |
290 | crypto_mod_put(alg); |
291 | return err; |
292 | } |
293 | |
294 | static struct crypto_template crypto_cmac_tmpl = { |
295 | .name = "cmac", |
296 | .create = cmac_create, |
297 | .free = shash_free_instance, |
298 | .module = THIS_MODULE, |
299 | }; |
300 | |
301 | static int __init crypto_cmac_module_init(void) |
302 | { |
303 | return crypto_register_template(&crypto_cmac_tmpl); |
304 | } |
305 | |
306 | static void __exit crypto_cmac_module_exit(void) |
307 | { |
308 | crypto_unregister_template(&crypto_cmac_tmpl); |
309 | } |
310 | |
311 | module_init(crypto_cmac_module_init); |
312 | module_exit(crypto_cmac_module_exit); |
313 | |
314 | MODULE_LICENSE("GPL"); |
315 | MODULE_DESCRIPTION("CMAC keyed hash algorithm"); |
316 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9