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Diffstat (limited to 'crypto/aes.c')
-rw-r--r-- | crypto/aes.c | 451 |
1 files changed, 451 insertions, 0 deletions
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1 | /* | ||
2 | * Cryptographic API. | ||
3 | * | ||
4 | * AES Cipher Algorithm. | ||
5 | * | ||
6 | * Based on Brian Gladman's code. | ||
7 | * | ||
8 | * Linux developers: | ||
9 | * Alexander Kjeldaas <astor@fast.no> | ||
10 | * Herbert Valerio Riedel <hvr@hvrlab.org> | ||
11 | * Kyle McMartin <kyle@debian.org> | ||
12 | * Adam J. Richter <adam@yggdrasil.com> (conversion to 2.5 API). | ||
13 | * | ||
14 | * This program is free software; you can redistribute it and/or modify | ||
15 | * it under the terms of the GNU General Public License as published by | ||
16 | * the Free Software Foundation; either version 2 of the License, or | ||
17 | * (at your option) any later version. | ||
18 | * | ||
19 | * --------------------------------------------------------------------------- | ||
20 | * Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK. | ||
21 | * All rights reserved. | ||
22 | * | ||
23 | * LICENSE TERMS | ||
24 | * | ||
25 | * The free distribution and use of this software in both source and binary | ||
26 | * form is allowed (with or without changes) provided that: | ||
27 | * | ||
28 | * 1. distributions of this source code include the above copyright | ||
29 | * notice, this list of conditions and the following disclaimer; | ||
30 | * | ||
31 | * 2. distributions in binary form include the above copyright | ||
32 | * notice, this list of conditions and the following disclaimer | ||
33 | * in the documentation and/or other associated materials; | ||
34 | * | ||
35 | * 3. the copyright holder's name is not used to endorse products | ||
36 | * built using this software without specific written permission. | ||
37 | * | ||
38 | * ALTERNATIVELY, provided that this notice is retained in full, this product | ||
39 | * may be distributed under the terms of the GNU General Public License (GPL), | ||
40 | * in which case the provisions of the GPL apply INSTEAD OF those given above. | ||
41 | * | ||
42 | * DISCLAIMER | ||
43 | * | ||
44 | * This software is provided 'as is' with no explicit or implied warranties | ||
45 | * in respect of its properties, including, but not limited to, correctness | ||
46 | * and/or fitness for purpose. | ||
47 | * --------------------------------------------------------------------------- | ||
48 | */ | ||
49 | |||
50 | /* Some changes from the Gladman version: | ||
51 | s/RIJNDAEL(e_key)/E_KEY/g | ||
52 | s/RIJNDAEL(d_key)/D_KEY/g | ||
53 | */ | ||
54 | |||
55 | #include <linux/module.h> | ||
56 | #include <linux/init.h> | ||
57 | #include <linux/types.h> | ||
58 | #include <linux/errno.h> | ||
59 | #include <linux/crypto.h> | ||
60 | #include <asm/byteorder.h> | ||
61 | |||
62 | #define AES_MIN_KEY_SIZE 16 | ||
63 | #define AES_MAX_KEY_SIZE 32 | ||
64 | |||
65 | #define AES_BLOCK_SIZE 16 | ||
66 | |||
67 | /* | ||
68 | * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) | ||
69 | */ | ||
70 | inline static u8 | ||
71 | byte(const u32 x, const unsigned n) | ||
72 | { | ||
73 | return x >> (n << 3); | ||
74 | } | ||
75 | |||
76 | #define u32_in(x) le32_to_cpu(*(const u32 *)(x)) | ||
77 | #define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from)) | ||
78 | |||
79 | struct aes_ctx { | ||
80 | int key_length; | ||
81 | u32 E[60]; | ||
82 | u32 D[60]; | ||
83 | }; | ||
84 | |||
85 | #define E_KEY ctx->E | ||
86 | #define D_KEY ctx->D | ||
87 | |||
88 | static u8 pow_tab[256] __initdata; | ||
89 | static u8 log_tab[256] __initdata; | ||
90 | static u8 sbx_tab[256] __initdata; | ||
91 | static u8 isb_tab[256] __initdata; | ||
92 | static u32 rco_tab[10]; | ||
93 | static u32 ft_tab[4][256]; | ||
94 | static u32 it_tab[4][256]; | ||
95 | |||
96 | static u32 fl_tab[4][256]; | ||
97 | static u32 il_tab[4][256]; | ||
98 | |||
99 | static inline u8 __init | ||
100 | f_mult (u8 a, u8 b) | ||
101 | { | ||
102 | u8 aa = log_tab[a], cc = aa + log_tab[b]; | ||
103 | |||
104 | return pow_tab[cc + (cc < aa ? 1 : 0)]; | ||
105 | } | ||
106 | |||
107 | #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) | ||
108 | |||
109 | #define f_rn(bo, bi, n, k) \ | ||
110 | bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ | ||
111 | ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ | ||
112 | ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | ||
113 | ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) | ||
114 | |||
115 | #define i_rn(bo, bi, n, k) \ | ||
116 | bo[n] = it_tab[0][byte(bi[n],0)] ^ \ | ||
117 | it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ | ||
118 | it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | ||
119 | it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) | ||
120 | |||
121 | #define ls_box(x) \ | ||
122 | ( fl_tab[0][byte(x, 0)] ^ \ | ||
123 | fl_tab[1][byte(x, 1)] ^ \ | ||
124 | fl_tab[2][byte(x, 2)] ^ \ | ||
125 | fl_tab[3][byte(x, 3)] ) | ||
126 | |||
127 | #define f_rl(bo, bi, n, k) \ | ||
128 | bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ | ||
129 | fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ | ||
130 | fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | ||
131 | fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) | ||
132 | |||
133 | #define i_rl(bo, bi, n, k) \ | ||
134 | bo[n] = il_tab[0][byte(bi[n],0)] ^ \ | ||
135 | il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ | ||
136 | il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | ||
137 | il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) | ||
138 | |||
139 | static void __init | ||
140 | gen_tabs (void) | ||
141 | { | ||
142 | u32 i, t; | ||
143 | u8 p, q; | ||
144 | |||
145 | /* log and power tables for GF(2**8) finite field with | ||
146 | 0x011b as modular polynomial - the simplest primitive | ||
147 | root is 0x03, used here to generate the tables */ | ||
148 | |||
149 | for (i = 0, p = 1; i < 256; ++i) { | ||
150 | pow_tab[i] = (u8) p; | ||
151 | log_tab[p] = (u8) i; | ||
152 | |||
153 | p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); | ||
154 | } | ||
155 | |||
156 | log_tab[1] = 0; | ||
157 | |||
158 | for (i = 0, p = 1; i < 10; ++i) { | ||
159 | rco_tab[i] = p; | ||
160 | |||
161 | p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); | ||
162 | } | ||
163 | |||
164 | for (i = 0; i < 256; ++i) { | ||
165 | p = (i ? pow_tab[255 - log_tab[i]] : 0); | ||
166 | q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); | ||
167 | p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); | ||
168 | sbx_tab[i] = p; | ||
169 | isb_tab[p] = (u8) i; | ||
170 | } | ||
171 | |||
172 | for (i = 0; i < 256; ++i) { | ||
173 | p = sbx_tab[i]; | ||
174 | |||
175 | t = p; | ||
176 | fl_tab[0][i] = t; | ||
177 | fl_tab[1][i] = rol32(t, 8); | ||
178 | fl_tab[2][i] = rol32(t, 16); | ||
179 | fl_tab[3][i] = rol32(t, 24); | ||
180 | |||
181 | t = ((u32) ff_mult (2, p)) | | ||
182 | ((u32) p << 8) | | ||
183 | ((u32) p << 16) | ((u32) ff_mult (3, p) << 24); | ||
184 | |||
185 | ft_tab[0][i] = t; | ||
186 | ft_tab[1][i] = rol32(t, 8); | ||
187 | ft_tab[2][i] = rol32(t, 16); | ||
188 | ft_tab[3][i] = rol32(t, 24); | ||
189 | |||
190 | p = isb_tab[i]; | ||
191 | |||
192 | t = p; | ||
193 | il_tab[0][i] = t; | ||
194 | il_tab[1][i] = rol32(t, 8); | ||
195 | il_tab[2][i] = rol32(t, 16); | ||
196 | il_tab[3][i] = rol32(t, 24); | ||
197 | |||
198 | t = ((u32) ff_mult (14, p)) | | ||
199 | ((u32) ff_mult (9, p) << 8) | | ||
200 | ((u32) ff_mult (13, p) << 16) | | ||
201 | ((u32) ff_mult (11, p) << 24); | ||
202 | |||
203 | it_tab[0][i] = t; | ||
204 | it_tab[1][i] = rol32(t, 8); | ||
205 | it_tab[2][i] = rol32(t, 16); | ||
206 | it_tab[3][i] = rol32(t, 24); | ||
207 | } | ||
208 | } | ||
209 | |||
210 | #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) | ||
211 | |||
212 | #define imix_col(y,x) \ | ||
213 | u = star_x(x); \ | ||
214 | v = star_x(u); \ | ||
215 | w = star_x(v); \ | ||
216 | t = w ^ (x); \ | ||
217 | (y) = u ^ v ^ w; \ | ||
218 | (y) ^= ror32(u ^ t, 8) ^ \ | ||
219 | ror32(v ^ t, 16) ^ \ | ||
220 | ror32(t,24) | ||
221 | |||
222 | /* initialise the key schedule from the user supplied key */ | ||
223 | |||
224 | #define loop4(i) \ | ||
225 | { t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ | ||
226 | t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ | ||
227 | t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ | ||
228 | t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ | ||
229 | t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ | ||
230 | } | ||
231 | |||
232 | #define loop6(i) \ | ||
233 | { t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ | ||
234 | t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ | ||
235 | t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ | ||
236 | t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ | ||
237 | t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ | ||
238 | t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ | ||
239 | t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ | ||
240 | } | ||
241 | |||
242 | #define loop8(i) \ | ||
243 | { t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ | ||
244 | t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ | ||
245 | t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ | ||
246 | t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ | ||
247 | t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ | ||
248 | t = E_KEY[8 * i + 4] ^ ls_box(t); \ | ||
249 | E_KEY[8 * i + 12] = t; \ | ||
250 | t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ | ||
251 | t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ | ||
252 | t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ | ||
253 | } | ||
254 | |||
255 | static int | ||
256 | aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags) | ||
257 | { | ||
258 | struct aes_ctx *ctx = ctx_arg; | ||
259 | u32 i, t, u, v, w; | ||
260 | |||
261 | if (key_len != 16 && key_len != 24 && key_len != 32) { | ||
262 | *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; | ||
263 | return -EINVAL; | ||
264 | } | ||
265 | |||
266 | ctx->key_length = key_len; | ||
267 | |||
268 | E_KEY[0] = u32_in (in_key); | ||
269 | E_KEY[1] = u32_in (in_key + 4); | ||
270 | E_KEY[2] = u32_in (in_key + 8); | ||
271 | E_KEY[3] = u32_in (in_key + 12); | ||
272 | |||
273 | switch (key_len) { | ||
274 | case 16: | ||
275 | t = E_KEY[3]; | ||
276 | for (i = 0; i < 10; ++i) | ||
277 | loop4 (i); | ||
278 | break; | ||
279 | |||
280 | case 24: | ||
281 | E_KEY[4] = u32_in (in_key + 16); | ||
282 | t = E_KEY[5] = u32_in (in_key + 20); | ||
283 | for (i = 0; i < 8; ++i) | ||
284 | loop6 (i); | ||
285 | break; | ||
286 | |||
287 | case 32: | ||
288 | E_KEY[4] = u32_in (in_key + 16); | ||
289 | E_KEY[5] = u32_in (in_key + 20); | ||
290 | E_KEY[6] = u32_in (in_key + 24); | ||
291 | t = E_KEY[7] = u32_in (in_key + 28); | ||
292 | for (i = 0; i < 7; ++i) | ||
293 | loop8 (i); | ||
294 | break; | ||
295 | } | ||
296 | |||
297 | D_KEY[0] = E_KEY[0]; | ||
298 | D_KEY[1] = E_KEY[1]; | ||
299 | D_KEY[2] = E_KEY[2]; | ||
300 | D_KEY[3] = E_KEY[3]; | ||
301 | |||
302 | for (i = 4; i < key_len + 24; ++i) { | ||
303 | imix_col (D_KEY[i], E_KEY[i]); | ||
304 | } | ||
305 | |||
306 | return 0; | ||
307 | } | ||
308 | |||
309 | /* encrypt a block of text */ | ||
310 | |||
311 | #define f_nround(bo, bi, k) \ | ||
312 | f_rn(bo, bi, 0, k); \ | ||
313 | f_rn(bo, bi, 1, k); \ | ||
314 | f_rn(bo, bi, 2, k); \ | ||
315 | f_rn(bo, bi, 3, k); \ | ||
316 | k += 4 | ||
317 | |||
318 | #define f_lround(bo, bi, k) \ | ||
319 | f_rl(bo, bi, 0, k); \ | ||
320 | f_rl(bo, bi, 1, k); \ | ||
321 | f_rl(bo, bi, 2, k); \ | ||
322 | f_rl(bo, bi, 3, k) | ||
323 | |||
324 | static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in) | ||
325 | { | ||
326 | const struct aes_ctx *ctx = ctx_arg; | ||
327 | u32 b0[4], b1[4]; | ||
328 | const u32 *kp = E_KEY + 4; | ||
329 | |||
330 | b0[0] = u32_in (in) ^ E_KEY[0]; | ||
331 | b0[1] = u32_in (in + 4) ^ E_KEY[1]; | ||
332 | b0[2] = u32_in (in + 8) ^ E_KEY[2]; | ||
333 | b0[3] = u32_in (in + 12) ^ E_KEY[3]; | ||
334 | |||
335 | if (ctx->key_length > 24) { | ||
336 | f_nround (b1, b0, kp); | ||
337 | f_nround (b0, b1, kp); | ||
338 | } | ||
339 | |||
340 | if (ctx->key_length > 16) { | ||
341 | f_nround (b1, b0, kp); | ||
342 | f_nround (b0, b1, kp); | ||
343 | } | ||
344 | |||
345 | f_nround (b1, b0, kp); | ||
346 | f_nround (b0, b1, kp); | ||
347 | f_nround (b1, b0, kp); | ||
348 | f_nround (b0, b1, kp); | ||
349 | f_nround (b1, b0, kp); | ||
350 | f_nround (b0, b1, kp); | ||
351 | f_nround (b1, b0, kp); | ||
352 | f_nround (b0, b1, kp); | ||
353 | f_nround (b1, b0, kp); | ||
354 | f_lround (b0, b1, kp); | ||
355 | |||
356 | u32_out (out, b0[0]); | ||
357 | u32_out (out + 4, b0[1]); | ||
358 | u32_out (out + 8, b0[2]); | ||
359 | u32_out (out + 12, b0[3]); | ||
360 | } | ||
361 | |||
362 | /* decrypt a block of text */ | ||
363 | |||
364 | #define i_nround(bo, bi, k) \ | ||
365 | i_rn(bo, bi, 0, k); \ | ||
366 | i_rn(bo, bi, 1, k); \ | ||
367 | i_rn(bo, bi, 2, k); \ | ||
368 | i_rn(bo, bi, 3, k); \ | ||
369 | k -= 4 | ||
370 | |||
371 | #define i_lround(bo, bi, k) \ | ||
372 | i_rl(bo, bi, 0, k); \ | ||
373 | i_rl(bo, bi, 1, k); \ | ||
374 | i_rl(bo, bi, 2, k); \ | ||
375 | i_rl(bo, bi, 3, k) | ||
376 | |||
377 | static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in) | ||
378 | { | ||
379 | const struct aes_ctx *ctx = ctx_arg; | ||
380 | u32 b0[4], b1[4]; | ||
381 | const int key_len = ctx->key_length; | ||
382 | const u32 *kp = D_KEY + key_len + 20; | ||
383 | |||
384 | b0[0] = u32_in (in) ^ E_KEY[key_len + 24]; | ||
385 | b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25]; | ||
386 | b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26]; | ||
387 | b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27]; | ||
388 | |||
389 | if (key_len > 24) { | ||
390 | i_nround (b1, b0, kp); | ||
391 | i_nround (b0, b1, kp); | ||
392 | } | ||
393 | |||
394 | if (key_len > 16) { | ||
395 | i_nround (b1, b0, kp); | ||
396 | i_nround (b0, b1, kp); | ||
397 | } | ||
398 | |||
399 | i_nround (b1, b0, kp); | ||
400 | i_nround (b0, b1, kp); | ||
401 | i_nround (b1, b0, kp); | ||
402 | i_nround (b0, b1, kp); | ||
403 | i_nround (b1, b0, kp); | ||
404 | i_nround (b0, b1, kp); | ||
405 | i_nround (b1, b0, kp); | ||
406 | i_nround (b0, b1, kp); | ||
407 | i_nround (b1, b0, kp); | ||
408 | i_lround (b0, b1, kp); | ||
409 | |||
410 | u32_out (out, b0[0]); | ||
411 | u32_out (out + 4, b0[1]); | ||
412 | u32_out (out + 8, b0[2]); | ||
413 | u32_out (out + 12, b0[3]); | ||
414 | } | ||
415 | |||
416 | |||
417 | static struct crypto_alg aes_alg = { | ||
418 | .cra_name = "aes", | ||
419 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, | ||
420 | .cra_blocksize = AES_BLOCK_SIZE, | ||
421 | .cra_ctxsize = sizeof(struct aes_ctx), | ||
422 | .cra_module = THIS_MODULE, | ||
423 | .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), | ||
424 | .cra_u = { | ||
425 | .cipher = { | ||
426 | .cia_min_keysize = AES_MIN_KEY_SIZE, | ||
427 | .cia_max_keysize = AES_MAX_KEY_SIZE, | ||
428 | .cia_setkey = aes_set_key, | ||
429 | .cia_encrypt = aes_encrypt, | ||
430 | .cia_decrypt = aes_decrypt | ||
431 | } | ||
432 | } | ||
433 | }; | ||
434 | |||
435 | static int __init aes_init(void) | ||
436 | { | ||
437 | gen_tabs(); | ||
438 | return crypto_register_alg(&aes_alg); | ||
439 | } | ||
440 | |||
441 | static void __exit aes_fini(void) | ||
442 | { | ||
443 | crypto_unregister_alg(&aes_alg); | ||
444 | } | ||
445 | |||
446 | module_init(aes_init); | ||
447 | module_exit(aes_fini); | ||
448 | |||
449 | MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm"); | ||
450 | MODULE_LICENSE("Dual BSD/GPL"); | ||
451 | |||