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1da177e4 LT |
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 | */ | |
77933d72 | 70 | static inline u8 |
1da177e4 LT |
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 |