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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 | ||
89e12654 | 55 | #include <crypto/aes.h> |
1da177e4 LT |
56 | #include <linux/module.h> |
57 | #include <linux/init.h> | |
58 | #include <linux/types.h> | |
59 | #include <linux/errno.h> | |
60 | #include <linux/crypto.h> | |
61 | #include <asm/byteorder.h> | |
62 | ||
1da177e4 LT |
63 | /* |
64 | * #define byte(x, nr) ((unsigned char)((x) >> (nr*8))) | |
65 | */ | |
77933d72 | 66 | static inline u8 |
1da177e4 LT |
67 | byte(const u32 x, const unsigned n) |
68 | { | |
69 | return x >> (n << 3); | |
70 | } | |
71 | ||
1da177e4 LT |
72 | struct aes_ctx { |
73 | int key_length; | |
55e9dce3 | 74 | u32 buf[120]; |
1da177e4 LT |
75 | }; |
76 | ||
55e9dce3 DM |
77 | #define E_KEY (&ctx->buf[0]) |
78 | #define D_KEY (&ctx->buf[60]) | |
1da177e4 LT |
79 | |
80 | static u8 pow_tab[256] __initdata; | |
81 | static u8 log_tab[256] __initdata; | |
82 | static u8 sbx_tab[256] __initdata; | |
83 | static u8 isb_tab[256] __initdata; | |
84 | static u32 rco_tab[10]; | |
85 | static u32 ft_tab[4][256]; | |
86 | static u32 it_tab[4][256]; | |
87 | ||
88 | static u32 fl_tab[4][256]; | |
89 | static u32 il_tab[4][256]; | |
90 | ||
91 | static inline u8 __init | |
92 | f_mult (u8 a, u8 b) | |
93 | { | |
94 | u8 aa = log_tab[a], cc = aa + log_tab[b]; | |
95 | ||
96 | return pow_tab[cc + (cc < aa ? 1 : 0)]; | |
97 | } | |
98 | ||
99 | #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0) | |
100 | ||
101 | #define f_rn(bo, bi, n, k) \ | |
102 | bo[n] = ft_tab[0][byte(bi[n],0)] ^ \ | |
103 | ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ | |
104 | ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | |
105 | ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) | |
106 | ||
107 | #define i_rn(bo, bi, n, k) \ | |
108 | bo[n] = it_tab[0][byte(bi[n],0)] ^ \ | |
109 | it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ | |
110 | it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | |
111 | it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) | |
112 | ||
113 | #define ls_box(x) \ | |
114 | ( fl_tab[0][byte(x, 0)] ^ \ | |
115 | fl_tab[1][byte(x, 1)] ^ \ | |
116 | fl_tab[2][byte(x, 2)] ^ \ | |
117 | fl_tab[3][byte(x, 3)] ) | |
118 | ||
119 | #define f_rl(bo, bi, n, k) \ | |
120 | bo[n] = fl_tab[0][byte(bi[n],0)] ^ \ | |
121 | fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \ | |
122 | fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | |
123 | fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n) | |
124 | ||
125 | #define i_rl(bo, bi, n, k) \ | |
126 | bo[n] = il_tab[0][byte(bi[n],0)] ^ \ | |
127 | il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \ | |
128 | il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \ | |
129 | il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n) | |
130 | ||
131 | static void __init | |
132 | gen_tabs (void) | |
133 | { | |
134 | u32 i, t; | |
135 | u8 p, q; | |
136 | ||
137 | /* log and power tables for GF(2**8) finite field with | |
138 | 0x011b as modular polynomial - the simplest primitive | |
139 | root is 0x03, used here to generate the tables */ | |
140 | ||
141 | for (i = 0, p = 1; i < 256; ++i) { | |
142 | pow_tab[i] = (u8) p; | |
143 | log_tab[p] = (u8) i; | |
144 | ||
145 | p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); | |
146 | } | |
147 | ||
148 | log_tab[1] = 0; | |
149 | ||
150 | for (i = 0, p = 1; i < 10; ++i) { | |
151 | rco_tab[i] = p; | |
152 | ||
153 | p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); | |
154 | } | |
155 | ||
156 | for (i = 0; i < 256; ++i) { | |
157 | p = (i ? pow_tab[255 - log_tab[i]] : 0); | |
158 | q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); | |
159 | p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); | |
160 | sbx_tab[i] = p; | |
161 | isb_tab[p] = (u8) i; | |
162 | } | |
163 | ||
164 | for (i = 0; i < 256; ++i) { | |
165 | p = sbx_tab[i]; | |
166 | ||
167 | t = p; | |
168 | fl_tab[0][i] = t; | |
169 | fl_tab[1][i] = rol32(t, 8); | |
170 | fl_tab[2][i] = rol32(t, 16); | |
171 | fl_tab[3][i] = rol32(t, 24); | |
172 | ||
173 | t = ((u32) ff_mult (2, p)) | | |
174 | ((u32) p << 8) | | |
175 | ((u32) p << 16) | ((u32) ff_mult (3, p) << 24); | |
176 | ||
177 | ft_tab[0][i] = t; | |
178 | ft_tab[1][i] = rol32(t, 8); | |
179 | ft_tab[2][i] = rol32(t, 16); | |
180 | ft_tab[3][i] = rol32(t, 24); | |
181 | ||
182 | p = isb_tab[i]; | |
183 | ||
184 | t = p; | |
185 | il_tab[0][i] = t; | |
186 | il_tab[1][i] = rol32(t, 8); | |
187 | il_tab[2][i] = rol32(t, 16); | |
188 | il_tab[3][i] = rol32(t, 24); | |
189 | ||
190 | t = ((u32) ff_mult (14, p)) | | |
191 | ((u32) ff_mult (9, p) << 8) | | |
192 | ((u32) ff_mult (13, p) << 16) | | |
193 | ((u32) ff_mult (11, p) << 24); | |
194 | ||
195 | it_tab[0][i] = t; | |
196 | it_tab[1][i] = rol32(t, 8); | |
197 | it_tab[2][i] = rol32(t, 16); | |
198 | it_tab[3][i] = rol32(t, 24); | |
199 | } | |
200 | } | |
201 | ||
202 | #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) | |
203 | ||
204 | #define imix_col(y,x) \ | |
205 | u = star_x(x); \ | |
206 | v = star_x(u); \ | |
207 | w = star_x(v); \ | |
208 | t = w ^ (x); \ | |
209 | (y) = u ^ v ^ w; \ | |
210 | (y) ^= ror32(u ^ t, 8) ^ \ | |
211 | ror32(v ^ t, 16) ^ \ | |
212 | ror32(t,24) | |
213 | ||
214 | /* initialise the key schedule from the user supplied key */ | |
215 | ||
216 | #define loop4(i) \ | |
217 | { t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ | |
218 | t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \ | |
219 | t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \ | |
220 | t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \ | |
221 | t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \ | |
222 | } | |
223 | ||
224 | #define loop6(i) \ | |
225 | { t = ror32(t, 8); t = ls_box(t) ^ rco_tab[i]; \ | |
226 | t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \ | |
227 | t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \ | |
228 | t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \ | |
229 | t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \ | |
230 | t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \ | |
231 | t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \ | |
232 | } | |
233 | ||
234 | #define loop8(i) \ | |
235 | { t = ror32(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \ | |
236 | t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \ | |
237 | t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \ | |
238 | t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \ | |
239 | t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \ | |
240 | t = E_KEY[8 * i + 4] ^ ls_box(t); \ | |
241 | E_KEY[8 * i + 12] = t; \ | |
242 | t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \ | |
243 | t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \ | |
244 | t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \ | |
245 | } | |
246 | ||
6c2bb98b | 247 | static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key, |
560c06ae | 248 | unsigned int key_len) |
1da177e4 | 249 | { |
6c2bb98b | 250 | struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 | 251 | const __le32 *key = (const __le32 *)in_key; |
560c06ae | 252 | u32 *flags = &tfm->crt_flags; |
1da177e4 LT |
253 | u32 i, t, u, v, w; |
254 | ||
560c06ae | 255 | if (key_len % 8) { |
1da177e4 LT |
256 | *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; |
257 | return -EINVAL; | |
258 | } | |
259 | ||
260 | ctx->key_length = key_len; | |
261 | ||
06ace7a9 HX |
262 | E_KEY[0] = le32_to_cpu(key[0]); |
263 | E_KEY[1] = le32_to_cpu(key[1]); | |
264 | E_KEY[2] = le32_to_cpu(key[2]); | |
265 | E_KEY[3] = le32_to_cpu(key[3]); | |
1da177e4 LT |
266 | |
267 | switch (key_len) { | |
268 | case 16: | |
269 | t = E_KEY[3]; | |
270 | for (i = 0; i < 10; ++i) | |
271 | loop4 (i); | |
272 | break; | |
273 | ||
274 | case 24: | |
06ace7a9 HX |
275 | E_KEY[4] = le32_to_cpu(key[4]); |
276 | t = E_KEY[5] = le32_to_cpu(key[5]); | |
1da177e4 LT |
277 | for (i = 0; i < 8; ++i) |
278 | loop6 (i); | |
279 | break; | |
280 | ||
281 | case 32: | |
06ace7a9 HX |
282 | E_KEY[4] = le32_to_cpu(key[4]); |
283 | E_KEY[5] = le32_to_cpu(key[5]); | |
284 | E_KEY[6] = le32_to_cpu(key[6]); | |
285 | t = E_KEY[7] = le32_to_cpu(key[7]); | |
1da177e4 LT |
286 | for (i = 0; i < 7; ++i) |
287 | loop8 (i); | |
288 | break; | |
289 | } | |
290 | ||
291 | D_KEY[0] = E_KEY[0]; | |
292 | D_KEY[1] = E_KEY[1]; | |
293 | D_KEY[2] = E_KEY[2]; | |
294 | D_KEY[3] = E_KEY[3]; | |
295 | ||
296 | for (i = 4; i < key_len + 24; ++i) { | |
297 | imix_col (D_KEY[i], E_KEY[i]); | |
298 | } | |
299 | ||
300 | return 0; | |
301 | } | |
302 | ||
303 | /* encrypt a block of text */ | |
304 | ||
305 | #define f_nround(bo, bi, k) \ | |
306 | f_rn(bo, bi, 0, k); \ | |
307 | f_rn(bo, bi, 1, k); \ | |
308 | f_rn(bo, bi, 2, k); \ | |
309 | f_rn(bo, bi, 3, k); \ | |
310 | k += 4 | |
311 | ||
312 | #define f_lround(bo, bi, k) \ | |
313 | f_rl(bo, bi, 0, k); \ | |
314 | f_rl(bo, bi, 1, k); \ | |
315 | f_rl(bo, bi, 2, k); \ | |
316 | f_rl(bo, bi, 3, k) | |
317 | ||
6c2bb98b | 318 | static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
1da177e4 | 319 | { |
6c2bb98b | 320 | const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 HX |
321 | const __le32 *src = (const __le32 *)in; |
322 | __le32 *dst = (__le32 *)out; | |
1da177e4 LT |
323 | u32 b0[4], b1[4]; |
324 | const u32 *kp = E_KEY + 4; | |
325 | ||
06ace7a9 HX |
326 | b0[0] = le32_to_cpu(src[0]) ^ E_KEY[0]; |
327 | b0[1] = le32_to_cpu(src[1]) ^ E_KEY[1]; | |
328 | b0[2] = le32_to_cpu(src[2]) ^ E_KEY[2]; | |
329 | b0[3] = le32_to_cpu(src[3]) ^ E_KEY[3]; | |
1da177e4 LT |
330 | |
331 | if (ctx->key_length > 24) { | |
332 | f_nround (b1, b0, kp); | |
333 | f_nround (b0, b1, kp); | |
334 | } | |
335 | ||
336 | if (ctx->key_length > 16) { | |
337 | f_nround (b1, b0, kp); | |
338 | f_nround (b0, b1, kp); | |
339 | } | |
340 | ||
341 | f_nround (b1, b0, kp); | |
342 | f_nround (b0, b1, kp); | |
343 | f_nround (b1, b0, kp); | |
344 | f_nround (b0, b1, kp); | |
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_lround (b0, b1, kp); | |
351 | ||
06ace7a9 HX |
352 | dst[0] = cpu_to_le32(b0[0]); |
353 | dst[1] = cpu_to_le32(b0[1]); | |
354 | dst[2] = cpu_to_le32(b0[2]); | |
355 | dst[3] = cpu_to_le32(b0[3]); | |
1da177e4 LT |
356 | } |
357 | ||
358 | /* decrypt a block of text */ | |
359 | ||
360 | #define i_nround(bo, bi, k) \ | |
361 | i_rn(bo, bi, 0, k); \ | |
362 | i_rn(bo, bi, 1, k); \ | |
363 | i_rn(bo, bi, 2, k); \ | |
364 | i_rn(bo, bi, 3, k); \ | |
365 | k -= 4 | |
366 | ||
367 | #define i_lround(bo, bi, k) \ | |
368 | i_rl(bo, bi, 0, k); \ | |
369 | i_rl(bo, bi, 1, k); \ | |
370 | i_rl(bo, bi, 2, k); \ | |
371 | i_rl(bo, bi, 3, k) | |
372 | ||
6c2bb98b | 373 | static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
1da177e4 | 374 | { |
6c2bb98b | 375 | const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 HX |
376 | const __le32 *src = (const __le32 *)in; |
377 | __le32 *dst = (__le32 *)out; | |
1da177e4 LT |
378 | u32 b0[4], b1[4]; |
379 | const int key_len = ctx->key_length; | |
380 | const u32 *kp = D_KEY + key_len + 20; | |
381 | ||
06ace7a9 HX |
382 | b0[0] = le32_to_cpu(src[0]) ^ E_KEY[key_len + 24]; |
383 | b0[1] = le32_to_cpu(src[1]) ^ E_KEY[key_len + 25]; | |
384 | b0[2] = le32_to_cpu(src[2]) ^ E_KEY[key_len + 26]; | |
385 | b0[3] = le32_to_cpu(src[3]) ^ E_KEY[key_len + 27]; | |
1da177e4 LT |
386 | |
387 | if (key_len > 24) { | |
388 | i_nround (b1, b0, kp); | |
389 | i_nround (b0, b1, kp); | |
390 | } | |
391 | ||
392 | if (key_len > 16) { | |
393 | i_nround (b1, b0, kp); | |
394 | i_nround (b0, b1, kp); | |
395 | } | |
396 | ||
397 | i_nround (b1, b0, kp); | |
398 | i_nround (b0, b1, kp); | |
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_lround (b0, b1, kp); | |
407 | ||
06ace7a9 HX |
408 | dst[0] = cpu_to_le32(b0[0]); |
409 | dst[1] = cpu_to_le32(b0[1]); | |
410 | dst[2] = cpu_to_le32(b0[2]); | |
411 | dst[3] = cpu_to_le32(b0[3]); | |
1da177e4 LT |
412 | } |
413 | ||
414 | ||
415 | static struct crypto_alg aes_alg = { | |
416 | .cra_name = "aes", | |
c8a19c91 HX |
417 | .cra_driver_name = "aes-generic", |
418 | .cra_priority = 100, | |
1da177e4 LT |
419 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
420 | .cra_blocksize = AES_BLOCK_SIZE, | |
421 | .cra_ctxsize = sizeof(struct aes_ctx), | |
a429d260 | 422 | .cra_alignmask = 3, |
1da177e4 LT |
423 | .cra_module = THIS_MODULE, |
424 | .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), | |
425 | .cra_u = { | |
426 | .cipher = { | |
427 | .cia_min_keysize = AES_MIN_KEY_SIZE, | |
428 | .cia_max_keysize = AES_MAX_KEY_SIZE, | |
429 | .cia_setkey = aes_set_key, | |
430 | .cia_encrypt = aes_encrypt, | |
431 | .cia_decrypt = aes_decrypt | |
432 | } | |
433 | } | |
434 | }; | |
435 | ||
436 | static int __init aes_init(void) | |
437 | { | |
438 | gen_tabs(); | |
439 | return crypto_register_alg(&aes_alg); | |
440 | } | |
441 | ||
442 | static void __exit aes_fini(void) | |
443 | { | |
444 | crypto_unregister_alg(&aes_alg); | |
445 | } | |
446 | ||
447 | module_init(aes_init); | |
448 | module_exit(aes_fini); | |
449 | ||
450 | MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm"); | |
451 | MODULE_LICENSE("Dual BSD/GPL"); | |
f8246af0 | 452 | MODULE_ALIAS("aes"); |