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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 | */ | |
be5fb270 | 66 | static inline u8 byte(const u32 x, const unsigned n) |
1da177e4 LT |
67 | { |
68 | return x >> (n << 3); | |
69 | } | |
70 | ||
1da177e4 LT |
71 | struct aes_ctx { |
72 | int key_length; | |
55e9dce3 | 73 | u32 buf[120]; |
1da177e4 LT |
74 | }; |
75 | ||
55e9dce3 DM |
76 | #define E_KEY (&ctx->buf[0]) |
77 | #define D_KEY (&ctx->buf[60]) | |
1da177e4 LT |
78 | |
79 | static u8 pow_tab[256] __initdata; | |
80 | static u8 log_tab[256] __initdata; | |
81 | static u8 sbx_tab[256] __initdata; | |
82 | static u8 isb_tab[256] __initdata; | |
83 | static u32 rco_tab[10]; | |
84 | static u32 ft_tab[4][256]; | |
85 | static u32 it_tab[4][256]; | |
86 | ||
87 | static u32 fl_tab[4][256]; | |
88 | static u32 il_tab[4][256]; | |
89 | ||
be5fb270 | 90 | static inline u8 __init f_mult(u8 a, u8 b) |
1da177e4 LT |
91 | { |
92 | u8 aa = log_tab[a], cc = aa + log_tab[b]; | |
93 | ||
94 | return pow_tab[cc + (cc < aa ? 1 : 0)]; | |
95 | } | |
96 | ||
be5fb270 SS |
97 | #define ff_mult(a, b) (a && b ? f_mult(a, b) : 0) |
98 | ||
99 | static void __init gen_tabs(void) | |
1da177e4 LT |
100 | { |
101 | u32 i, t; | |
102 | u8 p, q; | |
103 | ||
be5fb270 SS |
104 | /* |
105 | * log and power tables for GF(2**8) finite field with | |
106 | * 0x011b as modular polynomial - the simplest primitive | |
107 | * root is 0x03, used here to generate the tables | |
108 | */ | |
1da177e4 LT |
109 | |
110 | for (i = 0, p = 1; i < 256; ++i) { | |
111 | pow_tab[i] = (u8) p; | |
112 | log_tab[p] = (u8) i; | |
113 | ||
114 | p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0); | |
115 | } | |
116 | ||
117 | log_tab[1] = 0; | |
118 | ||
119 | for (i = 0, p = 1; i < 10; ++i) { | |
120 | rco_tab[i] = p; | |
121 | ||
122 | p = (p << 1) ^ (p & 0x80 ? 0x01b : 0); | |
123 | } | |
124 | ||
125 | for (i = 0; i < 256; ++i) { | |
126 | p = (i ? pow_tab[255 - log_tab[i]] : 0); | |
127 | q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2)); | |
128 | p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2)); | |
129 | sbx_tab[i] = p; | |
130 | isb_tab[p] = (u8) i; | |
131 | } | |
132 | ||
133 | for (i = 0; i < 256; ++i) { | |
134 | p = sbx_tab[i]; | |
135 | ||
136 | t = p; | |
137 | fl_tab[0][i] = t; | |
138 | fl_tab[1][i] = rol32(t, 8); | |
139 | fl_tab[2][i] = rol32(t, 16); | |
140 | fl_tab[3][i] = rol32(t, 24); | |
141 | ||
be5fb270 | 142 | t = ((u32) ff_mult(2, p)) | |
1da177e4 | 143 | ((u32) p << 8) | |
be5fb270 | 144 | ((u32) p << 16) | ((u32) ff_mult(3, p) << 24); |
1da177e4 LT |
145 | |
146 | ft_tab[0][i] = t; | |
147 | ft_tab[1][i] = rol32(t, 8); | |
148 | ft_tab[2][i] = rol32(t, 16); | |
149 | ft_tab[3][i] = rol32(t, 24); | |
150 | ||
151 | p = isb_tab[i]; | |
152 | ||
153 | t = p; | |
154 | il_tab[0][i] = t; | |
155 | il_tab[1][i] = rol32(t, 8); | |
156 | il_tab[2][i] = rol32(t, 16); | |
157 | il_tab[3][i] = rol32(t, 24); | |
158 | ||
be5fb270 SS |
159 | t = ((u32) ff_mult(14, p)) | |
160 | ((u32) ff_mult(9, p) << 8) | | |
161 | ((u32) ff_mult(13, p) << 16) | | |
162 | ((u32) ff_mult(11, p) << 24); | |
1da177e4 LT |
163 | |
164 | it_tab[0][i] = t; | |
165 | it_tab[1][i] = rol32(t, 8); | |
166 | it_tab[2][i] = rol32(t, 16); | |
167 | it_tab[3][i] = rol32(t, 24); | |
168 | } | |
169 | } | |
170 | ||
1da177e4 LT |
171 | /* initialise the key schedule from the user supplied key */ |
172 | ||
be5fb270 | 173 | #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b) |
1da177e4 | 174 | |
be5fb270 SS |
175 | #define imix_col(y,x) do { \ |
176 | u = star_x(x); \ | |
177 | v = star_x(u); \ | |
178 | w = star_x(v); \ | |
179 | t = w ^ (x); \ | |
180 | (y) = u ^ v ^ w; \ | |
181 | (y) ^= ror32(u ^ t, 8) ^ \ | |
182 | ror32(v ^ t, 16) ^ \ | |
183 | ror32(t, 24); \ | |
184 | } while (0) | |
185 | ||
186 | #define ls_box(x) \ | |
187 | fl_tab[0][byte(x, 0)] ^ \ | |
188 | fl_tab[1][byte(x, 1)] ^ \ | |
189 | fl_tab[2][byte(x, 2)] ^ \ | |
190 | fl_tab[3][byte(x, 3)] | |
191 | ||
192 | #define loop4(i) do { \ | |
193 | t = ror32(t, 8); \ | |
194 | t = ls_box(t) ^ rco_tab[i]; \ | |
195 | t ^= E_KEY[4 * i]; \ | |
196 | E_KEY[4 * i + 4] = t; \ | |
197 | t ^= E_KEY[4 * i + 1]; \ | |
198 | E_KEY[4 * i + 5] = t; \ | |
199 | t ^= E_KEY[4 * i + 2]; \ | |
200 | E_KEY[4 * i + 6] = t; \ | |
201 | t ^= E_KEY[4 * i + 3]; \ | |
202 | E_KEY[4 * i + 7] = t; \ | |
203 | } while (0) | |
204 | ||
205 | #define loop6(i) do { \ | |
206 | t = ror32(t, 8); \ | |
207 | t = ls_box(t) ^ rco_tab[i]; \ | |
208 | t ^= E_KEY[6 * i]; \ | |
209 | E_KEY[6 * i + 6] = t; \ | |
210 | t ^= E_KEY[6 * i + 1]; \ | |
211 | E_KEY[6 * i + 7] = t; \ | |
212 | t ^= E_KEY[6 * i + 2]; \ | |
213 | E_KEY[6 * i + 8] = t; \ | |
214 | t ^= E_KEY[6 * i + 3]; \ | |
215 | E_KEY[6 * i + 9] = t; \ | |
216 | t ^= E_KEY[6 * i + 4]; \ | |
217 | E_KEY[6 * i + 10] = t; \ | |
218 | t ^= E_KEY[6 * i + 5]; \ | |
219 | E_KEY[6 * i + 11] = t; \ | |
220 | } while (0) | |
221 | ||
222 | #define loop8(i) do { \ | |
223 | t = ror32(t, 8); \ | |
224 | t = ls_box(t) ^ rco_tab[i]; \ | |
225 | t ^= E_KEY[8 * i]; \ | |
226 | E_KEY[8 * i + 8] = t; \ | |
227 | t ^= E_KEY[8 * i + 1]; \ | |
228 | E_KEY[8 * i + 9] = t; \ | |
229 | t ^= E_KEY[8 * i + 2]; \ | |
230 | E_KEY[8 * i + 10] = t; \ | |
231 | t ^= E_KEY[8 * i + 3]; \ | |
232 | E_KEY[8 * i + 11] = t; \ | |
233 | t = E_KEY[8 * i + 4] ^ ls_box(t); \ | |
234 | E_KEY[8 * i + 12] = t; \ | |
235 | t ^= E_KEY[8 * i + 5]; \ | |
236 | E_KEY[8 * i + 13] = t; \ | |
237 | t ^= E_KEY[8 * i + 6]; \ | |
238 | E_KEY[8 * i + 14] = t; \ | |
239 | t ^= E_KEY[8 * i + 7]; \ | |
240 | E_KEY[8 * i + 15] = t; \ | |
241 | } while (0) | |
1da177e4 | 242 | |
6c2bb98b | 243 | static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key, |
be5fb270 | 244 | unsigned int key_len) |
1da177e4 | 245 | { |
6c2bb98b | 246 | struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 | 247 | const __le32 *key = (const __le32 *)in_key; |
560c06ae | 248 | u32 *flags = &tfm->crt_flags; |
1da177e4 LT |
249 | u32 i, t, u, v, w; |
250 | ||
560c06ae | 251 | if (key_len % 8) { |
1da177e4 LT |
252 | *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; |
253 | return -EINVAL; | |
254 | } | |
255 | ||
256 | ctx->key_length = key_len; | |
257 | ||
06ace7a9 HX |
258 | E_KEY[0] = le32_to_cpu(key[0]); |
259 | E_KEY[1] = le32_to_cpu(key[1]); | |
260 | E_KEY[2] = le32_to_cpu(key[2]); | |
261 | E_KEY[3] = le32_to_cpu(key[3]); | |
1da177e4 LT |
262 | |
263 | switch (key_len) { | |
264 | case 16: | |
265 | t = E_KEY[3]; | |
266 | for (i = 0; i < 10; ++i) | |
be5fb270 | 267 | loop4(i); |
1da177e4 LT |
268 | break; |
269 | ||
270 | case 24: | |
06ace7a9 HX |
271 | E_KEY[4] = le32_to_cpu(key[4]); |
272 | t = E_KEY[5] = le32_to_cpu(key[5]); | |
1da177e4 | 273 | for (i = 0; i < 8; ++i) |
be5fb270 | 274 | loop6(i); |
1da177e4 LT |
275 | break; |
276 | ||
277 | case 32: | |
06ace7a9 HX |
278 | E_KEY[4] = le32_to_cpu(key[4]); |
279 | E_KEY[5] = le32_to_cpu(key[5]); | |
280 | E_KEY[6] = le32_to_cpu(key[6]); | |
281 | t = E_KEY[7] = le32_to_cpu(key[7]); | |
1da177e4 | 282 | for (i = 0; i < 7; ++i) |
be5fb270 | 283 | loop8(i); |
1da177e4 LT |
284 | break; |
285 | } | |
286 | ||
287 | D_KEY[0] = E_KEY[0]; | |
288 | D_KEY[1] = E_KEY[1]; | |
289 | D_KEY[2] = E_KEY[2]; | |
290 | D_KEY[3] = E_KEY[3]; | |
291 | ||
292 | for (i = 4; i < key_len + 24; ++i) { | |
be5fb270 | 293 | imix_col(D_KEY[i], E_KEY[i]); |
1da177e4 LT |
294 | } |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | /* encrypt a block of text */ | |
300 | ||
be5fb270 SS |
301 | #define f_rn(bo, bi, n, k) do { \ |
302 | bo[n] = ft_tab[0][byte(bi[n], 0)] ^ \ | |
303 | ft_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \ | |
304 | ft_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \ | |
305 | ft_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \ | |
306 | } while (0) | |
307 | ||
308 | #define f_nround(bo, bi, k) do {\ | |
309 | f_rn(bo, bi, 0, k); \ | |
310 | f_rn(bo, bi, 1, k); \ | |
311 | f_rn(bo, bi, 2, k); \ | |
312 | f_rn(bo, bi, 3, k); \ | |
313 | k += 4; \ | |
314 | } while (0) | |
315 | ||
316 | #define f_rl(bo, bi, n, k) do { \ | |
317 | bo[n] = fl_tab[0][byte(bi[n], 0)] ^ \ | |
318 | fl_tab[1][byte(bi[(n + 1) & 3], 1)] ^ \ | |
319 | fl_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \ | |
320 | fl_tab[3][byte(bi[(n + 3) & 3], 3)] ^ *(k + n); \ | |
321 | } while (0) | |
322 | ||
323 | #define f_lround(bo, bi, k) do {\ | |
324 | f_rl(bo, bi, 0, k); \ | |
325 | f_rl(bo, bi, 1, k); \ | |
326 | f_rl(bo, bi, 2, k); \ | |
327 | f_rl(bo, bi, 3, k); \ | |
328 | } while (0) | |
1da177e4 | 329 | |
6c2bb98b | 330 | static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
1da177e4 | 331 | { |
6c2bb98b | 332 | const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 HX |
333 | const __le32 *src = (const __le32 *)in; |
334 | __le32 *dst = (__le32 *)out; | |
1da177e4 LT |
335 | u32 b0[4], b1[4]; |
336 | const u32 *kp = E_KEY + 4; | |
337 | ||
06ace7a9 HX |
338 | b0[0] = le32_to_cpu(src[0]) ^ E_KEY[0]; |
339 | b0[1] = le32_to_cpu(src[1]) ^ E_KEY[1]; | |
340 | b0[2] = le32_to_cpu(src[2]) ^ E_KEY[2]; | |
341 | b0[3] = le32_to_cpu(src[3]) ^ E_KEY[3]; | |
1da177e4 LT |
342 | |
343 | if (ctx->key_length > 24) { | |
be5fb270 SS |
344 | f_nround(b1, b0, kp); |
345 | f_nround(b0, b1, kp); | |
1da177e4 LT |
346 | } |
347 | ||
348 | if (ctx->key_length > 16) { | |
be5fb270 SS |
349 | f_nround(b1, b0, kp); |
350 | f_nround(b0, b1, kp); | |
1da177e4 LT |
351 | } |
352 | ||
be5fb270 SS |
353 | f_nround(b1, b0, kp); |
354 | f_nround(b0, b1, kp); | |
355 | f_nround(b1, b0, kp); | |
356 | f_nround(b0, b1, kp); | |
357 | f_nround(b1, b0, kp); | |
358 | f_nround(b0, b1, kp); | |
359 | f_nround(b1, b0, kp); | |
360 | f_nround(b0, b1, kp); | |
361 | f_nround(b1, b0, kp); | |
362 | f_lround(b0, b1, kp); | |
1da177e4 | 363 | |
06ace7a9 HX |
364 | dst[0] = cpu_to_le32(b0[0]); |
365 | dst[1] = cpu_to_le32(b0[1]); | |
366 | dst[2] = cpu_to_le32(b0[2]); | |
367 | dst[3] = cpu_to_le32(b0[3]); | |
1da177e4 LT |
368 | } |
369 | ||
370 | /* decrypt a block of text */ | |
371 | ||
be5fb270 SS |
372 | #define i_rn(bo, bi, n, k) do { \ |
373 | bo[n] = it_tab[0][byte(bi[n], 0)] ^ \ | |
374 | it_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \ | |
375 | it_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \ | |
376 | it_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \ | |
377 | } while (0) | |
378 | ||
379 | #define i_nround(bo, bi, k) do {\ | |
380 | i_rn(bo, bi, 0, k); \ | |
381 | i_rn(bo, bi, 1, k); \ | |
382 | i_rn(bo, bi, 2, k); \ | |
383 | i_rn(bo, bi, 3, k); \ | |
384 | k -= 4; \ | |
385 | } while (0) | |
386 | ||
387 | #define i_rl(bo, bi, n, k) do { \ | |
388 | bo[n] = il_tab[0][byte(bi[n], 0)] ^ \ | |
389 | il_tab[1][byte(bi[(n + 3) & 3], 1)] ^ \ | |
390 | il_tab[2][byte(bi[(n + 2) & 3], 2)] ^ \ | |
391 | il_tab[3][byte(bi[(n + 1) & 3], 3)] ^ *(k + n); \ | |
392 | } while (0) | |
393 | ||
394 | #define i_lround(bo, bi, k) do {\ | |
395 | i_rl(bo, bi, 0, k); \ | |
396 | i_rl(bo, bi, 1, k); \ | |
397 | i_rl(bo, bi, 2, k); \ | |
398 | i_rl(bo, bi, 3, k); \ | |
399 | } while (0) | |
1da177e4 | 400 | |
6c2bb98b | 401 | static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) |
1da177e4 | 402 | { |
6c2bb98b | 403 | const struct aes_ctx *ctx = crypto_tfm_ctx(tfm); |
06ace7a9 HX |
404 | const __le32 *src = (const __le32 *)in; |
405 | __le32 *dst = (__le32 *)out; | |
1da177e4 LT |
406 | u32 b0[4], b1[4]; |
407 | const int key_len = ctx->key_length; | |
408 | const u32 *kp = D_KEY + key_len + 20; | |
409 | ||
06ace7a9 HX |
410 | b0[0] = le32_to_cpu(src[0]) ^ E_KEY[key_len + 24]; |
411 | b0[1] = le32_to_cpu(src[1]) ^ E_KEY[key_len + 25]; | |
412 | b0[2] = le32_to_cpu(src[2]) ^ E_KEY[key_len + 26]; | |
413 | b0[3] = le32_to_cpu(src[3]) ^ E_KEY[key_len + 27]; | |
1da177e4 LT |
414 | |
415 | if (key_len > 24) { | |
be5fb270 SS |
416 | i_nround(b1, b0, kp); |
417 | i_nround(b0, b1, kp); | |
1da177e4 LT |
418 | } |
419 | ||
420 | if (key_len > 16) { | |
be5fb270 SS |
421 | i_nround(b1, b0, kp); |
422 | i_nround(b0, b1, kp); | |
1da177e4 LT |
423 | } |
424 | ||
be5fb270 SS |
425 | i_nround(b1, b0, kp); |
426 | i_nround(b0, b1, kp); | |
427 | i_nround(b1, b0, kp); | |
428 | i_nround(b0, b1, kp); | |
429 | i_nround(b1, b0, kp); | |
430 | i_nround(b0, b1, kp); | |
431 | i_nround(b1, b0, kp); | |
432 | i_nround(b0, b1, kp); | |
433 | i_nround(b1, b0, kp); | |
434 | i_lround(b0, b1, kp); | |
1da177e4 | 435 | |
06ace7a9 HX |
436 | dst[0] = cpu_to_le32(b0[0]); |
437 | dst[1] = cpu_to_le32(b0[1]); | |
438 | dst[2] = cpu_to_le32(b0[2]); | |
439 | dst[3] = cpu_to_le32(b0[3]); | |
1da177e4 LT |
440 | } |
441 | ||
1da177e4 LT |
442 | static struct crypto_alg aes_alg = { |
443 | .cra_name = "aes", | |
c8a19c91 HX |
444 | .cra_driver_name = "aes-generic", |
445 | .cra_priority = 100, | |
1da177e4 LT |
446 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, |
447 | .cra_blocksize = AES_BLOCK_SIZE, | |
448 | .cra_ctxsize = sizeof(struct aes_ctx), | |
a429d260 | 449 | .cra_alignmask = 3, |
1da177e4 LT |
450 | .cra_module = THIS_MODULE, |
451 | .cra_list = LIST_HEAD_INIT(aes_alg.cra_list), | |
452 | .cra_u = { | |
453 | .cipher = { | |
454 | .cia_min_keysize = AES_MIN_KEY_SIZE, | |
455 | .cia_max_keysize = AES_MAX_KEY_SIZE, | |
be5fb270 SS |
456 | .cia_setkey = aes_set_key, |
457 | .cia_encrypt = aes_encrypt, | |
458 | .cia_decrypt = aes_decrypt | |
1da177e4 LT |
459 | } |
460 | } | |
461 | }; | |
462 | ||
463 | static int __init aes_init(void) | |
464 | { | |
465 | gen_tabs(); | |
466 | return crypto_register_alg(&aes_alg); | |
467 | } | |
468 | ||
469 | static void __exit aes_fini(void) | |
470 | { | |
471 | crypto_unregister_alg(&aes_alg); | |
472 | } | |
473 | ||
474 | module_init(aes_init); | |
475 | module_exit(aes_fini); | |
476 | ||
477 | MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm"); | |
478 | MODULE_LICENSE("Dual BSD/GPL"); | |
f8246af0 | 479 | MODULE_ALIAS("aes"); |