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[CRYPTO] aes: Move common defines into a header file
[deliverable/linux.git] / crypto / aes_generic.c
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 <crypto/aes.h>
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
63 /*
64 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
65 */
66 static inline u8
67 byte(const u32 x, const unsigned n)
68 {
69 return x >> (n << 3);
70 }
71
72 struct aes_ctx {
73 int key_length;
74 u32 buf[120];
75 };
76
77 #define E_KEY (&ctx->buf[0])
78 #define D_KEY (&ctx->buf[60])
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
247 static int aes_set_key(struct crypto_tfm *tfm, const u8 *in_key,
248 unsigned int key_len)
249 {
250 struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
251 const __le32 *key = (const __le32 *)in_key;
252 u32 *flags = &tfm->crt_flags;
253 u32 i, t, u, v, w;
254
255 if (key_len % 8) {
256 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
257 return -EINVAL;
258 }
259
260 ctx->key_length = key_len;
261
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]);
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:
275 E_KEY[4] = le32_to_cpu(key[4]);
276 t = E_KEY[5] = le32_to_cpu(key[5]);
277 for (i = 0; i < 8; ++i)
278 loop6 (i);
279 break;
280
281 case 32:
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]);
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
318 static void aes_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
319 {
320 const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
321 const __le32 *src = (const __le32 *)in;
322 __le32 *dst = (__le32 *)out;
323 u32 b0[4], b1[4];
324 const u32 *kp = E_KEY + 4;
325
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];
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
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]);
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
373 static void aes_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
374 {
375 const struct aes_ctx *ctx = crypto_tfm_ctx(tfm);
376 const __le32 *src = (const __le32 *)in;
377 __le32 *dst = (__le32 *)out;
378 u32 b0[4], b1[4];
379 const int key_len = ctx->key_length;
380 const u32 *kp = D_KEY + key_len + 20;
381
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];
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
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]);
412 }
413
414
415 static struct crypto_alg aes_alg = {
416 .cra_name = "aes",
417 .cra_driver_name = "aes-generic",
418 .cra_priority = 100,
419 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
420 .cra_blocksize = AES_BLOCK_SIZE,
421 .cra_ctxsize = sizeof(struct aes_ctx),
422 .cra_alignmask = 3,
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");
452 MODULE_ALIAS("aes");
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