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 "rtl_crypto.h"
61 #include <asm/byteorder.h>
62
63 #define AES_MIN_KEY_SIZE 16
64 #define AES_MAX_KEY_SIZE 32
65
66 #define AES_BLOCK_SIZE 16
67
68 static inline
generic_rotr32(const u32 x,const unsigned bits)69 u32 generic_rotr32 (const u32 x, const unsigned bits)
70 {
71 const unsigned n = bits % 32;
72 return (x >> n) | (x << (32 - n));
73 }
74
75 static inline
generic_rotl32(const u32 x,const unsigned bits)76 u32 generic_rotl32 (const u32 x, const unsigned bits)
77 {
78 const unsigned n = bits % 32;
79 return (x << n) | (x >> (32 - n));
80 }
81
82 #define rotl generic_rotl32
83 #define rotr generic_rotr32
84
85 /*
86 * #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
87 */
88 inline static u8
byte(const u32 x,const unsigned n)89 byte(const u32 x, const unsigned n)
90 {
91 return x >> (n << 3);
92 }
93
94 #define u32_in(x) le32_to_cpu(*(const u32 *)(x))
95 #define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from))
96
97 struct aes_ctx {
98 int key_length;
99 u32 E[60];
100 u32 D[60];
101 };
102
103 #define E_KEY ctx->E
104 #define D_KEY ctx->D
105
106 static u8 pow_tab[256] __initdata;
107 static u8 log_tab[256] __initdata;
108 static u8 sbx_tab[256] __initdata;
109 static u8 isb_tab[256] __initdata;
110 static u32 rco_tab[10];
111 static u32 ft_tab[4][256];
112 static u32 it_tab[4][256];
113
114 static u32 fl_tab[4][256];
115 static u32 il_tab[4][256];
116
117 static inline u8 __init
f_mult(u8 a,u8 b)118 f_mult (u8 a, u8 b)
119 {
120 u8 aa = log_tab[a], cc = aa + log_tab[b];
121
122 return pow_tab[cc + (cc < aa ? 1 : 0)];
123 }
124
125 #define ff_mult(a,b) (a && b ? f_mult(a, b) : 0)
126
127 #define f_rn(bo, bi, n, k) \
128 bo[n] = ft_tab[0][byte(bi[n],0)] ^ \
129 ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
130 ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
131 ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
132
133 #define i_rn(bo, bi, n, k) \
134 bo[n] = it_tab[0][byte(bi[n],0)] ^ \
135 it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
136 it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
137 it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
138
139 #define ls_box(x) \
140 ( fl_tab[0][byte(x, 0)] ^ \
141 fl_tab[1][byte(x, 1)] ^ \
142 fl_tab[2][byte(x, 2)] ^ \
143 fl_tab[3][byte(x, 3)] )
144
145 #define f_rl(bo, bi, n, k) \
146 bo[n] = fl_tab[0][byte(bi[n],0)] ^ \
147 fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
148 fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
149 fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
150
151 #define i_rl(bo, bi, n, k) \
152 bo[n] = il_tab[0][byte(bi[n],0)] ^ \
153 il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
154 il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
155 il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
156
157 static void __init
gen_tabs(void)158 gen_tabs (void)
159 {
160 u32 i, t;
161 u8 p, q;
162
163 /* log and power tables for GF(2**8) finite field with
164 0x011b as modular polynomial - the simplest primitive
165 root is 0x03, used here to generate the tables */
166
167 for (i = 0, p = 1; i < 256; ++i) {
168 pow_tab[i] = (u8) p;
169 log_tab[p] = (u8) i;
170
171 p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
172 }
173
174 log_tab[1] = 0;
175
176 for (i = 0, p = 1; i < 10; ++i) {
177 rco_tab[i] = p;
178
179 p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
180 }
181
182 for (i = 0; i < 256; ++i) {
183 p = (i ? pow_tab[255 - log_tab[i]] : 0);
184 q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
185 p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
186 sbx_tab[i] = p;
187 isb_tab[p] = (u8) i;
188 }
189
190 for (i = 0; i < 256; ++i) {
191 p = sbx_tab[i];
192
193 t = p;
194 fl_tab[0][i] = t;
195 fl_tab[1][i] = rotl (t, 8);
196 fl_tab[2][i] = rotl (t, 16);
197 fl_tab[3][i] = rotl (t, 24);
198
199 t = ((u32) ff_mult (2, p)) |
200 ((u32) p << 8) |
201 ((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
202
203 ft_tab[0][i] = t;
204 ft_tab[1][i] = rotl (t, 8);
205 ft_tab[2][i] = rotl (t, 16);
206 ft_tab[3][i] = rotl (t, 24);
207
208 p = isb_tab[i];
209
210 t = p;
211 il_tab[0][i] = t;
212 il_tab[1][i] = rotl (t, 8);
213 il_tab[2][i] = rotl (t, 16);
214 il_tab[3][i] = rotl (t, 24);
215
216 t = ((u32) ff_mult (14, p)) |
217 ((u32) ff_mult (9, p) << 8) |
218 ((u32) ff_mult (13, p) << 16) |
219 ((u32) ff_mult (11, p) << 24);
220
221 it_tab[0][i] = t;
222 it_tab[1][i] = rotl (t, 8);
223 it_tab[2][i] = rotl (t, 16);
224 it_tab[3][i] = rotl (t, 24);
225 }
226 }
227
228 #define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
229
230 #define imix_col(y,x) \
231 u = star_x(x); \
232 v = star_x(u); \
233 w = star_x(v); \
234 t = w ^ (x); \
235 (y) = u ^ v ^ w; \
236 (y) ^= rotr(u ^ t, 8) ^ \
237 rotr(v ^ t, 16) ^ \
238 rotr(t,24)
239
240 /* initialise the key schedule from the user supplied key */
241
242 #define loop4(i) \
243 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \
244 t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
245 t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
246 t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
247 t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
248 }
249
250 #define loop6(i) \
251 { t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \
252 t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
253 t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
254 t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
255 t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
256 t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
257 t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
258 }
259
260 #define loop8(i) \
261 { t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
262 t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
263 t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
264 t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
265 t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
266 t = E_KEY[8 * i + 4] ^ ls_box(t); \
267 E_KEY[8 * i + 12] = t; \
268 t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
269 t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
270 t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
271 }
272
273 static int
aes_set_key(void * ctx_arg,const u8 * in_key,unsigned int key_len,u32 * flags)274 aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags)
275 {
276 struct aes_ctx *ctx = ctx_arg;
277 u32 i, t, u, v, w;
278
279 if (key_len != 16 && key_len != 24 && key_len != 32) {
280 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
281 return -EINVAL;
282 }
283
284 ctx->key_length = key_len;
285
286 E_KEY[0] = u32_in (in_key);
287 E_KEY[1] = u32_in (in_key + 4);
288 E_KEY[2] = u32_in (in_key + 8);
289 E_KEY[3] = u32_in (in_key + 12);
290
291 switch (key_len) {
292 case 16:
293 t = E_KEY[3];
294 for (i = 0; i < 10; ++i)
295 loop4 (i);
296 break;
297
298 case 24:
299 E_KEY[4] = u32_in (in_key + 16);
300 t = E_KEY[5] = u32_in (in_key + 20);
301 for (i = 0; i < 8; ++i)
302 loop6 (i);
303 break;
304
305 case 32:
306 E_KEY[4] = u32_in (in_key + 16);
307 E_KEY[5] = u32_in (in_key + 20);
308 E_KEY[6] = u32_in (in_key + 24);
309 t = E_KEY[7] = u32_in (in_key + 28);
310 for (i = 0; i < 7; ++i)
311 loop8 (i);
312 break;
313 }
314
315 D_KEY[0] = E_KEY[0];
316 D_KEY[1] = E_KEY[1];
317 D_KEY[2] = E_KEY[2];
318 D_KEY[3] = E_KEY[3];
319
320 for (i = 4; i < key_len + 24; ++i) {
321 imix_col (D_KEY[i], E_KEY[i]);
322 }
323
324 return 0;
325 }
326
327 /* encrypt a block of text */
328
329 #define f_nround(bo, bi, k) \
330 f_rn(bo, bi, 0, k); \
331 f_rn(bo, bi, 1, k); \
332 f_rn(bo, bi, 2, k); \
333 f_rn(bo, bi, 3, k); \
334 k += 4
335
336 #define f_lround(bo, bi, k) \
337 f_rl(bo, bi, 0, k); \
338 f_rl(bo, bi, 1, k); \
339 f_rl(bo, bi, 2, k); \
340 f_rl(bo, bi, 3, k)
341
aes_encrypt(void * ctx_arg,u8 * out,const u8 * in)342 static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in)
343 {
344 const struct aes_ctx *ctx = ctx_arg;
345 u32 b0[4], b1[4];
346 const u32 *kp = E_KEY + 4;
347
348 b0[0] = u32_in (in) ^ E_KEY[0];
349 b0[1] = u32_in (in + 4) ^ E_KEY[1];
350 b0[2] = u32_in (in + 8) ^ E_KEY[2];
351 b0[3] = u32_in (in + 12) ^ E_KEY[3];
352
353 if (ctx->key_length > 24) {
354 f_nround (b1, b0, kp);
355 f_nround (b0, b1, kp);
356 }
357
358 if (ctx->key_length > 16) {
359 f_nround (b1, b0, kp);
360 f_nround (b0, b1, kp);
361 }
362
363 f_nround (b1, b0, kp);
364 f_nround (b0, b1, kp);
365 f_nround (b1, b0, kp);
366 f_nround (b0, b1, kp);
367 f_nround (b1, b0, kp);
368 f_nround (b0, b1, kp);
369 f_nround (b1, b0, kp);
370 f_nround (b0, b1, kp);
371 f_nround (b1, b0, kp);
372 f_lround (b0, b1, kp);
373
374 u32_out (out, b0[0]);
375 u32_out (out + 4, b0[1]);
376 u32_out (out + 8, b0[2]);
377 u32_out (out + 12, b0[3]);
378 }
379
380 /* decrypt a block of text */
381
382 #define i_nround(bo, bi, k) \
383 i_rn(bo, bi, 0, k); \
384 i_rn(bo, bi, 1, k); \
385 i_rn(bo, bi, 2, k); \
386 i_rn(bo, bi, 3, k); \
387 k -= 4
388
389 #define i_lround(bo, bi, k) \
390 i_rl(bo, bi, 0, k); \
391 i_rl(bo, bi, 1, k); \
392 i_rl(bo, bi, 2, k); \
393 i_rl(bo, bi, 3, k)
394
aes_decrypt(void * ctx_arg,u8 * out,const u8 * in)395 static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in)
396 {
397 const struct aes_ctx *ctx = ctx_arg;
398 u32 b0[4], b1[4];
399 const int key_len = ctx->key_length;
400 const u32 *kp = D_KEY + key_len + 20;
401
402 b0[0] = u32_in (in) ^ E_KEY[key_len + 24];
403 b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25];
404 b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26];
405 b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27];
406
407 if (key_len > 24) {
408 i_nround (b1, b0, kp);
409 i_nround (b0, b1, kp);
410 }
411
412 if (key_len > 16) {
413 i_nround (b1, b0, kp);
414 i_nround (b0, b1, kp);
415 }
416
417 i_nround (b1, b0, kp);
418 i_nround (b0, b1, kp);
419 i_nround (b1, b0, kp);
420 i_nround (b0, b1, kp);
421 i_nround (b1, b0, kp);
422 i_nround (b0, b1, kp);
423 i_nround (b1, b0, kp);
424 i_nround (b0, b1, kp);
425 i_nround (b1, b0, kp);
426 i_lround (b0, b1, kp);
427
428 u32_out (out, b0[0]);
429 u32_out (out + 4, b0[1]);
430 u32_out (out + 8, b0[2]);
431 u32_out (out + 12, b0[3]);
432 }
433
434
435 static struct crypto_alg aes_alg = {
436 .cra_name = "aes",
437 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
438 .cra_blocksize = AES_BLOCK_SIZE,
439 .cra_ctxsize = sizeof(struct aes_ctx),
440 .cra_module = THIS_MODULE,
441 .cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
442 .cra_u = {
443 .cipher = {
444 .cia_min_keysize = AES_MIN_KEY_SIZE,
445 .cia_max_keysize = AES_MAX_KEY_SIZE,
446 .cia_setkey = aes_set_key,
447 .cia_encrypt = aes_encrypt,
448 .cia_decrypt = aes_decrypt
449 }
450 }
451 };
452
aes_init(void)453 static int __init aes_init(void)
454 {
455 gen_tabs();
456 return crypto_register_alg(&aes_alg);
457 }
458
aes_fini(void)459 static void __exit aes_fini(void)
460 {
461 crypto_unregister_alg(&aes_alg);
462 }
463
464 module_init(aes_init);
465 module_exit(aes_fini);
466
467 MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
468 MODULE_LICENSE("Dual BSD/GPL");
469
470