4
* AES Cipher Algorithm.
6
* Based on Brian Gladman's code.
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).
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.
19
* ---------------------------------------------------------------------------
20
* Copyright (c) 2002, Dr Brian Gladman <brg@gladman.me.uk>, Worcester, UK.
21
* All rights reserved.
25
* The free distribution and use of this software in both source and binary
26
* form is allowed (with or without changes) provided that:
28
* 1. distributions of this source code include the above copyright
29
* notice, this list of conditions and the following disclaimer;
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;
35
* 3. the copyright holder's name is not used to endorse products
36
* built using this software without specific written permission.
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.
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
* ---------------------------------------------------------------------------
50
/* Some changes from the Gladman version:
51
s/RIJNDAEL(e_key)/E_KEY/g
52
s/RIJNDAEL(d_key)/D_KEY/g
55
#include <linux/module.h>
56
#include <linux/init.h>
57
#include <linux/types.h>
58
#include <linux/errno.h>
59
#include "rtl_crypto.h"
60
#include <asm/byteorder.h>
62
#define AES_MIN_KEY_SIZE 16
63
#define AES_MAX_KEY_SIZE 32
65
#define AES_BLOCK_SIZE 16
68
u32 generic_rotr32 (const u32 x, const unsigned bits)
70
const unsigned n = bits % 32;
71
return (x >> n) | (x << (32 - n));
75
u32 generic_rotl32 (const u32 x, const unsigned bits)
77
const unsigned n = bits % 32;
78
return (x << n) | (x >> (32 - n));
81
#define rotl generic_rotl32
82
#define rotr generic_rotr32
85
* #define byte(x, nr) ((unsigned char)((x) >> (nr*8)))
88
byte(const u32 x, const unsigned n)
93
#define u32_in(x) le32_to_cpu(*(const u32 *)(x))
94
#define u32_out(to, from) (*(u32 *)(to) = cpu_to_le32(from))
105
static u8 pow_tab[256] __initdata;
106
static u8 log_tab[256] __initdata;
107
static u8 sbx_tab[256] __initdata;
108
static u8 isb_tab[256] __initdata;
109
static u32 rco_tab[10];
110
static u32 ft_tab[4][256];
111
static u32 it_tab[4][256];
113
static u32 fl_tab[4][256];
114
static u32 il_tab[4][256];
116
static inline u8 __init
119
u8 aa = log_tab[a], cc = aa + log_tab[b];
121
return pow_tab[cc + (cc < aa ? 1 : 0)];
124
#define ff_mult(a,b) (a && b ? f_mult(a, b) : 0)
126
#define f_rn(bo, bi, n, k) \
127
bo[n] = ft_tab[0][byte(bi[n],0)] ^ \
128
ft_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
129
ft_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
130
ft_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
132
#define i_rn(bo, bi, n, k) \
133
bo[n] = it_tab[0][byte(bi[n],0)] ^ \
134
it_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
135
it_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
136
it_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
139
( fl_tab[0][byte(x, 0)] ^ \
140
fl_tab[1][byte(x, 1)] ^ \
141
fl_tab[2][byte(x, 2)] ^ \
142
fl_tab[3][byte(x, 3)] )
144
#define f_rl(bo, bi, n, k) \
145
bo[n] = fl_tab[0][byte(bi[n],0)] ^ \
146
fl_tab[1][byte(bi[(n + 1) & 3],1)] ^ \
147
fl_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
148
fl_tab[3][byte(bi[(n + 3) & 3],3)] ^ *(k + n)
150
#define i_rl(bo, bi, n, k) \
151
bo[n] = il_tab[0][byte(bi[n],0)] ^ \
152
il_tab[1][byte(bi[(n + 3) & 3],1)] ^ \
153
il_tab[2][byte(bi[(n + 2) & 3],2)] ^ \
154
il_tab[3][byte(bi[(n + 1) & 3],3)] ^ *(k + n)
162
/* log and power tables for GF(2**8) finite field with
163
0x011b as modular polynomial - the simplest primitive
164
root is 0x03, used here to generate the tables */
166
for (i = 0, p = 1; i < 256; ++i) {
170
p ^= (p << 1) ^ (p & 0x80 ? 0x01b : 0);
175
for (i = 0, p = 1; i < 10; ++i) {
178
p = (p << 1) ^ (p & 0x80 ? 0x01b : 0);
181
for (i = 0; i < 256; ++i) {
182
p = (i ? pow_tab[255 - log_tab[i]] : 0);
183
q = ((p >> 7) | (p << 1)) ^ ((p >> 6) | (p << 2));
184
p ^= 0x63 ^ q ^ ((q >> 6) | (q << 2));
189
for (i = 0; i < 256; ++i) {
194
fl_tab[1][i] = rotl (t, 8);
195
fl_tab[2][i] = rotl (t, 16);
196
fl_tab[3][i] = rotl (t, 24);
198
t = ((u32) ff_mult (2, p)) |
200
((u32) p << 16) | ((u32) ff_mult (3, p) << 24);
203
ft_tab[1][i] = rotl (t, 8);
204
ft_tab[2][i] = rotl (t, 16);
205
ft_tab[3][i] = rotl (t, 24);
211
il_tab[1][i] = rotl (t, 8);
212
il_tab[2][i] = rotl (t, 16);
213
il_tab[3][i] = rotl (t, 24);
215
t = ((u32) ff_mult (14, p)) |
216
((u32) ff_mult (9, p) << 8) |
217
((u32) ff_mult (13, p) << 16) |
218
((u32) ff_mult (11, p) << 24);
221
it_tab[1][i] = rotl (t, 8);
222
it_tab[2][i] = rotl (t, 16);
223
it_tab[3][i] = rotl (t, 24);
227
#define star_x(x) (((x) & 0x7f7f7f7f) << 1) ^ ((((x) & 0x80808080) >> 7) * 0x1b)
229
#define imix_col(y,x) \
235
(y) ^= rotr(u ^ t, 8) ^ \
239
/* initialise the key schedule from the user supplied key */
242
{ t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \
243
t ^= E_KEY[4 * i]; E_KEY[4 * i + 4] = t; \
244
t ^= E_KEY[4 * i + 1]; E_KEY[4 * i + 5] = t; \
245
t ^= E_KEY[4 * i + 2]; E_KEY[4 * i + 6] = t; \
246
t ^= E_KEY[4 * i + 3]; E_KEY[4 * i + 7] = t; \
250
{ t = rotr(t, 8); t = ls_box(t) ^ rco_tab[i]; \
251
t ^= E_KEY[6 * i]; E_KEY[6 * i + 6] = t; \
252
t ^= E_KEY[6 * i + 1]; E_KEY[6 * i + 7] = t; \
253
t ^= E_KEY[6 * i + 2]; E_KEY[6 * i + 8] = t; \
254
t ^= E_KEY[6 * i + 3]; E_KEY[6 * i + 9] = t; \
255
t ^= E_KEY[6 * i + 4]; E_KEY[6 * i + 10] = t; \
256
t ^= E_KEY[6 * i + 5]; E_KEY[6 * i + 11] = t; \
260
{ t = rotr(t, 8); ; t = ls_box(t) ^ rco_tab[i]; \
261
t ^= E_KEY[8 * i]; E_KEY[8 * i + 8] = t; \
262
t ^= E_KEY[8 * i + 1]; E_KEY[8 * i + 9] = t; \
263
t ^= E_KEY[8 * i + 2]; E_KEY[8 * i + 10] = t; \
264
t ^= E_KEY[8 * i + 3]; E_KEY[8 * i + 11] = t; \
265
t = E_KEY[8 * i + 4] ^ ls_box(t); \
266
E_KEY[8 * i + 12] = t; \
267
t ^= E_KEY[8 * i + 5]; E_KEY[8 * i + 13] = t; \
268
t ^= E_KEY[8 * i + 6]; E_KEY[8 * i + 14] = t; \
269
t ^= E_KEY[8 * i + 7]; E_KEY[8 * i + 15] = t; \
273
aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags)
275
struct aes_ctx *ctx = ctx_arg;
278
if (key_len != 16 && key_len != 24 && key_len != 32) {
279
*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
283
ctx->key_length = key_len;
285
E_KEY[0] = u32_in (in_key);
286
E_KEY[1] = u32_in (in_key + 4);
287
E_KEY[2] = u32_in (in_key + 8);
288
E_KEY[3] = u32_in (in_key + 12);
293
for (i = 0; i < 10; ++i)
298
E_KEY[4] = u32_in (in_key + 16);
299
t = E_KEY[5] = u32_in (in_key + 20);
300
for (i = 0; i < 8; ++i)
305
E_KEY[4] = u32_in (in_key + 16);
306
E_KEY[5] = u32_in (in_key + 20);
307
E_KEY[6] = u32_in (in_key + 24);
308
t = E_KEY[7] = u32_in (in_key + 28);
309
for (i = 0; i < 7; ++i)
319
for (i = 4; i < key_len + 24; ++i) {
320
imix_col (D_KEY[i], E_KEY[i]);
326
/* encrypt a block of text */
328
#define f_nround(bo, bi, k) \
329
f_rn(bo, bi, 0, k); \
330
f_rn(bo, bi, 1, k); \
331
f_rn(bo, bi, 2, k); \
332
f_rn(bo, bi, 3, k); \
335
#define f_lround(bo, bi, k) \
336
f_rl(bo, bi, 0, k); \
337
f_rl(bo, bi, 1, k); \
338
f_rl(bo, bi, 2, k); \
341
static void aes_encrypt(void *ctx_arg, u8 *out, const u8 *in)
343
const struct aes_ctx *ctx = ctx_arg;
345
const u32 *kp = E_KEY + 4;
346
b0[0] = u32_in (in) ^ E_KEY[0];
347
b0[1] = u32_in (in + 4) ^ E_KEY[1];
348
b0[2] = u32_in (in + 8) ^ E_KEY[2];
349
b0[3] = u32_in (in + 12) ^ E_KEY[3];
351
if (ctx->key_length > 24) {
352
f_nround (b1, b0, kp);
353
f_nround (b0, b1, kp);
356
if (ctx->key_length > 16) {
357
f_nround (b1, b0, kp);
358
f_nround (b0, b1, kp);
361
f_nround (b1, b0, kp);
362
f_nround (b0, b1, kp);
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_lround (b0, b1, kp);
372
u32_out (out, b0[0]);
373
u32_out (out + 4, b0[1]);
374
u32_out (out + 8, b0[2]);
375
u32_out (out + 12, b0[3]);
378
/* decrypt a block of text */
380
#define i_nround(bo, bi, k) \
381
i_rn(bo, bi, 0, k); \
382
i_rn(bo, bi, 1, k); \
383
i_rn(bo, bi, 2, k); \
384
i_rn(bo, bi, 3, k); \
387
#define i_lround(bo, bi, k) \
388
i_rl(bo, bi, 0, k); \
389
i_rl(bo, bi, 1, k); \
390
i_rl(bo, bi, 2, k); \
393
static void aes_decrypt(void *ctx_arg, u8 *out, const u8 *in)
395
const struct aes_ctx *ctx = ctx_arg;
397
const int key_len = ctx->key_length;
398
const u32 *kp = D_KEY + key_len + 20;
400
b0[0] = u32_in (in) ^ E_KEY[key_len + 24];
401
b0[1] = u32_in (in + 4) ^ E_KEY[key_len + 25];
402
b0[2] = u32_in (in + 8) ^ E_KEY[key_len + 26];
403
b0[3] = u32_in (in + 12) ^ E_KEY[key_len + 27];
406
i_nround (b1, b0, kp);
407
i_nround (b0, b1, kp);
411
i_nround (b1, b0, kp);
412
i_nround (b0, b1, kp);
415
i_nround (b1, b0, kp);
416
i_nround (b0, b1, kp);
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_lround (b0, b1, kp);
426
u32_out (out, b0[0]);
427
u32_out (out + 4, b0[1]);
428
u32_out (out + 8, b0[2]);
429
u32_out (out + 12, b0[3]);
433
static struct crypto_alg aes_alg = {
435
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
436
.cra_blocksize = AES_BLOCK_SIZE,
437
.cra_ctxsize = sizeof(struct aes_ctx),
438
.cra_module = THIS_MODULE,
439
.cra_list = LIST_HEAD_INIT(aes_alg.cra_list),
442
.cia_min_keysize = AES_MIN_KEY_SIZE,
443
.cia_max_keysize = AES_MAX_KEY_SIZE,
444
.cia_setkey = aes_set_key,
445
.cia_encrypt = aes_encrypt,
446
.cia_decrypt = aes_decrypt
451
int __init aes_init(void)
454
return crypto_register_alg(&aes_alg);
457
void __exit aes_fini(void)
459
crypto_unregister_alg(&aes_alg);
462
#ifndef BUILT_IN_CRYPTO
463
module_init(aes_init);
464
module_exit(aes_fini);
466
MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm");
467
MODULE_LICENSE("Dual BSD/GPL");