aboutsummaryrefslogtreecommitdiff
path: root/arch/i386/crypto/aes.c
blob: a0e033510a3b98a9c49c6660167ca8102b4e642f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
/* 
 * 
 * Glue Code for optimized 586 assembler version of AES
 *
 * Copyright (c) 2002, Dr Brian Gladman <>, Worcester, UK.
 * All rights reserved.
 *
 * LICENSE TERMS
 *
 * The free distribution and use of this software in both source and binary
 * form is allowed (with or without changes) provided that:
 *
 *   1. distributions of this source code include the above copyright
 *      notice, this list of conditions and the following disclaimer;
 *
 *   2. distributions in binary form include the above copyright
 *      notice, this list of conditions and the following disclaimer
 *      in the documentation and/or other associated materials;
 *
 *   3. the copyright holder's name is not used to endorse products
 *      built using this software without specific written permission.
 *
 * ALTERNATIVELY, provided that this notice is retained in full, this product
 * may be distributed under the terms of the GNU General Public License (GPL),
 * in which case the provisions of the GPL apply INSTEAD OF those given above.
 *
 * DISCLAIMER
 *
 * This software is provided 'as is' with no explicit or implied warranties
 * in respect of its properties, including, but not limited to, correctness
 * and/or fitness for purpose.
 *
 * Copyright (c) 2003, Adam J. Richter <adam@yggdrasil.com> (conversion to
 * 2.5 API).
 * Copyright (c) 2003, 2004 Fruhwirth Clemens <clemens@endorphin.org>
 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
 *
 */

#include <asm/byteorder.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/linkage.h>

asmlinkage void aes_enc_blk(void *ctx, u8 *dst, const u8 *src);
asmlinkage void aes_dec_blk(void *ctx, u8 *dst, const u8 *src);

#define AES_MIN_KEY_SIZE	16
#define AES_MAX_KEY_SIZE	32
#define AES_BLOCK_SIZE		16
#define AES_KS_LENGTH		4 * AES_BLOCK_SIZE
#define RC_LENGTH		29

struct aes_ctx {
	u32 ekey[AES_KS_LENGTH];
	u32 rounds;
	u32 dkey[AES_KS_LENGTH];
};

#define WPOLY 0x011b
#define bytes2word(b0, b1, b2, b3)  \
	(((u32)(b3) << 24) | ((u32)(b2) << 16) | ((u32)(b1) << 8) | (b0))

/* define the finite field multiplies required for Rijndael */
#define f2(x) ((x) ? pow[log[x] + 0x19] : 0)
#define f3(x) ((x) ? pow[log[x] + 0x01] : 0)
#define f9(x) ((x) ? pow[log[x] + 0xc7] : 0)
#define fb(x) ((x) ? pow[log[x] + 0x68] : 0)
#define fd(x) ((x) ? pow[log[x] + 0xee] : 0)
#define fe(x) ((x) ? pow[log[x] + 0xdf] : 0)
#define fi(x) ((x) ?   pow[255 - log[x]]: 0)

static inline u32 upr(u32 x, int n)
{
	return (x << 8 * n) | (x >> (32 - 8 * n));
}

static inline u8 bval(u32 x, int n)
{
	return x >> 8 * n;
}

/* The forward and inverse affine transformations used in the S-box */
#define fwd_affine(x) \
	(w = (u32)x, w ^= (w<<1)^(w<<2)^(w<<3)^(w<<4), 0x63^(u8)(w^(w>>8)))

#define inv_affine(x) \
	(w = (u32)x, w = (w<<1)^(w<<3)^(w<<6), 0x05^(u8)(w^(w>>8)))

static u32 rcon_tab[RC_LENGTH];

u32 ft_tab[4][256];
u32 fl_tab[4][256];
static u32 im_tab[4][256];
u32 il_tab[4][256];
u32 it_tab[4][256];

static void gen_tabs(void)
{
	u32 i, w;
	u8 pow[512], log[256];

	/*
	 * log and power tables for GF(2^8) finite field with
	 * WPOLY as modular polynomial - the simplest primitive
	 * root is 0x03, used here to generate the tables.
	 */
	i = 0; w = 1; 
	
	do {
		pow[i] = (u8)w;
		pow[i + 255] = (u8)w;
		log[w] = (u8)i++;
		w ^=  (w << 1) ^ (w & 0x80 ? WPOLY : 0);
	} while (w != 1);
	
	for(i = 0, w = 1; i < RC_LENGTH; ++i) {
		rcon_tab[i] = bytes2word(w, 0, 0, 0);
		w = f2(w);
	}

	for(i = 0; i < 256; ++i) {
		u8 b;
		
		b = fwd_affine(fi((u8)i));
		w = bytes2word(f2(b), b, b, f3(b));

		/* tables for a normal encryption round */
		ft_tab[0][i] = w;
		ft_tab[1][i] = upr(w, 1);
		ft_tab[2][i] = upr(w, 2);
		ft_tab[3][i] = upr(w, 3);
		w = bytes2word(b, 0, 0, 0);
		
		/*
		 * tables for last encryption round
		 * (may also be used in the key schedule)
		 */
		fl_tab[0][i] = w;
		fl_tab[1][i] = upr(w, 1);
		fl_tab[2][i] = upr(w, 2);
		fl_tab[3][i] = upr(w, 3);
		
		b = fi(inv_affine((u8)i));
		w = bytes2word(fe(b), f9(b), fd(b), fb(b));

		/* tables for the inverse mix column operation  */
		im_tab[0][b] = w;
		im_tab[1][b] = upr(w, 1);
		im_tab[2][b] = upr(w, 2);
		im_tab[3][b] = upr(w, 3);

		/* tables for a normal decryption round */
		it_tab[0][i] = w;
		it_tab[1][i] = upr(w,1);
		it_tab[2][i] = upr(w,2);
		it_tab[3][i] = upr(w,3);

		w = bytes2word(b, 0, 0, 0);
		
		/* tables for last decryption round */
		il_tab[0][i] = w;
		il_tab[1][i] = upr(w,1);
		il_tab[2][i] = upr(w,2);
		il_tab[3][i] = upr(w,3);
    }
}

#define four_tables(x,tab,vf,rf,c)		\
(	tab[0][bval(vf(x,0,c),rf(0,c))]	^	\
	tab[1][bval(vf(x,1,c),rf(1,c))] ^	\
	tab[2][bval(vf(x,2,c),rf(2,c))] ^	\
	tab[3][bval(vf(x,3,c),rf(3,c))]		\
)

#define vf1(x,r,c)  (x)
#define rf1(r,c)    (r)
#define rf2(r,c)    ((r-c)&3)

#define inv_mcol(x) four_tables(x,im_tab,vf1,rf1,0)
#define ls_box(x,c) four_tables(x,fl_tab,vf1,rf2,c)

#define ff(x) inv_mcol(x)

#define ke4(k,i)							\
{									\
	k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i];		\
	k[4*(i)+5] = ss[1] ^= ss[0];					\
	k[4*(i)+6] = ss[2] ^= ss[1];					\
	k[4*(i)+7] = ss[3] ^= ss[2];					\
}

#define kel4(k,i)							\
{									\
	k[4*(i)+4] = ss[0] ^= ls_box(ss[3],3) ^ rcon_tab[i];		\
	k[4*(i)+5] = ss[1] ^= ss[0];					\
	k[4*(i)+6] = ss[2] ^= ss[1]; k[4*(i)+7] = ss[3] ^= ss[2];	\
}

#define ke6(k,i)							\
{									\
	k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i];		\
	k[6*(i)+ 7] = ss[1] ^= ss[0];					\
	k[6*(i)+ 8] = ss[2] ^= ss[1];					\
	k[6*(i)+ 9] = ss[3] ^= ss[2];					\
	k[6*(i)+10] = ss[4] ^= ss[3];					\
	k[6*(i)+11] = ss[5] ^= ss[4];					\
}

#define kel6(k,i)							\
{									\
	k[6*(i)+ 6] = ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i];		\
	k[6*(i)+ 7] = ss[1] ^= ss[0];					\
	k[6*(i)+ 8] = ss[2] ^= ss[1];					\
	k[6*(i)+ 9] = ss[3] ^= ss[2];					\
}

#define ke8(k,i)							\
{									\
	k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i];		\
	k[8*(i)+ 9] = ss[1] ^= ss[0];					\
	k[8*(i)+10] = ss[2] ^= ss[1];					\
	k[8*(i)+11] = ss[3] ^= ss[2];					\
	k[8*(i)+12] = ss[4] ^= ls_box(ss[3],0);				\
	k[8*(i)+13] = ss[5] ^= ss[4];					\
	k[8*(i)+14] = ss[6] ^= ss[5];					\
	k[8*(i)+15] = ss[7] ^= ss[6];					\
}

#define kel8(k,i)							\
{									\
	k[8*(i)+ 8] = ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i];		\
	k[8*(i)+ 9] = ss[1] ^= ss[0];					\
	k[8*(i)+10] = ss[2] ^= ss[1];					\
	k[8*(i)+11] = ss[3] ^= ss[2];					\
}

#define kdf4(k,i)							\
{									\
	ss[0] = ss[0] ^ ss[2] ^ ss[1] ^ ss[3];				\
	ss[1] = ss[1] ^ ss[3];						\
	ss[2] = ss[2] ^ ss[3];						\
	ss[3] = ss[3];							\
	ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i];			\
	ss[i % 4] ^= ss[4];						\
	ss[4] ^= k[4*(i)];						\
	k[4*(i)+4] = ff(ss[4]);						\
	ss[4] ^= k[4*(i)+1];						\
	k[4*(i)+5] = ff(ss[4]);						\
	ss[4] ^= k[4*(i)+2];						\
	k[4*(i)+6] = ff(ss[4]);						\
	ss[4] ^= k[4*(i)+3];						\
	k[4*(i)+7] = ff(ss[4]);						\
}

#define kd4(k,i)							\
{									\
	ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i];			\
	ss[i % 4] ^= ss[4];						\
	ss[4] = ff(ss[4]);						\
	k[4*(i)+4] = ss[4] ^= k[4*(i)];					\
	k[4*(i)+5] = ss[4] ^= k[4*(i)+1];				\
	k[4*(i)+6] = ss[4] ^= k[4*(i)+2];				\
	k[4*(i)+7] = ss[4] ^= k[4*(i)+3];				\
}

#define kdl4(k,i)							\
{									\
	ss[4] = ls_box(ss[(i+3) % 4], 3) ^ rcon_tab[i];			\
	ss[i % 4] ^= ss[4];						\
	k[4*(i)+4] = (ss[0] ^= ss[1]) ^ ss[2] ^ ss[3];			\
	k[4*(i)+5] = ss[1] ^ ss[3];					\
	k[4*(i)+6] = ss[0];						\
	k[4*(i)+7] = ss[1];						\
}

#define kdf6(k,i)							\
{									\
	ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i];				\
	k[6*(i)+ 6] = ff(ss[0]);					\
	ss[1] ^= ss[0];							\
	k[6*(i)+ 7] = ff(ss[1]);					\
	ss[2] ^= ss[1];							\
	k[6*(i)+ 8] = ff(ss[2]);					\
	ss[3] ^= ss[2];							\
	k[6*(i)+ 9] = ff(ss[3]);					\
	ss[4] ^= ss[3];							\
	k[6*(i)+10] = ff(ss[4]);					\
	ss[5] ^= ss[4];							\
	k[6*(i)+11] = ff(ss[5]);					\
}

#define kd6(k,i)							\
{									\
	ss[6] = ls_box(ss[5],3) ^ rcon_tab[i];				\
	ss[0] ^= ss[6]; ss[6] = ff(ss[6]);				\
	k[6*(i)+ 6] = ss[6] ^= k[6*(i)];				\
	ss[1] ^= ss[0];							\
	k[6*(i)+ 7] = ss[6] ^= k[6*(i)+ 1];				\
	ss[2] ^= ss[1];							\
	k[6*(i)+ 8] = ss[6] ^= k[6*(i)+ 2];				\
	ss[3] ^= ss[2];							\
	k[6*(i)+ 9] = ss[6] ^= k[6*(i)+ 3];				\
	ss[4] ^= ss[3];							\
	k[6*(i)+10] = ss[6] ^= k[6*(i)+ 4];				\
	ss[5] ^= ss[4];							\
	k[6*(i)+11] = ss[6] ^= k[6*(i)+ 5];				\
}

#define kdl6(k,i)							\
{									\
	ss[0] ^= ls_box(ss[5],3) ^ rcon_tab[i];				\
	k[6*(i)+ 6] = ss[0];						\
	ss[1] ^= ss[0];							\
	k[6*(i)+ 7] = ss[1];						\
	ss[2] ^= ss[1];							\
	k[6*(i)+ 8] = ss[2];						\
	ss[3] ^= ss[2];							\
	k[6*(i)+ 9] = ss[3];						\
}

#define kdf8(k,i)							\
{									\
	ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i];				\
	k[8*(i)+ 8] = ff(ss[0]);					\
	ss[1] ^= ss[0];							\
	k[8*(i)+ 9] = ff(ss[1]);					\
	ss[2] ^= ss[1];							\
	k[8*(i)+10] = ff(ss[2]);					\
	ss[3] ^= ss[2];							\
	k[8*(i)+11] = ff(ss[3]);					\
	ss[4] ^= ls_box(ss[3],0);					\
	k[8*(i)+12] = ff(ss[4]);					\
	ss[5] ^= ss[4];							\
	k[8*(i)+13] = ff(ss[5]);					\
	ss[6] ^= ss[5];							\
	k[8*(i)+14] = ff(ss[6]);					\
	ss[7] ^= ss[6];							\
	k[8*(i)+15] = ff(ss[7]);					\
}

#define kd8(k,i)							\
{									\
	u32 __g = ls_box(ss[7],3) ^ rcon_tab[i];			\
	ss[0] ^= __g;							\
	__g = ff(__g);							\
	k[8*(i)+ 8] = __g ^= k[8*(i)];					\
	ss[1] ^= ss[0];							\
	k[8*(i)+ 9] = __g ^= k[8*(i)+ 1];				\
	ss[2] ^= ss[1];							\
	k[8*(i)+10] = __g ^= k[8*(i)+ 2];				\
	ss[3] ^= ss[2];							\
	k[8*(i)+11] = __g ^= k[8*(i)+ 3];				\
	__g = ls_box(ss[3],0);						\
	ss[4] ^= __g;							\
	__g = ff(__g);							\
	k[8*(i)+12] = __g ^= k[8*(i)+ 4];				\
	ss[5] ^= ss[4];							\
	k[8*(i)+13] = __g ^= k[8*(i)+ 5];				\
	ss[6] ^= ss[5];							\
	k[8*(i)+14] = __g ^= k[8*(i)+ 6];				\
	ss[7] ^= ss[6];							\
	k[8*(i)+15] = __g ^= k[8*(i)+ 7];				\
}

#define kdl8(k,i)							\
{									\
	ss[0] ^= ls_box(ss[7],3) ^ rcon_tab[i];				\
	k[8*(i)+ 8] = ss[0];						\
	ss[1] ^= ss[0];							\
	k[8*(i)+ 9] = ss[1];						\
	ss[2] ^= ss[1];							\
	k[8*(i)+10] = ss[2];						\
	ss[3] ^= ss[2];							\
	k[8*(i)+11] = ss[3];						\
}

static int
aes_set_key(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags)
{
	int i;
	u32 ss[8];
	struct aes_ctx *ctx = ctx_arg;
	const __le32 *key = (const __le32 *)in_key;

	/* encryption schedule */
	
	ctx->ekey[0] = ss[0] = le32_to_cpu(key[0]);
	ctx->ekey[1] = ss[1] = le32_to_cpu(key[1]);
	ctx->ekey[2] = ss[2] = le32_to_cpu(key[2]);
	ctx->ekey[3] = ss[3] = le32_to_cpu(key[3]);

	switch(key_len) {
	case 16:
		for (i = 0; i < 9; i++)
			ke4(ctx->ekey, i);
		kel4(ctx->ekey, 9);
		ctx->rounds = 10;
		break;
		
	case 24:
		ctx->ekey[4] = ss[4] = le32_to_cpu(key[4]);
		ctx->ekey[5] = ss[5] = le32_to_cpu(key[5]);
		for (i = 0; i < 7; i++)
			ke6(ctx->ekey, i);
		kel6(ctx->ekey, 7); 
		ctx->rounds = 12;
		break;

	case 32:
		ctx->ekey[4] = ss[4] = le32_to_cpu(key[4]);
		ctx->ekey[5] = ss[5] = le32_to_cpu(key[5]);
		ctx->ekey[6] = ss[6] = le32_to_cpu(key[6]);
		ctx->ekey[7] = ss[7] = le32_to_cpu(key[7]);
		for (i = 0; i < 6; i++)
			ke8(ctx->ekey, i);
		kel8(ctx->ekey, 6);
		ctx->rounds = 14;
		break;

	default:
		*flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
		return -EINVAL;
	}
	
	/* decryption schedule */
	
	ctx->dkey[0] = ss[0] = le32_to_cpu(key[0]);
	ctx->dkey[1] = ss[1] = le32_to_cpu(key[1]);
	ctx->dkey[2] = ss[2] = le32_to_cpu(key[2]);
	ctx->dkey[3] = ss[3] = le32_to_cpu(key[3]);

	switch (key_len) {
	case 16:
		kdf4(ctx->dkey, 0);
		for (i = 1; i < 9; i++)
			kd4(ctx->dkey, i);
		kdl4(ctx->dkey, 9);
		break;
		
	case 24:
		ctx->dkey[4] = ff(ss[4] = le32_to_cpu(key[4]));
		ctx->dkey[5] = ff(ss[5] = le32_to_cpu(key[5]));
		kdf6(ctx->dkey, 0);
		for (i = 1; i < 7; i++)
			kd6(ctx->dkey, i);
		kdl6(ctx->dkey, 7);
		break;

	case 32:
		ctx->dkey[4] = ff(ss[4] = le32_to_cpu(key[4]));
		ctx->dkey[5] = ff(ss[5] = le32_to_cpu(key[5]));
		ctx->dkey[6] = ff(ss[6] = le32_to_cpu(key[6]));
		ctx->dkey[7] = ff(ss[7] = le32_to_cpu(key[7]));
		kdf8(ctx->dkey, 0);
		for (i = 1; i < 6; i++)
			kd8(ctx->dkey, i);
		kdl8(ctx->dkey, 6);
		break;
	}
	return 0;
}

static struct crypto_alg aes_alg = {
	.cra_name		=	"aes",
	.cra_driver_name	=	"aes-i586",
	.cra_priority		=	200,
	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
	.cra_blocksize		=	AES_BLOCK_SIZE,
	.cra_ctxsize		=	sizeof(struct aes_ctx),
	.cra_module		=	THIS_MODULE,
	.cra_list		=	LIST_HEAD_INIT(aes_alg.cra_list),
	.cra_u			=	{
		.cipher = {
			.cia_min_keysize	=	AES_MIN_KEY_SIZE,
			.cia_max_keysize	=	AES_MAX_KEY_SIZE,
			.cia_setkey	   	= 	aes_set_key,
			.cia_encrypt	 	=	aes_enc_blk,
			.cia_decrypt	  	=	aes_dec_blk
		}
	}
};

static int __init aes_init(void)
{
	gen_tabs();
	return crypto_register_alg(&aes_alg);
}

static void __exit aes_fini(void)
{
	crypto_unregister_alg(&aes_alg);
}

module_init(aes_init);
module_exit(aes_fini);

MODULE_DESCRIPTION("Rijndael (AES) Cipher Algorithm, i586 asm optimized");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Fruhwirth Clemens, James Morris, Brian Gladman, Adam Richter");
MODULE_ALIAS("aes");