Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  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
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Bit sliced AES using NEON instructions
 *
 * Copyright (C) 2016 - 2017 Linaro Ltd <ard.biesheuvel@linaro.org>
 */

#include <asm/neon.h>
#include <asm/simd.h>
#include <crypto/aes.h>
#include <crypto/ctr.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <crypto/xts.h>
#include <linux/module.h>

MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");

MODULE_ALIAS_CRYPTO("ecb(aes)");
MODULE_ALIAS_CRYPTO("cbc(aes)");
MODULE_ALIAS_CRYPTO("ctr(aes)");
MODULE_ALIAS_CRYPTO("xts(aes)");

asmlinkage void aesbs_convert_key(u8 out[], u32 const rk[], int rounds);

asmlinkage void aesbs_ecb_encrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks);
asmlinkage void aesbs_ecb_decrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks);

asmlinkage void aesbs_cbc_decrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks, u8 iv[]);

asmlinkage void aesbs_ctr_encrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks, u8 iv[], u8 final[]);

asmlinkage void aesbs_xts_encrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks, u8 iv[]);
asmlinkage void aesbs_xts_decrypt(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks, u8 iv[]);

/* borrowed from aes-neon-blk.ko */
asmlinkage void neon_aes_ecb_encrypt(u8 out[], u8 const in[], u32 const rk[],
				     int rounds, int blocks);
asmlinkage void neon_aes_cbc_encrypt(u8 out[], u8 const in[], u32 const rk[],
				     int rounds, int blocks, u8 iv[]);
asmlinkage void neon_aes_xts_encrypt(u8 out[], u8 const in[],
				     u32 const rk1[], int rounds, int bytes,
				     u32 const rk2[], u8 iv[], int first);
asmlinkage void neon_aes_xts_decrypt(u8 out[], u8 const in[],
				     u32 const rk1[], int rounds, int bytes,
				     u32 const rk2[], u8 iv[], int first);

struct aesbs_ctx {
	u8	rk[13 * (8 * AES_BLOCK_SIZE) + 32];
	int	rounds;
} __aligned(AES_BLOCK_SIZE);

struct aesbs_cbc_ctx {
	struct aesbs_ctx	key;
	u32			enc[AES_MAX_KEYLENGTH_U32];
};

struct aesbs_ctr_ctx {
	struct aesbs_ctx	key;		/* must be first member */
	struct crypto_aes_ctx	fallback;
};

struct aesbs_xts_ctx {
	struct aesbs_ctx	key;
	u32			twkey[AES_MAX_KEYLENGTH_U32];
	struct crypto_aes_ctx	cts;
};

static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
			unsigned int key_len)
{
	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_aes_ctx rk;
	int err;

	err = aes_expandkey(&rk, in_key, key_len);
	if (err)
		return err;

	ctx->rounds = 6 + key_len / 4;

	kernel_neon_begin();
	aesbs_convert_key(ctx->rk, rk.key_enc, ctx->rounds);
	kernel_neon_end();

	return 0;
}

static int __ecb_crypt(struct skcipher_request *req,
		       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks))
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes >= AES_BLOCK_SIZE) {
		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;

		if (walk.nbytes < walk.total)
			blocks = round_down(blocks,
					    walk.stride / AES_BLOCK_SIZE);

		kernel_neon_begin();
		fn(walk.dst.virt.addr, walk.src.virt.addr, ctx->rk,
		   ctx->rounds, blocks);
		kernel_neon_end();
		err = skcipher_walk_done(&walk,
					 walk.nbytes - blocks * AES_BLOCK_SIZE);
	}

	return err;
}

static int ecb_encrypt(struct skcipher_request *req)
{
	return __ecb_crypt(req, aesbs_ecb_encrypt);
}

static int ecb_decrypt(struct skcipher_request *req)
{
	return __ecb_crypt(req, aesbs_ecb_decrypt);
}

static int aesbs_cbc_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
			    unsigned int key_len)
{
	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_aes_ctx rk;
	int err;

	err = aes_expandkey(&rk, in_key, key_len);
	if (err)
		return err;

	ctx->key.rounds = 6 + key_len / 4;

	memcpy(ctx->enc, rk.key_enc, sizeof(ctx->enc));

	kernel_neon_begin();
	aesbs_convert_key(ctx->key.rk, rk.key_enc, ctx->key.rounds);
	kernel_neon_end();

	return 0;
}

static int cbc_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes >= AES_BLOCK_SIZE) {
		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;

		/* fall back to the non-bitsliced NEON implementation */
		kernel_neon_begin();
		neon_aes_cbc_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
				     ctx->enc, ctx->key.rounds, blocks,
				     walk.iv);
		kernel_neon_end();
		err = skcipher_walk_done(&walk, walk.nbytes % AES_BLOCK_SIZE);
	}
	return err;
}

static int cbc_decrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct aesbs_cbc_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes >= AES_BLOCK_SIZE) {
		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;

		if (walk.nbytes < walk.total)
			blocks = round_down(blocks,
					    walk.stride / AES_BLOCK_SIZE);

		kernel_neon_begin();
		aesbs_cbc_decrypt(walk.dst.virt.addr, walk.src.virt.addr,
				  ctx->key.rk, ctx->key.rounds, blocks,
				  walk.iv);
		kernel_neon_end();
		err = skcipher_walk_done(&walk,
					 walk.nbytes - blocks * AES_BLOCK_SIZE);
	}

	return err;
}

static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
				 unsigned int key_len)
{
	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
	int err;

	err = aes_expandkey(&ctx->fallback, in_key, key_len);
	if (err)
		return err;

	ctx->key.rounds = 6 + key_len / 4;

	kernel_neon_begin();
	aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
	kernel_neon_end();

	return 0;
}

static int ctr_encrypt(struct skcipher_request *req)
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct aesbs_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct skcipher_walk walk;
	u8 buf[AES_BLOCK_SIZE];
	int err;

	err = skcipher_walk_virt(&walk, req, false);

	while (walk.nbytes > 0) {
		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;
		u8 *final = (walk.total % AES_BLOCK_SIZE) ? buf : NULL;

		if (walk.nbytes < walk.total) {
			blocks = round_down(blocks,
					    walk.stride / AES_BLOCK_SIZE);
			final = NULL;
		}

		kernel_neon_begin();
		aesbs_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
				  ctx->rk, ctx->rounds, blocks, walk.iv, final);
		kernel_neon_end();

		if (final) {
			u8 *dst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
			u8 *src = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;

			crypto_xor_cpy(dst, src, final,
				       walk.total % AES_BLOCK_SIZE);

			err = skcipher_walk_done(&walk, 0);
			break;
		}
		err = skcipher_walk_done(&walk,
					 walk.nbytes - blocks * AES_BLOCK_SIZE);
	}
	return err;
}

static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
			    unsigned int key_len)
{
	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
	struct crypto_aes_ctx rk;
	int err;

	err = xts_verify_key(tfm, in_key, key_len);
	if (err)
		return err;

	key_len /= 2;
	err = aes_expandkey(&ctx->cts, in_key, key_len);
	if (err)
		return err;

	err = aes_expandkey(&rk, in_key + key_len, key_len);
	if (err)
		return err;

	memcpy(ctx->twkey, rk.key_enc, sizeof(ctx->twkey));

	return aesbs_setkey(tfm, in_key, key_len);
}

static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
{
	struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
	unsigned long flags;

	/*
	 * Temporarily disable interrupts to avoid races where
	 * cachelines are evicted when the CPU is interrupted
	 * to do something else.
	 */
	local_irq_save(flags);
	aes_encrypt(&ctx->fallback, dst, src);
	local_irq_restore(flags);
}

static int ctr_encrypt_sync(struct skcipher_request *req)
{
	if (!crypto_simd_usable())
		return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);

	return ctr_encrypt(req);
}

static int __xts_crypt(struct skcipher_request *req, bool encrypt,
		       void (*fn)(u8 out[], u8 const in[], u8 const rk[],
				  int rounds, int blocks, u8 iv[]))
{
	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
	struct aesbs_xts_ctx *ctx = crypto_skcipher_ctx(tfm);
	int tail = req->cryptlen % (8 * AES_BLOCK_SIZE);
	struct scatterlist sg_src[2], sg_dst[2];
	struct skcipher_request subreq;
	struct scatterlist *src, *dst;
	struct skcipher_walk walk;
	int nbytes, err;
	int first = 1;
	u8 *out, *in;

	if (req->cryptlen < AES_BLOCK_SIZE)
		return -EINVAL;

	/* ensure that the cts tail is covered by a single step */
	if (unlikely(tail > 0 && tail < AES_BLOCK_SIZE)) {
		int xts_blocks = DIV_ROUND_UP(req->cryptlen,
					      AES_BLOCK_SIZE) - 2;

		skcipher_request_set_tfm(&subreq, tfm);
		skcipher_request_set_callback(&subreq,
					      skcipher_request_flags(req),
					      NULL, NULL);
		skcipher_request_set_crypt(&subreq, req->src, req->dst,
					   xts_blocks * AES_BLOCK_SIZE,
					   req->iv);
		req = &subreq;
	} else {
		tail = 0;
	}

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
		return err;

	while (walk.nbytes >= AES_BLOCK_SIZE) {
		unsigned int blocks = walk.nbytes / AES_BLOCK_SIZE;

		if (walk.nbytes < walk.total || walk.nbytes % AES_BLOCK_SIZE)
			blocks = round_down(blocks,
					    walk.stride / AES_BLOCK_SIZE);

		out = walk.dst.virt.addr;
		in = walk.src.virt.addr;
		nbytes = walk.nbytes;

		kernel_neon_begin();
		if (likely(blocks > 6)) { /* plain NEON is faster otherwise */
			if (first)
				neon_aes_ecb_encrypt(walk.iv, walk.iv,
						     ctx->twkey,
						     ctx->key.rounds, 1);
			first = 0;

			fn(out, in, ctx->key.rk, ctx->key.rounds, blocks,
			   walk.iv);

			out += blocks * AES_BLOCK_SIZE;
			in += blocks * AES_BLOCK_SIZE;
			nbytes -= blocks * AES_BLOCK_SIZE;
		}

		if (walk.nbytes == walk.total && nbytes > 0)
			goto xts_tail;

		kernel_neon_end();
		skcipher_walk_done(&walk, nbytes);
	}

	if (err || likely(!tail))
		return err;

	/* handle ciphertext stealing */
	dst = src = scatterwalk_ffwd(sg_src, req->src, req->cryptlen);
	if (req->dst != req->src)
		dst = scatterwalk_ffwd(sg_dst, req->dst, req->cryptlen);

	skcipher_request_set_crypt(req, src, dst, AES_BLOCK_SIZE + tail,
				   req->iv);

	err = skcipher_walk_virt(&walk, req, false);
	if (err)
		return err;

	out = walk.dst.virt.addr;
	in = walk.src.virt.addr;
	nbytes = walk.nbytes;

	kernel_neon_begin();
xts_tail:
	if (encrypt)
		neon_aes_xts_encrypt(out, in, ctx->cts.key_enc, ctx->key.rounds,
				     nbytes, ctx->twkey, walk.iv, first ?: 2);
	else
		neon_aes_xts_decrypt(out, in, ctx->cts.key_dec, ctx->key.rounds,
				     nbytes, ctx->twkey, walk.iv, first ?: 2);
	kernel_neon_end();

	return skcipher_walk_done(&walk, 0);
}

static int xts_encrypt(struct skcipher_request *req)
{
	return __xts_crypt(req, true, aesbs_xts_encrypt);
}

static int xts_decrypt(struct skcipher_request *req)
{
	return __xts_crypt(req, false, aesbs_xts_decrypt);
}

static struct skcipher_alg aes_algs[] = { {
	.base.cra_name		= "__ecb(aes)",
	.base.cra_driver_name	= "__ecb-aes-neonbs",
	.base.cra_priority	= 250,
	.base.cra_blocksize	= AES_BLOCK_SIZE,
	.base.cra_ctxsize	= sizeof(struct aesbs_ctx),
	.base.cra_module	= THIS_MODULE,
	.base.cra_flags		= CRYPTO_ALG_INTERNAL,

	.min_keysize		= AES_MIN_KEY_SIZE,
	.max_keysize		= AES_MAX_KEY_SIZE,
	.walksize		= 8 * AES_BLOCK_SIZE,
	.setkey			= aesbs_setkey,
	.encrypt		= ecb_encrypt,
	.decrypt		= ecb_decrypt,
}, {
	.base.cra_name		= "__cbc(aes)",
	.base.cra_driver_name	= "__cbc-aes-neonbs",
	.base.cra_priority	= 250,
	.base.cra_blocksize	= AES_BLOCK_SIZE,
	.base.cra_ctxsize	= sizeof(struct aesbs_cbc_ctx),
	.base.cra_module	= THIS_MODULE,
	.base.cra_flags		= CRYPTO_ALG_INTERNAL,

	.min_keysize		= AES_MIN_KEY_SIZE,
	.max_keysize		= AES_MAX_KEY_SIZE,
	.walksize		= 8 * AES_BLOCK_SIZE,
	.ivsize			= AES_BLOCK_SIZE,
	.setkey			= aesbs_cbc_setkey,
	.encrypt		= cbc_encrypt,
	.decrypt		= cbc_decrypt,
}, {
	.base.cra_name		= "__ctr(aes)",
	.base.cra_driver_name	= "__ctr-aes-neonbs",
	.base.cra_priority	= 250,
	.base.cra_blocksize	= 1,
	.base.cra_ctxsize	= sizeof(struct aesbs_ctx),
	.base.cra_module	= THIS_MODULE,
	.base.cra_flags		= CRYPTO_ALG_INTERNAL,

	.min_keysize		= AES_MIN_KEY_SIZE,
	.max_keysize		= AES_MAX_KEY_SIZE,
	.chunksize		= AES_BLOCK_SIZE,
	.walksize		= 8 * AES_BLOCK_SIZE,
	.ivsize			= AES_BLOCK_SIZE,
	.setkey			= aesbs_setkey,
	.encrypt		= ctr_encrypt,
	.decrypt		= ctr_encrypt,
}, {
	.base.cra_name		= "ctr(aes)",
	.base.cra_driver_name	= "ctr-aes-neonbs",
	.base.cra_priority	= 250 - 1,
	.base.cra_blocksize	= 1,
	.base.cra_ctxsize	= sizeof(struct aesbs_ctr_ctx),
	.base.cra_module	= THIS_MODULE,

	.min_keysize		= AES_MIN_KEY_SIZE,
	.max_keysize		= AES_MAX_KEY_SIZE,
	.chunksize		= AES_BLOCK_SIZE,
	.walksize		= 8 * AES_BLOCK_SIZE,
	.ivsize			= AES_BLOCK_SIZE,
	.setkey			= aesbs_ctr_setkey_sync,
	.encrypt		= ctr_encrypt_sync,
	.decrypt		= ctr_encrypt_sync,
}, {
	.base.cra_name		= "__xts(aes)",
	.base.cra_driver_name	= "__xts-aes-neonbs",
	.base.cra_priority	= 250,
	.base.cra_blocksize	= AES_BLOCK_SIZE,
	.base.cra_ctxsize	= sizeof(struct aesbs_xts_ctx),
	.base.cra_module	= THIS_MODULE,
	.base.cra_flags		= CRYPTO_ALG_INTERNAL,

	.min_keysize		= 2 * AES_MIN_KEY_SIZE,
	.max_keysize		= 2 * AES_MAX_KEY_SIZE,
	.walksize		= 8 * AES_BLOCK_SIZE,
	.ivsize			= AES_BLOCK_SIZE,
	.setkey			= aesbs_xts_setkey,
	.encrypt		= xts_encrypt,
	.decrypt		= xts_decrypt,
} };

static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];

static void aes_exit(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
		if (aes_simd_algs[i])
			simd_skcipher_free(aes_simd_algs[i]);

	crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}

static int __init aes_init(void)
{
	struct simd_skcipher_alg *simd;
	const char *basename;
	const char *algname;
	const char *drvname;
	int err;
	int i;

	if (!cpu_have_named_feature(ASIMD))
		return -ENODEV;

	err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
	if (err)
		return err;

	for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
		if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
			continue;

		algname = aes_algs[i].base.cra_name + 2;
		drvname = aes_algs[i].base.cra_driver_name + 2;
		basename = aes_algs[i].base.cra_driver_name;
		simd = simd_skcipher_create_compat(algname, drvname, basename);
		err = PTR_ERR(simd);
		if (IS_ERR(simd))
			goto unregister_simds;

		aes_simd_algs[i] = simd;
	}
	return 0;

unregister_simds:
	aes_exit();
	return err;
}

module_init(aes_init);
module_exit(aes_exit);