summaryrefslogtreecommitdiffstats
path: root/net/tls/tls_sw.c
blob: 61f394d369bf86d69c44b84950632cd5c3519905 (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
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
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
/*
 * Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
 * Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
 * Copyright (c) 2016-2017, Lance Chao <lancerchao@fb.com>. All rights reserved.
 * Copyright (c) 2016, Fridolin Pokorny <fridolin.pokorny@gmail.com>. All rights reserved.
 * Copyright (c) 2016, Nikos Mavrogiannopoulos <nmav@gnutls.org>. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/module.h>
#include <crypto/aead.h>

#include <net/tls.h>

static void trim_sg(struct sock *sk, struct scatterlist *sg,
		    int *sg_num_elem, unsigned int *sg_size, int target_size)
{
	int i = *sg_num_elem - 1;
	int trim = *sg_size - target_size;

	if (trim <= 0) {
		WARN_ON(trim < 0);
		return;
	}

	*sg_size = target_size;
	while (trim >= sg[i].length) {
		trim -= sg[i].length;
		sk_mem_uncharge(sk, sg[i].length);
		put_page(sg_page(&sg[i]));
		i--;

		if (i < 0)
			goto out;
	}

	sg[i].length -= trim;
	sk_mem_uncharge(sk, trim);

out:
	*sg_num_elem = i + 1;
}

static void trim_both_sgl(struct sock *sk, int target_size)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);

	trim_sg(sk, ctx->sg_plaintext_data,
		&ctx->sg_plaintext_num_elem,
		&ctx->sg_plaintext_size,
		target_size);

	if (target_size > 0)
		target_size += tls_ctx->overhead_size;

	trim_sg(sk, ctx->sg_encrypted_data,
		&ctx->sg_encrypted_num_elem,
		&ctx->sg_encrypted_size,
		target_size);
}

static int alloc_sg(struct sock *sk, int len, struct scatterlist *sg,
		    int *sg_num_elem, unsigned int *sg_size,
		    int first_coalesce)
{
	struct page_frag *pfrag;
	unsigned int size = *sg_size;
	int num_elem = *sg_num_elem, use = 0, rc = 0;
	struct scatterlist *sge;
	unsigned int orig_offset;

	len -= size;
	pfrag = sk_page_frag(sk);

	while (len > 0) {
		if (!sk_page_frag_refill(sk, pfrag)) {
			rc = -ENOMEM;
			goto out;
		}

		use = min_t(int, len, pfrag->size - pfrag->offset);

		if (!sk_wmem_schedule(sk, use)) {
			rc = -ENOMEM;
			goto out;
		}

		sk_mem_charge(sk, use);
		size += use;
		orig_offset = pfrag->offset;
		pfrag->offset += use;

		sge = sg + num_elem - 1;
		if (num_elem > first_coalesce && sg_page(sg) == pfrag->page &&
		    sg->offset + sg->length == orig_offset) {
			sg->length += use;
		} else {
			sge++;
			sg_unmark_end(sge);
			sg_set_page(sge, pfrag->page, use, orig_offset);
			get_page(pfrag->page);
			++num_elem;
			if (num_elem == MAX_SKB_FRAGS) {
				rc = -ENOSPC;
				break;
			}
		}

		len -= use;
	}
	goto out;

out:
	*sg_size = size;
	*sg_num_elem = num_elem;
	return rc;
}

static int alloc_encrypted_sg(struct sock *sk, int len)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	int rc = 0;

	rc = alloc_sg(sk, len, ctx->sg_encrypted_data,
		      &ctx->sg_encrypted_num_elem, &ctx->sg_encrypted_size, 0);

	return rc;
}

static int alloc_plaintext_sg(struct sock *sk, int len)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	int rc = 0;

	rc = alloc_sg(sk, len, ctx->sg_plaintext_data,
		      &ctx->sg_plaintext_num_elem, &ctx->sg_plaintext_size,
		      tls_ctx->pending_open_record_frags);

	return rc;
}

static void free_sg(struct sock *sk, struct scatterlist *sg,
		    int *sg_num_elem, unsigned int *sg_size)
{
	int i, n = *sg_num_elem;

	for (i = 0; i < n; ++i) {
		sk_mem_uncharge(sk, sg[i].length);
		put_page(sg_page(&sg[i]));
	}
	*sg_num_elem = 0;
	*sg_size = 0;
}

static void tls_free_both_sg(struct sock *sk)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);

	free_sg(sk, ctx->sg_encrypted_data, &ctx->sg_encrypted_num_elem,
		&ctx->sg_encrypted_size);

	free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem,
		&ctx->sg_plaintext_size);
}

static int tls_do_encryption(struct tls_context *tls_ctx,
			     struct tls_sw_context *ctx, size_t data_len,
			     gfp_t flags)
{
	unsigned int req_size = sizeof(struct aead_request) +
		crypto_aead_reqsize(ctx->aead_send);
	struct aead_request *aead_req;
	int rc;

	aead_req = kzalloc(req_size, flags);
	if (!aead_req)
		return -ENOMEM;

	ctx->sg_encrypted_data[0].offset += tls_ctx->prepend_size;
	ctx->sg_encrypted_data[0].length -= tls_ctx->prepend_size;

	aead_request_set_tfm(aead_req, ctx->aead_send);
	aead_request_set_ad(aead_req, TLS_AAD_SPACE_SIZE);
	aead_request_set_crypt(aead_req, ctx->sg_aead_in, ctx->sg_aead_out,
			       data_len, tls_ctx->iv);
	rc = crypto_aead_encrypt(aead_req);

	ctx->sg_encrypted_data[0].offset -= tls_ctx->prepend_size;
	ctx->sg_encrypted_data[0].length += tls_ctx->prepend_size;

	kfree(aead_req);
	return rc;
}

static int tls_push_record(struct sock *sk, int flags,
			   unsigned char record_type)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	int rc;

	sg_mark_end(ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem - 1);
	sg_mark_end(ctx->sg_encrypted_data + ctx->sg_encrypted_num_elem - 1);

	tls_make_aad(ctx->aad_space, ctx->sg_plaintext_size,
		     tls_ctx->rec_seq, tls_ctx->rec_seq_size,
		     record_type);

	tls_fill_prepend(tls_ctx,
			 page_address(sg_page(&ctx->sg_encrypted_data[0])) +
			 ctx->sg_encrypted_data[0].offset,
			 ctx->sg_plaintext_size, record_type);

	tls_ctx->pending_open_record_frags = 0;
	set_bit(TLS_PENDING_CLOSED_RECORD, &tls_ctx->flags);

	rc = tls_do_encryption(tls_ctx, ctx, ctx->sg_plaintext_size,
			       sk->sk_allocation);
	if (rc < 0) {
		/* If we are called from write_space and
		 * we fail, we need to set this SOCK_NOSPACE
		 * to trigger another write_space in the future.
		 */
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
		return rc;
	}

	free_sg(sk, ctx->sg_plaintext_data, &ctx->sg_plaintext_num_elem,
		&ctx->sg_plaintext_size);

	ctx->sg_encrypted_num_elem = 0;
	ctx->sg_encrypted_size = 0;

	/* Only pass through MSG_DONTWAIT and MSG_NOSIGNAL flags */
	rc = tls_push_sg(sk, tls_ctx, ctx->sg_encrypted_data, 0, flags);
	if (rc < 0 && rc != -EAGAIN)
		tls_err_abort(sk);

	tls_advance_record_sn(sk, tls_ctx);
	return rc;
}

static int tls_sw_push_pending_record(struct sock *sk, int flags)
{
	return tls_push_record(sk, flags, TLS_RECORD_TYPE_DATA);
}

static int zerocopy_from_iter(struct sock *sk, struct iov_iter *from,
			      int length)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	struct page *pages[MAX_SKB_FRAGS];

	size_t offset;
	ssize_t copied, use;
	int i = 0;
	unsigned int size = ctx->sg_plaintext_size;
	int num_elem = ctx->sg_plaintext_num_elem;
	int rc = 0;
	int maxpages;

	while (length > 0) {
		i = 0;
		maxpages = ARRAY_SIZE(ctx->sg_plaintext_data) - num_elem;
		if (maxpages == 0) {
			rc = -EFAULT;
			goto out;
		}
		copied = iov_iter_get_pages(from, pages,
					    length,
					    maxpages, &offset);
		if (copied <= 0) {
			rc = -EFAULT;
			goto out;
		}

		iov_iter_advance(from, copied);

		length -= copied;
		size += copied;
		while (copied) {
			use = min_t(int, copied, PAGE_SIZE - offset);

			sg_set_page(&ctx->sg_plaintext_data[num_elem],
				    pages[i], use, offset);
			sg_unmark_end(&ctx->sg_plaintext_data[num_elem]);
			sk_mem_charge(sk, use);

			offset = 0;
			copied -= use;

			++i;
			++num_elem;
		}
	}

out:
	ctx->sg_plaintext_size = size;
	ctx->sg_plaintext_num_elem = num_elem;
	return rc;
}

static int memcopy_from_iter(struct sock *sk, struct iov_iter *from,
			     int bytes)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	struct scatterlist *sg = ctx->sg_plaintext_data;
	int copy, i, rc = 0;

	for (i = tls_ctx->pending_open_record_frags;
	     i < ctx->sg_plaintext_num_elem; ++i) {
		copy = sg[i].length;
		if (copy_from_iter(
				page_address(sg_page(&sg[i])) + sg[i].offset,
				copy, from) != copy) {
			rc = -EFAULT;
			goto out;
		}
		bytes -= copy;

		++tls_ctx->pending_open_record_frags;

		if (!bytes)
			break;
	}

out:
	return rc;
}

int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	int ret = 0;
	int required_size;
	long timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
	bool eor = !(msg->msg_flags & MSG_MORE);
	size_t try_to_copy, copied = 0;
	unsigned char record_type = TLS_RECORD_TYPE_DATA;
	int record_room;
	bool full_record;
	int orig_size;

	if (msg->msg_flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL))
		return -ENOTSUPP;

	lock_sock(sk);

	if (tls_complete_pending_work(sk, tls_ctx, msg->msg_flags, &timeo))
		goto send_end;

	if (unlikely(msg->msg_controllen)) {
		ret = tls_proccess_cmsg(sk, msg, &record_type);
		if (ret)
			goto send_end;
	}

	while (msg_data_left(msg)) {
		if (sk->sk_err) {
			ret = -sk->sk_err;
			goto send_end;
		}

		orig_size = ctx->sg_plaintext_size;
		full_record = false;
		try_to_copy = msg_data_left(msg);
		record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size;
		if (try_to_copy >= record_room) {
			try_to_copy = record_room;
			full_record = true;
		}

		required_size = ctx->sg_plaintext_size + try_to_copy +
				tls_ctx->overhead_size;

		if (!sk_stream_memory_free(sk))
			goto wait_for_sndbuf;
alloc_encrypted:
		ret = alloc_encrypted_sg(sk, required_size);
		if (ret) {
			if (ret != -ENOSPC)
				goto wait_for_memory;

			/* Adjust try_to_copy according to the amount that was
			 * actually allocated. The difference is due
			 * to max sg elements limit
			 */
			try_to_copy -= required_size - ctx->sg_encrypted_size;
			full_record = true;
		}

		if (full_record || eor) {
			ret = zerocopy_from_iter(sk, &msg->msg_iter,
						 try_to_copy);
			if (ret)
				goto fallback_to_reg_send;

			copied += try_to_copy;
			ret = tls_push_record(sk, msg->msg_flags, record_type);
			if (!ret)
				continue;
			if (ret == -EAGAIN)
				goto send_end;

			copied -= try_to_copy;
fallback_to_reg_send:
			iov_iter_revert(&msg->msg_iter,
					ctx->sg_plaintext_size - orig_size);
			trim_sg(sk, ctx->sg_plaintext_data,
				&ctx->sg_plaintext_num_elem,
				&ctx->sg_plaintext_size,
				orig_size);
		}

		required_size = ctx->sg_plaintext_size + try_to_copy;
alloc_plaintext:
		ret = alloc_plaintext_sg(sk, required_size);
		if (ret) {
			if (ret != -ENOSPC)
				goto wait_for_memory;

			/* Adjust try_to_copy according to the amount that was
			 * actually allocated. The difference is due
			 * to max sg elements limit
			 */
			try_to_copy -= required_size - ctx->sg_plaintext_size;
			full_record = true;

			trim_sg(sk, ctx->sg_encrypted_data,
				&ctx->sg_encrypted_num_elem,
				&ctx->sg_encrypted_size,
				ctx->sg_plaintext_size +
				tls_ctx->overhead_size);
		}

		ret = memcopy_from_iter(sk, &msg->msg_iter, try_to_copy);
		if (ret)
			goto trim_sgl;

		copied += try_to_copy;
		if (full_record || eor) {
push_record:
			ret = tls_push_record(sk, msg->msg_flags, record_type);
			if (ret) {
				if (ret == -ENOMEM)
					goto wait_for_memory;

				goto send_end;
			}
		}

		continue;

wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
		ret = sk_stream_wait_memory(sk, &timeo);
		if (ret) {
trim_sgl:
			trim_both_sgl(sk, orig_size);
			goto send_end;
		}

		if (tls_is_pending_closed_record(tls_ctx))
			goto push_record;

		if (ctx->sg_encrypted_size < required_size)
			goto alloc_encrypted;

		goto alloc_plaintext;
	}

send_end:
	ret = sk_stream_error(sk, msg->msg_flags, ret);

	release_sock(sk);
	return copied ? copied : ret;
}

int tls_sw_sendpage(struct sock *sk, struct page *page,
		    int offset, size_t size, int flags)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);
	int ret = 0;
	long timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
	bool eor;
	size_t orig_size = size;
	unsigned char record_type = TLS_RECORD_TYPE_DATA;
	struct scatterlist *sg;
	bool full_record;
	int record_room;

	if (flags & ~(MSG_MORE | MSG_DONTWAIT | MSG_NOSIGNAL |
		      MSG_SENDPAGE_NOTLAST))
		return -ENOTSUPP;

	/* No MSG_EOR from splice, only look at MSG_MORE */
	eor = !(flags & (MSG_MORE | MSG_SENDPAGE_NOTLAST));

	lock_sock(sk);

	sk_clear_bit(SOCKWQ_ASYNC_NOSPACE, sk);

	if (tls_complete_pending_work(sk, tls_ctx, flags, &timeo))
		goto sendpage_end;

	/* Call the sk_stream functions to manage the sndbuf mem. */
	while (size > 0) {
		size_t copy, required_size;

		if (sk->sk_err) {
			ret = -sk->sk_err;
			goto sendpage_end;
		}

		full_record = false;
		record_room = TLS_MAX_PAYLOAD_SIZE - ctx->sg_plaintext_size;
		copy = size;
		if (copy >= record_room) {
			copy = record_room;
			full_record = true;
		}
		required_size = ctx->sg_plaintext_size + copy +
			      tls_ctx->overhead_size;

		if (!sk_stream_memory_free(sk))
			goto wait_for_sndbuf;
alloc_payload:
		ret = alloc_encrypted_sg(sk, required_size);
		if (ret) {
			if (ret != -ENOSPC)
				goto wait_for_memory;

			/* Adjust copy according to the amount that was
			 * actually allocated. The difference is due
			 * to max sg elements limit
			 */
			copy -= required_size - ctx->sg_plaintext_size;
			full_record = true;
		}

		get_page(page);
		sg = ctx->sg_plaintext_data + ctx->sg_plaintext_num_elem;
		sg_set_page(sg, page, copy, offset);
		ctx->sg_plaintext_num_elem++;

		sk_mem_charge(sk, copy);
		offset += copy;
		size -= copy;
		ctx->sg_plaintext_size += copy;
		tls_ctx->pending_open_record_frags = ctx->sg_plaintext_num_elem;

		if (full_record || eor ||
		    ctx->sg_plaintext_num_elem ==
		    ARRAY_SIZE(ctx->sg_plaintext_data)) {
push_record:
			ret = tls_push_record(sk, flags, record_type);
			if (ret) {
				if (ret == -ENOMEM)
					goto wait_for_memory;

				goto sendpage_end;
			}
		}
		continue;
wait_for_sndbuf:
		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
wait_for_memory:
		ret = sk_stream_wait_memory(sk, &timeo);
		if (ret) {
			trim_both_sgl(sk, ctx->sg_plaintext_size);
			goto sendpage_end;
		}

		if (tls_is_pending_closed_record(tls_ctx))
			goto push_record;

		goto alloc_payload;
	}

sendpage_end:
	if (orig_size > size)
		ret = orig_size - size;
	else
		ret = sk_stream_error(sk, flags, ret);

	release_sock(sk);
	return ret;
}

void tls_sw_free_tx_resources(struct sock *sk)
{
	struct tls_context *tls_ctx = tls_get_ctx(sk);
	struct tls_sw_context *ctx = tls_sw_ctx(tls_ctx);

	if (ctx->aead_send)
		crypto_free_aead(ctx->aead_send);

	tls_free_both_sg(sk);

	kfree(ctx);
	kfree(tls_ctx);
}

int tls_set_sw_offload(struct sock *sk, struct tls_context *ctx)
{
	char keyval[TLS_CIPHER_AES_GCM_128_KEY_SIZE];
	struct tls_crypto_info *crypto_info;
	struct tls12_crypto_info_aes_gcm_128 *gcm_128_info;
	struct tls_sw_context *sw_ctx;
	u16 nonce_size, tag_size, iv_size, rec_seq_size;
	char *iv, *rec_seq;
	int rc = 0;

	if (!ctx) {
		rc = -EINVAL;
		goto out;
	}

	if (ctx->priv_ctx) {
		rc = -EEXIST;
		goto out;
	}

	sw_ctx = kzalloc(sizeof(*sw_ctx), GFP_KERNEL);
	if (!sw_ctx) {
		rc = -ENOMEM;
		goto out;
	}

	ctx->priv_ctx = (struct tls_offload_context *)sw_ctx;

	crypto_info = &ctx->crypto_send;
	switch (crypto_info->cipher_type) {
	case TLS_CIPHER_AES_GCM_128: {
		nonce_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
		tag_size = TLS_CIPHER_AES_GCM_128_TAG_SIZE;
		iv_size = TLS_CIPHER_AES_GCM_128_IV_SIZE;
		iv = ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->iv;
		rec_seq_size = TLS_CIPHER_AES_GCM_128_REC_SEQ_SIZE;
		rec_seq =
		 ((struct tls12_crypto_info_aes_gcm_128 *)crypto_info)->rec_seq;
		gcm_128_info =
			(struct tls12_crypto_info_aes_gcm_128 *)crypto_info;
		break;
	}
	default:
		rc = -EINVAL;
		goto free_priv;
	}

	ctx->prepend_size = TLS_HEADER_SIZE + nonce_size;
	ctx->tag_size = tag_size;
	ctx->overhead_size = ctx->prepend_size + ctx->tag_size;
	ctx->iv_size = iv_size;
	ctx->iv = kmalloc(iv_size + TLS_CIPHER_AES_GCM_128_SALT_SIZE, GFP_KERNEL);
	if (!ctx->iv) {
		rc = -ENOMEM;
		goto free_priv;
	}
	memcpy(ctx->iv, gcm_128_info->salt, TLS_CIPHER_AES_GCM_128_SALT_SIZE);
	memcpy(ctx->iv + TLS_CIPHER_AES_GCM_128_SALT_SIZE, iv, iv_size);
	ctx->rec_seq_size = rec_seq_size;
	ctx->rec_seq = kmalloc(rec_seq_size, GFP_KERNEL);
	if (!ctx->rec_seq) {
		rc = -ENOMEM;
		goto free_iv;
	}
	memcpy(ctx->rec_seq, rec_seq, rec_seq_size);

	sg_init_table(sw_ctx->sg_encrypted_data,
		      ARRAY_SIZE(sw_ctx->sg_encrypted_data));
	sg_init_table(sw_ctx->sg_plaintext_data,
		      ARRAY_SIZE(sw_ctx->sg_plaintext_data));

	sg_init_table(sw_ctx->sg_aead_in, 2);
	sg_set_buf(&sw_ctx->sg_aead_in[0], sw_ctx->aad_space,
		   sizeof(sw_ctx->aad_space));
	sg_unmark_end(&sw_ctx->sg_aead_in[1]);
	sg_chain(sw_ctx->sg_aead_in, 2, sw_ctx->sg_plaintext_data);
	sg_init_table(sw_ctx->sg_aead_out, 2);
	sg_set_buf(&sw_ctx->sg_aead_out[0], sw_ctx->aad_space,
		   sizeof(sw_ctx->aad_space));
	sg_unmark_end(&sw_ctx->sg_aead_out[1]);
	sg_chain(sw_ctx->sg_aead_out, 2, sw_ctx->sg_encrypted_data);

	if (!sw_ctx->aead_send) {
		sw_ctx->aead_send = crypto_alloc_aead("gcm(aes)", 0, 0);
		if (IS_ERR(sw_ctx->aead_send)) {
			rc = PTR_ERR(sw_ctx->aead_send);
			sw_ctx->aead_send = NULL;
			goto free_rec_seq;
		}
	}

	ctx->push_pending_record = tls_sw_push_pending_record;

	memcpy(keyval, gcm_128_info->key, TLS_CIPHER_AES_GCM_128_KEY_SIZE);

	rc = crypto_aead_setkey(sw_ctx->aead_send, keyval,
				TLS_CIPHER_AES_GCM_128_KEY_SIZE);
	if (rc)
		goto free_aead;

	rc = crypto_aead_setauthsize(sw_ctx->aead_send, ctx->tag_size);
	if (!rc)
		return 0;

free_aead:
	crypto_free_aead(sw_ctx->aead_send);
	sw_ctx->aead_send = NULL;
free_rec_seq:
	kfree(ctx->rec_seq);
	ctx->rec_seq = NULL;
free_iv:
	kfree(ctx->iv);
	ctx->iv = NULL;
free_priv:
	kfree(ctx->priv_ctx);
	ctx->priv_ctx = NULL;
out:
	return rc;
}