summaryrefslogtreecommitdiffstats
path: root/crypto/algif_skcipher.c
blob: a19c027b29bde504ac8eae4b4572947a69ed2335 (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
/*
 * algif_skcipher: User-space interface for skcipher algorithms
 *
 * This file provides the user-space API for symmetric key ciphers.
 *
 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */

#include <crypto/scatterwalk.h>
#include <crypto/skcipher.h>
#include <crypto/if_alg.h>
#include <linux/init.h>
#include <linux/list.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/net.h>
#include <net/sock.h>

struct skcipher_sg_list {
	struct list_head list;

	int cur;

	struct scatterlist sg[0];
};

struct skcipher_ctx {
	struct list_head tsgl;
	struct af_alg_sgl rsgl;

	void *iv;

	struct af_alg_completion completion;

	unsigned used;

	unsigned int len;
	bool more;
	bool merge;
	bool enc;

	struct ablkcipher_request req;
};

#define MAX_SGL_ENTS ((PAGE_SIZE - sizeof(struct skcipher_sg_list)) / \
		      sizeof(struct scatterlist) - 1)

static inline int skcipher_sndbuf(struct sock *sk)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;

	return max_t(int, max_t(int, sk->sk_sndbuf & PAGE_MASK, PAGE_SIZE) -
			  ctx->used, 0);
}

static inline bool skcipher_writable(struct sock *sk)
{
	return PAGE_SIZE <= skcipher_sndbuf(sk);
}

static int skcipher_alloc_sgl(struct sock *sk)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct skcipher_sg_list *sgl;
	struct scatterlist *sg = NULL;

	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
	if (!list_empty(&ctx->tsgl))
		sg = sgl->sg;

	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
		sgl = sock_kmalloc(sk, sizeof(*sgl) +
				       sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
				   GFP_KERNEL);
		if (!sgl)
			return -ENOMEM;

		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
		sgl->cur = 0;

		if (sg)
			scatterwalk_sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);

		list_add_tail(&sgl->list, &ctx->tsgl);
	}

	return 0;
}

static void skcipher_pull_sgl(struct sock *sk, int used)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct skcipher_sg_list *sgl;
	struct scatterlist *sg;
	int i;

	while (!list_empty(&ctx->tsgl)) {
		sgl = list_first_entry(&ctx->tsgl, struct skcipher_sg_list,
				       list);
		sg = sgl->sg;

		for (i = 0; i < sgl->cur; i++) {
			int plen = min_t(int, used, sg[i].length);

			if (!sg_page(sg + i))
				continue;

			sg[i].length -= plen;
			sg[i].offset += plen;

			used -= plen;
			ctx->used -= plen;

			if (sg[i].length)
				return;

			put_page(sg_page(sg + i));
			sg_assign_page(sg + i, NULL);
		}

		list_del(&sgl->list);
		sock_kfree_s(sk, sgl,
			     sizeof(*sgl) + sizeof(sgl->sg[0]) *
					    (MAX_SGL_ENTS + 1));
	}

	if (!ctx->used)
		ctx->merge = 0;
}

static void skcipher_free_sgl(struct sock *sk)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;

	skcipher_pull_sgl(sk, ctx->used);
}

static int skcipher_wait_for_wmem(struct sock *sk, unsigned flags)
{
	long timeout;
	DEFINE_WAIT(wait);
	int err = -ERESTARTSYS;

	if (flags & MSG_DONTWAIT)
		return -EAGAIN;

	set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);

	for (;;) {
		if (signal_pending(current))
			break;
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
		timeout = MAX_SCHEDULE_TIMEOUT;
		if (sk_wait_event(sk, &timeout, skcipher_writable(sk))) {
			err = 0;
			break;
		}
	}
	finish_wait(sk_sleep(sk), &wait);

	return err;
}

static void skcipher_wmem_wakeup(struct sock *sk)
{
	struct socket_wq *wq;

	if (!skcipher_writable(sk))
		return;

	rcu_read_lock();
	wq = rcu_dereference(sk->sk_wq);
	if (wq_has_sleeper(wq))
		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
							   POLLRDNORM |
							   POLLRDBAND);
	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
	rcu_read_unlock();
}

static int skcipher_wait_for_data(struct sock *sk, unsigned flags)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	long timeout;
	DEFINE_WAIT(wait);
	int err = -ERESTARTSYS;

	if (flags & MSG_DONTWAIT) {
		return -EAGAIN;
	}

	set_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);

	for (;;) {
		if (signal_pending(current))
			break;
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
		timeout = MAX_SCHEDULE_TIMEOUT;
		if (sk_wait_event(sk, &timeout, ctx->used)) {
			err = 0;
			break;
		}
	}
	finish_wait(sk_sleep(sk), &wait);

	clear_bit(SOCK_ASYNC_WAITDATA, &sk->sk_socket->flags);

	return err;
}

static void skcipher_data_wakeup(struct sock *sk)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct socket_wq *wq;

	if (!ctx->used)
		return;

	rcu_read_lock();
	wq = rcu_dereference(sk->sk_wq);
	if (wq_has_sleeper(wq))
		wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
							   POLLRDNORM |
							   POLLRDBAND);
	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
	rcu_read_unlock();
}

static int skcipher_sendmsg(struct kiocb *unused, struct socket *sock,
			    struct msghdr *msg, size_t size)
{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);
	unsigned ivsize = crypto_ablkcipher_ivsize(tfm);
	struct skcipher_sg_list *sgl;
	struct af_alg_control con = {};
	long copied = 0;
	bool enc = 0;
	int err;
	int i;

	if (msg->msg_controllen) {
		err = af_alg_cmsg_send(msg, &con);
		if (err)
			return err;

		switch (con.op) {
		case ALG_OP_ENCRYPT:
			enc = 1;
			break;
		case ALG_OP_DECRYPT:
			enc = 0;
			break;
		default:
			return -EINVAL;
		}

		if (con.iv && con.iv->ivlen != ivsize)
			return -EINVAL;
	}

	err = -EINVAL;

	lock_sock(sk);
	if (!ctx->more && ctx->used)
		goto unlock;

	if (!ctx->used) {
		ctx->enc = enc;
		if (con.iv)
			memcpy(ctx->iv, con.iv->iv, ivsize);
	}

	while (size) {
		struct scatterlist *sg;
		unsigned long len = size;
		int plen;

		if (ctx->merge) {
			sgl = list_entry(ctx->tsgl.prev,
					 struct skcipher_sg_list, list);
			sg = sgl->sg + sgl->cur - 1;
			len = min_t(unsigned long, len,
				    PAGE_SIZE - sg->offset - sg->length);

			err = memcpy_fromiovec(page_address(sg_page(sg)) +
					       sg->offset + sg->length,
					       msg->msg_iov, len);
			if (err)
				goto unlock;

			sg->length += len;
			ctx->merge = (sg->offset + sg->length) &
				     (PAGE_SIZE - 1);

			ctx->used += len;
			copied += len;
			size -= len;
			continue;
		}

		if (!skcipher_writable(sk)) {
			err = skcipher_wait_for_wmem(sk, msg->msg_flags);
			if (err)
				goto unlock;
		}

		len = min_t(unsigned long, len, skcipher_sndbuf(sk));

		err = skcipher_alloc_sgl(sk);
		if (err)
			goto unlock;

		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);
		sg = sgl->sg;
		do {
			i = sgl->cur;
			plen = min_t(int, len, PAGE_SIZE);

			sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
			err = -ENOMEM;
			if (!sg_page(sg + i))
				goto unlock;

			err = memcpy_fromiovec(page_address(sg_page(sg + i)),
					       msg->msg_iov, plen);
			if (err) {
				__free_page(sg_page(sg + i));
				sg_assign_page(sg + i, NULL);
				goto unlock;
			}

			sg[i].length = plen;
			len -= plen;
			ctx->used += plen;
			copied += plen;
			size -= plen;
			sgl->cur++;
		} while (len && sgl->cur < MAX_SGL_ENTS);

		ctx->merge = plen & (PAGE_SIZE - 1);
	}

	err = 0;

	ctx->more = msg->msg_flags & MSG_MORE;
	if (!ctx->more && !list_empty(&ctx->tsgl))
		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);

unlock:
	skcipher_data_wakeup(sk);
	release_sock(sk);

	return copied ?: err;
}

static ssize_t skcipher_sendpage(struct socket *sock, struct page *page,
				 int offset, size_t size, int flags)
{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct skcipher_sg_list *sgl;
	int err = -EINVAL;

	if (flags & MSG_SENDPAGE_NOTLAST)
		flags |= MSG_MORE;

	lock_sock(sk);
	if (!ctx->more && ctx->used)
		goto unlock;

	if (!size)
		goto done;

	if (!skcipher_writable(sk)) {
		err = skcipher_wait_for_wmem(sk, flags);
		if (err)
			goto unlock;
	}

	err = skcipher_alloc_sgl(sk);
	if (err)
		goto unlock;

	ctx->merge = 0;
	sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);

	get_page(page);
	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
	sgl->cur++;
	ctx->used += size;

done:
	ctx->more = flags & MSG_MORE;
	if (!ctx->more && !list_empty(&ctx->tsgl))
		sgl = list_entry(ctx->tsgl.prev, struct skcipher_sg_list, list);

unlock:
	skcipher_data_wakeup(sk);
	release_sock(sk);

	return err ?: size;
}

static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
			    struct msghdr *msg, size_t ignored, int flags)
{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	unsigned bs = crypto_ablkcipher_blocksize(crypto_ablkcipher_reqtfm(
		&ctx->req));
	struct skcipher_sg_list *sgl;
	struct scatterlist *sg;
	unsigned long iovlen;
	struct iovec *iov;
	int err = -EAGAIN;
	int used;
	long copied = 0;

	lock_sock(sk);
	for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
	     iovlen--, iov++) {
		unsigned long seglen = iov->iov_len;
		char __user *from = iov->iov_base;

		while (seglen) {
			sgl = list_first_entry(&ctx->tsgl,
					       struct skcipher_sg_list, list);
			sg = sgl->sg;

			while (!sg->length)
				sg++;

			used = ctx->used;
			if (!used) {
				err = skcipher_wait_for_data(sk, flags);
				if (err)
					goto unlock;
			}

			used = min_t(unsigned long, used, seglen);

			used = af_alg_make_sg(&ctx->rsgl, from, used, 1);
			err = used;
			if (err < 0)
				goto unlock;

			if (ctx->more || used < ctx->used)
				used -= used % bs;

			err = -EINVAL;
			if (!used)
				goto free;

			ablkcipher_request_set_crypt(&ctx->req, sg,
						     ctx->rsgl.sg, used,
						     ctx->iv);

			err = af_alg_wait_for_completion(
				ctx->enc ?
					crypto_ablkcipher_encrypt(&ctx->req) :
					crypto_ablkcipher_decrypt(&ctx->req),
				&ctx->completion);

free:
			af_alg_free_sg(&ctx->rsgl);

			if (err)
				goto unlock;

			copied += used;
			from += used;
			seglen -= used;
			skcipher_pull_sgl(sk, used);
		}
	}

	err = 0;

unlock:
	skcipher_wmem_wakeup(sk);
	release_sock(sk);

	return copied ?: err;
}


static unsigned int skcipher_poll(struct file *file, struct socket *sock,
				  poll_table *wait)
{
	struct sock *sk = sock->sk;
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	unsigned int mask;

	sock_poll_wait(file, sk_sleep(sk), wait);
	mask = 0;

	if (ctx->used)
		mask |= POLLIN | POLLRDNORM;

	if (skcipher_writable(sk))
		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;

	return mask;
}

static struct proto_ops algif_skcipher_ops = {
	.family		=	PF_ALG,

	.connect	=	sock_no_connect,
	.socketpair	=	sock_no_socketpair,
	.getname	=	sock_no_getname,
	.ioctl		=	sock_no_ioctl,
	.listen		=	sock_no_listen,
	.shutdown	=	sock_no_shutdown,
	.getsockopt	=	sock_no_getsockopt,
	.mmap		=	sock_no_mmap,
	.bind		=	sock_no_bind,
	.accept		=	sock_no_accept,
	.setsockopt	=	sock_no_setsockopt,

	.release	=	af_alg_release,
	.sendmsg	=	skcipher_sendmsg,
	.sendpage	=	skcipher_sendpage,
	.recvmsg	=	skcipher_recvmsg,
	.poll		=	skcipher_poll,
};

static void *skcipher_bind(const char *name, u32 type, u32 mask)
{
	return crypto_alloc_ablkcipher(name, type, mask);
}

static void skcipher_release(void *private)
{
	crypto_free_ablkcipher(private);
}

static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
{
	return crypto_ablkcipher_setkey(private, key, keylen);
}

static void skcipher_sock_destruct(struct sock *sk)
{
	struct alg_sock *ask = alg_sk(sk);
	struct skcipher_ctx *ctx = ask->private;
	struct crypto_ablkcipher *tfm = crypto_ablkcipher_reqtfm(&ctx->req);

	skcipher_free_sgl(sk);
	sock_kfree_s(sk, ctx->iv, crypto_ablkcipher_ivsize(tfm));
	sock_kfree_s(sk, ctx, ctx->len);
	af_alg_release_parent(sk);
}

static int skcipher_accept_parent(void *private, struct sock *sk)
{
	struct skcipher_ctx *ctx;
	struct alg_sock *ask = alg_sk(sk);
	unsigned int len = sizeof(*ctx) + crypto_ablkcipher_reqsize(private);

	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
	if (!ctx)
		return -ENOMEM;

	ctx->iv = sock_kmalloc(sk, crypto_ablkcipher_ivsize(private),
			       GFP_KERNEL);
	if (!ctx->iv) {
		sock_kfree_s(sk, ctx, len);
		return -ENOMEM;
	}

	memset(ctx->iv, 0, crypto_ablkcipher_ivsize(private));

	INIT_LIST_HEAD(&ctx->tsgl);
	ctx->len = len;
	ctx->used = 0;
	ctx->more = 0;
	ctx->merge = 0;
	ctx->enc = 0;
	af_alg_init_completion(&ctx->completion);

	ask->private = ctx;

	ablkcipher_request_set_tfm(&ctx->req, private);
	ablkcipher_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
					af_alg_complete, &ctx->completion);

	sk->sk_destruct = skcipher_sock_destruct;

	return 0;
}

static const struct af_alg_type algif_type_skcipher = {
	.bind		=	skcipher_bind,
	.release	=	skcipher_release,
	.setkey		=	skcipher_setkey,
	.accept		=	skcipher_accept_parent,
	.ops		=	&algif_skcipher_ops,
	.name		=	"skcipher",
	.owner		=	THIS_MODULE
};

static int __init algif_skcipher_init(void)
{
	return af_alg_register_type(&algif_type_skcipher);
}

static void __exit algif_skcipher_exit(void)
{
	int err = af_alg_unregister_type(&algif_type_skcipher);
	BUG_ON(err);
}

module_init(algif_skcipher_init);
module_exit(algif_skcipher_exit);
MODULE_LICENSE("GPL");