xref: /openbmc/linux/crypto/af_alg.c (revision 68198dca)
1 /*
2  * af_alg: User-space algorithm interface
3  *
4  * This file provides the user-space API for algorithms.
5  *
6  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms of the GNU General Public License as published by the Free
10  * Software Foundation; either version 2 of the License, or (at your option)
11  * any later version.
12  *
13  */
14 
15 #include <linux/atomic.h>
16 #include <crypto/if_alg.h>
17 #include <linux/crypto.h>
18 #include <linux/init.h>
19 #include <linux/kernel.h>
20 #include <linux/list.h>
21 #include <linux/module.h>
22 #include <linux/net.h>
23 #include <linux/rwsem.h>
24 #include <linux/sched/signal.h>
25 #include <linux/security.h>
26 
27 struct alg_type_list {
28 	const struct af_alg_type *type;
29 	struct list_head list;
30 };
31 
32 static atomic_long_t alg_memory_allocated;
33 
34 static struct proto alg_proto = {
35 	.name			= "ALG",
36 	.owner			= THIS_MODULE,
37 	.memory_allocated	= &alg_memory_allocated,
38 	.obj_size		= sizeof(struct alg_sock),
39 };
40 
41 static LIST_HEAD(alg_types);
42 static DECLARE_RWSEM(alg_types_sem);
43 
44 static const struct af_alg_type *alg_get_type(const char *name)
45 {
46 	const struct af_alg_type *type = ERR_PTR(-ENOENT);
47 	struct alg_type_list *node;
48 
49 	down_read(&alg_types_sem);
50 	list_for_each_entry(node, &alg_types, list) {
51 		if (strcmp(node->type->name, name))
52 			continue;
53 
54 		if (try_module_get(node->type->owner))
55 			type = node->type;
56 		break;
57 	}
58 	up_read(&alg_types_sem);
59 
60 	return type;
61 }
62 
63 int af_alg_register_type(const struct af_alg_type *type)
64 {
65 	struct alg_type_list *node;
66 	int err = -EEXIST;
67 
68 	down_write(&alg_types_sem);
69 	list_for_each_entry(node, &alg_types, list) {
70 		if (!strcmp(node->type->name, type->name))
71 			goto unlock;
72 	}
73 
74 	node = kmalloc(sizeof(*node), GFP_KERNEL);
75 	err = -ENOMEM;
76 	if (!node)
77 		goto unlock;
78 
79 	type->ops->owner = THIS_MODULE;
80 	if (type->ops_nokey)
81 		type->ops_nokey->owner = THIS_MODULE;
82 	node->type = type;
83 	list_add(&node->list, &alg_types);
84 	err = 0;
85 
86 unlock:
87 	up_write(&alg_types_sem);
88 
89 	return err;
90 }
91 EXPORT_SYMBOL_GPL(af_alg_register_type);
92 
93 int af_alg_unregister_type(const struct af_alg_type *type)
94 {
95 	struct alg_type_list *node;
96 	int err = -ENOENT;
97 
98 	down_write(&alg_types_sem);
99 	list_for_each_entry(node, &alg_types, list) {
100 		if (strcmp(node->type->name, type->name))
101 			continue;
102 
103 		list_del(&node->list);
104 		kfree(node);
105 		err = 0;
106 		break;
107 	}
108 	up_write(&alg_types_sem);
109 
110 	return err;
111 }
112 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
113 
114 static void alg_do_release(const struct af_alg_type *type, void *private)
115 {
116 	if (!type)
117 		return;
118 
119 	type->release(private);
120 	module_put(type->owner);
121 }
122 
123 int af_alg_release(struct socket *sock)
124 {
125 	if (sock->sk)
126 		sock_put(sock->sk);
127 	return 0;
128 }
129 EXPORT_SYMBOL_GPL(af_alg_release);
130 
131 void af_alg_release_parent(struct sock *sk)
132 {
133 	struct alg_sock *ask = alg_sk(sk);
134 	unsigned int nokey = ask->nokey_refcnt;
135 	bool last = nokey && !ask->refcnt;
136 
137 	sk = ask->parent;
138 	ask = alg_sk(sk);
139 
140 	lock_sock(sk);
141 	ask->nokey_refcnt -= nokey;
142 	if (!last)
143 		last = !--ask->refcnt;
144 	release_sock(sk);
145 
146 	if (last)
147 		sock_put(sk);
148 }
149 EXPORT_SYMBOL_GPL(af_alg_release_parent);
150 
151 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
152 {
153 	const u32 forbidden = CRYPTO_ALG_INTERNAL;
154 	struct sock *sk = sock->sk;
155 	struct alg_sock *ask = alg_sk(sk);
156 	struct sockaddr_alg *sa = (void *)uaddr;
157 	const struct af_alg_type *type;
158 	void *private;
159 	int err;
160 
161 	if (sock->state == SS_CONNECTED)
162 		return -EINVAL;
163 
164 	if (addr_len < sizeof(*sa))
165 		return -EINVAL;
166 
167 	sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
168 	sa->salg_name[sizeof(sa->salg_name) + addr_len - sizeof(*sa) - 1] = 0;
169 
170 	type = alg_get_type(sa->salg_type);
171 	if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
172 		request_module("algif-%s", sa->salg_type);
173 		type = alg_get_type(sa->salg_type);
174 	}
175 
176 	if (IS_ERR(type))
177 		return PTR_ERR(type);
178 
179 	private = type->bind(sa->salg_name,
180 			     sa->salg_feat & ~forbidden,
181 			     sa->salg_mask & ~forbidden);
182 	if (IS_ERR(private)) {
183 		module_put(type->owner);
184 		return PTR_ERR(private);
185 	}
186 
187 	err = -EBUSY;
188 	lock_sock(sk);
189 	if (ask->refcnt | ask->nokey_refcnt)
190 		goto unlock;
191 
192 	swap(ask->type, type);
193 	swap(ask->private, private);
194 
195 	err = 0;
196 
197 unlock:
198 	release_sock(sk);
199 
200 	alg_do_release(type, private);
201 
202 	return err;
203 }
204 
205 static int alg_setkey(struct sock *sk, char __user *ukey,
206 		      unsigned int keylen)
207 {
208 	struct alg_sock *ask = alg_sk(sk);
209 	const struct af_alg_type *type = ask->type;
210 	u8 *key;
211 	int err;
212 
213 	key = sock_kmalloc(sk, keylen, GFP_KERNEL);
214 	if (!key)
215 		return -ENOMEM;
216 
217 	err = -EFAULT;
218 	if (copy_from_user(key, ukey, keylen))
219 		goto out;
220 
221 	err = type->setkey(ask->private, key, keylen);
222 
223 out:
224 	sock_kzfree_s(sk, key, keylen);
225 
226 	return err;
227 }
228 
229 static int alg_setsockopt(struct socket *sock, int level, int optname,
230 			  char __user *optval, unsigned int optlen)
231 {
232 	struct sock *sk = sock->sk;
233 	struct alg_sock *ask = alg_sk(sk);
234 	const struct af_alg_type *type;
235 	int err = -EBUSY;
236 
237 	lock_sock(sk);
238 	if (ask->refcnt)
239 		goto unlock;
240 
241 	type = ask->type;
242 
243 	err = -ENOPROTOOPT;
244 	if (level != SOL_ALG || !type)
245 		goto unlock;
246 
247 	switch (optname) {
248 	case ALG_SET_KEY:
249 		if (sock->state == SS_CONNECTED)
250 			goto unlock;
251 		if (!type->setkey)
252 			goto unlock;
253 
254 		err = alg_setkey(sk, optval, optlen);
255 		break;
256 	case ALG_SET_AEAD_AUTHSIZE:
257 		if (sock->state == SS_CONNECTED)
258 			goto unlock;
259 		if (!type->setauthsize)
260 			goto unlock;
261 		err = type->setauthsize(ask->private, optlen);
262 	}
263 
264 unlock:
265 	release_sock(sk);
266 
267 	return err;
268 }
269 
270 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
271 {
272 	struct alg_sock *ask = alg_sk(sk);
273 	const struct af_alg_type *type;
274 	struct sock *sk2;
275 	unsigned int nokey;
276 	int err;
277 
278 	lock_sock(sk);
279 	type = ask->type;
280 
281 	err = -EINVAL;
282 	if (!type)
283 		goto unlock;
284 
285 	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
286 	err = -ENOMEM;
287 	if (!sk2)
288 		goto unlock;
289 
290 	sock_init_data(newsock, sk2);
291 	security_sock_graft(sk2, newsock);
292 	security_sk_clone(sk, sk2);
293 
294 	err = type->accept(ask->private, sk2);
295 
296 	nokey = err == -ENOKEY;
297 	if (nokey && type->accept_nokey)
298 		err = type->accept_nokey(ask->private, sk2);
299 
300 	if (err)
301 		goto unlock;
302 
303 	sk2->sk_family = PF_ALG;
304 
305 	if (nokey || !ask->refcnt++)
306 		sock_hold(sk);
307 	ask->nokey_refcnt += nokey;
308 	alg_sk(sk2)->parent = sk;
309 	alg_sk(sk2)->type = type;
310 	alg_sk(sk2)->nokey_refcnt = nokey;
311 
312 	newsock->ops = type->ops;
313 	newsock->state = SS_CONNECTED;
314 
315 	if (nokey)
316 		newsock->ops = type->ops_nokey;
317 
318 	err = 0;
319 
320 unlock:
321 	release_sock(sk);
322 
323 	return err;
324 }
325 EXPORT_SYMBOL_GPL(af_alg_accept);
326 
327 static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
328 		      bool kern)
329 {
330 	return af_alg_accept(sock->sk, newsock, kern);
331 }
332 
333 static const struct proto_ops alg_proto_ops = {
334 	.family		=	PF_ALG,
335 	.owner		=	THIS_MODULE,
336 
337 	.connect	=	sock_no_connect,
338 	.socketpair	=	sock_no_socketpair,
339 	.getname	=	sock_no_getname,
340 	.ioctl		=	sock_no_ioctl,
341 	.listen		=	sock_no_listen,
342 	.shutdown	=	sock_no_shutdown,
343 	.getsockopt	=	sock_no_getsockopt,
344 	.mmap		=	sock_no_mmap,
345 	.sendpage	=	sock_no_sendpage,
346 	.sendmsg	=	sock_no_sendmsg,
347 	.recvmsg	=	sock_no_recvmsg,
348 	.poll		=	sock_no_poll,
349 
350 	.bind		=	alg_bind,
351 	.release	=	af_alg_release,
352 	.setsockopt	=	alg_setsockopt,
353 	.accept		=	alg_accept,
354 };
355 
356 static void alg_sock_destruct(struct sock *sk)
357 {
358 	struct alg_sock *ask = alg_sk(sk);
359 
360 	alg_do_release(ask->type, ask->private);
361 }
362 
363 static int alg_create(struct net *net, struct socket *sock, int protocol,
364 		      int kern)
365 {
366 	struct sock *sk;
367 	int err;
368 
369 	if (sock->type != SOCK_SEQPACKET)
370 		return -ESOCKTNOSUPPORT;
371 	if (protocol != 0)
372 		return -EPROTONOSUPPORT;
373 
374 	err = -ENOMEM;
375 	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
376 	if (!sk)
377 		goto out;
378 
379 	sock->ops = &alg_proto_ops;
380 	sock_init_data(sock, sk);
381 
382 	sk->sk_family = PF_ALG;
383 	sk->sk_destruct = alg_sock_destruct;
384 
385 	return 0;
386 out:
387 	return err;
388 }
389 
390 static const struct net_proto_family alg_family = {
391 	.family	=	PF_ALG,
392 	.create	=	alg_create,
393 	.owner	=	THIS_MODULE,
394 };
395 
396 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
397 {
398 	size_t off;
399 	ssize_t n;
400 	int npages, i;
401 
402 	n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
403 	if (n < 0)
404 		return n;
405 
406 	npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
407 	if (WARN_ON(npages == 0))
408 		return -EINVAL;
409 	/* Add one extra for linking */
410 	sg_init_table(sgl->sg, npages + 1);
411 
412 	for (i = 0, len = n; i < npages; i++) {
413 		int plen = min_t(int, len, PAGE_SIZE - off);
414 
415 		sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
416 
417 		off = 0;
418 		len -= plen;
419 	}
420 	sg_mark_end(sgl->sg + npages - 1);
421 	sgl->npages = npages;
422 
423 	return n;
424 }
425 EXPORT_SYMBOL_GPL(af_alg_make_sg);
426 
427 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
428 {
429 	sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
430 	sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
431 }
432 EXPORT_SYMBOL_GPL(af_alg_link_sg);
433 
434 void af_alg_free_sg(struct af_alg_sgl *sgl)
435 {
436 	int i;
437 
438 	for (i = 0; i < sgl->npages; i++)
439 		put_page(sgl->pages[i]);
440 }
441 EXPORT_SYMBOL_GPL(af_alg_free_sg);
442 
443 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
444 {
445 	struct cmsghdr *cmsg;
446 
447 	for_each_cmsghdr(cmsg, msg) {
448 		if (!CMSG_OK(msg, cmsg))
449 			return -EINVAL;
450 		if (cmsg->cmsg_level != SOL_ALG)
451 			continue;
452 
453 		switch (cmsg->cmsg_type) {
454 		case ALG_SET_IV:
455 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
456 				return -EINVAL;
457 			con->iv = (void *)CMSG_DATA(cmsg);
458 			if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
459 						      sizeof(*con->iv)))
460 				return -EINVAL;
461 			break;
462 
463 		case ALG_SET_OP:
464 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
465 				return -EINVAL;
466 			con->op = *(u32 *)CMSG_DATA(cmsg);
467 			break;
468 
469 		case ALG_SET_AEAD_ASSOCLEN:
470 			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
471 				return -EINVAL;
472 			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
473 			break;
474 
475 		default:
476 			return -EINVAL;
477 		}
478 	}
479 
480 	return 0;
481 }
482 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
483 
484 /**
485  * af_alg_alloc_tsgl - allocate the TX SGL
486  *
487  * @sk socket of connection to user space
488  * @return: 0 upon success, < 0 upon error
489  */
490 int af_alg_alloc_tsgl(struct sock *sk)
491 {
492 	struct alg_sock *ask = alg_sk(sk);
493 	struct af_alg_ctx *ctx = ask->private;
494 	struct af_alg_tsgl *sgl;
495 	struct scatterlist *sg = NULL;
496 
497 	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
498 	if (!list_empty(&ctx->tsgl_list))
499 		sg = sgl->sg;
500 
501 	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
502 		sgl = sock_kmalloc(sk, sizeof(*sgl) +
503 				       sizeof(sgl->sg[0]) * (MAX_SGL_ENTS + 1),
504 				   GFP_KERNEL);
505 		if (!sgl)
506 			return -ENOMEM;
507 
508 		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
509 		sgl->cur = 0;
510 
511 		if (sg)
512 			sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
513 
514 		list_add_tail(&sgl->list, &ctx->tsgl_list);
515 	}
516 
517 	return 0;
518 }
519 EXPORT_SYMBOL_GPL(af_alg_alloc_tsgl);
520 
521 /**
522  * aead_count_tsgl - Count number of TX SG entries
523  *
524  * The counting starts from the beginning of the SGL to @bytes. If
525  * an offset is provided, the counting of the SG entries starts at the offset.
526  *
527  * @sk socket of connection to user space
528  * @bytes Count the number of SG entries holding given number of bytes.
529  * @offset Start the counting of SG entries from the given offset.
530  * @return Number of TX SG entries found given the constraints
531  */
532 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
533 {
534 	struct alg_sock *ask = alg_sk(sk);
535 	struct af_alg_ctx *ctx = ask->private;
536 	struct af_alg_tsgl *sgl, *tmp;
537 	unsigned int i;
538 	unsigned int sgl_count = 0;
539 
540 	if (!bytes)
541 		return 0;
542 
543 	list_for_each_entry_safe(sgl, tmp, &ctx->tsgl_list, list) {
544 		struct scatterlist *sg = sgl->sg;
545 
546 		for (i = 0; i < sgl->cur; i++) {
547 			size_t bytes_count;
548 
549 			/* Skip offset */
550 			if (offset >= sg[i].length) {
551 				offset -= sg[i].length;
552 				bytes -= sg[i].length;
553 				continue;
554 			}
555 
556 			bytes_count = sg[i].length - offset;
557 
558 			offset = 0;
559 			sgl_count++;
560 
561 			/* If we have seen requested number of bytes, stop */
562 			if (bytes_count >= bytes)
563 				return sgl_count;
564 
565 			bytes -= bytes_count;
566 		}
567 	}
568 
569 	return sgl_count;
570 }
571 EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
572 
573 /**
574  * aead_pull_tsgl - Release the specified buffers from TX SGL
575  *
576  * If @dst is non-null, reassign the pages to dst. The caller must release
577  * the pages. If @dst_offset is given only reassign the pages to @dst starting
578  * at the @dst_offset (byte). The caller must ensure that @dst is large
579  * enough (e.g. by using af_alg_count_tsgl with the same offset).
580  *
581  * @sk socket of connection to user space
582  * @used Number of bytes to pull from TX SGL
583  * @dst If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
584  *	caller must release the buffers in dst.
585  * @dst_offset Reassign the TX SGL from given offset. All buffers before
586  *	       reaching the offset is released.
587  */
588 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
589 		      size_t dst_offset)
590 {
591 	struct alg_sock *ask = alg_sk(sk);
592 	struct af_alg_ctx *ctx = ask->private;
593 	struct af_alg_tsgl *sgl;
594 	struct scatterlist *sg;
595 	unsigned int i, j = 0;
596 
597 	while (!list_empty(&ctx->tsgl_list)) {
598 		sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
599 				       list);
600 		sg = sgl->sg;
601 
602 		for (i = 0; i < sgl->cur; i++) {
603 			size_t plen = min_t(size_t, used, sg[i].length);
604 			struct page *page = sg_page(sg + i);
605 
606 			if (!page)
607 				continue;
608 
609 			/*
610 			 * Assumption: caller created af_alg_count_tsgl(len)
611 			 * SG entries in dst.
612 			 */
613 			if (dst) {
614 				if (dst_offset >= plen) {
615 					/* discard page before offset */
616 					dst_offset -= plen;
617 				} else {
618 					/* reassign page to dst after offset */
619 					get_page(page);
620 					sg_set_page(dst + j, page,
621 						    plen - dst_offset,
622 						    sg[i].offset + dst_offset);
623 					dst_offset = 0;
624 					j++;
625 				}
626 			}
627 
628 			sg[i].length -= plen;
629 			sg[i].offset += plen;
630 
631 			used -= plen;
632 			ctx->used -= plen;
633 
634 			if (sg[i].length)
635 				return;
636 
637 			put_page(page);
638 			sg_assign_page(sg + i, NULL);
639 		}
640 
641 		list_del(&sgl->list);
642 		sock_kfree_s(sk, sgl, sizeof(*sgl) + sizeof(sgl->sg[0]) *
643 						     (MAX_SGL_ENTS + 1));
644 	}
645 
646 	if (!ctx->used)
647 		ctx->merge = 0;
648 }
649 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
650 
651 /**
652  * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
653  *
654  * @areq Request holding the TX and RX SGL
655  */
656 void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
657 {
658 	struct sock *sk = areq->sk;
659 	struct alg_sock *ask = alg_sk(sk);
660 	struct af_alg_ctx *ctx = ask->private;
661 	struct af_alg_rsgl *rsgl, *tmp;
662 	struct scatterlist *tsgl;
663 	struct scatterlist *sg;
664 	unsigned int i;
665 
666 	list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
667 		ctx->rcvused -= rsgl->sg_num_bytes;
668 		af_alg_free_sg(&rsgl->sgl);
669 		list_del(&rsgl->list);
670 		if (rsgl != &areq->first_rsgl)
671 			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
672 	}
673 
674 	tsgl = areq->tsgl;
675 	if (tsgl) {
676 		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
677 			if (!sg_page(sg))
678 				continue;
679 			put_page(sg_page(sg));
680 		}
681 
682 		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
683 	}
684 }
685 EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls);
686 
687 /**
688  * af_alg_wait_for_wmem - wait for availability of writable memory
689  *
690  * @sk socket of connection to user space
691  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
692  * @return 0 when writable memory is available, < 0 upon error
693  */
694 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
695 {
696 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
697 	int err = -ERESTARTSYS;
698 	long timeout;
699 
700 	if (flags & MSG_DONTWAIT)
701 		return -EAGAIN;
702 
703 	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
704 
705 	add_wait_queue(sk_sleep(sk), &wait);
706 	for (;;) {
707 		if (signal_pending(current))
708 			break;
709 		timeout = MAX_SCHEDULE_TIMEOUT;
710 		if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
711 			err = 0;
712 			break;
713 		}
714 	}
715 	remove_wait_queue(sk_sleep(sk), &wait);
716 
717 	return err;
718 }
719 EXPORT_SYMBOL_GPL(af_alg_wait_for_wmem);
720 
721 /**
722  * af_alg_wmem_wakeup - wakeup caller when writable memory is available
723  *
724  * @sk socket of connection to user space
725  */
726 void af_alg_wmem_wakeup(struct sock *sk)
727 {
728 	struct socket_wq *wq;
729 
730 	if (!af_alg_writable(sk))
731 		return;
732 
733 	rcu_read_lock();
734 	wq = rcu_dereference(sk->sk_wq);
735 	if (skwq_has_sleeper(wq))
736 		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
737 							   POLLRDNORM |
738 							   POLLRDBAND);
739 	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
740 	rcu_read_unlock();
741 }
742 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
743 
744 /**
745  * af_alg_wait_for_data - wait for availability of TX data
746  *
747  * @sk socket of connection to user space
748  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
749  * @return 0 when writable memory is available, < 0 upon error
750  */
751 int af_alg_wait_for_data(struct sock *sk, unsigned flags)
752 {
753 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
754 	struct alg_sock *ask = alg_sk(sk);
755 	struct af_alg_ctx *ctx = ask->private;
756 	long timeout;
757 	int err = -ERESTARTSYS;
758 
759 	if (flags & MSG_DONTWAIT)
760 		return -EAGAIN;
761 
762 	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
763 
764 	add_wait_queue(sk_sleep(sk), &wait);
765 	for (;;) {
766 		if (signal_pending(current))
767 			break;
768 		timeout = MAX_SCHEDULE_TIMEOUT;
769 		if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
770 				  &wait)) {
771 			err = 0;
772 			break;
773 		}
774 	}
775 	remove_wait_queue(sk_sleep(sk), &wait);
776 
777 	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
778 
779 	return err;
780 }
781 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
782 
783 /**
784  * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
785  *
786  * @sk socket of connection to user space
787  */
788 
789 void af_alg_data_wakeup(struct sock *sk)
790 {
791 	struct alg_sock *ask = alg_sk(sk);
792 	struct af_alg_ctx *ctx = ask->private;
793 	struct socket_wq *wq;
794 
795 	if (!ctx->used)
796 		return;
797 
798 	rcu_read_lock();
799 	wq = rcu_dereference(sk->sk_wq);
800 	if (skwq_has_sleeper(wq))
801 		wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
802 							   POLLRDNORM |
803 							   POLLRDBAND);
804 	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
805 	rcu_read_unlock();
806 }
807 EXPORT_SYMBOL_GPL(af_alg_data_wakeup);
808 
809 /**
810  * af_alg_sendmsg - implementation of sendmsg system call handler
811  *
812  * The sendmsg system call handler obtains the user data and stores it
813  * in ctx->tsgl_list. This implies allocation of the required numbers of
814  * struct af_alg_tsgl.
815  *
816  * In addition, the ctx is filled with the information sent via CMSG.
817  *
818  * @sock socket of connection to user space
819  * @msg message from user space
820  * @size size of message from user space
821  * @ivsize the size of the IV for the cipher operation to verify that the
822  *	   user-space-provided IV has the right size
823  * @return the number of copied data upon success, < 0 upon error
824  */
825 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
826 		   unsigned int ivsize)
827 {
828 	struct sock *sk = sock->sk;
829 	struct alg_sock *ask = alg_sk(sk);
830 	struct af_alg_ctx *ctx = ask->private;
831 	struct af_alg_tsgl *sgl;
832 	struct af_alg_control con = {};
833 	long copied = 0;
834 	bool enc = 0;
835 	bool init = 0;
836 	int err = 0;
837 
838 	if (msg->msg_controllen) {
839 		err = af_alg_cmsg_send(msg, &con);
840 		if (err)
841 			return err;
842 
843 		init = 1;
844 		switch (con.op) {
845 		case ALG_OP_ENCRYPT:
846 			enc = 1;
847 			break;
848 		case ALG_OP_DECRYPT:
849 			enc = 0;
850 			break;
851 		default:
852 			return -EINVAL;
853 		}
854 
855 		if (con.iv && con.iv->ivlen != ivsize)
856 			return -EINVAL;
857 	}
858 
859 	lock_sock(sk);
860 	if (!ctx->more && ctx->used) {
861 		err = -EINVAL;
862 		goto unlock;
863 	}
864 
865 	if (init) {
866 		ctx->enc = enc;
867 		if (con.iv)
868 			memcpy(ctx->iv, con.iv->iv, ivsize);
869 
870 		ctx->aead_assoclen = con.aead_assoclen;
871 	}
872 
873 	while (size) {
874 		struct scatterlist *sg;
875 		size_t len = size;
876 		size_t plen;
877 
878 		/* use the existing memory in an allocated page */
879 		if (ctx->merge) {
880 			sgl = list_entry(ctx->tsgl_list.prev,
881 					 struct af_alg_tsgl, list);
882 			sg = sgl->sg + sgl->cur - 1;
883 			len = min_t(size_t, len,
884 				    PAGE_SIZE - sg->offset - sg->length);
885 
886 			err = memcpy_from_msg(page_address(sg_page(sg)) +
887 					      sg->offset + sg->length,
888 					      msg, len);
889 			if (err)
890 				goto unlock;
891 
892 			sg->length += len;
893 			ctx->merge = (sg->offset + sg->length) &
894 				     (PAGE_SIZE - 1);
895 
896 			ctx->used += len;
897 			copied += len;
898 			size -= len;
899 			continue;
900 		}
901 
902 		if (!af_alg_writable(sk)) {
903 			err = af_alg_wait_for_wmem(sk, msg->msg_flags);
904 			if (err)
905 				goto unlock;
906 		}
907 
908 		/* allocate a new page */
909 		len = min_t(unsigned long, len, af_alg_sndbuf(sk));
910 
911 		err = af_alg_alloc_tsgl(sk);
912 		if (err)
913 			goto unlock;
914 
915 		sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
916 				 list);
917 		sg = sgl->sg;
918 		if (sgl->cur)
919 			sg_unmark_end(sg + sgl->cur - 1);
920 
921 		do {
922 			unsigned int i = sgl->cur;
923 
924 			plen = min_t(size_t, len, PAGE_SIZE);
925 
926 			sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
927 			if (!sg_page(sg + i)) {
928 				err = -ENOMEM;
929 				goto unlock;
930 			}
931 
932 			err = memcpy_from_msg(page_address(sg_page(sg + i)),
933 					      msg, plen);
934 			if (err) {
935 				__free_page(sg_page(sg + i));
936 				sg_assign_page(sg + i, NULL);
937 				goto unlock;
938 			}
939 
940 			sg[i].length = plen;
941 			len -= plen;
942 			ctx->used += plen;
943 			copied += plen;
944 			size -= plen;
945 			sgl->cur++;
946 		} while (len && sgl->cur < MAX_SGL_ENTS);
947 
948 		if (!size)
949 			sg_mark_end(sg + sgl->cur - 1);
950 
951 		ctx->merge = plen & (PAGE_SIZE - 1);
952 	}
953 
954 	err = 0;
955 
956 	ctx->more = msg->msg_flags & MSG_MORE;
957 
958 unlock:
959 	af_alg_data_wakeup(sk);
960 	release_sock(sk);
961 
962 	return copied ?: err;
963 }
964 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
965 
966 /**
967  * af_alg_sendpage - sendpage system call handler
968  *
969  * This is a generic implementation of sendpage to fill ctx->tsgl_list.
970  */
971 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
972 			int offset, size_t size, int flags)
973 {
974 	struct sock *sk = sock->sk;
975 	struct alg_sock *ask = alg_sk(sk);
976 	struct af_alg_ctx *ctx = ask->private;
977 	struct af_alg_tsgl *sgl;
978 	int err = -EINVAL;
979 
980 	if (flags & MSG_SENDPAGE_NOTLAST)
981 		flags |= MSG_MORE;
982 
983 	lock_sock(sk);
984 	if (!ctx->more && ctx->used)
985 		goto unlock;
986 
987 	if (!size)
988 		goto done;
989 
990 	if (!af_alg_writable(sk)) {
991 		err = af_alg_wait_for_wmem(sk, flags);
992 		if (err)
993 			goto unlock;
994 	}
995 
996 	err = af_alg_alloc_tsgl(sk);
997 	if (err)
998 		goto unlock;
999 
1000 	ctx->merge = 0;
1001 	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
1002 
1003 	if (sgl->cur)
1004 		sg_unmark_end(sgl->sg + sgl->cur - 1);
1005 
1006 	sg_mark_end(sgl->sg + sgl->cur);
1007 
1008 	get_page(page);
1009 	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
1010 	sgl->cur++;
1011 	ctx->used += size;
1012 
1013 done:
1014 	ctx->more = flags & MSG_MORE;
1015 
1016 unlock:
1017 	af_alg_data_wakeup(sk);
1018 	release_sock(sk);
1019 
1020 	return err ?: size;
1021 }
1022 EXPORT_SYMBOL_GPL(af_alg_sendpage);
1023 
1024 /**
1025  * af_alg_free_resources - release resources required for crypto request
1026  */
1027 void af_alg_free_resources(struct af_alg_async_req *areq)
1028 {
1029 	struct sock *sk = areq->sk;
1030 
1031 	af_alg_free_areq_sgls(areq);
1032 	sock_kfree_s(sk, areq, areq->areqlen);
1033 }
1034 EXPORT_SYMBOL_GPL(af_alg_free_resources);
1035 
1036 /**
1037  * af_alg_async_cb - AIO callback handler
1038  *
1039  * This handler cleans up the struct af_alg_async_req upon completion of the
1040  * AIO operation.
1041  *
1042  * The number of bytes to be generated with the AIO operation must be set
1043  * in areq->outlen before the AIO callback handler is invoked.
1044  */
1045 void af_alg_async_cb(struct crypto_async_request *_req, int err)
1046 {
1047 	struct af_alg_async_req *areq = _req->data;
1048 	struct sock *sk = areq->sk;
1049 	struct kiocb *iocb = areq->iocb;
1050 	unsigned int resultlen;
1051 
1052 	/* Buffer size written by crypto operation. */
1053 	resultlen = areq->outlen;
1054 
1055 	af_alg_free_resources(areq);
1056 	sock_put(sk);
1057 
1058 	iocb->ki_complete(iocb, err ? err : resultlen, 0);
1059 }
1060 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1061 
1062 /**
1063  * af_alg_poll - poll system call handler
1064  */
1065 unsigned int af_alg_poll(struct file *file, struct socket *sock,
1066 			 poll_table *wait)
1067 {
1068 	struct sock *sk = sock->sk;
1069 	struct alg_sock *ask = alg_sk(sk);
1070 	struct af_alg_ctx *ctx = ask->private;
1071 	unsigned int mask;
1072 
1073 	sock_poll_wait(file, sk_sleep(sk), wait);
1074 	mask = 0;
1075 
1076 	if (!ctx->more || ctx->used)
1077 		mask |= POLLIN | POLLRDNORM;
1078 
1079 	if (af_alg_writable(sk))
1080 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
1081 
1082 	return mask;
1083 }
1084 EXPORT_SYMBOL_GPL(af_alg_poll);
1085 
1086 /**
1087  * af_alg_alloc_areq - allocate struct af_alg_async_req
1088  *
1089  * @sk socket of connection to user space
1090  * @areqlen size of struct af_alg_async_req + crypto_*_reqsize
1091  * @return allocated data structure or ERR_PTR upon error
1092  */
1093 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1094 					   unsigned int areqlen)
1095 {
1096 	struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1097 
1098 	if (unlikely(!areq))
1099 		return ERR_PTR(-ENOMEM);
1100 
1101 	areq->areqlen = areqlen;
1102 	areq->sk = sk;
1103 	areq->last_rsgl = NULL;
1104 	INIT_LIST_HEAD(&areq->rsgl_list);
1105 	areq->tsgl = NULL;
1106 	areq->tsgl_entries = 0;
1107 
1108 	return areq;
1109 }
1110 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1111 
1112 /**
1113  * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1114  *		     operation
1115  *
1116  * @sk socket of connection to user space
1117  * @msg user space message
1118  * @flags flags used to invoke recvmsg with
1119  * @areq instance of the cryptographic request that will hold the RX SGL
1120  * @maxsize maximum number of bytes to be pulled from user space
1121  * @outlen number of bytes in the RX SGL
1122  * @return 0 on success, < 0 upon error
1123  */
1124 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1125 		    struct af_alg_async_req *areq, size_t maxsize,
1126 		    size_t *outlen)
1127 {
1128 	struct alg_sock *ask = alg_sk(sk);
1129 	struct af_alg_ctx *ctx = ask->private;
1130 	size_t len = 0;
1131 
1132 	while (maxsize > len && msg_data_left(msg)) {
1133 		struct af_alg_rsgl *rsgl;
1134 		size_t seglen;
1135 		int err;
1136 
1137 		/* limit the amount of readable buffers */
1138 		if (!af_alg_readable(sk))
1139 			break;
1140 
1141 		if (!ctx->used) {
1142 			err = af_alg_wait_for_data(sk, flags);
1143 			if (err)
1144 				return err;
1145 		}
1146 
1147 		seglen = min_t(size_t, (maxsize - len),
1148 			       msg_data_left(msg));
1149 
1150 		if (list_empty(&areq->rsgl_list)) {
1151 			rsgl = &areq->first_rsgl;
1152 		} else {
1153 			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1154 			if (unlikely(!rsgl))
1155 				return -ENOMEM;
1156 		}
1157 
1158 		rsgl->sgl.npages = 0;
1159 		list_add_tail(&rsgl->list, &areq->rsgl_list);
1160 
1161 		/* make one iovec available as scatterlist */
1162 		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1163 		if (err < 0)
1164 			return err;
1165 
1166 		/* chain the new scatterlist with previous one */
1167 		if (areq->last_rsgl)
1168 			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1169 
1170 		areq->last_rsgl = rsgl;
1171 		len += err;
1172 		ctx->rcvused += err;
1173 		rsgl->sg_num_bytes = err;
1174 		iov_iter_advance(&msg->msg_iter, err);
1175 	}
1176 
1177 	*outlen = len;
1178 	return 0;
1179 }
1180 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1181 
1182 static int __init af_alg_init(void)
1183 {
1184 	int err = proto_register(&alg_proto, 0);
1185 
1186 	if (err)
1187 		goto out;
1188 
1189 	err = sock_register(&alg_family);
1190 	if (err != 0)
1191 		goto out_unregister_proto;
1192 
1193 out:
1194 	return err;
1195 
1196 out_unregister_proto:
1197 	proto_unregister(&alg_proto);
1198 	goto out;
1199 }
1200 
1201 static void __exit af_alg_exit(void)
1202 {
1203 	sock_unregister(PF_ALG);
1204 	proto_unregister(&alg_proto);
1205 }
1206 
1207 module_init(af_alg_init);
1208 module_exit(af_alg_exit);
1209 MODULE_LICENSE("GPL");
1210 MODULE_ALIAS_NETPROTO(AF_ALG);
1211