xref: /openbmc/linux/crypto/af_alg.c (revision 680ef72a)
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 	for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
676 		if (!sg_page(sg))
677 			continue;
678 		put_page(sg_page(sg));
679 	}
680 
681 	if (areq->tsgl && areq->tsgl_entries)
682 		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
683 }
684 EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls);
685 
686 /**
687  * af_alg_wait_for_wmem - wait for availability of writable memory
688  *
689  * @sk socket of connection to user space
690  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
691  * @return 0 when writable memory is available, < 0 upon error
692  */
693 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
694 {
695 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
696 	int err = -ERESTARTSYS;
697 	long timeout;
698 
699 	if (flags & MSG_DONTWAIT)
700 		return -EAGAIN;
701 
702 	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
703 
704 	add_wait_queue(sk_sleep(sk), &wait);
705 	for (;;) {
706 		if (signal_pending(current))
707 			break;
708 		timeout = MAX_SCHEDULE_TIMEOUT;
709 		if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
710 			err = 0;
711 			break;
712 		}
713 	}
714 	remove_wait_queue(sk_sleep(sk), &wait);
715 
716 	return err;
717 }
718 EXPORT_SYMBOL_GPL(af_alg_wait_for_wmem);
719 
720 /**
721  * af_alg_wmem_wakeup - wakeup caller when writable memory is available
722  *
723  * @sk socket of connection to user space
724  */
725 void af_alg_wmem_wakeup(struct sock *sk)
726 {
727 	struct socket_wq *wq;
728 
729 	if (!af_alg_writable(sk))
730 		return;
731 
732 	rcu_read_lock();
733 	wq = rcu_dereference(sk->sk_wq);
734 	if (skwq_has_sleeper(wq))
735 		wake_up_interruptible_sync_poll(&wq->wait, POLLIN |
736 							   POLLRDNORM |
737 							   POLLRDBAND);
738 	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
739 	rcu_read_unlock();
740 }
741 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
742 
743 /**
744  * af_alg_wait_for_data - wait for availability of TX data
745  *
746  * @sk socket of connection to user space
747  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
748  * @return 0 when writable memory is available, < 0 upon error
749  */
750 int af_alg_wait_for_data(struct sock *sk, unsigned flags)
751 {
752 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
753 	struct alg_sock *ask = alg_sk(sk);
754 	struct af_alg_ctx *ctx = ask->private;
755 	long timeout;
756 	int err = -ERESTARTSYS;
757 
758 	if (flags & MSG_DONTWAIT)
759 		return -EAGAIN;
760 
761 	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
762 
763 	add_wait_queue(sk_sleep(sk), &wait);
764 	for (;;) {
765 		if (signal_pending(current))
766 			break;
767 		timeout = MAX_SCHEDULE_TIMEOUT;
768 		if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
769 				  &wait)) {
770 			err = 0;
771 			break;
772 		}
773 	}
774 	remove_wait_queue(sk_sleep(sk), &wait);
775 
776 	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
777 
778 	return err;
779 }
780 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
781 
782 /**
783  * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
784  *
785  * @sk socket of connection to user space
786  */
787 
788 void af_alg_data_wakeup(struct sock *sk)
789 {
790 	struct alg_sock *ask = alg_sk(sk);
791 	struct af_alg_ctx *ctx = ask->private;
792 	struct socket_wq *wq;
793 
794 	if (!ctx->used)
795 		return;
796 
797 	rcu_read_lock();
798 	wq = rcu_dereference(sk->sk_wq);
799 	if (skwq_has_sleeper(wq))
800 		wake_up_interruptible_sync_poll(&wq->wait, POLLOUT |
801 							   POLLRDNORM |
802 							   POLLRDBAND);
803 	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
804 	rcu_read_unlock();
805 }
806 EXPORT_SYMBOL_GPL(af_alg_data_wakeup);
807 
808 /**
809  * af_alg_sendmsg - implementation of sendmsg system call handler
810  *
811  * The sendmsg system call handler obtains the user data and stores it
812  * in ctx->tsgl_list. This implies allocation of the required numbers of
813  * struct af_alg_tsgl.
814  *
815  * In addition, the ctx is filled with the information sent via CMSG.
816  *
817  * @sock socket of connection to user space
818  * @msg message from user space
819  * @size size of message from user space
820  * @ivsize the size of the IV for the cipher operation to verify that the
821  *	   user-space-provided IV has the right size
822  * @return the number of copied data upon success, < 0 upon error
823  */
824 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
825 		   unsigned int ivsize)
826 {
827 	struct sock *sk = sock->sk;
828 	struct alg_sock *ask = alg_sk(sk);
829 	struct af_alg_ctx *ctx = ask->private;
830 	struct af_alg_tsgl *sgl;
831 	struct af_alg_control con = {};
832 	long copied = 0;
833 	bool enc = 0;
834 	bool init = 0;
835 	int err = 0;
836 
837 	if (msg->msg_controllen) {
838 		err = af_alg_cmsg_send(msg, &con);
839 		if (err)
840 			return err;
841 
842 		init = 1;
843 		switch (con.op) {
844 		case ALG_OP_ENCRYPT:
845 			enc = 1;
846 			break;
847 		case ALG_OP_DECRYPT:
848 			enc = 0;
849 			break;
850 		default:
851 			return -EINVAL;
852 		}
853 
854 		if (con.iv && con.iv->ivlen != ivsize)
855 			return -EINVAL;
856 	}
857 
858 	lock_sock(sk);
859 	if (!ctx->more && ctx->used) {
860 		err = -EINVAL;
861 		goto unlock;
862 	}
863 
864 	if (init) {
865 		ctx->enc = enc;
866 		if (con.iv)
867 			memcpy(ctx->iv, con.iv->iv, ivsize);
868 
869 		ctx->aead_assoclen = con.aead_assoclen;
870 	}
871 
872 	while (size) {
873 		struct scatterlist *sg;
874 		size_t len = size;
875 		size_t plen;
876 
877 		/* use the existing memory in an allocated page */
878 		if (ctx->merge) {
879 			sgl = list_entry(ctx->tsgl_list.prev,
880 					 struct af_alg_tsgl, list);
881 			sg = sgl->sg + sgl->cur - 1;
882 			len = min_t(size_t, len,
883 				    PAGE_SIZE - sg->offset - sg->length);
884 
885 			err = memcpy_from_msg(page_address(sg_page(sg)) +
886 					      sg->offset + sg->length,
887 					      msg, len);
888 			if (err)
889 				goto unlock;
890 
891 			sg->length += len;
892 			ctx->merge = (sg->offset + sg->length) &
893 				     (PAGE_SIZE - 1);
894 
895 			ctx->used += len;
896 			copied += len;
897 			size -= len;
898 			continue;
899 		}
900 
901 		if (!af_alg_writable(sk)) {
902 			err = af_alg_wait_for_wmem(sk, msg->msg_flags);
903 			if (err)
904 				goto unlock;
905 		}
906 
907 		/* allocate a new page */
908 		len = min_t(unsigned long, len, af_alg_sndbuf(sk));
909 
910 		err = af_alg_alloc_tsgl(sk);
911 		if (err)
912 			goto unlock;
913 
914 		sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
915 				 list);
916 		sg = sgl->sg;
917 		if (sgl->cur)
918 			sg_unmark_end(sg + sgl->cur - 1);
919 
920 		do {
921 			unsigned int i = sgl->cur;
922 
923 			plen = min_t(size_t, len, PAGE_SIZE);
924 
925 			sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
926 			if (!sg_page(sg + i)) {
927 				err = -ENOMEM;
928 				goto unlock;
929 			}
930 
931 			err = memcpy_from_msg(page_address(sg_page(sg + i)),
932 					      msg, plen);
933 			if (err) {
934 				__free_page(sg_page(sg + i));
935 				sg_assign_page(sg + i, NULL);
936 				goto unlock;
937 			}
938 
939 			sg[i].length = plen;
940 			len -= plen;
941 			ctx->used += plen;
942 			copied += plen;
943 			size -= plen;
944 			sgl->cur++;
945 		} while (len && sgl->cur < MAX_SGL_ENTS);
946 
947 		if (!size)
948 			sg_mark_end(sg + sgl->cur - 1);
949 
950 		ctx->merge = plen & (PAGE_SIZE - 1);
951 	}
952 
953 	err = 0;
954 
955 	ctx->more = msg->msg_flags & MSG_MORE;
956 
957 unlock:
958 	af_alg_data_wakeup(sk);
959 	release_sock(sk);
960 
961 	return copied ?: err;
962 }
963 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
964 
965 /**
966  * af_alg_sendpage - sendpage system call handler
967  *
968  * This is a generic implementation of sendpage to fill ctx->tsgl_list.
969  */
970 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
971 			int offset, size_t size, int flags)
972 {
973 	struct sock *sk = sock->sk;
974 	struct alg_sock *ask = alg_sk(sk);
975 	struct af_alg_ctx *ctx = ask->private;
976 	struct af_alg_tsgl *sgl;
977 	int err = -EINVAL;
978 
979 	if (flags & MSG_SENDPAGE_NOTLAST)
980 		flags |= MSG_MORE;
981 
982 	lock_sock(sk);
983 	if (!ctx->more && ctx->used)
984 		goto unlock;
985 
986 	if (!size)
987 		goto done;
988 
989 	if (!af_alg_writable(sk)) {
990 		err = af_alg_wait_for_wmem(sk, flags);
991 		if (err)
992 			goto unlock;
993 	}
994 
995 	err = af_alg_alloc_tsgl(sk);
996 	if (err)
997 		goto unlock;
998 
999 	ctx->merge = 0;
1000 	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
1001 
1002 	if (sgl->cur)
1003 		sg_unmark_end(sgl->sg + sgl->cur - 1);
1004 
1005 	sg_mark_end(sgl->sg + sgl->cur);
1006 
1007 	get_page(page);
1008 	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
1009 	sgl->cur++;
1010 	ctx->used += size;
1011 
1012 done:
1013 	ctx->more = flags & MSG_MORE;
1014 
1015 unlock:
1016 	af_alg_data_wakeup(sk);
1017 	release_sock(sk);
1018 
1019 	return err ?: size;
1020 }
1021 EXPORT_SYMBOL_GPL(af_alg_sendpage);
1022 
1023 /**
1024  * af_alg_async_cb - AIO callback handler
1025  *
1026  * This handler cleans up the struct af_alg_async_req upon completion of the
1027  * AIO operation.
1028  *
1029  * The number of bytes to be generated with the AIO operation must be set
1030  * in areq->outlen before the AIO callback handler is invoked.
1031  */
1032 void af_alg_async_cb(struct crypto_async_request *_req, int err)
1033 {
1034 	struct af_alg_async_req *areq = _req->data;
1035 	struct sock *sk = areq->sk;
1036 	struct kiocb *iocb = areq->iocb;
1037 	unsigned int resultlen;
1038 
1039 	lock_sock(sk);
1040 
1041 	/* Buffer size written by crypto operation. */
1042 	resultlen = areq->outlen;
1043 
1044 	af_alg_free_areq_sgls(areq);
1045 	sock_kfree_s(sk, areq, areq->areqlen);
1046 	__sock_put(sk);
1047 
1048 	iocb->ki_complete(iocb, err ? err : resultlen, 0);
1049 
1050 	release_sock(sk);
1051 }
1052 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1053 
1054 /**
1055  * af_alg_poll - poll system call handler
1056  */
1057 __poll_t af_alg_poll(struct file *file, struct socket *sock,
1058 			 poll_table *wait)
1059 {
1060 	struct sock *sk = sock->sk;
1061 	struct alg_sock *ask = alg_sk(sk);
1062 	struct af_alg_ctx *ctx = ask->private;
1063 	__poll_t mask;
1064 
1065 	sock_poll_wait(file, sk_sleep(sk), wait);
1066 	mask = 0;
1067 
1068 	if (!ctx->more || ctx->used)
1069 		mask |= POLLIN | POLLRDNORM;
1070 
1071 	if (af_alg_writable(sk))
1072 		mask |= POLLOUT | POLLWRNORM | POLLWRBAND;
1073 
1074 	return mask;
1075 }
1076 EXPORT_SYMBOL_GPL(af_alg_poll);
1077 
1078 /**
1079  * af_alg_alloc_areq - allocate struct af_alg_async_req
1080  *
1081  * @sk socket of connection to user space
1082  * @areqlen size of struct af_alg_async_req + crypto_*_reqsize
1083  * @return allocated data structure or ERR_PTR upon error
1084  */
1085 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1086 					   unsigned int areqlen)
1087 {
1088 	struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1089 
1090 	if (unlikely(!areq))
1091 		return ERR_PTR(-ENOMEM);
1092 
1093 	areq->areqlen = areqlen;
1094 	areq->sk = sk;
1095 	areq->last_rsgl = NULL;
1096 	INIT_LIST_HEAD(&areq->rsgl_list);
1097 	areq->tsgl = NULL;
1098 	areq->tsgl_entries = 0;
1099 
1100 	return areq;
1101 }
1102 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1103 
1104 /**
1105  * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1106  *		     operation
1107  *
1108  * @sk socket of connection to user space
1109  * @msg user space message
1110  * @flags flags used to invoke recvmsg with
1111  * @areq instance of the cryptographic request that will hold the RX SGL
1112  * @maxsize maximum number of bytes to be pulled from user space
1113  * @outlen number of bytes in the RX SGL
1114  * @return 0 on success, < 0 upon error
1115  */
1116 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1117 		    struct af_alg_async_req *areq, size_t maxsize,
1118 		    size_t *outlen)
1119 {
1120 	struct alg_sock *ask = alg_sk(sk);
1121 	struct af_alg_ctx *ctx = ask->private;
1122 	size_t len = 0;
1123 
1124 	while (maxsize > len && msg_data_left(msg)) {
1125 		struct af_alg_rsgl *rsgl;
1126 		size_t seglen;
1127 		int err;
1128 
1129 		/* limit the amount of readable buffers */
1130 		if (!af_alg_readable(sk))
1131 			break;
1132 
1133 		if (!ctx->used) {
1134 			err = af_alg_wait_for_data(sk, flags);
1135 			if (err)
1136 				return err;
1137 		}
1138 
1139 		seglen = min_t(size_t, (maxsize - len),
1140 			       msg_data_left(msg));
1141 
1142 		if (list_empty(&areq->rsgl_list)) {
1143 			rsgl = &areq->first_rsgl;
1144 		} else {
1145 			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1146 			if (unlikely(!rsgl))
1147 				return -ENOMEM;
1148 		}
1149 
1150 		rsgl->sgl.npages = 0;
1151 		list_add_tail(&rsgl->list, &areq->rsgl_list);
1152 
1153 		/* make one iovec available as scatterlist */
1154 		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1155 		if (err < 0)
1156 			return err;
1157 
1158 		/* chain the new scatterlist with previous one */
1159 		if (areq->last_rsgl)
1160 			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1161 
1162 		areq->last_rsgl = rsgl;
1163 		len += err;
1164 		ctx->rcvused += err;
1165 		rsgl->sg_num_bytes = err;
1166 		iov_iter_advance(&msg->msg_iter, err);
1167 	}
1168 
1169 	*outlen = len;
1170 	return 0;
1171 }
1172 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1173 
1174 static int __init af_alg_init(void)
1175 {
1176 	int err = proto_register(&alg_proto, 0);
1177 
1178 	if (err)
1179 		goto out;
1180 
1181 	err = sock_register(&alg_family);
1182 	if (err != 0)
1183 		goto out_unregister_proto;
1184 
1185 out:
1186 	return err;
1187 
1188 out_unregister_proto:
1189 	proto_unregister(&alg_proto);
1190 	goto out;
1191 }
1192 
1193 static void __exit af_alg_exit(void)
1194 {
1195 	sock_unregister(PF_ALG);
1196 	proto_unregister(&alg_proto);
1197 }
1198 
1199 module_init(af_alg_init);
1200 module_exit(af_alg_exit);
1201 MODULE_LICENSE("GPL");
1202 MODULE_ALIAS_NETPROTO(AF_ALG);
1203