1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * af_alg: User-space algorithm interface
4 *
5 * This file provides the user-space API for algorithms.
6 *
7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
8 */
9
10#include <linux/atomic.h>
11#include <crypto/if_alg.h>
12#include <linux/crypto.h>
13#include <linux/init.h>
14#include <linux/kernel.h>
15#include <linux/key.h>
16#include <linux/key-type.h>
17#include <linux/list.h>
18#include <linux/module.h>
19#include <linux/net.h>
20#include <linux/rwsem.h>
21#include <linux/sched.h>
22#include <linux/sched/signal.h>
23#include <linux/security.h>
24#include <linux/string.h>
25#include <keys/user-type.h>
26#include <keys/trusted-type.h>
27#include <keys/encrypted-type.h>
28
29struct alg_type_list {
30	const struct af_alg_type *type;
31	struct list_head list;
32};
33
34static struct proto alg_proto = {
35	.name			= "ALG",
36	.owner			= THIS_MODULE,
37	.obj_size		= sizeof(struct alg_sock),
38};
39
40static LIST_HEAD(alg_types);
41static DECLARE_RWSEM(alg_types_sem);
42
43static const struct af_alg_type *alg_get_type(const char *name)
44{
45	const struct af_alg_type *type = ERR_PTR(-ENOENT);
46	struct alg_type_list *node;
47
48	down_read(&alg_types_sem);
49	list_for_each_entry(node, &alg_types, list) {
50		if (strcmp(node->type->name, name))
51			continue;
52
53		if (try_module_get(node->type->owner))
54			type = node->type;
55		break;
56	}
57	up_read(&alg_types_sem);
58
59	return type;
60}
61
62int af_alg_register_type(const struct af_alg_type *type)
63{
64	struct alg_type_list *node;
65	int err = -EEXIST;
66
67	down_write(&alg_types_sem);
68	list_for_each_entry(node, &alg_types, list) {
69		if (!strcmp(node->type->name, type->name))
70			goto unlock;
71	}
72
73	node = kmalloc(sizeof(*node), GFP_KERNEL);
74	err = -ENOMEM;
75	if (!node)
76		goto unlock;
77
78	type->ops->owner = THIS_MODULE;
79	if (type->ops_nokey)
80		type->ops_nokey->owner = THIS_MODULE;
81	node->type = type;
82	list_add(&node->list, &alg_types);
83	err = 0;
84
85unlock:
86	up_write(&alg_types_sem);
87
88	return err;
89}
90EXPORT_SYMBOL_GPL(af_alg_register_type);
91
92int af_alg_unregister_type(const struct af_alg_type *type)
93{
94	struct alg_type_list *node;
95	int err = -ENOENT;
96
97	down_write(&alg_types_sem);
98	list_for_each_entry(node, &alg_types, list) {
99		if (strcmp(node->type->name, type->name))
100			continue;
101
102		list_del(&node->list);
103		kfree(node);
104		err = 0;
105		break;
106	}
107	up_write(&alg_types_sem);
108
109	return err;
110}
111EXPORT_SYMBOL_GPL(af_alg_unregister_type);
112
113static void alg_do_release(const struct af_alg_type *type, void *private)
114{
115	if (!type)
116		return;
117
118	type->release(private);
119	module_put(type->owner);
120}
121
122int af_alg_release(struct socket *sock)
123{
124	if (sock->sk) {
125		sock_put(sock->sk);
126		sock->sk = NULL;
127	}
128	return 0;
129}
130EXPORT_SYMBOL_GPL(af_alg_release);
131
132void af_alg_release_parent(struct sock *sk)
133{
134	struct alg_sock *ask = alg_sk(sk);
135	unsigned int nokey = atomic_read(&ask->nokey_refcnt);
136
137	sk = ask->parent;
138	ask = alg_sk(sk);
139
140	if (nokey)
141		atomic_dec(&ask->nokey_refcnt);
142
143	if (atomic_dec_and_test(&ask->refcnt))
144		sock_put(sk);
145}
146EXPORT_SYMBOL_GPL(af_alg_release_parent);
147
148static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
149{
150	const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
151	struct sock *sk = sock->sk;
152	struct alg_sock *ask = alg_sk(sk);
153	struct sockaddr_alg_new *sa = (void *)uaddr;
154	const struct af_alg_type *type;
155	void *private;
156	int err;
157
158	if (sock->state == SS_CONNECTED)
159		return -EINVAL;
160
161	BUILD_BUG_ON(offsetof(struct sockaddr_alg_new, salg_name) !=
162		     offsetof(struct sockaddr_alg, salg_name));
163	BUILD_BUG_ON(offsetof(struct sockaddr_alg, salg_name) != sizeof(*sa));
164
165	if (addr_len < sizeof(*sa) + 1)
166		return -EINVAL;
167
168	/* If caller uses non-allowed flag, return error. */
169	if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
170		return -EINVAL;
171
172	sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
173	sa->salg_name[addr_len - sizeof(*sa) - 1] = 0;
174
175	type = alg_get_type(sa->salg_type);
176	if (PTR_ERR(type) == -ENOENT) {
177		request_module("algif-%s", sa->salg_type);
178		type = alg_get_type(sa->salg_type);
179	}
180
181	if (IS_ERR(type))
182		return PTR_ERR(type);
183
184	private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
185	if (IS_ERR(private)) {
186		module_put(type->owner);
187		return PTR_ERR(private);
188	}
189
190	err = -EBUSY;
191	lock_sock(sk);
192	if (atomic_read(&ask->refcnt))
193		goto unlock;
194
195	swap(ask->type, type);
196	swap(ask->private, private);
197
198	err = 0;
199
200unlock:
201	release_sock(sk);
202
203	alg_do_release(type, private);
204
205	return err;
206}
207
208static int alg_setkey(struct sock *sk, sockptr_t ukey, unsigned int keylen)
209{
210	struct alg_sock *ask = alg_sk(sk);
211	const struct af_alg_type *type = ask->type;
212	u8 *key;
213	int err;
214
215	key = sock_kmalloc(sk, keylen, GFP_KERNEL);
216	if (!key)
217		return -ENOMEM;
218
219	err = -EFAULT;
220	if (copy_from_sockptr(key, ukey, keylen))
221		goto out;
222
223	err = type->setkey(ask->private, key, keylen);
224
225out:
226	sock_kzfree_s(sk, key, keylen);
227
228	return err;
229}
230
231#ifdef CONFIG_KEYS
232
233static const u8 *key_data_ptr_user(const struct key *key,
234				   unsigned int *datalen)
235{
236	const struct user_key_payload *ukp;
237
238	ukp = user_key_payload_locked(key);
239	if (IS_ERR_OR_NULL(ukp))
240		return ERR_PTR(-EKEYREVOKED);
241
242	*datalen = key->datalen;
243
244	return ukp->data;
245}
246
247static const u8 *key_data_ptr_encrypted(const struct key *key,
248					unsigned int *datalen)
249{
250	const struct encrypted_key_payload *ekp;
251
252	ekp = dereference_key_locked(key);
253	if (IS_ERR_OR_NULL(ekp))
254		return ERR_PTR(-EKEYREVOKED);
255
256	*datalen = ekp->decrypted_datalen;
257
258	return ekp->decrypted_data;
259}
260
261static const u8 *key_data_ptr_trusted(const struct key *key,
262				      unsigned int *datalen)
263{
264	const struct trusted_key_payload *tkp;
265
266	tkp = dereference_key_locked(key);
267	if (IS_ERR_OR_NULL(tkp))
268		return ERR_PTR(-EKEYREVOKED);
269
270	*datalen = tkp->key_len;
271
272	return tkp->key;
273}
274
275static struct key *lookup_key(key_serial_t serial)
276{
277	key_ref_t key_ref;
278
279	key_ref = lookup_user_key(serial, 0, KEY_NEED_SEARCH);
280	if (IS_ERR(key_ref))
281		return ERR_CAST(key_ref);
282
283	return key_ref_to_ptr(key_ref);
284}
285
286static int alg_setkey_by_key_serial(struct alg_sock *ask, sockptr_t optval,
287				    unsigned int optlen)
288{
289	const struct af_alg_type *type = ask->type;
290	u8 *key_data = NULL;
291	unsigned int key_datalen;
292	key_serial_t serial;
293	struct key *key;
294	const u8 *ret;
295	int err;
296
297	if (optlen != sizeof(serial))
298		return -EINVAL;
299
300	if (copy_from_sockptr(&serial, optval, optlen))
301		return -EFAULT;
302
303	key = lookup_key(serial);
304	if (IS_ERR(key))
305		return PTR_ERR(key);
306
307	down_read(&key->sem);
308
309	ret = ERR_PTR(-ENOPROTOOPT);
310	if (!strcmp(key->type->name, "user") ||
311	    !strcmp(key->type->name, "logon")) {
312		ret = key_data_ptr_user(key, &key_datalen);
313	} else if (IS_REACHABLE(CONFIG_ENCRYPTED_KEYS) &&
314			   !strcmp(key->type->name, "encrypted")) {
315		ret = key_data_ptr_encrypted(key, &key_datalen);
316	} else if (IS_REACHABLE(CONFIG_TRUSTED_KEYS) &&
317			   !strcmp(key->type->name, "trusted")) {
318		ret = key_data_ptr_trusted(key, &key_datalen);
319	}
320
321	if (IS_ERR(ret)) {
322		up_read(&key->sem);
323		key_put(key);
324		return PTR_ERR(ret);
325	}
326
327	key_data = sock_kmalloc(&ask->sk, key_datalen, GFP_KERNEL);
328	if (!key_data) {
329		up_read(&key->sem);
330		key_put(key);
331		return -ENOMEM;
332	}
333
334	memcpy(key_data, ret, key_datalen);
335
336	up_read(&key->sem);
337	key_put(key);
338
339	err = type->setkey(ask->private, key_data, key_datalen);
340
341	sock_kzfree_s(&ask->sk, key_data, key_datalen);
342
343	return err;
344}
345
346#else
347
348static inline int alg_setkey_by_key_serial(struct alg_sock *ask,
349					   sockptr_t optval,
350					   unsigned int optlen)
351{
352	return -ENOPROTOOPT;
353}
354
355#endif
356
357static int alg_setsockopt(struct socket *sock, int level, int optname,
358			  sockptr_t optval, unsigned int optlen)
359{
360	struct sock *sk = sock->sk;
361	struct alg_sock *ask = alg_sk(sk);
362	const struct af_alg_type *type;
363	int err = -EBUSY;
364
365	lock_sock(sk);
366	if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
367		goto unlock;
368
369	type = ask->type;
370
371	err = -ENOPROTOOPT;
372	if (level != SOL_ALG || !type)
373		goto unlock;
374
375	switch (optname) {
376	case ALG_SET_KEY:
377	case ALG_SET_KEY_BY_KEY_SERIAL:
378		if (sock->state == SS_CONNECTED)
379			goto unlock;
380		if (!type->setkey)
381			goto unlock;
382
383		if (optname == ALG_SET_KEY_BY_KEY_SERIAL)
384			err = alg_setkey_by_key_serial(ask, optval, optlen);
385		else
386			err = alg_setkey(sk, optval, optlen);
387		break;
388	case ALG_SET_AEAD_AUTHSIZE:
389		if (sock->state == SS_CONNECTED)
390			goto unlock;
391		if (!type->setauthsize)
392			goto unlock;
393		err = type->setauthsize(ask->private, optlen);
394		break;
395	case ALG_SET_DRBG_ENTROPY:
396		if (sock->state == SS_CONNECTED)
397			goto unlock;
398		if (!type->setentropy)
399			goto unlock;
400
401		err = type->setentropy(ask->private, optval, optlen);
402	}
403
404unlock:
405	release_sock(sk);
406
407	return err;
408}
409
410int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
411{
412	struct alg_sock *ask = alg_sk(sk);
413	const struct af_alg_type *type;
414	struct sock *sk2;
415	unsigned int nokey;
416	int err;
417
418	lock_sock(sk);
419	type = ask->type;
420
421	err = -EINVAL;
422	if (!type)
423		goto unlock;
424
425	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
426	err = -ENOMEM;
427	if (!sk2)
428		goto unlock;
429
430	sock_init_data(newsock, sk2);
431	security_sock_graft(sk2, newsock);
432	security_sk_clone(sk, sk2);
433
434	/*
435	 * newsock->ops assigned here to allow type->accept call to override
436	 * them when required.
437	 */
438	newsock->ops = type->ops;
439	err = type->accept(ask->private, sk2);
440
441	nokey = err == -ENOKEY;
442	if (nokey && type->accept_nokey)
443		err = type->accept_nokey(ask->private, sk2);
444
445	if (err)
446		goto unlock;
447
448	if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
449		sock_hold(sk);
450	if (nokey) {
451		atomic_inc(&ask->nokey_refcnt);
452		atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
453	}
454	alg_sk(sk2)->parent = sk;
455	alg_sk(sk2)->type = type;
456
457	newsock->state = SS_CONNECTED;
458
459	if (nokey)
460		newsock->ops = type->ops_nokey;
461
462	err = 0;
463
464unlock:
465	release_sock(sk);
466
467	return err;
468}
469EXPORT_SYMBOL_GPL(af_alg_accept);
470
471static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
472		      bool kern)
473{
474	return af_alg_accept(sock->sk, newsock, kern);
475}
476
477static const struct proto_ops alg_proto_ops = {
478	.family		=	PF_ALG,
479	.owner		=	THIS_MODULE,
480
481	.connect	=	sock_no_connect,
482	.socketpair	=	sock_no_socketpair,
483	.getname	=	sock_no_getname,
484	.ioctl		=	sock_no_ioctl,
485	.listen		=	sock_no_listen,
486	.shutdown	=	sock_no_shutdown,
487	.mmap		=	sock_no_mmap,
488	.sendmsg	=	sock_no_sendmsg,
489	.recvmsg	=	sock_no_recvmsg,
490
491	.bind		=	alg_bind,
492	.release	=	af_alg_release,
493	.setsockopt	=	alg_setsockopt,
494	.accept		=	alg_accept,
495};
496
497static void alg_sock_destruct(struct sock *sk)
498{
499	struct alg_sock *ask = alg_sk(sk);
500
501	alg_do_release(ask->type, ask->private);
502}
503
504static int alg_create(struct net *net, struct socket *sock, int protocol,
505		      int kern)
506{
507	struct sock *sk;
508	int err;
509
510	if (sock->type != SOCK_SEQPACKET)
511		return -ESOCKTNOSUPPORT;
512	if (protocol != 0)
513		return -EPROTONOSUPPORT;
514
515	err = -ENOMEM;
516	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
517	if (!sk)
518		goto out;
519
520	sock->ops = &alg_proto_ops;
521	sock_init_data(sock, sk);
522
523	sk->sk_destruct = alg_sock_destruct;
524
525	return 0;
526out:
527	return err;
528}
529
530static const struct net_proto_family alg_family = {
531	.family	=	PF_ALG,
532	.create	=	alg_create,
533	.owner	=	THIS_MODULE,
534};
535
536static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
537			   struct af_alg_sgl *sgl_new)
538{
539	sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
540	sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
541}
542
543void af_alg_free_sg(struct af_alg_sgl *sgl)
544{
545	int i;
546
547	if (sgl->sgt.sgl) {
548		if (sgl->need_unpin)
549			for (i = 0; i < sgl->sgt.nents; i++)
550				unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
551		if (sgl->sgt.sgl != sgl->sgl)
552			kvfree(sgl->sgt.sgl);
553		sgl->sgt.sgl = NULL;
554	}
555}
556EXPORT_SYMBOL_GPL(af_alg_free_sg);
557
558static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
559{
560	struct cmsghdr *cmsg;
561
562	for_each_cmsghdr(cmsg, msg) {
563		if (!CMSG_OK(msg, cmsg))
564			return -EINVAL;
565		if (cmsg->cmsg_level != SOL_ALG)
566			continue;
567
568		switch (cmsg->cmsg_type) {
569		case ALG_SET_IV:
570			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
571				return -EINVAL;
572			con->iv = (void *)CMSG_DATA(cmsg);
573			if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
574						      sizeof(*con->iv)))
575				return -EINVAL;
576			break;
577
578		case ALG_SET_OP:
579			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
580				return -EINVAL;
581			con->op = *(u32 *)CMSG_DATA(cmsg);
582			break;
583
584		case ALG_SET_AEAD_ASSOCLEN:
585			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
586				return -EINVAL;
587			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
588			break;
589
590		default:
591			return -EINVAL;
592		}
593	}
594
595	return 0;
596}
597
598/**
599 * af_alg_alloc_tsgl - allocate the TX SGL
600 *
601 * @sk: socket of connection to user space
602 * Return: 0 upon success, < 0 upon error
603 */
604static int af_alg_alloc_tsgl(struct sock *sk)
605{
606	struct alg_sock *ask = alg_sk(sk);
607	struct af_alg_ctx *ctx = ask->private;
608	struct af_alg_tsgl *sgl;
609	struct scatterlist *sg = NULL;
610
611	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
612	if (!list_empty(&ctx->tsgl_list))
613		sg = sgl->sg;
614
615	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
616		sgl = sock_kmalloc(sk,
617				   struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
618				   GFP_KERNEL);
619		if (!sgl)
620			return -ENOMEM;
621
622		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
623		sgl->cur = 0;
624
625		if (sg)
626			sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
627
628		list_add_tail(&sgl->list, &ctx->tsgl_list);
629	}
630
631	return 0;
632}
633
634/**
635 * af_alg_count_tsgl - Count number of TX SG entries
636 *
637 * The counting starts from the beginning of the SGL to @bytes. If
638 * an @offset is provided, the counting of the SG entries starts at the @offset.
639 *
640 * @sk: socket of connection to user space
641 * @bytes: Count the number of SG entries holding given number of bytes.
642 * @offset: Start the counting of SG entries from the given offset.
643 * Return: Number of TX SG entries found given the constraints
644 */
645unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
646{
647	const struct alg_sock *ask = alg_sk(sk);
648	const struct af_alg_ctx *ctx = ask->private;
649	const struct af_alg_tsgl *sgl;
650	unsigned int i;
651	unsigned int sgl_count = 0;
652
653	if (!bytes)
654		return 0;
655
656	list_for_each_entry(sgl, &ctx->tsgl_list, list) {
657		const struct scatterlist *sg = sgl->sg;
658
659		for (i = 0; i < sgl->cur; i++) {
660			size_t bytes_count;
661
662			/* Skip offset */
663			if (offset >= sg[i].length) {
664				offset -= sg[i].length;
665				bytes -= sg[i].length;
666				continue;
667			}
668
669			bytes_count = sg[i].length - offset;
670
671			offset = 0;
672			sgl_count++;
673
674			/* If we have seen requested number of bytes, stop */
675			if (bytes_count >= bytes)
676				return sgl_count;
677
678			bytes -= bytes_count;
679		}
680	}
681
682	return sgl_count;
683}
684EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
685
686/**
687 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
688 *
689 * If @dst is non-null, reassign the pages to @dst. The caller must release
690 * the pages. If @dst_offset is given only reassign the pages to @dst starting
691 * at the @dst_offset (byte). The caller must ensure that @dst is large
692 * enough (e.g. by using af_alg_count_tsgl with the same offset).
693 *
694 * @sk: socket of connection to user space
695 * @used: Number of bytes to pull from TX SGL
696 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
697 *	 caller must release the buffers in dst.
698 * @dst_offset: Reassign the TX SGL from given offset. All buffers before
699 *	        reaching the offset is released.
700 */
701void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
702		      size_t dst_offset)
703{
704	struct alg_sock *ask = alg_sk(sk);
705	struct af_alg_ctx *ctx = ask->private;
706	struct af_alg_tsgl *sgl;
707	struct scatterlist *sg;
708	unsigned int i, j = 0;
709
710	while (!list_empty(&ctx->tsgl_list)) {
711		sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
712				       list);
713		sg = sgl->sg;
714
715		for (i = 0; i < sgl->cur; i++) {
716			size_t plen = min_t(size_t, used, sg[i].length);
717			struct page *page = sg_page(sg + i);
718
719			if (!page)
720				continue;
721
722			/*
723			 * Assumption: caller created af_alg_count_tsgl(len)
724			 * SG entries in dst.
725			 */
726			if (dst) {
727				if (dst_offset >= plen) {
728					/* discard page before offset */
729					dst_offset -= plen;
730				} else {
731					/* reassign page to dst after offset */
732					get_page(page);
733					sg_set_page(dst + j, page,
734						    plen - dst_offset,
735						    sg[i].offset + dst_offset);
736					dst_offset = 0;
737					j++;
738				}
739			}
740
741			sg[i].length -= plen;
742			sg[i].offset += plen;
743
744			used -= plen;
745			ctx->used -= plen;
746
747			if (sg[i].length)
748				return;
749
750			put_page(page);
751			sg_assign_page(sg + i, NULL);
752		}
753
754		list_del(&sgl->list);
755		sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
756	}
757
758	if (!ctx->used)
759		ctx->merge = 0;
760	ctx->init = ctx->more;
761}
762EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
763
764/**
765 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
766 *
767 * @areq: Request holding the TX and RX SGL
768 */
769static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
770{
771	struct sock *sk = areq->sk;
772	struct alg_sock *ask = alg_sk(sk);
773	struct af_alg_ctx *ctx = ask->private;
774	struct af_alg_rsgl *rsgl, *tmp;
775	struct scatterlist *tsgl;
776	struct scatterlist *sg;
777	unsigned int i;
778
779	list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
780		atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
781		af_alg_free_sg(&rsgl->sgl);
782		list_del(&rsgl->list);
783		if (rsgl != &areq->first_rsgl)
784			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
785	}
786
787	tsgl = areq->tsgl;
788	if (tsgl) {
789		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
790			if (!sg_page(sg))
791				continue;
792			put_page(sg_page(sg));
793		}
794
795		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
796	}
797}
798
799/**
800 * af_alg_wait_for_wmem - wait for availability of writable memory
801 *
802 * @sk: socket of connection to user space
803 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
804 * Return: 0 when writable memory is available, < 0 upon error
805 */
806static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
807{
808	DEFINE_WAIT_FUNC(wait, woken_wake_function);
809	int err = -ERESTARTSYS;
810	long timeout;
811
812	if (flags & MSG_DONTWAIT)
813		return -EAGAIN;
814
815	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
816
817	add_wait_queue(sk_sleep(sk), &wait);
818	for (;;) {
819		if (signal_pending(current))
820			break;
821		timeout = MAX_SCHEDULE_TIMEOUT;
822		if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
823			err = 0;
824			break;
825		}
826	}
827	remove_wait_queue(sk_sleep(sk), &wait);
828
829	return err;
830}
831
832/**
833 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
834 *
835 * @sk: socket of connection to user space
836 */
837void af_alg_wmem_wakeup(struct sock *sk)
838{
839	struct socket_wq *wq;
840
841	if (!af_alg_writable(sk))
842		return;
843
844	rcu_read_lock();
845	wq = rcu_dereference(sk->sk_wq);
846	if (skwq_has_sleeper(wq))
847		wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
848							   EPOLLRDNORM |
849							   EPOLLRDBAND);
850	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
851	rcu_read_unlock();
852}
853EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
854
855/**
856 * af_alg_wait_for_data - wait for availability of TX data
857 *
858 * @sk: socket of connection to user space
859 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
860 * @min: Set to minimum request size if partial requests are allowed.
861 * Return: 0 when writable memory is available, < 0 upon error
862 */
863int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
864{
865	DEFINE_WAIT_FUNC(wait, woken_wake_function);
866	struct alg_sock *ask = alg_sk(sk);
867	struct af_alg_ctx *ctx = ask->private;
868	long timeout;
869	int err = -ERESTARTSYS;
870
871	if (flags & MSG_DONTWAIT)
872		return -EAGAIN;
873
874	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
875
876	add_wait_queue(sk_sleep(sk), &wait);
877	for (;;) {
878		if (signal_pending(current))
879			break;
880		timeout = MAX_SCHEDULE_TIMEOUT;
881		if (sk_wait_event(sk, &timeout,
882				  ctx->init && (!ctx->more ||
883						(min && ctx->used >= min)),
884				  &wait)) {
885			err = 0;
886			break;
887		}
888	}
889	remove_wait_queue(sk_sleep(sk), &wait);
890
891	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
892
893	return err;
894}
895EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
896
897/**
898 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
899 *
900 * @sk: socket of connection to user space
901 */
902static void af_alg_data_wakeup(struct sock *sk)
903{
904	struct alg_sock *ask = alg_sk(sk);
905	struct af_alg_ctx *ctx = ask->private;
906	struct socket_wq *wq;
907
908	if (!ctx->used)
909		return;
910
911	rcu_read_lock();
912	wq = rcu_dereference(sk->sk_wq);
913	if (skwq_has_sleeper(wq))
914		wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
915							   EPOLLRDNORM |
916							   EPOLLRDBAND);
917	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
918	rcu_read_unlock();
919}
920
921/**
922 * af_alg_sendmsg - implementation of sendmsg system call handler
923 *
924 * The sendmsg system call handler obtains the user data and stores it
925 * in ctx->tsgl_list. This implies allocation of the required numbers of
926 * struct af_alg_tsgl.
927 *
928 * In addition, the ctx is filled with the information sent via CMSG.
929 *
930 * @sock: socket of connection to user space
931 * @msg: message from user space
932 * @size: size of message from user space
933 * @ivsize: the size of the IV for the cipher operation to verify that the
934 *	   user-space-provided IV has the right size
935 * Return: the number of copied data upon success, < 0 upon error
936 */
937int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
938		   unsigned int ivsize)
939{
940	struct sock *sk = sock->sk;
941	struct alg_sock *ask = alg_sk(sk);
942	struct af_alg_ctx *ctx = ask->private;
943	struct af_alg_tsgl *sgl;
944	struct af_alg_control con = {};
945	long copied = 0;
946	bool enc = false;
947	bool init = false;
948	int err = 0;
949
950	if (msg->msg_controllen) {
951		err = af_alg_cmsg_send(msg, &con);
952		if (err)
953			return err;
954
955		init = true;
956		switch (con.op) {
957		case ALG_OP_ENCRYPT:
958			enc = true;
959			break;
960		case ALG_OP_DECRYPT:
961			enc = false;
962			break;
963		default:
964			return -EINVAL;
965		}
966
967		if (con.iv && con.iv->ivlen != ivsize)
968			return -EINVAL;
969	}
970
971	lock_sock(sk);
972	if (ctx->init && !ctx->more) {
973		if (ctx->used) {
974			err = -EINVAL;
975			goto unlock;
976		}
977
978		pr_info_once(
979			"%s sent an empty control message without MSG_MORE.\n",
980			current->comm);
981	}
982	ctx->init = true;
983
984	if (init) {
985		ctx->enc = enc;
986		if (con.iv)
987			memcpy(ctx->iv, con.iv->iv, ivsize);
988
989		ctx->aead_assoclen = con.aead_assoclen;
990	}
991
992	while (size) {
993		struct scatterlist *sg;
994		size_t len = size;
995		ssize_t plen;
996
997		/* use the existing memory in an allocated page */
998		if (ctx->merge && !(msg->msg_flags & MSG_SPLICE_PAGES)) {
999			sgl = list_entry(ctx->tsgl_list.prev,
1000					 struct af_alg_tsgl, list);
1001			sg = sgl->sg + sgl->cur - 1;
1002			len = min_t(size_t, len,
1003				    PAGE_SIZE - sg->offset - sg->length);
1004
1005			err = memcpy_from_msg(page_address(sg_page(sg)) +
1006					      sg->offset + sg->length,
1007					      msg, len);
1008			if (err)
1009				goto unlock;
1010
1011			sg->length += len;
1012			ctx->merge = (sg->offset + sg->length) &
1013				     (PAGE_SIZE - 1);
1014
1015			ctx->used += len;
1016			copied += len;
1017			size -= len;
1018			continue;
1019		}
1020
1021		if (!af_alg_writable(sk)) {
1022			err = af_alg_wait_for_wmem(sk, msg->msg_flags);
1023			if (err)
1024				goto unlock;
1025		}
1026
1027		/* allocate a new page */
1028		len = min_t(unsigned long, len, af_alg_sndbuf(sk));
1029
1030		err = af_alg_alloc_tsgl(sk);
1031		if (err)
1032			goto unlock;
1033
1034		sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
1035				 list);
1036		sg = sgl->sg;
1037		if (sgl->cur)
1038			sg_unmark_end(sg + sgl->cur - 1);
1039
1040		if (msg->msg_flags & MSG_SPLICE_PAGES) {
1041			struct sg_table sgtable = {
1042				.sgl		= sg,
1043				.nents		= sgl->cur,
1044				.orig_nents	= sgl->cur,
1045			};
1046
1047			plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable,
1048						  MAX_SGL_ENTS - sgl->cur, 0);
1049			if (plen < 0) {
1050				err = plen;
1051				goto unlock;
1052			}
1053
1054			for (; sgl->cur < sgtable.nents; sgl->cur++)
1055				get_page(sg_page(&sg[sgl->cur]));
1056			len -= plen;
1057			ctx->used += plen;
1058			copied += plen;
1059			size -= plen;
1060			ctx->merge = 0;
1061		} else {
1062			do {
1063				struct page *pg;
1064				unsigned int i = sgl->cur;
1065
1066				plen = min_t(size_t, len, PAGE_SIZE);
1067
1068				pg = alloc_page(GFP_KERNEL);
1069				if (!pg) {
1070					err = -ENOMEM;
1071					goto unlock;
1072				}
1073
1074				sg_assign_page(sg + i, pg);
1075
1076				err = memcpy_from_msg(
1077					page_address(sg_page(sg + i)),
1078					msg, plen);
1079				if (err) {
1080					__free_page(sg_page(sg + i));
1081					sg_assign_page(sg + i, NULL);
1082					goto unlock;
1083				}
1084
1085				sg[i].length = plen;
1086				len -= plen;
1087				ctx->used += plen;
1088				copied += plen;
1089				size -= plen;
1090				sgl->cur++;
1091			} while (len && sgl->cur < MAX_SGL_ENTS);
1092
1093			ctx->merge = plen & (PAGE_SIZE - 1);
1094		}
1095
1096		if (!size)
1097			sg_mark_end(sg + sgl->cur - 1);
1098	}
1099
1100	err = 0;
1101
1102	ctx->more = msg->msg_flags & MSG_MORE;
1103
1104unlock:
1105	af_alg_data_wakeup(sk);
1106	release_sock(sk);
1107
1108	return copied ?: err;
1109}
1110EXPORT_SYMBOL_GPL(af_alg_sendmsg);
1111
1112/**
1113 * af_alg_free_resources - release resources required for crypto request
1114 * @areq: Request holding the TX and RX SGL
1115 */
1116void af_alg_free_resources(struct af_alg_async_req *areq)
1117{
1118	struct sock *sk = areq->sk;
1119	struct af_alg_ctx *ctx;
1120
1121	af_alg_free_areq_sgls(areq);
1122	sock_kfree_s(sk, areq, areq->areqlen);
1123
1124	ctx = alg_sk(sk)->private;
1125	ctx->inflight = false;
1126}
1127EXPORT_SYMBOL_GPL(af_alg_free_resources);
1128
1129/**
1130 * af_alg_async_cb - AIO callback handler
1131 * @data: async request completion data
1132 * @err: if non-zero, error result to be returned via ki_complete();
1133 *       otherwise return the AIO output length via ki_complete().
1134 *
1135 * This handler cleans up the struct af_alg_async_req upon completion of the
1136 * AIO operation.
1137 *
1138 * The number of bytes to be generated with the AIO operation must be set
1139 * in areq->outlen before the AIO callback handler is invoked.
1140 */
1141void af_alg_async_cb(void *data, int err)
1142{
1143	struct af_alg_async_req *areq = data;
1144	struct sock *sk = areq->sk;
1145	struct kiocb *iocb = areq->iocb;
1146	unsigned int resultlen;
1147
1148	/* Buffer size written by crypto operation. */
1149	resultlen = areq->outlen;
1150
1151	af_alg_free_resources(areq);
1152	sock_put(sk);
1153
1154	iocb->ki_complete(iocb, err ? err : (int)resultlen);
1155}
1156EXPORT_SYMBOL_GPL(af_alg_async_cb);
1157
1158/**
1159 * af_alg_poll - poll system call handler
1160 * @file: file pointer
1161 * @sock: socket to poll
1162 * @wait: poll_table
1163 */
1164__poll_t af_alg_poll(struct file *file, struct socket *sock,
1165			 poll_table *wait)
1166{
1167	struct sock *sk = sock->sk;
1168	struct alg_sock *ask = alg_sk(sk);
1169	struct af_alg_ctx *ctx = ask->private;
1170	__poll_t mask;
1171
1172	sock_poll_wait(file, sock, wait);
1173	mask = 0;
1174
1175	if (!ctx->more || ctx->used)
1176		mask |= EPOLLIN | EPOLLRDNORM;
1177
1178	if (af_alg_writable(sk))
1179		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1180
1181	return mask;
1182}
1183EXPORT_SYMBOL_GPL(af_alg_poll);
1184
1185/**
1186 * af_alg_alloc_areq - allocate struct af_alg_async_req
1187 *
1188 * @sk: socket of connection to user space
1189 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1190 * Return: allocated data structure or ERR_PTR upon error
1191 */
1192struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1193					   unsigned int areqlen)
1194{
1195	struct af_alg_ctx *ctx = alg_sk(sk)->private;
1196	struct af_alg_async_req *areq;
1197
1198	/* Only one AIO request can be in flight. */
1199	if (ctx->inflight)
1200		return ERR_PTR(-EBUSY);
1201
1202	areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1203	if (unlikely(!areq))
1204		return ERR_PTR(-ENOMEM);
1205
1206	ctx->inflight = true;
1207
1208	areq->areqlen = areqlen;
1209	areq->sk = sk;
1210	areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl;
1211	areq->last_rsgl = NULL;
1212	INIT_LIST_HEAD(&areq->rsgl_list);
1213	areq->tsgl = NULL;
1214	areq->tsgl_entries = 0;
1215
1216	return areq;
1217}
1218EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1219
1220/**
1221 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1222 *		     operation
1223 *
1224 * @sk: socket of connection to user space
1225 * @msg: user space message
1226 * @flags: flags used to invoke recvmsg with
1227 * @areq: instance of the cryptographic request that will hold the RX SGL
1228 * @maxsize: maximum number of bytes to be pulled from user space
1229 * @outlen: number of bytes in the RX SGL
1230 * Return: 0 on success, < 0 upon error
1231 */
1232int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1233		    struct af_alg_async_req *areq, size_t maxsize,
1234		    size_t *outlen)
1235{
1236	struct alg_sock *ask = alg_sk(sk);
1237	struct af_alg_ctx *ctx = ask->private;
1238	size_t len = 0;
1239
1240	while (maxsize > len && msg_data_left(msg)) {
1241		struct af_alg_rsgl *rsgl;
1242		ssize_t err;
1243		size_t seglen;
1244
1245		/* limit the amount of readable buffers */
1246		if (!af_alg_readable(sk))
1247			break;
1248
1249		seglen = min_t(size_t, (maxsize - len),
1250			       msg_data_left(msg));
1251
1252		if (list_empty(&areq->rsgl_list)) {
1253			rsgl = &areq->first_rsgl;
1254		} else {
1255			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1256			if (unlikely(!rsgl))
1257				return -ENOMEM;
1258		}
1259
1260		rsgl->sgl.need_unpin =
1261			iov_iter_extract_will_pin(&msg->msg_iter);
1262		rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
1263		rsgl->sgl.sgt.nents = 0;
1264		rsgl->sgl.sgt.orig_nents = 0;
1265		list_add_tail(&rsgl->list, &areq->rsgl_list);
1266
1267		sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
1268		err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
1269					 ALG_MAX_PAGES, 0);
1270		if (err < 0) {
1271			rsgl->sg_num_bytes = 0;
1272			return err;
1273		}
1274
1275		sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
1276
1277		/* chain the new scatterlist with previous one */
1278		if (areq->last_rsgl)
1279			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1280
1281		areq->last_rsgl = rsgl;
1282		len += err;
1283		atomic_add(err, &ctx->rcvused);
1284		rsgl->sg_num_bytes = err;
1285	}
1286
1287	*outlen = len;
1288	return 0;
1289}
1290EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1291
1292static int __init af_alg_init(void)
1293{
1294	int err = proto_register(&alg_proto, 0);
1295
1296	if (err)
1297		goto out;
1298
1299	err = sock_register(&alg_family);
1300	if (err != 0)
1301		goto out_unregister_proto;
1302
1303out:
1304	return err;
1305
1306out_unregister_proto:
1307	proto_unregister(&alg_proto);
1308	goto out;
1309}
1310
1311static void __exit af_alg_exit(void)
1312{
1313	sock_unregister(PF_ALG);
1314	proto_unregister(&alg_proto);
1315}
1316
1317module_init(af_alg_init);
1318module_exit(af_alg_exit);
1319MODULE_LICENSE("GPL");
1320MODULE_ALIAS_NETPROTO(AF_ALG);
1321