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,
411		  struct proto_accept_arg *arg)
412{
413	struct alg_sock *ask = alg_sk(sk);
414	const struct af_alg_type *type;
415	struct sock *sk2;
416	unsigned int nokey;
417	int err;
418
419	lock_sock(sk);
420	type = ask->type;
421
422	err = -EINVAL;
423	if (!type)
424		goto unlock;
425
426	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, arg->kern);
427	err = -ENOMEM;
428	if (!sk2)
429		goto unlock;
430
431	sock_init_data(newsock, sk2);
432	security_sock_graft(sk2, newsock);
433	security_sk_clone(sk, sk2);
434
435	/*
436	 * newsock->ops assigned here to allow type->accept call to override
437	 * them when required.
438	 */
439	newsock->ops = type->ops;
440	err = type->accept(ask->private, sk2);
441
442	nokey = err == -ENOKEY;
443	if (nokey && type->accept_nokey)
444		err = type->accept_nokey(ask->private, sk2);
445
446	if (err)
447		goto unlock;
448
449	if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
450		sock_hold(sk);
451	if (nokey) {
452		atomic_inc(&ask->nokey_refcnt);
453		atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
454	}
455	alg_sk(sk2)->parent = sk;
456	alg_sk(sk2)->type = type;
457
458	newsock->state = SS_CONNECTED;
459
460	if (nokey)
461		newsock->ops = type->ops_nokey;
462
463	err = 0;
464
465unlock:
466	release_sock(sk);
467
468	return err;
469}
470EXPORT_SYMBOL_GPL(af_alg_accept);
471
472static int alg_accept(struct socket *sock, struct socket *newsock,
473		      struct proto_accept_arg *arg)
474{
475	return af_alg_accept(sock->sk, newsock, arg);
476}
477
478static const struct proto_ops alg_proto_ops = {
479	.family		=	PF_ALG,
480	.owner		=	THIS_MODULE,
481
482	.connect	=	sock_no_connect,
483	.socketpair	=	sock_no_socketpair,
484	.getname	=	sock_no_getname,
485	.ioctl		=	sock_no_ioctl,
486	.listen		=	sock_no_listen,
487	.shutdown	=	sock_no_shutdown,
488	.mmap		=	sock_no_mmap,
489	.sendmsg	=	sock_no_sendmsg,
490	.recvmsg	=	sock_no_recvmsg,
491
492	.bind		=	alg_bind,
493	.release	=	af_alg_release,
494	.setsockopt	=	alg_setsockopt,
495	.accept		=	alg_accept,
496};
497
498static void alg_sock_destruct(struct sock *sk)
499{
500	struct alg_sock *ask = alg_sk(sk);
501
502	alg_do_release(ask->type, ask->private);
503}
504
505static int alg_create(struct net *net, struct socket *sock, int protocol,
506		      int kern)
507{
508	struct sock *sk;
509	int err;
510
511	if (sock->type != SOCK_SEQPACKET)
512		return -ESOCKTNOSUPPORT;
513	if (protocol != 0)
514		return -EPROTONOSUPPORT;
515
516	err = -ENOMEM;
517	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
518	if (!sk)
519		goto out;
520
521	sock->ops = &alg_proto_ops;
522	sock_init_data(sock, sk);
523
524	sk->sk_destruct = alg_sock_destruct;
525
526	return 0;
527out:
528	return err;
529}
530
531static const struct net_proto_family alg_family = {
532	.family	=	PF_ALG,
533	.create	=	alg_create,
534	.owner	=	THIS_MODULE,
535};
536
537static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
538			   struct af_alg_sgl *sgl_new)
539{
540	sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1);
541	sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl);
542}
543
544void af_alg_free_sg(struct af_alg_sgl *sgl)
545{
546	int i;
547
548	if (sgl->sgt.sgl) {
549		if (sgl->need_unpin)
550			for (i = 0; i < sgl->sgt.nents; i++)
551				unpin_user_page(sg_page(&sgl->sgt.sgl[i]));
552		if (sgl->sgt.sgl != sgl->sgl)
553			kvfree(sgl->sgt.sgl);
554		sgl->sgt.sgl = NULL;
555	}
556}
557EXPORT_SYMBOL_GPL(af_alg_free_sg);
558
559static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
560{
561	struct cmsghdr *cmsg;
562
563	for_each_cmsghdr(cmsg, msg) {
564		if (!CMSG_OK(msg, cmsg))
565			return -EINVAL;
566		if (cmsg->cmsg_level != SOL_ALG)
567			continue;
568
569		switch (cmsg->cmsg_type) {
570		case ALG_SET_IV:
571			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
572				return -EINVAL;
573			con->iv = (void *)CMSG_DATA(cmsg);
574			if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
575						      sizeof(*con->iv)))
576				return -EINVAL;
577			break;
578
579		case ALG_SET_OP:
580			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
581				return -EINVAL;
582			con->op = *(u32 *)CMSG_DATA(cmsg);
583			break;
584
585		case ALG_SET_AEAD_ASSOCLEN:
586			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
587				return -EINVAL;
588			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
589			break;
590
591		default:
592			return -EINVAL;
593		}
594	}
595
596	return 0;
597}
598
599/**
600 * af_alg_alloc_tsgl - allocate the TX SGL
601 *
602 * @sk: socket of connection to user space
603 * Return: 0 upon success, < 0 upon error
604 */
605static int af_alg_alloc_tsgl(struct sock *sk)
606{
607	struct alg_sock *ask = alg_sk(sk);
608	struct af_alg_ctx *ctx = ask->private;
609	struct af_alg_tsgl *sgl;
610	struct scatterlist *sg = NULL;
611
612	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
613	if (!list_empty(&ctx->tsgl_list))
614		sg = sgl->sg;
615
616	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
617		sgl = sock_kmalloc(sk,
618				   struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
619				   GFP_KERNEL);
620		if (!sgl)
621			return -ENOMEM;
622
623		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
624		sgl->cur = 0;
625
626		if (sg)
627			sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
628
629		list_add_tail(&sgl->list, &ctx->tsgl_list);
630	}
631
632	return 0;
633}
634
635/**
636 * af_alg_count_tsgl - Count number of TX SG entries
637 *
638 * The counting starts from the beginning of the SGL to @bytes. If
639 * an @offset is provided, the counting of the SG entries starts at the @offset.
640 *
641 * @sk: socket of connection to user space
642 * @bytes: Count the number of SG entries holding given number of bytes.
643 * @offset: Start the counting of SG entries from the given offset.
644 * Return: Number of TX SG entries found given the constraints
645 */
646unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
647{
648	const struct alg_sock *ask = alg_sk(sk);
649	const struct af_alg_ctx *ctx = ask->private;
650	const struct af_alg_tsgl *sgl;
651	unsigned int i;
652	unsigned int sgl_count = 0;
653
654	if (!bytes)
655		return 0;
656
657	list_for_each_entry(sgl, &ctx->tsgl_list, list) {
658		const struct scatterlist *sg = sgl->sg;
659
660		for (i = 0; i < sgl->cur; i++) {
661			size_t bytes_count;
662
663			/* Skip offset */
664			if (offset >= sg[i].length) {
665				offset -= sg[i].length;
666				bytes -= sg[i].length;
667				continue;
668			}
669
670			bytes_count = sg[i].length - offset;
671
672			offset = 0;
673			sgl_count++;
674
675			/* If we have seen requested number of bytes, stop */
676			if (bytes_count >= bytes)
677				return sgl_count;
678
679			bytes -= bytes_count;
680		}
681	}
682
683	return sgl_count;
684}
685EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
686
687/**
688 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
689 *
690 * If @dst is non-null, reassign the pages to @dst. The caller must release
691 * the pages. If @dst_offset is given only reassign the pages to @dst starting
692 * at the @dst_offset (byte). The caller must ensure that @dst is large
693 * enough (e.g. by using af_alg_count_tsgl with the same offset).
694 *
695 * @sk: socket of connection to user space
696 * @used: Number of bytes to pull from TX SGL
697 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
698 *	 caller must release the buffers in dst.
699 * @dst_offset: Reassign the TX SGL from given offset. All buffers before
700 *	        reaching the offset is released.
701 */
702void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
703		      size_t dst_offset)
704{
705	struct alg_sock *ask = alg_sk(sk);
706	struct af_alg_ctx *ctx = ask->private;
707	struct af_alg_tsgl *sgl;
708	struct scatterlist *sg;
709	unsigned int i, j = 0;
710
711	while (!list_empty(&ctx->tsgl_list)) {
712		sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
713				       list);
714		sg = sgl->sg;
715
716		for (i = 0; i < sgl->cur; i++) {
717			size_t plen = min_t(size_t, used, sg[i].length);
718			struct page *page = sg_page(sg + i);
719
720			if (!page)
721				continue;
722
723			/*
724			 * Assumption: caller created af_alg_count_tsgl(len)
725			 * SG entries in dst.
726			 */
727			if (dst) {
728				if (dst_offset >= plen) {
729					/* discard page before offset */
730					dst_offset -= plen;
731				} else {
732					/* reassign page to dst after offset */
733					get_page(page);
734					sg_set_page(dst + j, page,
735						    plen - dst_offset,
736						    sg[i].offset + dst_offset);
737					dst_offset = 0;
738					j++;
739				}
740			}
741
742			sg[i].length -= plen;
743			sg[i].offset += plen;
744
745			used -= plen;
746			ctx->used -= plen;
747
748			if (sg[i].length)
749				return;
750
751			put_page(page);
752			sg_assign_page(sg + i, NULL);
753		}
754
755		list_del(&sgl->list);
756		sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
757	}
758
759	if (!ctx->used)
760		ctx->merge = 0;
761	ctx->init = ctx->more;
762}
763EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
764
765/**
766 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
767 *
768 * @areq: Request holding the TX and RX SGL
769 */
770static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
771{
772	struct sock *sk = areq->sk;
773	struct alg_sock *ask = alg_sk(sk);
774	struct af_alg_ctx *ctx = ask->private;
775	struct af_alg_rsgl *rsgl, *tmp;
776	struct scatterlist *tsgl;
777	struct scatterlist *sg;
778	unsigned int i;
779
780	list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
781		atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
782		af_alg_free_sg(&rsgl->sgl);
783		list_del(&rsgl->list);
784		if (rsgl != &areq->first_rsgl)
785			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
786	}
787
788	tsgl = areq->tsgl;
789	if (tsgl) {
790		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
791			if (!sg_page(sg))
792				continue;
793			put_page(sg_page(sg));
794		}
795
796		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
797	}
798}
799
800/**
801 * af_alg_wait_for_wmem - wait for availability of writable memory
802 *
803 * @sk: socket of connection to user space
804 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
805 * Return: 0 when writable memory is available, < 0 upon error
806 */
807static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
808{
809	DEFINE_WAIT_FUNC(wait, woken_wake_function);
810	int err = -ERESTARTSYS;
811	long timeout;
812
813	if (flags & MSG_DONTWAIT)
814		return -EAGAIN;
815
816	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
817
818	add_wait_queue(sk_sleep(sk), &wait);
819	for (;;) {
820		if (signal_pending(current))
821			break;
822		timeout = MAX_SCHEDULE_TIMEOUT;
823		if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
824			err = 0;
825			break;
826		}
827	}
828	remove_wait_queue(sk_sleep(sk), &wait);
829
830	return err;
831}
832
833/**
834 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
835 *
836 * @sk: socket of connection to user space
837 */
838void af_alg_wmem_wakeup(struct sock *sk)
839{
840	struct socket_wq *wq;
841
842	if (!af_alg_writable(sk))
843		return;
844
845	rcu_read_lock();
846	wq = rcu_dereference(sk->sk_wq);
847	if (skwq_has_sleeper(wq))
848		wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
849							   EPOLLRDNORM |
850							   EPOLLRDBAND);
851	sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN);
852	rcu_read_unlock();
853}
854EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
855
856/**
857 * af_alg_wait_for_data - wait for availability of TX data
858 *
859 * @sk: socket of connection to user space
860 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
861 * @min: Set to minimum request size if partial requests are allowed.
862 * Return: 0 when writable memory is available, < 0 upon error
863 */
864int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
865{
866	DEFINE_WAIT_FUNC(wait, woken_wake_function);
867	struct alg_sock *ask = alg_sk(sk);
868	struct af_alg_ctx *ctx = ask->private;
869	long timeout;
870	int err = -ERESTARTSYS;
871
872	if (flags & MSG_DONTWAIT)
873		return -EAGAIN;
874
875	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
876
877	add_wait_queue(sk_sleep(sk), &wait);
878	for (;;) {
879		if (signal_pending(current))
880			break;
881		timeout = MAX_SCHEDULE_TIMEOUT;
882		if (sk_wait_event(sk, &timeout,
883				  ctx->init && (!ctx->more ||
884						(min && ctx->used >= min)),
885				  &wait)) {
886			err = 0;
887			break;
888		}
889	}
890	remove_wait_queue(sk_sleep(sk), &wait);
891
892	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
893
894	return err;
895}
896EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
897
898/**
899 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
900 *
901 * @sk: socket of connection to user space
902 */
903static void af_alg_data_wakeup(struct sock *sk)
904{
905	struct alg_sock *ask = alg_sk(sk);
906	struct af_alg_ctx *ctx = ask->private;
907	struct socket_wq *wq;
908
909	if (!ctx->used)
910		return;
911
912	rcu_read_lock();
913	wq = rcu_dereference(sk->sk_wq);
914	if (skwq_has_sleeper(wq))
915		wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
916							   EPOLLRDNORM |
917							   EPOLLRDBAND);
918	sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT);
919	rcu_read_unlock();
920}
921
922/**
923 * af_alg_sendmsg - implementation of sendmsg system call handler
924 *
925 * The sendmsg system call handler obtains the user data and stores it
926 * in ctx->tsgl_list. This implies allocation of the required numbers of
927 * struct af_alg_tsgl.
928 *
929 * In addition, the ctx is filled with the information sent via CMSG.
930 *
931 * @sock: socket of connection to user space
932 * @msg: message from user space
933 * @size: size of message from user space
934 * @ivsize: the size of the IV for the cipher operation to verify that the
935 *	   user-space-provided IV has the right size
936 * Return: the number of copied data upon success, < 0 upon error
937 */
938int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
939		   unsigned int ivsize)
940{
941	struct sock *sk = sock->sk;
942	struct alg_sock *ask = alg_sk(sk);
943	struct af_alg_ctx *ctx = ask->private;
944	struct af_alg_tsgl *sgl;
945	struct af_alg_control con = {};
946	long copied = 0;
947	bool enc = false;
948	bool init = false;
949	int err = 0;
950
951	if (msg->msg_controllen) {
952		err = af_alg_cmsg_send(msg, &con);
953		if (err)
954			return err;
955
956		init = true;
957		switch (con.op) {
958		case ALG_OP_ENCRYPT:
959			enc = true;
960			break;
961		case ALG_OP_DECRYPT:
962			enc = false;
963			break;
964		default:
965			return -EINVAL;
966		}
967
968		if (con.iv && con.iv->ivlen != ivsize)
969			return -EINVAL;
970	}
971
972	lock_sock(sk);
973	if (ctx->init && !ctx->more) {
974		if (ctx->used) {
975			err = -EINVAL;
976			goto unlock;
977		}
978
979		pr_info_once(
980			"%s sent an empty control message without MSG_MORE.\n",
981			current->comm);
982	}
983	ctx->init = true;
984
985	if (init) {
986		ctx->enc = enc;
987		if (con.iv)
988			memcpy(ctx->iv, con.iv->iv, ivsize);
989
990		ctx->aead_assoclen = con.aead_assoclen;
991	}
992
993	while (size) {
994		struct scatterlist *sg;
995		size_t len = size;
996		ssize_t plen;
997
998		/* use the existing memory in an allocated page */
999		if (ctx->merge && !(msg->msg_flags & MSG_SPLICE_PAGES)) {
1000			sgl = list_entry(ctx->tsgl_list.prev,
1001					 struct af_alg_tsgl, list);
1002			sg = sgl->sg + sgl->cur - 1;
1003			len = min_t(size_t, len,
1004				    PAGE_SIZE - sg->offset - sg->length);
1005
1006			err = memcpy_from_msg(page_address(sg_page(sg)) +
1007					      sg->offset + sg->length,
1008					      msg, len);
1009			if (err)
1010				goto unlock;
1011
1012			sg->length += len;
1013			ctx->merge = (sg->offset + sg->length) &
1014				     (PAGE_SIZE - 1);
1015
1016			ctx->used += len;
1017			copied += len;
1018			size -= len;
1019			continue;
1020		}
1021
1022		if (!af_alg_writable(sk)) {
1023			err = af_alg_wait_for_wmem(sk, msg->msg_flags);
1024			if (err)
1025				goto unlock;
1026		}
1027
1028		/* allocate a new page */
1029		len = min_t(unsigned long, len, af_alg_sndbuf(sk));
1030
1031		err = af_alg_alloc_tsgl(sk);
1032		if (err)
1033			goto unlock;
1034
1035		sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
1036				 list);
1037		sg = sgl->sg;
1038		if (sgl->cur)
1039			sg_unmark_end(sg + sgl->cur - 1);
1040
1041		if (msg->msg_flags & MSG_SPLICE_PAGES) {
1042			struct sg_table sgtable = {
1043				.sgl		= sg,
1044				.nents		= sgl->cur,
1045				.orig_nents	= sgl->cur,
1046			};
1047
1048			plen = extract_iter_to_sg(&msg->msg_iter, len, &sgtable,
1049						  MAX_SGL_ENTS - sgl->cur, 0);
1050			if (plen < 0) {
1051				err = plen;
1052				goto unlock;
1053			}
1054
1055			for (; sgl->cur < sgtable.nents; sgl->cur++)
1056				get_page(sg_page(&sg[sgl->cur]));
1057			len -= plen;
1058			ctx->used += plen;
1059			copied += plen;
1060			size -= plen;
1061			ctx->merge = 0;
1062		} else {
1063			do {
1064				struct page *pg;
1065				unsigned int i = sgl->cur;
1066
1067				plen = min_t(size_t, len, PAGE_SIZE);
1068
1069				pg = alloc_page(GFP_KERNEL);
1070				if (!pg) {
1071					err = -ENOMEM;
1072					goto unlock;
1073				}
1074
1075				sg_assign_page(sg + i, pg);
1076
1077				err = memcpy_from_msg(
1078					page_address(sg_page(sg + i)),
1079					msg, plen);
1080				if (err) {
1081					__free_page(sg_page(sg + i));
1082					sg_assign_page(sg + i, NULL);
1083					goto unlock;
1084				}
1085
1086				sg[i].length = plen;
1087				len -= plen;
1088				ctx->used += plen;
1089				copied += plen;
1090				size -= plen;
1091				sgl->cur++;
1092			} while (len && sgl->cur < MAX_SGL_ENTS);
1093
1094			ctx->merge = plen & (PAGE_SIZE - 1);
1095		}
1096
1097		if (!size)
1098			sg_mark_end(sg + sgl->cur - 1);
1099	}
1100
1101	err = 0;
1102
1103	ctx->more = msg->msg_flags & MSG_MORE;
1104
1105unlock:
1106	af_alg_data_wakeup(sk);
1107	release_sock(sk);
1108
1109	return copied ?: err;
1110}
1111EXPORT_SYMBOL_GPL(af_alg_sendmsg);
1112
1113/**
1114 * af_alg_free_resources - release resources required for crypto request
1115 * @areq: Request holding the TX and RX SGL
1116 */
1117void af_alg_free_resources(struct af_alg_async_req *areq)
1118{
1119	struct sock *sk = areq->sk;
1120	struct af_alg_ctx *ctx;
1121
1122	af_alg_free_areq_sgls(areq);
1123	sock_kfree_s(sk, areq, areq->areqlen);
1124
1125	ctx = alg_sk(sk)->private;
1126	ctx->inflight = false;
1127}
1128EXPORT_SYMBOL_GPL(af_alg_free_resources);
1129
1130/**
1131 * af_alg_async_cb - AIO callback handler
1132 * @data: async request completion data
1133 * @err: if non-zero, error result to be returned via ki_complete();
1134 *       otherwise return the AIO output length via ki_complete().
1135 *
1136 * This handler cleans up the struct af_alg_async_req upon completion of the
1137 * AIO operation.
1138 *
1139 * The number of bytes to be generated with the AIO operation must be set
1140 * in areq->outlen before the AIO callback handler is invoked.
1141 */
1142void af_alg_async_cb(void *data, int err)
1143{
1144	struct af_alg_async_req *areq = data;
1145	struct sock *sk = areq->sk;
1146	struct kiocb *iocb = areq->iocb;
1147	unsigned int resultlen;
1148
1149	/* Buffer size written by crypto operation. */
1150	resultlen = areq->outlen;
1151
1152	af_alg_free_resources(areq);
1153	sock_put(sk);
1154
1155	iocb->ki_complete(iocb, err ? err : (int)resultlen);
1156}
1157EXPORT_SYMBOL_GPL(af_alg_async_cb);
1158
1159/**
1160 * af_alg_poll - poll system call handler
1161 * @file: file pointer
1162 * @sock: socket to poll
1163 * @wait: poll_table
1164 */
1165__poll_t af_alg_poll(struct file *file, struct socket *sock,
1166			 poll_table *wait)
1167{
1168	struct sock *sk = sock->sk;
1169	struct alg_sock *ask = alg_sk(sk);
1170	struct af_alg_ctx *ctx = ask->private;
1171	__poll_t mask;
1172
1173	sock_poll_wait(file, sock, wait);
1174	mask = 0;
1175
1176	if (!ctx->more || ctx->used)
1177		mask |= EPOLLIN | EPOLLRDNORM;
1178
1179	if (af_alg_writable(sk))
1180		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1181
1182	return mask;
1183}
1184EXPORT_SYMBOL_GPL(af_alg_poll);
1185
1186/**
1187 * af_alg_alloc_areq - allocate struct af_alg_async_req
1188 *
1189 * @sk: socket of connection to user space
1190 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1191 * Return: allocated data structure or ERR_PTR upon error
1192 */
1193struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1194					   unsigned int areqlen)
1195{
1196	struct af_alg_ctx *ctx = alg_sk(sk)->private;
1197	struct af_alg_async_req *areq;
1198
1199	/* Only one AIO request can be in flight. */
1200	if (ctx->inflight)
1201		return ERR_PTR(-EBUSY);
1202
1203	areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1204	if (unlikely(!areq))
1205		return ERR_PTR(-ENOMEM);
1206
1207	ctx->inflight = true;
1208
1209	areq->areqlen = areqlen;
1210	areq->sk = sk;
1211	areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl;
1212	areq->last_rsgl = NULL;
1213	INIT_LIST_HEAD(&areq->rsgl_list);
1214	areq->tsgl = NULL;
1215	areq->tsgl_entries = 0;
1216
1217	return areq;
1218}
1219EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1220
1221/**
1222 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1223 *		     operation
1224 *
1225 * @sk: socket of connection to user space
1226 * @msg: user space message
1227 * @flags: flags used to invoke recvmsg with
1228 * @areq: instance of the cryptographic request that will hold the RX SGL
1229 * @maxsize: maximum number of bytes to be pulled from user space
1230 * @outlen: number of bytes in the RX SGL
1231 * Return: 0 on success, < 0 upon error
1232 */
1233int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1234		    struct af_alg_async_req *areq, size_t maxsize,
1235		    size_t *outlen)
1236{
1237	struct alg_sock *ask = alg_sk(sk);
1238	struct af_alg_ctx *ctx = ask->private;
1239	size_t len = 0;
1240
1241	while (maxsize > len && msg_data_left(msg)) {
1242		struct af_alg_rsgl *rsgl;
1243		ssize_t err;
1244		size_t seglen;
1245
1246		/* limit the amount of readable buffers */
1247		if (!af_alg_readable(sk))
1248			break;
1249
1250		seglen = min_t(size_t, (maxsize - len),
1251			       msg_data_left(msg));
1252
1253		if (list_empty(&areq->rsgl_list)) {
1254			rsgl = &areq->first_rsgl;
1255		} else {
1256			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1257			if (unlikely(!rsgl))
1258				return -ENOMEM;
1259		}
1260
1261		rsgl->sgl.need_unpin =
1262			iov_iter_extract_will_pin(&msg->msg_iter);
1263		rsgl->sgl.sgt.sgl = rsgl->sgl.sgl;
1264		rsgl->sgl.sgt.nents = 0;
1265		rsgl->sgl.sgt.orig_nents = 0;
1266		list_add_tail(&rsgl->list, &areq->rsgl_list);
1267
1268		sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES);
1269		err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt,
1270					 ALG_MAX_PAGES, 0);
1271		if (err < 0) {
1272			rsgl->sg_num_bytes = 0;
1273			return err;
1274		}
1275
1276		sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1);
1277
1278		/* chain the new scatterlist with previous one */
1279		if (areq->last_rsgl)
1280			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1281
1282		areq->last_rsgl = rsgl;
1283		len += err;
1284		atomic_add(err, &ctx->rcvused);
1285		rsgl->sg_num_bytes = err;
1286	}
1287
1288	*outlen = len;
1289	return 0;
1290}
1291EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1292
1293static int __init af_alg_init(void)
1294{
1295	int err = proto_register(&alg_proto, 0);
1296
1297	if (err)
1298		goto out;
1299
1300	err = sock_register(&alg_family);
1301	if (err != 0)
1302		goto out_unregister_proto;
1303
1304out:
1305	return err;
1306
1307out_unregister_proto:
1308	proto_unregister(&alg_proto);
1309	goto out;
1310}
1311
1312static void __exit af_alg_exit(void)
1313{
1314	sock_unregister(PF_ALG);
1315	proto_unregister(&alg_proto);
1316}
1317
1318module_init(af_alg_init);
1319module_exit(af_alg_exit);
1320MODULE_LICENSE("GPL");
1321MODULE_ALIAS_NETPROTO(AF_ALG);
1322