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