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		return PTR_ERR(ret);
 324	}
 325
 326	key_data = sock_kmalloc(&ask->sk, key_datalen, GFP_KERNEL);
 327	if (!key_data) {
 328		up_read(&key->sem);
 329		return -ENOMEM;
 330	}
 331
 332	memcpy(key_data, ret, key_datalen);
 333
 334	up_read(&key->sem);
 335
 336	err = type->setkey(ask->private, key_data, key_datalen);
 337
 338	sock_kzfree_s(&ask->sk, key_data, key_datalen);
 339
 340	return err;
 341}
 342
 343#else
 344
 345static inline int alg_setkey_by_key_serial(struct alg_sock *ask,
 346					   sockptr_t optval,
 347					   unsigned int optlen)
 348{
 349	return -ENOPROTOOPT;
 350}
 351
 352#endif
 353
 354static int alg_setsockopt(struct socket *sock, int level, int optname,
 355			  sockptr_t optval, unsigned int optlen)
 356{
 357	struct sock *sk = sock->sk;
 358	struct alg_sock *ask = alg_sk(sk);
 359	const struct af_alg_type *type;
 360	int err = -EBUSY;
 361
 362	lock_sock(sk);
 363	if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
 364		goto unlock;
 365
 366	type = ask->type;
 367
 368	err = -ENOPROTOOPT;
 369	if (level != SOL_ALG || !type)
 370		goto unlock;
 371
 372	switch (optname) {
 373	case ALG_SET_KEY:
 374	case ALG_SET_KEY_BY_KEY_SERIAL:
 375		if (sock->state == SS_CONNECTED)
 376			goto unlock;
 377		if (!type->setkey)
 378			goto unlock;
 379
 380		if (optname == ALG_SET_KEY_BY_KEY_SERIAL)
 381			err = alg_setkey_by_key_serial(ask, optval, optlen);
 382		else
 383			err = alg_setkey(sk, optval, optlen);
 384		break;
 385	case ALG_SET_AEAD_AUTHSIZE:
 386		if (sock->state == SS_CONNECTED)
 387			goto unlock;
 388		if (!type->setauthsize)
 389			goto unlock;
 390		err = type->setauthsize(ask->private, optlen);
 391		break;
 392	case ALG_SET_DRBG_ENTROPY:
 393		if (sock->state == SS_CONNECTED)
 394			goto unlock;
 395		if (!type->setentropy)
 396			goto unlock;
 397
 398		err = type->setentropy(ask->private, optval, optlen);
 399	}
 400
 401unlock:
 402	release_sock(sk);
 403
 404	return err;
 405}
 406
 407int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
 408{
 409	struct alg_sock *ask = alg_sk(sk);
 410	const struct af_alg_type *type;
 411	struct sock *sk2;
 412	unsigned int nokey;
 413	int err;
 414
 415	lock_sock(sk);
 416	type = ask->type;
 417
 418	err = -EINVAL;
 419	if (!type)
 420		goto unlock;
 421
 422	sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
 423	err = -ENOMEM;
 424	if (!sk2)
 425		goto unlock;
 426
 427	sock_init_data(newsock, sk2);
 428	security_sock_graft(sk2, newsock);
 429	security_sk_clone(sk, sk2);
 430
 431	/*
 432	 * newsock->ops assigned here to allow type->accept call to override
 433	 * them when required.
 434	 */
 435	newsock->ops = type->ops;
 436	err = type->accept(ask->private, sk2);
 437
 438	nokey = err == -ENOKEY;
 439	if (nokey && type->accept_nokey)
 440		err = type->accept_nokey(ask->private, sk2);
 441
 442	if (err)
 443		goto unlock;
 444
 445	if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
 
 
 446		sock_hold(sk);
 447	if (nokey) {
 448		atomic_inc(&ask->nokey_refcnt);
 449		atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
 450	}
 451	alg_sk(sk2)->parent = sk;
 452	alg_sk(sk2)->type = type;
 
 453
 
 454	newsock->state = SS_CONNECTED;
 455
 456	if (nokey)
 457		newsock->ops = type->ops_nokey;
 458
 459	err = 0;
 460
 461unlock:
 462	release_sock(sk);
 463
 464	return err;
 465}
 466EXPORT_SYMBOL_GPL(af_alg_accept);
 467
 468static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
 469		      bool kern)
 470{
 471	return af_alg_accept(sock->sk, newsock, kern);
 472}
 473
 474static const struct proto_ops alg_proto_ops = {
 475	.family		=	PF_ALG,
 476	.owner		=	THIS_MODULE,
 477
 478	.connect	=	sock_no_connect,
 479	.socketpair	=	sock_no_socketpair,
 480	.getname	=	sock_no_getname,
 481	.ioctl		=	sock_no_ioctl,
 482	.listen		=	sock_no_listen,
 483	.shutdown	=	sock_no_shutdown,
 
 484	.mmap		=	sock_no_mmap,
 485	.sendpage	=	sock_no_sendpage,
 486	.sendmsg	=	sock_no_sendmsg,
 487	.recvmsg	=	sock_no_recvmsg,
 
 488
 489	.bind		=	alg_bind,
 490	.release	=	af_alg_release,
 491	.setsockopt	=	alg_setsockopt,
 492	.accept		=	alg_accept,
 493};
 494
 495static void alg_sock_destruct(struct sock *sk)
 496{
 497	struct alg_sock *ask = alg_sk(sk);
 498
 499	alg_do_release(ask->type, ask->private);
 500}
 501
 502static int alg_create(struct net *net, struct socket *sock, int protocol,
 503		      int kern)
 504{
 505	struct sock *sk;
 506	int err;
 507
 508	if (sock->type != SOCK_SEQPACKET)
 509		return -ESOCKTNOSUPPORT;
 510	if (protocol != 0)
 511		return -EPROTONOSUPPORT;
 512
 513	err = -ENOMEM;
 514	sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 515	if (!sk)
 516		goto out;
 517
 518	sock->ops = &alg_proto_ops;
 519	sock_init_data(sock, sk);
 520
 
 521	sk->sk_destruct = alg_sock_destruct;
 522
 523	return 0;
 524out:
 525	return err;
 526}
 527
 528static const struct net_proto_family alg_family = {
 529	.family	=	PF_ALG,
 530	.create	=	alg_create,
 531	.owner	=	THIS_MODULE,
 532};
 533
 534int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 535{
 536	size_t off;
 537	ssize_t n;
 538	int npages, i;
 539
 540	n = iov_iter_get_pages2(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 541	if (n < 0)
 542		return n;
 543
 544	npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
 545	if (WARN_ON(npages == 0))
 546		return -EINVAL;
 547	/* Add one extra for linking */
 548	sg_init_table(sgl->sg, npages + 1);
 549
 550	for (i = 0, len = n; i < npages; i++) {
 551		int plen = min_t(int, len, PAGE_SIZE - off);
 552
 553		sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 554
 555		off = 0;
 556		len -= plen;
 557	}
 558	sg_mark_end(sgl->sg + npages - 1);
 559	sgl->npages = npages;
 560
 561	return n;
 562}
 563EXPORT_SYMBOL_GPL(af_alg_make_sg);
 564
 565static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
 566			   struct af_alg_sgl *sgl_new)
 567{
 568	sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 569	sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 570}
 
 571
 572void af_alg_free_sg(struct af_alg_sgl *sgl)
 573{
 574	int i;
 575
 576	for (i = 0; i < sgl->npages; i++)
 577		put_page(sgl->pages[i]);
 578}
 579EXPORT_SYMBOL_GPL(af_alg_free_sg);
 580
 581static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 582{
 583	struct cmsghdr *cmsg;
 584
 585	for_each_cmsghdr(cmsg, msg) {
 586		if (!CMSG_OK(msg, cmsg))
 587			return -EINVAL;
 588		if (cmsg->cmsg_level != SOL_ALG)
 589			continue;
 590
 591		switch (cmsg->cmsg_type) {
 592		case ALG_SET_IV:
 593			if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 594				return -EINVAL;
 595			con->iv = (void *)CMSG_DATA(cmsg);
 596			if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 597						      sizeof(*con->iv)))
 598				return -EINVAL;
 599			break;
 600
 601		case ALG_SET_OP:
 602			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 603				return -EINVAL;
 604			con->op = *(u32 *)CMSG_DATA(cmsg);
 605			break;
 606
 607		case ALG_SET_AEAD_ASSOCLEN:
 608			if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 609				return -EINVAL;
 610			con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 611			break;
 612
 613		default:
 614			return -EINVAL;
 615		}
 616	}
 617
 618	return 0;
 619}
 
 620
 621/**
 622 * af_alg_alloc_tsgl - allocate the TX SGL
 623 *
 624 * @sk: socket of connection to user space
 625 * Return: 0 upon success, < 0 upon error
 626 */
 627static int af_alg_alloc_tsgl(struct sock *sk)
 628{
 629	struct alg_sock *ask = alg_sk(sk);
 630	struct af_alg_ctx *ctx = ask->private;
 631	struct af_alg_tsgl *sgl;
 632	struct scatterlist *sg = NULL;
 633
 634	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
 635	if (!list_empty(&ctx->tsgl_list))
 636		sg = sgl->sg;
 637
 638	if (!sg || sgl->cur >= MAX_SGL_ENTS) {
 639		sgl = sock_kmalloc(sk,
 640				   struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
 641				   GFP_KERNEL);
 642		if (!sgl)
 643			return -ENOMEM;
 644
 645		sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
 646		sgl->cur = 0;
 647
 648		if (sg)
 649			sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
 650
 651		list_add_tail(&sgl->list, &ctx->tsgl_list);
 652	}
 653
 654	return 0;
 655}
 656
 657/**
 658 * af_alg_count_tsgl - Count number of TX SG entries
 659 *
 660 * The counting starts from the beginning of the SGL to @bytes. If
 661 * an @offset is provided, the counting of the SG entries starts at the @offset.
 662 *
 663 * @sk: socket of connection to user space
 664 * @bytes: Count the number of SG entries holding given number of bytes.
 665 * @offset: Start the counting of SG entries from the given offset.
 666 * Return: Number of TX SG entries found given the constraints
 667 */
 668unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
 669{
 670	const struct alg_sock *ask = alg_sk(sk);
 671	const struct af_alg_ctx *ctx = ask->private;
 672	const struct af_alg_tsgl *sgl;
 673	unsigned int i;
 674	unsigned int sgl_count = 0;
 675
 676	if (!bytes)
 677		return 0;
 678
 679	list_for_each_entry(sgl, &ctx->tsgl_list, list) {
 680		const struct scatterlist *sg = sgl->sg;
 681
 682		for (i = 0; i < sgl->cur; i++) {
 683			size_t bytes_count;
 684
 685			/* Skip offset */
 686			if (offset >= sg[i].length) {
 687				offset -= sg[i].length;
 688				bytes -= sg[i].length;
 689				continue;
 690			}
 691
 692			bytes_count = sg[i].length - offset;
 693
 694			offset = 0;
 695			sgl_count++;
 696
 697			/* If we have seen requested number of bytes, stop */
 698			if (bytes_count >= bytes)
 699				return sgl_count;
 700
 701			bytes -= bytes_count;
 702		}
 703	}
 704
 705	return sgl_count;
 706}
 707EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
 708
 709/**
 710 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
 711 *
 712 * If @dst is non-null, reassign the pages to @dst. The caller must release
 713 * the pages. If @dst_offset is given only reassign the pages to @dst starting
 714 * at the @dst_offset (byte). The caller must ensure that @dst is large
 715 * enough (e.g. by using af_alg_count_tsgl with the same offset).
 716 *
 717 * @sk: socket of connection to user space
 718 * @used: Number of bytes to pull from TX SGL
 719 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
 720 *	 caller must release the buffers in dst.
 721 * @dst_offset: Reassign the TX SGL from given offset. All buffers before
 722 *	        reaching the offset is released.
 723 */
 724void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 725		      size_t dst_offset)
 726{
 727	struct alg_sock *ask = alg_sk(sk);
 728	struct af_alg_ctx *ctx = ask->private;
 729	struct af_alg_tsgl *sgl;
 730	struct scatterlist *sg;
 731	unsigned int i, j = 0;
 732
 733	while (!list_empty(&ctx->tsgl_list)) {
 734		sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
 735				       list);
 736		sg = sgl->sg;
 737
 738		for (i = 0; i < sgl->cur; i++) {
 739			size_t plen = min_t(size_t, used, sg[i].length);
 740			struct page *page = sg_page(sg + i);
 741
 742			if (!page)
 743				continue;
 744
 745			/*
 746			 * Assumption: caller created af_alg_count_tsgl(len)
 747			 * SG entries in dst.
 748			 */
 749			if (dst) {
 750				if (dst_offset >= plen) {
 751					/* discard page before offset */
 752					dst_offset -= plen;
 753				} else {
 754					/* reassign page to dst after offset */
 755					get_page(page);
 756					sg_set_page(dst + j, page,
 757						    plen - dst_offset,
 758						    sg[i].offset + dst_offset);
 759					dst_offset = 0;
 760					j++;
 761				}
 762			}
 763
 764			sg[i].length -= plen;
 765			sg[i].offset += plen;
 766
 767			used -= plen;
 768			ctx->used -= plen;
 769
 770			if (sg[i].length)
 771				return;
 772
 773			put_page(page);
 774			sg_assign_page(sg + i, NULL);
 775		}
 776
 777		list_del(&sgl->list);
 778		sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
 779	}
 780
 781	if (!ctx->used)
 782		ctx->merge = 0;
 783	ctx->init = ctx->more;
 784}
 785EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
 786
 787/**
 788 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
 789 *
 790 * @areq: Request holding the TX and RX SGL
 791 */
 792static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
 793{
 794	struct sock *sk = areq->sk;
 795	struct alg_sock *ask = alg_sk(sk);
 796	struct af_alg_ctx *ctx = ask->private;
 797	struct af_alg_rsgl *rsgl, *tmp;
 798	struct scatterlist *tsgl;
 799	struct scatterlist *sg;
 800	unsigned int i;
 801
 802	list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
 803		atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
 804		af_alg_free_sg(&rsgl->sgl);
 805		list_del(&rsgl->list);
 806		if (rsgl != &areq->first_rsgl)
 807			sock_kfree_s(sk, rsgl, sizeof(*rsgl));
 808	}
 809
 810	tsgl = areq->tsgl;
 811	if (tsgl) {
 812		for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
 813			if (!sg_page(sg))
 814				continue;
 815			put_page(sg_page(sg));
 816		}
 817
 818		sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
 819	}
 820}
 821
 822/**
 823 * af_alg_wait_for_wmem - wait for availability of writable memory
 824 *
 825 * @sk: socket of connection to user space
 826 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
 827 * Return: 0 when writable memory is available, < 0 upon error
 828 */
 829static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
 830{
 831	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 832	int err = -ERESTARTSYS;
 833	long timeout;
 834
 835	if (flags & MSG_DONTWAIT)
 836		return -EAGAIN;
 837
 838	sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 839
 840	add_wait_queue(sk_sleep(sk), &wait);
 841	for (;;) {
 842		if (signal_pending(current))
 843			break;
 844		timeout = MAX_SCHEDULE_TIMEOUT;
 845		if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
 846			err = 0;
 847			break;
 848		}
 849	}
 850	remove_wait_queue(sk_sleep(sk), &wait);
 851
 852	return err;
 853}
 854
 855/**
 856 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
 857 *
 858 * @sk: socket of connection to user space
 859 */
 860void af_alg_wmem_wakeup(struct sock *sk)
 861{
 862	struct socket_wq *wq;
 863
 864	if (!af_alg_writable(sk))
 865		return;
 866
 867	rcu_read_lock();
 868	wq = rcu_dereference(sk->sk_wq);
 869	if (skwq_has_sleeper(wq))
 870		wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
 871							   EPOLLRDNORM |
 872							   EPOLLRDBAND);
 873	sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 874	rcu_read_unlock();
 875}
 876EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
 877
 878/**
 879 * af_alg_wait_for_data - wait for availability of TX data
 880 *
 881 * @sk: socket of connection to user space
 882 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
 883 * @min: Set to minimum request size if partial requests are allowed.
 884 * Return: 0 when writable memory is available, < 0 upon error
 885 */
 886int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
 887{
 888	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 889	struct alg_sock *ask = alg_sk(sk);
 890	struct af_alg_ctx *ctx = ask->private;
 891	long timeout;
 892	int err = -ERESTARTSYS;
 893
 894	if (flags & MSG_DONTWAIT)
 895		return -EAGAIN;
 896
 897	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 898
 899	add_wait_queue(sk_sleep(sk), &wait);
 900	for (;;) {
 901		if (signal_pending(current))
 902			break;
 903		timeout = MAX_SCHEDULE_TIMEOUT;
 904		if (sk_wait_event(sk, &timeout,
 905				  ctx->init && (!ctx->more ||
 906						(min && ctx->used >= min)),
 907				  &wait)) {
 908			err = 0;
 909			break;
 910		}
 911	}
 912	remove_wait_queue(sk_sleep(sk), &wait);
 913
 914	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 915
 916	return err;
 917}
 918EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
 919
 920/**
 921 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
 922 *
 923 * @sk: socket of connection to user space
 924 */
 925static void af_alg_data_wakeup(struct sock *sk)
 926{
 927	struct alg_sock *ask = alg_sk(sk);
 928	struct af_alg_ctx *ctx = ask->private;
 929	struct socket_wq *wq;
 930
 931	if (!ctx->used)
 932		return;
 933
 934	rcu_read_lock();
 935	wq = rcu_dereference(sk->sk_wq);
 936	if (skwq_has_sleeper(wq))
 937		wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
 938							   EPOLLRDNORM |
 939							   EPOLLRDBAND);
 940	sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 941	rcu_read_unlock();
 942}
 943
 944/**
 945 * af_alg_sendmsg - implementation of sendmsg system call handler
 946 *
 947 * The sendmsg system call handler obtains the user data and stores it
 948 * in ctx->tsgl_list. This implies allocation of the required numbers of
 949 * struct af_alg_tsgl.
 950 *
 951 * In addition, the ctx is filled with the information sent via CMSG.
 952 *
 953 * @sock: socket of connection to user space
 954 * @msg: message from user space
 955 * @size: size of message from user space
 956 * @ivsize: the size of the IV for the cipher operation to verify that the
 957 *	   user-space-provided IV has the right size
 958 * Return: the number of copied data upon success, < 0 upon error
 959 */
 960int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 961		   unsigned int ivsize)
 962{
 963	struct sock *sk = sock->sk;
 964	struct alg_sock *ask = alg_sk(sk);
 965	struct af_alg_ctx *ctx = ask->private;
 966	struct af_alg_tsgl *sgl;
 967	struct af_alg_control con = {};
 968	long copied = 0;
 969	bool enc = false;
 970	bool init = false;
 971	int err = 0;
 972
 973	if (msg->msg_controllen) {
 974		err = af_alg_cmsg_send(msg, &con);
 975		if (err)
 976			return err;
 977
 978		init = true;
 979		switch (con.op) {
 980		case ALG_OP_ENCRYPT:
 981			enc = true;
 982			break;
 983		case ALG_OP_DECRYPT:
 984			enc = false;
 985			break;
 986		default:
 987			return -EINVAL;
 988		}
 989
 990		if (con.iv && con.iv->ivlen != ivsize)
 991			return -EINVAL;
 992	}
 993
 994	lock_sock(sk);
 995	if (ctx->init && !ctx->more) {
 996		if (ctx->used) {
 997			err = -EINVAL;
 998			goto unlock;
 999		}
1000
1001		pr_info_once(
1002			"%s sent an empty control message without MSG_MORE.\n",
1003			current->comm);
1004	}
1005	ctx->init = true;
1006
1007	if (init) {
1008		ctx->enc = enc;
1009		if (con.iv)
1010			memcpy(ctx->iv, con.iv->iv, ivsize);
1011
1012		ctx->aead_assoclen = con.aead_assoclen;
1013	}
1014
1015	while (size) {
1016		struct scatterlist *sg;
1017		size_t len = size;
1018		size_t plen;
1019
1020		/* use the existing memory in an allocated page */
1021		if (ctx->merge) {
1022			sgl = list_entry(ctx->tsgl_list.prev,
1023					 struct af_alg_tsgl, list);
1024			sg = sgl->sg + sgl->cur - 1;
1025			len = min_t(size_t, len,
1026				    PAGE_SIZE - sg->offset - sg->length);
1027
1028			err = memcpy_from_msg(page_address(sg_page(sg)) +
1029					      sg->offset + sg->length,
1030					      msg, len);
1031			if (err)
1032				goto unlock;
1033
1034			sg->length += len;
1035			ctx->merge = (sg->offset + sg->length) &
1036				     (PAGE_SIZE - 1);
1037
1038			ctx->used += len;
1039			copied += len;
1040			size -= len;
1041			continue;
1042		}
1043
1044		if (!af_alg_writable(sk)) {
1045			err = af_alg_wait_for_wmem(sk, msg->msg_flags);
1046			if (err)
1047				goto unlock;
1048		}
1049
1050		/* allocate a new page */
1051		len = min_t(unsigned long, len, af_alg_sndbuf(sk));
1052
1053		err = af_alg_alloc_tsgl(sk);
1054		if (err)
1055			goto unlock;
1056
1057		sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
1058				 list);
1059		sg = sgl->sg;
1060		if (sgl->cur)
1061			sg_unmark_end(sg + sgl->cur - 1);
1062
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(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		if (!size)
1094			sg_mark_end(sg + sgl->cur - 1);
1095
1096		ctx->merge = plen & (PAGE_SIZE - 1);
1097	}
1098
1099	err = 0;
1100
1101	ctx->more = msg->msg_flags & MSG_MORE;
1102
1103unlock:
1104	af_alg_data_wakeup(sk);
1105	release_sock(sk);
1106
1107	return copied ?: err;
1108}
1109EXPORT_SYMBOL_GPL(af_alg_sendmsg);
1110
1111/**
1112 * af_alg_sendpage - sendpage system call handler
1113 * @sock: socket of connection to user space to write to
1114 * @page: data to send
1115 * @offset: offset into page to begin sending
1116 * @size: length of data
1117 * @flags: message send/receive flags
1118 *
1119 * This is a generic implementation of sendpage to fill ctx->tsgl_list.
1120 */
1121ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
1122			int offset, size_t size, int flags)
1123{
1124	struct sock *sk = sock->sk;
1125	struct alg_sock *ask = alg_sk(sk);
1126	struct af_alg_ctx *ctx = ask->private;
1127	struct af_alg_tsgl *sgl;
1128	int err = -EINVAL;
1129
1130	if (flags & MSG_SENDPAGE_NOTLAST)
1131		flags |= MSG_MORE;
1132
1133	lock_sock(sk);
1134	if (!ctx->more && ctx->used)
1135		goto unlock;
1136
1137	if (!size)
1138		goto done;
1139
1140	if (!af_alg_writable(sk)) {
1141		err = af_alg_wait_for_wmem(sk, flags);
1142		if (err)
1143			goto unlock;
1144	}
1145
1146	err = af_alg_alloc_tsgl(sk);
1147	if (err)
1148		goto unlock;
1149
1150	ctx->merge = 0;
1151	sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
1152
1153	if (sgl->cur)
1154		sg_unmark_end(sgl->sg + sgl->cur - 1);
1155
1156	sg_mark_end(sgl->sg + sgl->cur);
1157
1158	get_page(page);
1159	sg_set_page(sgl->sg + sgl->cur, page, size, offset);
1160	sgl->cur++;
1161	ctx->used += size;
1162
1163done:
1164	ctx->more = flags & MSG_MORE;
1165
1166unlock:
1167	af_alg_data_wakeup(sk);
1168	release_sock(sk);
1169
1170	return err ?: size;
1171}
1172EXPORT_SYMBOL_GPL(af_alg_sendpage);
1173
1174/**
1175 * af_alg_free_resources - release resources required for crypto request
1176 * @areq: Request holding the TX and RX SGL
1177 */
1178void af_alg_free_resources(struct af_alg_async_req *areq)
1179{
1180	struct sock *sk = areq->sk;
1181
1182	af_alg_free_areq_sgls(areq);
1183	sock_kfree_s(sk, areq, areq->areqlen);
1184}
1185EXPORT_SYMBOL_GPL(af_alg_free_resources);
1186
1187/**
1188 * af_alg_async_cb - AIO callback handler
1189 * @_req: async request info
1190 * @err: if non-zero, error result to be returned via ki_complete();
1191 *       otherwise return the AIO output length via ki_complete().
1192 *
1193 * This handler cleans up the struct af_alg_async_req upon completion of the
1194 * AIO operation.
1195 *
1196 * The number of bytes to be generated with the AIO operation must be set
1197 * in areq->outlen before the AIO callback handler is invoked.
1198 */
1199void af_alg_async_cb(struct crypto_async_request *_req, int err)
1200{
1201	struct af_alg_async_req *areq = _req->data;
1202	struct sock *sk = areq->sk;
1203	struct kiocb *iocb = areq->iocb;
1204	unsigned int resultlen;
1205
1206	/* Buffer size written by crypto operation. */
1207	resultlen = areq->outlen;
1208
1209	af_alg_free_resources(areq);
1210	sock_put(sk);
1211
1212	iocb->ki_complete(iocb, err ? err : (int)resultlen);
1213}
1214EXPORT_SYMBOL_GPL(af_alg_async_cb);
1215
1216/**
1217 * af_alg_poll - poll system call handler
1218 * @file: file pointer
1219 * @sock: socket to poll
1220 * @wait: poll_table
1221 */
1222__poll_t af_alg_poll(struct file *file, struct socket *sock,
1223			 poll_table *wait)
1224{
1225	struct sock *sk = sock->sk;
1226	struct alg_sock *ask = alg_sk(sk);
1227	struct af_alg_ctx *ctx = ask->private;
1228	__poll_t mask;
1229
1230	sock_poll_wait(file, sock, wait);
1231	mask = 0;
1232
1233	if (!ctx->more || ctx->used)
1234		mask |= EPOLLIN | EPOLLRDNORM;
1235
1236	if (af_alg_writable(sk))
1237		mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1238
1239	return mask;
1240}
1241EXPORT_SYMBOL_GPL(af_alg_poll);
1242
1243/**
1244 * af_alg_alloc_areq - allocate struct af_alg_async_req
1245 *
1246 * @sk: socket of connection to user space
1247 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1248 * Return: allocated data structure or ERR_PTR upon error
1249 */
1250struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1251					   unsigned int areqlen)
1252{
1253	struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1254
1255	if (unlikely(!areq))
1256		return ERR_PTR(-ENOMEM);
1257
1258	areq->areqlen = areqlen;
1259	areq->sk = sk;
1260	areq->last_rsgl = NULL;
1261	INIT_LIST_HEAD(&areq->rsgl_list);
1262	areq->tsgl = NULL;
1263	areq->tsgl_entries = 0;
1264
1265	return areq;
1266}
1267EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1268
1269/**
1270 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1271 *		     operation
1272 *
1273 * @sk: socket of connection to user space
1274 * @msg: user space message
1275 * @flags: flags used to invoke recvmsg with
1276 * @areq: instance of the cryptographic request that will hold the RX SGL
1277 * @maxsize: maximum number of bytes to be pulled from user space
1278 * @outlen: number of bytes in the RX SGL
1279 * Return: 0 on success, < 0 upon error
1280 */
1281int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1282		    struct af_alg_async_req *areq, size_t maxsize,
1283		    size_t *outlen)
1284{
1285	struct alg_sock *ask = alg_sk(sk);
1286	struct af_alg_ctx *ctx = ask->private;
1287	size_t len = 0;
1288
1289	while (maxsize > len && msg_data_left(msg)) {
1290		struct af_alg_rsgl *rsgl;
1291		size_t seglen;
1292		int err;
1293
1294		/* limit the amount of readable buffers */
1295		if (!af_alg_readable(sk))
1296			break;
1297
1298		seglen = min_t(size_t, (maxsize - len),
1299			       msg_data_left(msg));
1300
1301		if (list_empty(&areq->rsgl_list)) {
1302			rsgl = &areq->first_rsgl;
1303		} else {
1304			rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1305			if (unlikely(!rsgl))
1306				return -ENOMEM;
1307		}
1308
1309		rsgl->sgl.npages = 0;
1310		list_add_tail(&rsgl->list, &areq->rsgl_list);
1311
1312		/* make one iovec available as scatterlist */
1313		err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1314		if (err < 0) {
1315			rsgl->sg_num_bytes = 0;
1316			return err;
1317		}
1318
1319		/* chain the new scatterlist with previous one */
1320		if (areq->last_rsgl)
1321			af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1322
1323		areq->last_rsgl = rsgl;
1324		len += err;
1325		atomic_add(err, &ctx->rcvused);
1326		rsgl->sg_num_bytes = err;
1327	}
1328
1329	*outlen = len;
1330	return 0;
1331}
1332EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1333
1334static int __init af_alg_init(void)
1335{
1336	int err = proto_register(&alg_proto, 0);
1337
1338	if (err)
1339		goto out;
1340
1341	err = sock_register(&alg_family);
1342	if (err != 0)
1343		goto out_unregister_proto;
1344
1345out:
1346	return err;
1347
1348out_unregister_proto:
1349	proto_unregister(&alg_proto);
1350	goto out;
1351}
1352
1353static void __exit af_alg_exit(void)
1354{
1355	sock_unregister(PF_ALG);
1356	proto_unregister(&alg_proto);
1357}
1358
1359module_init(af_alg_init);
1360module_exit(af_alg_exit);
1361MODULE_LICENSE("GPL");
1362MODULE_ALIAS_NETPROTO(AF_ALG);