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