1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/fanotify.h>
   3#include <linux/fcntl.h>
   4#include <linux/file.h>
   5#include <linux/fs.h>
   6#include <linux/anon_inodes.h>
   7#include <linux/fsnotify_backend.h>
   8#include <linux/init.h>
   9#include <linux/mount.h>
  10#include <linux/namei.h>
  11#include <linux/poll.h>
  12#include <linux/security.h>
  13#include <linux/syscalls.h>
  14#include <linux/slab.h>
  15#include <linux/types.h>
  16#include <linux/uaccess.h>
  17#include <linux/compat.h>
  18#include <linux/sched/signal.h>
  19#include <linux/memcontrol.h>
  20#include <linux/statfs.h>
  21#include <linux/exportfs.h>
  22
  23#include <asm/ioctls.h>
  24
  25#include "../fsnotify.h"
  26#include "../fdinfo.h"
  27#include "fanotify.h"
  28
  29#define FANOTIFY_DEFAULT_MAX_EVENTS	16384
  30#define FANOTIFY_OLD_DEFAULT_MAX_MARKS	8192
  31#define FANOTIFY_DEFAULT_MAX_GROUPS	128
  32#define FANOTIFY_DEFAULT_FEE_POOL_SIZE	32
  33
  34/*
  35 * Legacy fanotify marks limits (8192) is per group and we introduced a tunable
  36 * limit of marks per user, similar to inotify.  Effectively, the legacy limit
  37 * of fanotify marks per user is <max marks per group> * <max groups per user>.
  38 * This default limit (1M) also happens to match the increased limit of inotify
  39 * max_user_watches since v5.10.
  40 */
  41#define FANOTIFY_DEFAULT_MAX_USER_MARKS	\
  42	(FANOTIFY_OLD_DEFAULT_MAX_MARKS * FANOTIFY_DEFAULT_MAX_GROUPS)
  43
  44/*
  45 * Most of the memory cost of adding an inode mark is pinning the marked inode.
  46 * The size of the filesystem inode struct is not uniform across filesystems,
  47 * so double the size of a VFS inode is used as a conservative approximation.
  48 */
  49#define INODE_MARK_COST	(2 * sizeof(struct inode))
  50
  51/* configurable via /proc/sys/fs/fanotify/ */
  52static int fanotify_max_queued_events __read_mostly;
  53
  54#ifdef CONFIG_SYSCTL
  55
  56#include <linux/sysctl.h>
  57
  58static long ft_zero = 0;
  59static long ft_int_max = INT_MAX;
  60
  61static struct ctl_table fanotify_table[] = {
  62	{
  63		.procname	= "max_user_groups",
  64		.data	= &init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS],
  65		.maxlen		= sizeof(long),
  66		.mode		= 0644,
  67		.proc_handler	= proc_doulongvec_minmax,
  68		.extra1		= &ft_zero,
  69		.extra2		= &ft_int_max,
  70	},
  71	{
  72		.procname	= "max_user_marks",
  73		.data	= &init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS],
  74		.maxlen		= sizeof(long),
  75		.mode		= 0644,
  76		.proc_handler	= proc_doulongvec_minmax,
  77		.extra1		= &ft_zero,
  78		.extra2		= &ft_int_max,
  79	},
  80	{
  81		.procname	= "max_queued_events",
  82		.data		= &fanotify_max_queued_events,
  83		.maxlen		= sizeof(int),
  84		.mode		= 0644,
  85		.proc_handler	= proc_dointvec_minmax,
  86		.extra1		= SYSCTL_ZERO
  87	},
  88};
  89
  90static void __init fanotify_sysctls_init(void)
  91{
  92	register_sysctl("fs/fanotify", fanotify_table);
  93}
  94#else
  95#define fanotify_sysctls_init() do { } while (0)
  96#endif /* CONFIG_SYSCTL */
  97
  98/*
  99 * All flags that may be specified in parameter event_f_flags of fanotify_init.
 100 *
 101 * Internal and external open flags are stored together in field f_flags of
 102 * struct file. Only external open flags shall be allowed in event_f_flags.
 103 * Internal flags like FMODE_NONOTIFY, FMODE_EXEC, FMODE_NOCMTIME shall be
 104 * excluded.
 105 */
 106#define	FANOTIFY_INIT_ALL_EVENT_F_BITS				( \
 107		O_ACCMODE	| O_APPEND	| O_NONBLOCK	| \
 108		__O_SYNC	| O_DSYNC	| O_CLOEXEC     | \
 109		O_LARGEFILE	| O_NOATIME	)
 110
 111extern const struct fsnotify_ops fanotify_fsnotify_ops;
 112
 113struct kmem_cache *fanotify_mark_cache __ro_after_init;
 114struct kmem_cache *fanotify_fid_event_cachep __ro_after_init;
 115struct kmem_cache *fanotify_path_event_cachep __ro_after_init;
 116struct kmem_cache *fanotify_perm_event_cachep __ro_after_init;
 117
 118#define FANOTIFY_EVENT_ALIGN 4
 119#define FANOTIFY_FID_INFO_HDR_LEN \
 120	(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
 121#define FANOTIFY_PIDFD_INFO_HDR_LEN \
 122	sizeof(struct fanotify_event_info_pidfd)
 123#define FANOTIFY_ERROR_INFO_LEN \
 124	(sizeof(struct fanotify_event_info_error))
 125
 126static int fanotify_fid_info_len(int fh_len, int name_len)
 127{
 128	int info_len = fh_len;
 129
 130	if (name_len)
 131		info_len += name_len + 1;
 132
 133	return roundup(FANOTIFY_FID_INFO_HDR_LEN + info_len,
 134		       FANOTIFY_EVENT_ALIGN);
 135}
 136
 137/* FAN_RENAME may have one or two dir+name info records */
 138static int fanotify_dir_name_info_len(struct fanotify_event *event)
 139{
 140	struct fanotify_info *info = fanotify_event_info(event);
 141	int dir_fh_len = fanotify_event_dir_fh_len(event);
 142	int dir2_fh_len = fanotify_event_dir2_fh_len(event);
 143	int info_len = 0;
 144
 145	if (dir_fh_len)
 146		info_len += fanotify_fid_info_len(dir_fh_len,
 147						  info->name_len);
 148	if (dir2_fh_len)
 149		info_len += fanotify_fid_info_len(dir2_fh_len,
 150						  info->name2_len);
 151
 152	return info_len;
 153}
 154
 155static size_t fanotify_event_len(unsigned int info_mode,
 156				 struct fanotify_event *event)
 157{
 158	size_t event_len = FAN_EVENT_METADATA_LEN;
 159	int fh_len;
 160	int dot_len = 0;
 161
 162	if (!info_mode)
 163		return event_len;
 164
 165	if (fanotify_is_error_event(event->mask))
 166		event_len += FANOTIFY_ERROR_INFO_LEN;
 167
 168	if (fanotify_event_has_any_dir_fh(event)) {
 169		event_len += fanotify_dir_name_info_len(event);
 170	} else if ((info_mode & FAN_REPORT_NAME) &&
 171		   (event->mask & FAN_ONDIR)) {
 172		/*
 173		 * With group flag FAN_REPORT_NAME, if name was not recorded in
 174		 * event on a directory, we will report the name ".".
 175		 */
 176		dot_len = 1;
 177	}
 178
 179	if (info_mode & FAN_REPORT_PIDFD)
 180		event_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
 181
 182	if (fanotify_event_has_object_fh(event)) {
 183		fh_len = fanotify_event_object_fh_len(event);
 184		event_len += fanotify_fid_info_len(fh_len, dot_len);
 185	}
 186
 187	return event_len;
 188}
 189
 190/*
 191 * Remove an hashed event from merge hash table.
 192 */
 193static void fanotify_unhash_event(struct fsnotify_group *group,
 194				  struct fanotify_event *event)
 195{
 196	assert_spin_locked(&group->notification_lock);
 197
 198	pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
 199		 group, event, fanotify_event_hash_bucket(group, event));
 200
 201	if (WARN_ON_ONCE(hlist_unhashed(&event->merge_list)))
 202		return;
 203
 204	hlist_del_init(&event->merge_list);
 205}
 206
 207/*
 208 * Get an fanotify notification event if one exists and is small
 209 * enough to fit in "count". Return an error pointer if the count
 210 * is not large enough. When permission event is dequeued, its state is
 211 * updated accordingly.
 
 212 */
 213static struct fanotify_event *get_one_event(struct fsnotify_group *group,
 214					    size_t count)
 215{
 216	size_t event_size;
 217	struct fanotify_event *event = NULL;
 218	struct fsnotify_event *fsn_event;
 219	unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
 220
 221	pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
 222
 223	spin_lock(&group->notification_lock);
 224	fsn_event = fsnotify_peek_first_event(group);
 225	if (!fsn_event)
 226		goto out;
 227
 228	event = FANOTIFY_E(fsn_event);
 229	event_size = fanotify_event_len(info_mode, event);
 230
 231	if (event_size > count) {
 232		event = ERR_PTR(-EINVAL);
 233		goto out;
 234	}
 235
 236	/*
 237	 * Held the notification_lock the whole time, so this is the
 238	 * same event we peeked above.
 239	 */
 240	fsnotify_remove_first_event(group);
 241	if (fanotify_is_perm_event(event->mask))
 242		FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
 243	if (fanotify_is_hashed_event(event->mask))
 244		fanotify_unhash_event(group, event);
 245out:
 246	spin_unlock(&group->notification_lock);
 247	return event;
 248}
 249
 250static int create_fd(struct fsnotify_group *group, const struct path *path,
 
 251		     struct file **file)
 252{
 253	int client_fd;
 254	struct file *new_file;
 255
 
 
 256	client_fd = get_unused_fd_flags(group->fanotify_data.f_flags);
 257	if (client_fd < 0)
 258		return client_fd;
 259
 260	/*
 261	 * we need a new file handle for the userspace program so it can read even if it was
 262	 * originally opened O_WRONLY.
 263	 */
 264	new_file = dentry_open(path,
 265			       group->fanotify_data.f_flags | __FMODE_NONOTIFY,
 266			       current_cred());
 
 
 
 
 
 267	if (IS_ERR(new_file)) {
 
 
 
 
 
 
 
 268		put_unused_fd(client_fd);
 269		client_fd = PTR_ERR(new_file);
 270	} else {
 271		*file = new_file;
 272	}
 273
 274	return client_fd;
 275}
 276
 277static int process_access_response_info(const char __user *info,
 278					size_t info_len,
 279				struct fanotify_response_info_audit_rule *friar)
 
 280{
 281	if (info_len != sizeof(*friar))
 282		return -EINVAL;
 283
 284	if (copy_from_user(friar, info, sizeof(*friar)))
 285		return -EFAULT;
 286
 287	if (friar->hdr.type != FAN_RESPONSE_INFO_AUDIT_RULE)
 288		return -EINVAL;
 289	if (friar->hdr.pad != 0)
 290		return -EINVAL;
 291	if (friar->hdr.len != sizeof(*friar))
 292		return -EINVAL;
 
 
 
 
 
 
 
 
 
 293
 294	return info_len;
 295}
 296
 297/*
 298 * Finish processing of permission event by setting it to ANSWERED state and
 299 * drop group->notification_lock.
 300 */
 301static void finish_permission_event(struct fsnotify_group *group,
 302				    struct fanotify_perm_event *event, u32 response,
 303				    struct fanotify_response_info_audit_rule *friar)
 304				    __releases(&group->notification_lock)
 305{
 306	bool destroy = false;
 307
 308	assert_spin_locked(&group->notification_lock);
 309	event->response = response & ~FAN_INFO;
 310	if (response & FAN_INFO)
 311		memcpy(&event->audit_rule, friar, sizeof(*friar));
 
 312
 313	if (event->state == FAN_EVENT_CANCELED)
 314		destroy = true;
 315	else
 316		event->state = FAN_EVENT_ANSWERED;
 317	spin_unlock(&group->notification_lock);
 318	if (destroy)
 319		fsnotify_destroy_event(group, &event->fae.fse);
 
 
 320}
 321
 322static int process_access_response(struct fsnotify_group *group,
 323				   struct fanotify_response *response_struct,
 324				   const char __user *info,
 325				   size_t info_len)
 326{
 327	struct fanotify_perm_event *event;
 328	int fd = response_struct->fd;
 329	u32 response = response_struct->response;
 330	int ret = info_len;
 331	struct fanotify_response_info_audit_rule friar;
 332
 333	pr_debug("%s: group=%p fd=%d response=%u buf=%p size=%zu\n", __func__,
 334		 group, fd, response, info, info_len);
 335	/*
 336	 * make sure the response is valid, if invalid we do nothing and either
 337	 * userspace can send a valid response or we will clean it up after the
 338	 * timeout
 339	 */
 340	if (response & ~FANOTIFY_RESPONSE_VALID_MASK)
 341		return -EINVAL;
 342
 343	switch (response & FANOTIFY_RESPONSE_ACCESS) {
 344	case FAN_ALLOW:
 345	case FAN_DENY:
 346		break;
 347	default:
 348		return -EINVAL;
 349	}
 350
 351	if ((response & FAN_AUDIT) && !FAN_GROUP_FLAG(group, FAN_ENABLE_AUDIT))
 352		return -EINVAL;
 353
 354	if (response & FAN_INFO) {
 355		ret = process_access_response_info(info, info_len, &friar);
 356		if (ret < 0)
 357			return ret;
 358		if (fd == FAN_NOFD)
 359			return ret;
 360	} else {
 361		ret = 0;
 362	}
 363
 364	if (fd < 0)
 365		return -EINVAL;
 366
 367	spin_lock(&group->notification_lock);
 368	list_for_each_entry(event, &group->fanotify_data.access_list,
 369			    fae.fse.list) {
 370		if (event->fd != fd)
 371			continue;
 372
 373		list_del_init(&event->fae.fse.list);
 374		finish_permission_event(group, event, response, &friar);
 375		wake_up(&group->fanotify_data.access_waitq);
 376		return ret;
 377	}
 378	spin_unlock(&group->notification_lock);
 379
 380	return -ENOENT;
 381}
 382
 383static size_t copy_error_info_to_user(struct fanotify_event *event,
 384				      char __user *buf, int count)
 385{
 386	struct fanotify_event_info_error info = { };
 387	struct fanotify_error_event *fee = FANOTIFY_EE(event);
 388
 389	info.hdr.info_type = FAN_EVENT_INFO_TYPE_ERROR;
 390	info.hdr.len = FANOTIFY_ERROR_INFO_LEN;
 391
 392	if (WARN_ON(count < info.hdr.len))
 393		return -EFAULT;
 394
 395	info.error = fee->error;
 396	info.error_count = fee->err_count;
 397
 398	if (copy_to_user(buf, &info, sizeof(info)))
 399		return -EFAULT;
 400
 401	return info.hdr.len;
 402}
 403
 404static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
 405				 int info_type, const char *name,
 406				 size_t name_len,
 407				 char __user *buf, size_t count)
 408{
 409	struct fanotify_event_info_fid info = { };
 410	struct file_handle handle = { };
 411	unsigned char bounce[FANOTIFY_INLINE_FH_LEN], *fh_buf;
 412	size_t fh_len = fh ? fh->len : 0;
 413	size_t info_len = fanotify_fid_info_len(fh_len, name_len);
 414	size_t len = info_len;
 415
 416	pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n",
 417		 __func__, fh_len, name_len, info_len, count);
 418
 419	if (WARN_ON_ONCE(len < sizeof(info) || len > count))
 420		return -EFAULT;
 421
 422	/*
 423	 * Copy event info fid header followed by variable sized file handle
 424	 * and optionally followed by variable sized filename.
 425	 */
 426	switch (info_type) {
 427	case FAN_EVENT_INFO_TYPE_FID:
 428	case FAN_EVENT_INFO_TYPE_DFID:
 429		if (WARN_ON_ONCE(name_len))
 430			return -EFAULT;
 431		break;
 432	case FAN_EVENT_INFO_TYPE_DFID_NAME:
 433	case FAN_EVENT_INFO_TYPE_OLD_DFID_NAME:
 434	case FAN_EVENT_INFO_TYPE_NEW_DFID_NAME:
 435		if (WARN_ON_ONCE(!name || !name_len))
 436			return -EFAULT;
 437		break;
 438	default:
 439		return -EFAULT;
 440	}
 441
 442	info.hdr.info_type = info_type;
 443	info.hdr.len = len;
 444	info.fsid = *fsid;
 445	if (copy_to_user(buf, &info, sizeof(info)))
 446		return -EFAULT;
 447
 448	buf += sizeof(info);
 449	len -= sizeof(info);
 450	if (WARN_ON_ONCE(len < sizeof(handle)))
 451		return -EFAULT;
 452
 453	handle.handle_type = fh->type;
 454	handle.handle_bytes = fh_len;
 455
 456	/* Mangle handle_type for bad file_handle */
 457	if (!fh_len)
 458		handle.handle_type = FILEID_INVALID;
 459
 460	if (copy_to_user(buf, &handle, sizeof(handle)))
 461		return -EFAULT;
 462
 463	buf += sizeof(handle);
 464	len -= sizeof(handle);
 465	if (WARN_ON_ONCE(len < fh_len))
 466		return -EFAULT;
 467
 468	/*
 469	 * For an inline fh and inline file name, copy through stack to exclude
 470	 * the copy from usercopy hardening protections.
 471	 */
 472	fh_buf = fanotify_fh_buf(fh);
 473	if (fh_len <= FANOTIFY_INLINE_FH_LEN) {
 474		memcpy(bounce, fh_buf, fh_len);
 475		fh_buf = bounce;
 476	}
 477	if (copy_to_user(buf, fh_buf, fh_len))
 478		return -EFAULT;
 479
 480	buf += fh_len;
 481	len -= fh_len;
 482
 483	if (name_len) {
 484		/* Copy the filename with terminating null */
 485		name_len++;
 486		if (WARN_ON_ONCE(len < name_len))
 487			return -EFAULT;
 488
 489		if (copy_to_user(buf, name, name_len))
 490			return -EFAULT;
 491
 492		buf += name_len;
 493		len -= name_len;
 494	}
 495
 496	/* Pad with 0's */
 497	WARN_ON_ONCE(len < 0 || len >= FANOTIFY_EVENT_ALIGN);
 498	if (len > 0 && clear_user(buf, len))
 499		return -EFAULT;
 500
 501	return info_len;
 502}
 503
 504static int copy_pidfd_info_to_user(int pidfd,
 505				   char __user *buf,
 506				   size_t count)
 507{
 508	struct fanotify_event_info_pidfd info = { };
 509	size_t info_len = FANOTIFY_PIDFD_INFO_HDR_LEN;
 510
 511	if (WARN_ON_ONCE(info_len > count))
 512		return -EFAULT;
 513
 514	info.hdr.info_type = FAN_EVENT_INFO_TYPE_PIDFD;
 515	info.hdr.len = info_len;
 516	info.pidfd = pidfd;
 517
 518	if (copy_to_user(buf, &info, info_len))
 519		return -EFAULT;
 520
 521	return info_len;
 522}
 523
 524static int copy_info_records_to_user(struct fanotify_event *event,
 525				     struct fanotify_info *info,
 526				     unsigned int info_mode, int pidfd,
 527				     char __user *buf, size_t count)
 528{
 529	int ret, total_bytes = 0, info_type = 0;
 530	unsigned int fid_mode = info_mode & FANOTIFY_FID_BITS;
 531	unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
 532
 533	/*
 534	 * Event info records order is as follows:
 535	 * 1. dir fid + name
 536	 * 2. (optional) new dir fid + new name
 537	 * 3. (optional) child fid
 538	 */
 539	if (fanotify_event_has_dir_fh(event)) {
 540		info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
 541					     FAN_EVENT_INFO_TYPE_DFID;
 542
 543		/* FAN_RENAME uses special info types */
 544		if (event->mask & FAN_RENAME)
 545			info_type = FAN_EVENT_INFO_TYPE_OLD_DFID_NAME;
 546
 547		ret = copy_fid_info_to_user(fanotify_event_fsid(event),
 548					    fanotify_info_dir_fh(info),
 549					    info_type,
 550					    fanotify_info_name(info),
 551					    info->name_len, buf, count);
 552		if (ret < 0)
 553			return ret;
 554
 555		buf += ret;
 556		count -= ret;
 557		total_bytes += ret;
 558	}
 559
 560	/* New dir fid+name may be reported in addition to old dir fid+name */
 561	if (fanotify_event_has_dir2_fh(event)) {
 562		info_type = FAN_EVENT_INFO_TYPE_NEW_DFID_NAME;
 563		ret = copy_fid_info_to_user(fanotify_event_fsid(event),
 564					    fanotify_info_dir2_fh(info),
 565					    info_type,
 566					    fanotify_info_name2(info),
 567					    info->name2_len, buf, count);
 568		if (ret < 0)
 569			return ret;
 570
 571		buf += ret;
 572		count -= ret;
 573		total_bytes += ret;
 574	}
 575
 576	if (fanotify_event_has_object_fh(event)) {
 577		const char *dot = NULL;
 578		int dot_len = 0;
 579
 580		if (fid_mode == FAN_REPORT_FID || info_type) {
 581			/*
 582			 * With only group flag FAN_REPORT_FID only type FID is
 583			 * reported. Second info record type is always FID.
 584			 */
 585			info_type = FAN_EVENT_INFO_TYPE_FID;
 586		} else if ((fid_mode & FAN_REPORT_NAME) &&
 587			   (event->mask & FAN_ONDIR)) {
 588			/*
 589			 * With group flag FAN_REPORT_NAME, if name was not
 590			 * recorded in an event on a directory, report the name
 591			 * "." with info type DFID_NAME.
 592			 */
 593			info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
 594			dot = ".";
 595			dot_len = 1;
 596		} else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
 597			   (event->mask & FAN_ONDIR)) {
 598			/*
 599			 * With group flag FAN_REPORT_DIR_FID, a single info
 600			 * record has type DFID for directory entry modification
 601			 * event and for event on a directory.
 602			 */
 603			info_type = FAN_EVENT_INFO_TYPE_DFID;
 604		} else {
 605			/*
 606			 * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID,
 607			 * a single info record has type FID for event on a
 608			 * non-directory, when there is no directory to report.
 609			 * For example, on FAN_DELETE_SELF event.
 610			 */
 611			info_type = FAN_EVENT_INFO_TYPE_FID;
 612		}
 613
 614		ret = copy_fid_info_to_user(fanotify_event_fsid(event),
 615					    fanotify_event_object_fh(event),
 616					    info_type, dot, dot_len,
 617					    buf, count);
 618		if (ret < 0)
 619			return ret;
 620
 621		buf += ret;
 622		count -= ret;
 623		total_bytes += ret;
 624	}
 625
 626	if (pidfd_mode) {
 627		ret = copy_pidfd_info_to_user(pidfd, buf, count);
 628		if (ret < 0)
 629			return ret;
 630
 631		buf += ret;
 632		count -= ret;
 633		total_bytes += ret;
 634	}
 635
 636	if (fanotify_is_error_event(event->mask)) {
 637		ret = copy_error_info_to_user(event, buf, count);
 638		if (ret < 0)
 639			return ret;
 640		buf += ret;
 641		count -= ret;
 642		total_bytes += ret;
 643	}
 644
 645	return total_bytes;
 646}
 
 647
 648static ssize_t copy_event_to_user(struct fsnotify_group *group,
 649				  struct fanotify_event *event,
 650				  char __user *buf, size_t count)
 651{
 652	struct fanotify_event_metadata metadata;
 653	const struct path *path = fanotify_event_path(event);
 654	struct fanotify_info *info = fanotify_event_info(event);
 655	unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
 656	unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
 657	struct file *f = NULL, *pidfd_file = NULL;
 658	int ret, pidfd = -ESRCH, fd = -EBADF;
 659
 660	pr_debug("%s: group=%p event=%p\n", __func__, group, event);
 661
 662	metadata.event_len = fanotify_event_len(info_mode, event);
 663	metadata.metadata_len = FAN_EVENT_METADATA_LEN;
 664	metadata.vers = FANOTIFY_METADATA_VERSION;
 665	metadata.reserved = 0;
 666	metadata.mask = event->mask & FANOTIFY_OUTGOING_EVENTS;
 667	metadata.pid = pid_vnr(event->pid);
 668	/*
 669	 * For an unprivileged listener, event->pid can be used to identify the
 670	 * events generated by the listener process itself, without disclosing
 671	 * the pids of other processes.
 672	 */
 673	if (FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
 674	    task_tgid(current) != event->pid)
 675		metadata.pid = 0;
 676
 677	/*
 678	 * For now, fid mode is required for an unprivileged listener and
 679	 * fid mode does not report fd in events.  Keep this check anyway
 680	 * for safety in case fid mode requirement is relaxed in the future
 681	 * to allow unprivileged listener to get events with no fd and no fid.
 682	 */
 683	if (!FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV) &&
 684	    path && path->mnt && path->dentry) {
 685		fd = create_fd(group, path, &f);
 686		/*
 687		 * Opening an fd from dentry can fail for several reasons.
 688		 * For example, when tasks are gone and we try to open their
 689		 * /proc files or we try to open a WRONLY file like in sysfs
 690		 * or when trying to open a file that was deleted on the
 691		 * remote network server.
 692		 *
 693		 * For a group with FAN_REPORT_FD_ERROR, we will send the
 694		 * event with the error instead of the open fd, otherwise
 695		 * Userspace may not get the error at all.
 696		 * In any case, userspace will not know which file failed to
 697		 * open, so add a debug print for further investigation.
 698		 */
 699		if (fd < 0) {
 700			pr_debug("fanotify: create_fd(%pd2) failed err=%d\n",
 701				 path->dentry, fd);
 702			if (!FAN_GROUP_FLAG(group, FAN_REPORT_FD_ERROR)) {
 703				/*
 704				 * Historically, we've handled EOPENSTALE in a
 705				 * special way and silently dropped such
 706				 * events. Now we have to keep it to maintain
 707				 * backward compatibility...
 708				 */
 709				if (fd == -EOPENSTALE)
 710					fd = 0;
 711				return fd;
 712			}
 713		}
 714	}
 715	if (FAN_GROUP_FLAG(group, FAN_REPORT_FD_ERROR))
 716		metadata.fd = fd;
 717	else
 718		metadata.fd = fd >= 0 ? fd : FAN_NOFD;
 719
 720	if (pidfd_mode) {
 721		/*
 722		 * Complain if the FAN_REPORT_PIDFD and FAN_REPORT_TID mutual
 723		 * exclusion is ever lifted. At the time of incoporating pidfd
 724		 * support within fanotify, the pidfd API only supported the
 725		 * creation of pidfds for thread-group leaders.
 726		 */
 727		WARN_ON_ONCE(FAN_GROUP_FLAG(group, FAN_REPORT_TID));
 728
 729		/*
 730		 * The PIDTYPE_TGID check for an event->pid is performed
 731		 * preemptively in an attempt to catch out cases where the event
 732		 * listener reads events after the event generating process has
 733		 * already terminated.  Depending on flag FAN_REPORT_FD_ERROR,
 734		 * report either -ESRCH or FAN_NOPIDFD to the event listener in
 735		 * those cases with all other pidfd creation errors reported as
 736		 * the error code itself or as FAN_EPIDFD.
 737		 */
 738		if (metadata.pid && pid_has_task(event->pid, PIDTYPE_TGID))
 739			pidfd = pidfd_prepare(event->pid, 0, &pidfd_file);
 740
 741		if (!FAN_GROUP_FLAG(group, FAN_REPORT_FD_ERROR) && pidfd < 0)
 742			pidfd = pidfd == -ESRCH ? FAN_NOPIDFD : FAN_EPIDFD;
 743	}
 744
 
 745	ret = -EFAULT;
 746	/*
 747	 * Sanity check copy size in case get_one_event() and
 748	 * event_len sizes ever get out of sync.
 749	 */
 750	if (WARN_ON_ONCE(metadata.event_len > count))
 751		goto out_close_fd;
 752
 753	if (copy_to_user(buf, &metadata, FAN_EVENT_METADATA_LEN))
 754		goto out_close_fd;
 755
 756	buf += FAN_EVENT_METADATA_LEN;
 757	count -= FAN_EVENT_METADATA_LEN;
 758
 759	if (info_mode) {
 760		ret = copy_info_records_to_user(event, info, info_mode, pidfd,
 761						buf, count);
 762		if (ret < 0)
 763			goto out_close_fd;
 764	}
 765
 766	if (f)
 767		fd_install(fd, f);
 768
 769	if (pidfd_file)
 770		fd_install(pidfd, pidfd_file);
 771
 772	if (fanotify_is_perm_event(event->mask))
 773		FANOTIFY_PERM(event)->fd = fd;
 774
 775	return metadata.event_len;
 776
 777out_close_fd:
 778	if (f) {
 779		put_unused_fd(fd);
 780		fput(f);
 781	}
 782
 783	if (pidfd_file) {
 784		put_unused_fd(pidfd);
 785		fput(pidfd_file);
 786	}
 787
 788	return ret;
 789}
 790
 791/* intofiy userspace file descriptor functions */
 792static __poll_t fanotify_poll(struct file *file, poll_table *wait)
 793{
 794	struct fsnotify_group *group = file->private_data;
 795	__poll_t ret = 0;
 796
 797	poll_wait(file, &group->notification_waitq, wait);
 798	spin_lock(&group->notification_lock);
 799	if (!fsnotify_notify_queue_is_empty(group))
 800		ret = EPOLLIN | EPOLLRDNORM;
 801	spin_unlock(&group->notification_lock);
 802
 803	return ret;
 804}
 805
 806static ssize_t fanotify_read(struct file *file, char __user *buf,
 807			     size_t count, loff_t *pos)
 808{
 809	struct fsnotify_group *group;
 810	struct fanotify_event *event;
 811	char __user *start;
 812	int ret;
 813	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 814
 815	start = buf;
 816	group = file->private_data;
 817
 818	pr_debug("%s: group=%p\n", __func__, group);
 819
 820	add_wait_queue(&group->notification_waitq, &wait);
 821	while (1) {
 822		/*
 823		 * User can supply arbitrarily large buffer. Avoid softlockups
 824		 * in case there are lots of available events.
 825		 */
 826		cond_resched();
 827		event = get_one_event(group, count);
 828		if (IS_ERR(event)) {
 829			ret = PTR_ERR(event);
 830			break;
 831		}
 832
 833		if (!event) {
 834			ret = -EAGAIN;
 835			if (file->f_flags & O_NONBLOCK)
 836				break;
 837
 838			ret = -ERESTARTSYS;
 839			if (signal_pending(current))
 840				break;
 841
 842			if (start != buf)
 843				break;
 844
 845			wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
 846			continue;
 847		}
 848
 849		ret = copy_event_to_user(group, event, buf, count);
 850
 851		/*
 852		 * Permission events get queued to wait for response.  Other
 853		 * events can be destroyed now.
 854		 */
 855		if (!fanotify_is_perm_event(event->mask)) {
 856			fsnotify_destroy_event(group, &event->fse);
 
 
 857		} else {
 858			if (ret <= 0 || FANOTIFY_PERM(event)->fd < 0) {
 859				spin_lock(&group->notification_lock);
 860				finish_permission_event(group,
 861					FANOTIFY_PERM(event), FAN_DENY, NULL);
 862				wake_up(&group->fanotify_data.access_waitq);
 863			} else {
 864				spin_lock(&group->notification_lock);
 865				list_add_tail(&event->fse.list,
 866					&group->fanotify_data.access_list);
 867				spin_unlock(&group->notification_lock);
 868			}
 
 
 
 
 
 869		}
 870		if (ret < 0)
 871			break;
 872		buf += ret;
 873		count -= ret;
 874	}
 875	remove_wait_queue(&group->notification_waitq, &wait);
 876
 877	if (start != buf && ret != -EFAULT)
 878		ret = buf - start;
 879	return ret;
 880}
 881
 882static ssize_t fanotify_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
 883{
 884	struct fanotify_response response;
 
 885	struct fsnotify_group *group;
 886	int ret;
 887	const char __user *info_buf = buf + sizeof(struct fanotify_response);
 888	size_t info_len;
 889
 890	if (!IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
 891		return -EINVAL;
 892
 893	group = file->private_data;
 894
 895	pr_debug("%s: group=%p count=%zu\n", __func__, group, count);
 
 896
 897	if (count < sizeof(response))
 898		return -EINVAL;
 899
 900	if (copy_from_user(&response, buf, sizeof(response)))
 901		return -EFAULT;
 902
 903	info_len = count - sizeof(response);
 904
 905	ret = process_access_response(group, &response, info_buf, info_len);
 906	if (ret < 0)
 907		count = ret;
 908	else
 909		count = sizeof(response) + ret;
 910
 911	return count;
 
 
 
 912}
 913
 914static int fanotify_release(struct inode *ignored, struct file *file)
 915{
 916	struct fsnotify_group *group = file->private_data;
 
 
 
 917	struct fsnotify_event *fsn_event;
 918
 919	/*
 920	 * Stop new events from arriving in the notification queue. since
 921	 * userspace cannot use fanotify fd anymore, no event can enter or
 922	 * leave access_list by now either.
 923	 */
 924	fsnotify_group_stop_queueing(group);
 925
 926	/*
 927	 * Process all permission events on access_list and notification queue
 928	 * and simulate reply from userspace.
 929	 */
 930	spin_lock(&group->notification_lock);
 931	while (!list_empty(&group->fanotify_data.access_list)) {
 932		struct fanotify_perm_event *event;
 
 
 933
 934		event = list_first_entry(&group->fanotify_data.access_list,
 935				struct fanotify_perm_event, fae.fse.list);
 936		list_del_init(&event->fae.fse.list);
 937		finish_permission_event(group, event, FAN_ALLOW, NULL);
 938		spin_lock(&group->notification_lock);
 939	}
 940
 941	/*
 942	 * Destroy all non-permission events. For permission events just
 943	 * dequeue them and set the response. They will be freed once the
 944	 * response is consumed and fanotify_get_response() returns.
 945	 */
 946	while ((fsn_event = fsnotify_remove_first_event(group))) {
 947		struct fanotify_event *event = FANOTIFY_E(fsn_event);
 948
 949		if (!(event->mask & FANOTIFY_PERM_EVENTS)) {
 950			spin_unlock(&group->notification_lock);
 951			fsnotify_destroy_event(group, fsn_event);
 952		} else {
 953			finish_permission_event(group, FANOTIFY_PERM(event),
 954						FAN_ALLOW, NULL);
 955		}
 956		spin_lock(&group->notification_lock);
 957	}
 958	spin_unlock(&group->notification_lock);
 959
 960	/* Response for all permission events it set, wakeup waiters */
 961	wake_up(&group->fanotify_data.access_waitq);
 
 962
 963	/* matches the fanotify_init->fsnotify_alloc_group */
 964	fsnotify_destroy_group(group);
 965
 966	return 0;
 967}
 968
 969static long fanotify_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 970{
 971	struct fsnotify_group *group;
 972	struct fsnotify_event *fsn_event;
 973	void __user *p;
 974	int ret = -ENOTTY;
 975	size_t send_len = 0;
 976
 977	group = file->private_data;
 978
 979	p = (void __user *) arg;
 980
 981	switch (cmd) {
 982	case FIONREAD:
 983		spin_lock(&group->notification_lock);
 984		list_for_each_entry(fsn_event, &group->notification_list, list)
 985			send_len += FAN_EVENT_METADATA_LEN;
 986		spin_unlock(&group->notification_lock);
 987		ret = put_user(send_len, (int __user *) p);
 988		break;
 989	}
 990
 991	return ret;
 992}
 993
 994static const struct file_operations fanotify_fops = {
 995	.show_fdinfo	= fanotify_show_fdinfo,
 996	.poll		= fanotify_poll,
 997	.read		= fanotify_read,
 998	.write		= fanotify_write,
 999	.fasync		= NULL,
1000	.release	= fanotify_release,
1001	.unlocked_ioctl	= fanotify_ioctl,
1002	.compat_ioctl	= compat_ptr_ioctl,
1003	.llseek		= noop_llseek,
1004};
1005
 
 
 
 
 
1006static int fanotify_find_path(int dfd, const char __user *filename,
1007			      struct path *path, unsigned int flags, __u64 mask,
1008			      unsigned int obj_type)
1009{
1010	int ret;
1011
1012	pr_debug("%s: dfd=%d filename=%p flags=%x\n", __func__,
1013		 dfd, filename, flags);
1014
1015	if (filename == NULL) {
1016		CLASS(fd, f)(dfd);
1017
1018		if (fd_empty(f))
1019			return -EBADF;
 
1020
 
1021		if ((flags & FAN_MARK_ONLYDIR) &&
1022		    !(S_ISDIR(file_inode(fd_file(f))->i_mode)))
1023			return -ENOTDIR;
 
 
1024
1025		*path = fd_file(f)->f_path;
1026		path_get(path);
 
1027	} else {
1028		unsigned int lookup_flags = 0;
1029
1030		if (!(flags & FAN_MARK_DONT_FOLLOW))
1031			lookup_flags |= LOOKUP_FOLLOW;
1032		if (flags & FAN_MARK_ONLYDIR)
1033			lookup_flags |= LOOKUP_DIRECTORY;
1034
1035		ret = user_path_at(dfd, filename, lookup_flags, path);
1036		if (ret)
1037			goto out;
1038	}
1039
1040	/* you can only watch an inode if you have read permissions on it */
1041	ret = path_permission(path, MAY_READ);
1042	if (ret) {
1043		path_put(path);
1044		goto out;
1045	}
1046
1047	ret = security_path_notify(path, mask, obj_type);
1048	if (ret)
1049		path_put(path);
1050
1051out:
1052	return ret;
1053}
1054
1055static __u32 fanotify_mark_remove_from_mask(struct fsnotify_mark *fsn_mark,
1056					    __u32 mask, unsigned int flags,
1057					    __u32 umask, int *destroy)
 
1058{
1059	__u32 oldmask, newmask;
1060
1061	/* umask bits cannot be removed by user */
1062	mask &= ~umask;
1063	spin_lock(&fsn_mark->lock);
1064	oldmask = fsnotify_calc_mask(fsn_mark);
1065	if (!(flags & FANOTIFY_MARK_IGNORE_BITS)) {
1066		fsn_mark->mask &= ~mask;
 
 
 
 
 
1067	} else {
1068		fsn_mark->ignore_mask &= ~mask;
 
 
 
 
1069	}
1070	newmask = fsnotify_calc_mask(fsn_mark);
1071	/*
1072	 * We need to keep the mark around even if remaining mask cannot
1073	 * result in any events (e.g. mask == FAN_ONDIR) to support incremenal
1074	 * changes to the mask.
1075	 * Destroy mark when only umask bits remain.
1076	 */
1077	*destroy = !((fsn_mark->mask | fsn_mark->ignore_mask) & ~umask);
1078	spin_unlock(&fsn_mark->lock);
1079
1080	return oldmask & ~newmask;
1081}
1082
1083static int fanotify_remove_mark(struct fsnotify_group *group,
1084				void *obj, unsigned int obj_type, __u32 mask,
1085				unsigned int flags, __u32 umask)
1086{
1087	struct fsnotify_mark *fsn_mark = NULL;
1088	__u32 removed;
1089	int destroy_mark;
1090
1091	fsnotify_group_lock(group);
1092	fsn_mark = fsnotify_find_mark(obj, obj_type, group);
1093	if (!fsn_mark) {
1094		fsnotify_group_unlock(group);
1095		return -ENOENT;
1096	}
1097
1098	removed = fanotify_mark_remove_from_mask(fsn_mark, mask, flags,
1099						 umask, &destroy_mark);
1100	if (removed & fsnotify_conn_mask(fsn_mark->connector))
1101		fsnotify_recalc_mask(fsn_mark->connector);
1102	if (destroy_mark)
1103		fsnotify_detach_mark(fsn_mark);
1104	fsnotify_group_unlock(group);
1105	if (destroy_mark)
1106		fsnotify_free_mark(fsn_mark);
1107
1108	/* matches the fsnotify_find_mark() */
1109	fsnotify_put_mark(fsn_mark);
 
 
 
1110	return 0;
1111}
1112
1113static bool fanotify_mark_update_flags(struct fsnotify_mark *fsn_mark,
1114				       unsigned int fan_flags)
 
1115{
1116	bool want_iref = !(fan_flags & FAN_MARK_EVICTABLE);
1117	unsigned int ignore = fan_flags & FANOTIFY_MARK_IGNORE_BITS;
1118	bool recalc = false;
1119
1120	/*
1121	 * When using FAN_MARK_IGNORE for the first time, mark starts using
1122	 * independent event flags in ignore mask.  After that, trying to
1123	 * update the ignore mask with the old FAN_MARK_IGNORED_MASK API
1124	 * will result in EEXIST error.
1125	 */
1126	if (ignore == FAN_MARK_IGNORE)
1127		fsn_mark->flags |= FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS;
1128
1129	/*
1130	 * Setting FAN_MARK_IGNORED_SURV_MODIFY for the first time may lead to
1131	 * the removal of the FS_MODIFY bit in calculated mask if it was set
1132	 * because of an ignore mask that is now going to survive FS_MODIFY.
1133	 */
1134	if (ignore && (fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1135	    !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)) {
1136		fsn_mark->flags |= FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY;
1137		if (!(fsn_mark->mask & FS_MODIFY))
1138			recalc = true;
1139	}
1140
1141	if (fsn_mark->connector->type != FSNOTIFY_OBJ_TYPE_INODE ||
1142	    want_iref == !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
1143		return recalc;
 
 
 
 
1144
1145	/*
1146	 * NO_IREF may be removed from a mark, but not added.
1147	 * When removed, fsnotify_recalc_mask() will take the inode ref.
1148	 */
1149	WARN_ON_ONCE(!want_iref);
1150	fsn_mark->flags &= ~FSNOTIFY_MARK_FLAG_NO_IREF;
1151
1152	return true;
1153}
1154
1155static bool fanotify_mark_add_to_mask(struct fsnotify_mark *fsn_mark,
1156				      __u32 mask, unsigned int fan_flags)
 
1157{
1158	bool recalc;
1159
1160	spin_lock(&fsn_mark->lock);
1161	if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS))
1162		fsn_mark->mask |= mask;
1163	else
1164		fsn_mark->ignore_mask |= mask;
1165
1166	recalc = fsnotify_calc_mask(fsn_mark) &
1167		~fsnotify_conn_mask(fsn_mark->connector);
1168
1169	recalc |= fanotify_mark_update_flags(fsn_mark, fan_flags);
1170	spin_unlock(&fsn_mark->lock);
1171
1172	return recalc;
1173}
1174
1175struct fan_fsid {
1176	struct super_block *sb;
1177	__kernel_fsid_t id;
1178	bool weak;
1179};
1180
1181static int fanotify_set_mark_fsid(struct fsnotify_group *group,
1182				  struct fsnotify_mark *mark,
1183				  struct fan_fsid *fsid)
1184{
1185	struct fsnotify_mark_connector *conn;
1186	struct fsnotify_mark *old;
1187	struct super_block *old_sb = NULL;
1188
1189	FANOTIFY_MARK(mark)->fsid = fsid->id;
1190	mark->flags |= FSNOTIFY_MARK_FLAG_HAS_FSID;
1191	if (fsid->weak)
1192		mark->flags |= FSNOTIFY_MARK_FLAG_WEAK_FSID;
1193
1194	/* First mark added will determine if group is single or multi fsid */
1195	if (list_empty(&group->marks_list))
1196		return 0;
1197
1198	/* Find sb of an existing mark */
1199	list_for_each_entry(old, &group->marks_list, g_list) {
1200		conn = READ_ONCE(old->connector);
1201		if (!conn)
1202			continue;
1203		old_sb = fsnotify_connector_sb(conn);
1204		if (old_sb)
1205			break;
 
 
1206	}
 
1207
1208	/* Only detached marks left? */
1209	if (!old_sb)
1210		return 0;
1211
1212	/* Do not allow mixing of marks with weak and strong fsid */
1213	if ((mark->flags ^ old->flags) & FSNOTIFY_MARK_FLAG_WEAK_FSID)
1214		return -EXDEV;
1215
1216	/* Allow mixing of marks with strong fsid from different fs */
1217	if (!fsid->weak)
1218		return 0;
1219
1220	/* Do not allow mixing marks with weak fsid from different fs */
1221	if (old_sb != fsid->sb)
1222		return -EXDEV;
1223
1224	/* Do not allow mixing marks from different btrfs sub-volumes */
1225	if (!fanotify_fsid_equal(&FANOTIFY_MARK(old)->fsid,
1226				 &FANOTIFY_MARK(mark)->fsid))
1227		return -EXDEV;
1228
1229	return 0;
1230}
1231
1232static struct fsnotify_mark *fanotify_add_new_mark(struct fsnotify_group *group,
1233						   void *obj,
1234						   unsigned int obj_type,
1235						   unsigned int fan_flags,
1236						   struct fan_fsid *fsid)
1237{
1238	struct ucounts *ucounts = group->fanotify_data.ucounts;
1239	struct fanotify_mark *fan_mark;
1240	struct fsnotify_mark *mark;
1241	int ret;
1242
1243	/*
1244	 * Enforce per user marks limits per user in all containing user ns.
1245	 * A group with FAN_UNLIMITED_MARKS does not contribute to mark count
1246	 * in the limited groups account.
1247	 */
1248	if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS) &&
1249	    !inc_ucount(ucounts->ns, ucounts->uid, UCOUNT_FANOTIFY_MARKS))
1250		return ERR_PTR(-ENOSPC);
1251
1252	fan_mark = kmem_cache_alloc(fanotify_mark_cache, GFP_KERNEL);
1253	if (!fan_mark) {
1254		ret = -ENOMEM;
1255		goto out_dec_ucounts;
1256	}
1257
1258	mark = &fan_mark->fsn_mark;
1259	fsnotify_init_mark(mark, group);
1260	if (fan_flags & FAN_MARK_EVICTABLE)
1261		mark->flags |= FSNOTIFY_MARK_FLAG_NO_IREF;
1262
1263	/* Cache fsid of filesystem containing the marked object */
1264	if (fsid) {
1265		ret = fanotify_set_mark_fsid(group, mark, fsid);
1266		if (ret)
1267			goto out_put_mark;
1268	} else {
1269		fan_mark->fsid.val[0] = fan_mark->fsid.val[1] = 0;
1270	}
1271
1272	ret = fsnotify_add_mark_locked(mark, obj, obj_type, 0);
1273	if (ret)
1274		goto out_put_mark;
1275
1276	return mark;
1277
1278out_put_mark:
1279	fsnotify_put_mark(mark);
1280out_dec_ucounts:
1281	if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS))
1282		dec_ucount(ucounts, UCOUNT_FANOTIFY_MARKS);
1283	return ERR_PTR(ret);
1284}
1285
1286static int fanotify_group_init_error_pool(struct fsnotify_group *group)
1287{
1288	if (mempool_initialized(&group->fanotify_data.error_events_pool))
1289		return 0;
1290
1291	return mempool_init_kmalloc_pool(&group->fanotify_data.error_events_pool,
1292					 FANOTIFY_DEFAULT_FEE_POOL_SIZE,
1293					 sizeof(struct fanotify_error_event));
1294}
1295
1296static int fanotify_may_update_existing_mark(struct fsnotify_mark *fsn_mark,
1297					      unsigned int fan_flags)
1298{
1299	/*
1300	 * Non evictable mark cannot be downgraded to evictable mark.
1301	 */
1302	if (fan_flags & FAN_MARK_EVICTABLE &&
1303	    !(fsn_mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF))
1304		return -EEXIST;
1305
1306	/*
1307	 * New ignore mask semantics cannot be downgraded to old semantics.
1308	 */
1309	if (fan_flags & FAN_MARK_IGNORED_MASK &&
1310	    fsn_mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS)
1311		return -EEXIST;
1312
1313	/*
1314	 * An ignore mask that survives modify could never be downgraded to not
1315	 * survive modify.  With new FAN_MARK_IGNORE semantics we make that rule
1316	 * explicit and return an error when trying to update the ignore mask
1317	 * without the original FAN_MARK_IGNORED_SURV_MODIFY value.
1318	 */
1319	if (fan_flags & FAN_MARK_IGNORE &&
1320	    !(fan_flags & FAN_MARK_IGNORED_SURV_MODIFY) &&
1321	    fsn_mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY)
1322		return -EEXIST;
1323
1324	return 0;
1325}
1326
1327static int fanotify_add_mark(struct fsnotify_group *group,
1328			     void *obj, unsigned int obj_type,
1329			     __u32 mask, unsigned int fan_flags,
1330			     struct fan_fsid *fsid)
1331{
1332	struct fsnotify_mark *fsn_mark;
1333	bool recalc;
1334	int ret = 0;
1335
1336	fsnotify_group_lock(group);
1337	fsn_mark = fsnotify_find_mark(obj, obj_type, group);
1338	if (!fsn_mark) {
1339		fsn_mark = fanotify_add_new_mark(group, obj, obj_type,
1340						 fan_flags, fsid);
1341		if (IS_ERR(fsn_mark)) {
1342			fsnotify_group_unlock(group);
1343			return PTR_ERR(fsn_mark);
1344		}
1345	}
 
 
1346
1347	/*
1348	 * Check if requested mark flags conflict with an existing mark flags.
1349	 */
1350	ret = fanotify_may_update_existing_mark(fsn_mark, fan_flags);
1351	if (ret)
1352		goto out;
1353
1354	/*
1355	 * Error events are pre-allocated per group, only if strictly
1356	 * needed (i.e. FAN_FS_ERROR was requested).
1357	 */
1358	if (!(fan_flags & FANOTIFY_MARK_IGNORE_BITS) &&
1359	    (mask & FAN_FS_ERROR)) {
1360		ret = fanotify_group_init_error_pool(group);
1361		if (ret)
1362			goto out;
1363	}
1364
1365	recalc = fanotify_mark_add_to_mask(fsn_mark, mask, fan_flags);
1366	if (recalc)
1367		fsnotify_recalc_mask(fsn_mark->connector);
1368
1369out:
1370	fsnotify_group_unlock(group);
1371
1372	fsnotify_put_mark(fsn_mark);
1373	return ret;
1374}
1375
1376static struct fsnotify_event *fanotify_alloc_overflow_event(void)
 
 
1377{
1378	struct fanotify_event *oevent;
1379
1380	oevent = kmalloc(sizeof(*oevent), GFP_KERNEL_ACCOUNT);
1381	if (!oevent)
1382		return NULL;
1383
1384	fanotify_init_event(oevent, 0, FS_Q_OVERFLOW);
1385	oevent->type = FANOTIFY_EVENT_TYPE_OVERFLOW;
1386
1387	return &oevent->fse;
1388}
1389
1390static struct hlist_head *fanotify_alloc_merge_hash(void)
1391{
1392	struct hlist_head *hash;
 
 
 
 
 
 
1393
1394	hash = kmalloc(sizeof(struct hlist_head) << FANOTIFY_HTABLE_BITS,
1395		       GFP_KERNEL_ACCOUNT);
1396	if (!hash)
1397		return NULL;
 
 
 
 
 
 
 
1398
1399	__hash_init(hash, FANOTIFY_HTABLE_SIZE);
 
1400
1401	return hash;
 
1402}
1403
1404/* fanotify syscalls */
1405SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
1406{
1407	struct fsnotify_group *group;
1408	int f_flags, fd;
1409	unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
1410	unsigned int class = flags & FANOTIFY_CLASS_BITS;
1411	unsigned int internal_flags = 0;
1412
1413	pr_debug("%s: flags=%x event_f_flags=%x\n",
1414		 __func__, flags, event_f_flags);
1415
1416	if (!capable(CAP_SYS_ADMIN)) {
1417		/*
1418		 * An unprivileged user can setup an fanotify group with
1419		 * limited functionality - an unprivileged group is limited to
1420		 * notification events with file handles and it cannot use
1421		 * unlimited queue/marks.
1422		 */
1423		if ((flags & FANOTIFY_ADMIN_INIT_FLAGS) || !fid_mode)
1424			return -EPERM;
1425
1426		/*
1427		 * Setting the internal flag FANOTIFY_UNPRIV on the group
1428		 * prevents setting mount/filesystem marks on this group and
1429		 * prevents reporting pid and open fd in events.
1430		 */
1431		internal_flags |= FANOTIFY_UNPRIV;
1432	}
1433
1434#ifdef CONFIG_AUDITSYSCALL
1435	if (flags & ~(FANOTIFY_INIT_FLAGS | FAN_ENABLE_AUDIT))
1436#else
1437	if (flags & ~FANOTIFY_INIT_FLAGS)
1438#endif
1439		return -EINVAL;
1440
1441	/*
1442	 * A pidfd can only be returned for a thread-group leader; thus
1443	 * FAN_REPORT_PIDFD and FAN_REPORT_TID need to remain mutually
1444	 * exclusive.
1445	 */
1446	if ((flags & FAN_REPORT_PIDFD) && (flags & FAN_REPORT_TID))
1447		return -EINVAL;
1448
1449	if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS)
1450		return -EINVAL;
1451
1452	switch (event_f_flags & O_ACCMODE) {
1453	case O_RDONLY:
1454	case O_RDWR:
1455	case O_WRONLY:
1456		break;
1457	default:
1458		return -EINVAL;
1459	}
1460
1461	if (fid_mode && class != FAN_CLASS_NOTIF)
1462		return -EINVAL;
1463
1464	/*
1465	 * Child name is reported with parent fid so requires dir fid.
1466	 * We can report both child fid and dir fid with or without name.
1467	 */
1468	if ((fid_mode & FAN_REPORT_NAME) && !(fid_mode & FAN_REPORT_DIR_FID))
1469		return -EINVAL;
1470
1471	/*
1472	 * FAN_REPORT_TARGET_FID requires FAN_REPORT_NAME and FAN_REPORT_FID
1473	 * and is used as an indication to report both dir and child fid on all
1474	 * dirent events.
1475	 */
1476	if ((fid_mode & FAN_REPORT_TARGET_FID) &&
1477	    (!(fid_mode & FAN_REPORT_NAME) || !(fid_mode & FAN_REPORT_FID)))
1478		return -EINVAL;
1479
1480	f_flags = O_RDWR | __FMODE_NONOTIFY;
1481	if (flags & FAN_CLOEXEC)
1482		f_flags |= O_CLOEXEC;
1483	if (flags & FAN_NONBLOCK)
1484		f_flags |= O_NONBLOCK;
1485
1486	/* fsnotify_alloc_group takes a ref.  Dropped in fanotify_release */
1487	group = fsnotify_alloc_group(&fanotify_fsnotify_ops,
1488				     FSNOTIFY_GROUP_USER);
1489	if (IS_ERR(group)) {
 
1490		return PTR_ERR(group);
1491	}
1492
1493	/* Enforce groups limits per user in all containing user ns */
1494	group->fanotify_data.ucounts = inc_ucount(current_user_ns(),
1495						  current_euid(),
1496						  UCOUNT_FANOTIFY_GROUPS);
1497	if (!group->fanotify_data.ucounts) {
1498		fd = -EMFILE;
1499		goto out_destroy_group;
1500	}
1501
1502	group->fanotify_data.flags = flags | internal_flags;
1503	group->memcg = get_mem_cgroup_from_mm(current->mm);
1504
1505	group->fanotify_data.merge_hash = fanotify_alloc_merge_hash();
1506	if (!group->fanotify_data.merge_hash) {
1507		fd = -ENOMEM;
1508		goto out_destroy_group;
1509	}
1510
1511	group->overflow_event = fanotify_alloc_overflow_event();
1512	if (unlikely(!group->overflow_event)) {
1513		fd = -ENOMEM;
1514		goto out_destroy_group;
1515	}
 
1516
1517	if (force_o_largefile())
1518		event_f_flags |= O_LARGEFILE;
1519	group->fanotify_data.f_flags = event_f_flags;
 
1520	init_waitqueue_head(&group->fanotify_data.access_waitq);
1521	INIT_LIST_HEAD(&group->fanotify_data.access_list);
1522	switch (class) {
 
1523	case FAN_CLASS_NOTIF:
1524		group->priority = FSNOTIFY_PRIO_NORMAL;
1525		break;
1526	case FAN_CLASS_CONTENT:
1527		group->priority = FSNOTIFY_PRIO_CONTENT;
1528		break;
1529	case FAN_CLASS_PRE_CONTENT:
1530		group->priority = FSNOTIFY_PRIO_PRE_CONTENT;
1531		break;
1532	default:
1533		fd = -EINVAL;
1534		goto out_destroy_group;
1535	}
1536
1537	if (flags & FAN_UNLIMITED_QUEUE) {
1538		fd = -EPERM;
1539		if (!capable(CAP_SYS_ADMIN))
1540			goto out_destroy_group;
1541		group->max_events = UINT_MAX;
1542	} else {
1543		group->max_events = fanotify_max_queued_events;
1544	}
1545
1546	if (flags & FAN_UNLIMITED_MARKS) {
1547		fd = -EPERM;
1548		if (!capable(CAP_SYS_ADMIN))
1549			goto out_destroy_group;
1550	}
1551
1552	if (flags & FAN_ENABLE_AUDIT) {
1553		fd = -EPERM;
1554		if (!capable(CAP_AUDIT_WRITE))
1555			goto out_destroy_group;
1556	}
1557
1558	fd = anon_inode_getfd("[fanotify]", &fanotify_fops, group, f_flags);
1559	if (fd < 0)
1560		goto out_destroy_group;
1561
1562	return fd;
1563
1564out_destroy_group:
1565	fsnotify_destroy_group(group);
1566	return fd;
1567}
1568
1569static int fanotify_test_fsid(struct dentry *dentry, unsigned int flags,
1570			      struct fan_fsid *fsid)
1571{
1572	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1573	__kernel_fsid_t root_fsid;
1574	int err;
1575
1576	/*
1577	 * Make sure dentry is not of a filesystem with zero fsid (e.g. fuse).
1578	 */
1579	err = vfs_get_fsid(dentry, &fsid->id);
1580	if (err)
1581		return err;
1582
1583	fsid->sb = dentry->d_sb;
1584	if (!fsid->id.val[0] && !fsid->id.val[1]) {
1585		err = -ENODEV;
1586		goto weak;
1587	}
1588
1589	/*
1590	 * Make sure dentry is not of a filesystem subvolume (e.g. btrfs)
1591	 * which uses a different fsid than sb root.
1592	 */
1593	err = vfs_get_fsid(dentry->d_sb->s_root, &root_fsid);
1594	if (err)
1595		return err;
1596
1597	if (!fanotify_fsid_equal(&root_fsid, &fsid->id)) {
1598		err = -EXDEV;
1599		goto weak;
1600	}
1601
1602	fsid->weak = false;
1603	return 0;
1604
1605weak:
1606	/* Allow weak fsid when marking inodes */
1607	fsid->weak = true;
1608	return (mark_type == FAN_MARK_INODE) ? 0 : err;
1609}
1610
1611/* Check if filesystem can encode a unique fid */
1612static int fanotify_test_fid(struct dentry *dentry, unsigned int flags)
1613{
1614	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1615	const struct export_operations *nop = dentry->d_sb->s_export_op;
1616
1617	/*
1618	 * We need to make sure that the filesystem supports encoding of
1619	 * file handles so user can use name_to_handle_at() to compare fids
1620	 * reported with events to the file handle of watched objects.
1621	 */
1622	if (!exportfs_can_encode_fid(nop))
1623		return -EOPNOTSUPP;
1624
1625	/*
1626	 * For sb/mount mark, we also need to make sure that the filesystem
1627	 * supports decoding file handles, so user has a way to map back the
1628	 * reported fids to filesystem objects.
1629	 */
1630	if (mark_type != FAN_MARK_INODE && !exportfs_can_decode_fh(nop))
1631		return -EOPNOTSUPP;
1632
1633	return 0;
1634}
1635
1636static int fanotify_events_supported(struct fsnotify_group *group,
1637				     const struct path *path, __u64 mask,
1638				     unsigned int flags)
1639{
1640	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1641	/* Strict validation of events in non-dir inode mask with v5.17+ APIs */
1642	bool strict_dir_events = FAN_GROUP_FLAG(group, FAN_REPORT_TARGET_FID) ||
1643				 (mask & FAN_RENAME) ||
1644				 (flags & FAN_MARK_IGNORE);
1645
1646	/*
1647	 * Some filesystems such as 'proc' acquire unusual locks when opening
1648	 * files. For them fanotify permission events have high chances of
1649	 * deadlocking the system - open done when reporting fanotify event
1650	 * blocks on this "unusual" lock while another process holding the lock
1651	 * waits for fanotify permission event to be answered. Just disallow
1652	 * permission events for such filesystems.
1653	 */
1654	if (mask & FANOTIFY_PERM_EVENTS &&
1655	    path->mnt->mnt_sb->s_type->fs_flags & FS_DISALLOW_NOTIFY_PERM)
1656		return -EINVAL;
1657
1658	/*
1659	 * mount and sb marks are not allowed on kernel internal pseudo fs,
1660	 * like pipe_mnt, because that would subscribe to events on all the
1661	 * anonynous pipes in the system.
1662	 *
1663	 * SB_NOUSER covers all of the internal pseudo fs whose objects are not
1664	 * exposed to user's mount namespace, but there are other SB_KERNMOUNT
1665	 * fs, like nsfs, debugfs, for which the value of allowing sb and mount
1666	 * mark is questionable. For now we leave them alone.
1667	 */
1668	if (mark_type != FAN_MARK_INODE &&
1669	    path->mnt->mnt_sb->s_flags & SB_NOUSER)
1670		return -EINVAL;
1671
1672	/*
1673	 * We shouldn't have allowed setting dirent events and the directory
1674	 * flags FAN_ONDIR and FAN_EVENT_ON_CHILD in mask of non-dir inode,
1675	 * but because we always allowed it, error only when using new APIs.
1676	 */
1677	if (strict_dir_events && mark_type == FAN_MARK_INODE &&
1678	    !d_is_dir(path->dentry) && (mask & FANOTIFY_DIRONLY_EVENT_BITS))
1679		return -ENOTDIR;
1680
1681	return 0;
1682}
1683
1684static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
1685			    int dfd, const char  __user *pathname)
1686{
1687	struct inode *inode = NULL;
1688	struct vfsmount *mnt = NULL;
1689	struct fsnotify_group *group;
 
1690	struct path path;
1691	struct fan_fsid __fsid, *fsid = NULL;
1692	u32 valid_mask = FANOTIFY_EVENTS | FANOTIFY_EVENT_FLAGS;
1693	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
1694	unsigned int mark_cmd = flags & FANOTIFY_MARK_CMD_BITS;
1695	unsigned int ignore = flags & FANOTIFY_MARK_IGNORE_BITS;
1696	unsigned int obj_type, fid_mode;
1697	void *obj;
1698	u32 umask = 0;
1699	int ret;
1700
1701	pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
1702		 __func__, fanotify_fd, flags, dfd, pathname, mask);
1703
1704	/* we only use the lower 32 bits as of right now. */
1705	if (upper_32_bits(mask))
1706		return -EINVAL;
1707
1708	if (flags & ~FANOTIFY_MARK_FLAGS)
1709		return -EINVAL;
1710
1711	switch (mark_type) {
1712	case FAN_MARK_INODE:
1713		obj_type = FSNOTIFY_OBJ_TYPE_INODE;
1714		break;
1715	case FAN_MARK_MOUNT:
1716		obj_type = FSNOTIFY_OBJ_TYPE_VFSMOUNT;
1717		break;
1718	case FAN_MARK_FILESYSTEM:
1719		obj_type = FSNOTIFY_OBJ_TYPE_SB;
1720		break;
1721	default:
1722		return -EINVAL;
1723	}
1724
1725	switch (mark_cmd) {
1726	case FAN_MARK_ADD:
1727	case FAN_MARK_REMOVE:
1728		if (!mask)
1729			return -EINVAL;
1730		break;
1731	case FAN_MARK_FLUSH:
1732		if (flags & ~(FANOTIFY_MARK_TYPE_BITS | FAN_MARK_FLUSH))
1733			return -EINVAL;
1734		break;
1735	default:
1736		return -EINVAL;
1737	}
1738
1739	if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
1740		valid_mask |= FANOTIFY_PERM_EVENTS;
1741
1742	if (mask & ~valid_mask)
1743		return -EINVAL;
1744
1745
1746	/* We don't allow FAN_MARK_IGNORE & FAN_MARK_IGNORED_MASK together */
1747	if (ignore == (FAN_MARK_IGNORE | FAN_MARK_IGNORED_MASK))
 
 
 
1748		return -EINVAL;
1749
1750	/*
1751	 * Event flags (FAN_ONDIR, FAN_EVENT_ON_CHILD) have no effect with
1752	 * FAN_MARK_IGNORED_MASK.
1753	 */
1754	if (ignore == FAN_MARK_IGNORED_MASK) {
1755		mask &= ~FANOTIFY_EVENT_FLAGS;
1756		umask = FANOTIFY_EVENT_FLAGS;
1757	}
1758
1759	CLASS(fd, f)(fanotify_fd);
1760	if (fd_empty(f))
1761		return -EBADF;
1762
1763	/* verify that this is indeed an fanotify instance */
1764	if (unlikely(fd_file(f)->f_op != &fanotify_fops))
1765		return -EINVAL;
1766	group = fd_file(f)->private_data;
1767
1768	/*
1769	 * An unprivileged user is not allowed to setup mount nor filesystem
1770	 * marks.  This also includes setting up such marks by a group that
1771	 * was initialized by an unprivileged user.
1772	 */
1773	if ((!capable(CAP_SYS_ADMIN) ||
1774	     FAN_GROUP_FLAG(group, FANOTIFY_UNPRIV)) &&
1775	    mark_type != FAN_MARK_INODE)
1776		return -EPERM;
1777
1778	/*
1779	 * Permission events require minimum priority FAN_CLASS_CONTENT.
1780	 */
1781	if (mask & FANOTIFY_PERM_EVENTS &&
1782	    group->priority < FSNOTIFY_PRIO_CONTENT)
1783		return -EINVAL;
1784
1785	if (mask & FAN_FS_ERROR &&
1786	    mark_type != FAN_MARK_FILESYSTEM)
1787		return -EINVAL;
1788
1789	/*
1790	 * Evictable is only relevant for inode marks, because only inode object
1791	 * can be evicted on memory pressure.
1792	 */
1793	if (flags & FAN_MARK_EVICTABLE &&
1794	     mark_type != FAN_MARK_INODE)
1795		return -EINVAL;
1796
1797	/*
1798	 * Events that do not carry enough information to report
1799	 * event->fd require a group that supports reporting fid.  Those
1800	 * events are not supported on a mount mark, because they do not
1801	 * carry enough information (i.e. path) to be filtered by mount
1802	 * point.
1803	 */
1804	fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
1805	if (mask & ~(FANOTIFY_FD_EVENTS|FANOTIFY_EVENT_FLAGS) &&
1806	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
1807		return -EINVAL;
1808
1809	/*
1810	 * FAN_RENAME uses special info type records to report the old and
1811	 * new parent+name.  Reporting only old and new parent id is less
1812	 * useful and was not implemented.
1813	 */
1814	if (mask & FAN_RENAME && !(fid_mode & FAN_REPORT_NAME))
1815		return -EINVAL;
1816
1817	if (mark_cmd == FAN_MARK_FLUSH) {
1818		if (mark_type == FAN_MARK_MOUNT)
 
1819			fsnotify_clear_vfsmount_marks_by_group(group);
1820		else if (mark_type == FAN_MARK_FILESYSTEM)
1821			fsnotify_clear_sb_marks_by_group(group);
1822		else
1823			fsnotify_clear_inode_marks_by_group(group);
1824		return 0;
1825	}
1826
1827	ret = fanotify_find_path(dfd, pathname, &path, flags,
1828			(mask & ALL_FSNOTIFY_EVENTS), obj_type);
1829	if (ret)
1830		return ret;
1831
1832	if (mark_cmd == FAN_MARK_ADD) {
1833		ret = fanotify_events_supported(group, &path, mask, flags);
1834		if (ret)
1835			goto path_put_and_out;
1836	}
1837
1838	if (fid_mode) {
1839		ret = fanotify_test_fsid(path.dentry, flags, &__fsid);
1840		if (ret)
1841			goto path_put_and_out;
1842
1843		ret = fanotify_test_fid(path.dentry, flags);
1844		if (ret)
1845			goto path_put_and_out;
1846
1847		fsid = &__fsid;
1848	}
1849
1850	/* inode held in place by reference to path; group by fget on fd */
1851	if (mark_type == FAN_MARK_INODE) {
1852		inode = path.dentry->d_inode;
1853		obj = inode;
1854	} else {
1855		mnt = path.mnt;
1856		if (mark_type == FAN_MARK_MOUNT)
1857			obj = mnt;
1858		else
1859			obj = mnt->mnt_sb;
1860	}
1861
1862	/*
1863	 * If some other task has this inode open for write we should not add
1864	 * an ignore mask, unless that ignore mask is supposed to survive
1865	 * modification changes anyway.
1866	 */
1867	if (mark_cmd == FAN_MARK_ADD && (flags & FANOTIFY_MARK_IGNORE_BITS) &&
1868	    !(flags & FAN_MARK_IGNORED_SURV_MODIFY)) {
1869		ret = mnt ? -EINVAL : -EISDIR;
1870		/* FAN_MARK_IGNORE requires SURV_MODIFY for sb/mount/dir marks */
1871		if (ignore == FAN_MARK_IGNORE &&
1872		    (mnt || S_ISDIR(inode->i_mode)))
1873			goto path_put_and_out;
1874
1875		ret = 0;
1876		if (inode && inode_is_open_for_write(inode))
1877			goto path_put_and_out;
1878	}
1879
1880	/* Mask out FAN_EVENT_ON_CHILD flag for sb/mount/non-dir marks */
1881	if (mnt || !S_ISDIR(inode->i_mode)) {
1882		mask &= ~FAN_EVENT_ON_CHILD;
1883		umask = FAN_EVENT_ON_CHILD;
1884		/*
1885		 * If group needs to report parent fid, register for getting
1886		 * events with parent/name info for non-directory.
1887		 */
1888		if ((fid_mode & FAN_REPORT_DIR_FID) &&
1889		    (flags & FAN_MARK_ADD) && !ignore)
1890			mask |= FAN_EVENT_ON_CHILD;
1891	}
1892
1893	/* create/update an inode mark */
1894	switch (mark_cmd) {
1895	case FAN_MARK_ADD:
1896		ret = fanotify_add_mark(group, obj, obj_type, mask, flags,
1897					fsid);
 
 
1898		break;
1899	case FAN_MARK_REMOVE:
1900		ret = fanotify_remove_mark(group, obj, obj_type, mask, flags,
1901					   umask);
 
 
1902		break;
1903	default:
1904		ret = -EINVAL;
1905	}
1906
1907path_put_and_out:
1908	path_put(&path);
 
 
1909	return ret;
1910}
1911
1912#ifndef CONFIG_ARCH_SPLIT_ARG64
1913SYSCALL_DEFINE5(fanotify_mark, int, fanotify_fd, unsigned int, flags,
1914			      __u64, mask, int, dfd,
1915			      const char  __user *, pathname)
1916{
1917	return do_fanotify_mark(fanotify_fd, flags, mask, dfd, pathname);
1918}
1919#endif
1920
1921#if defined(CONFIG_ARCH_SPLIT_ARG64) || defined(CONFIG_COMPAT)
1922SYSCALL32_DEFINE6(fanotify_mark,
1923				int, fanotify_fd, unsigned int, flags,
1924				SC_ARG64(mask), int, dfd,
1925				const char  __user *, pathname)
1926{
1927	return do_fanotify_mark(fanotify_fd, flags, SC_VAL64(__u64, mask),
1928				dfd, pathname);
 
 
 
 
 
1929}
1930#endif
1931
1932/*
1933 * fanotify_user_setup - Our initialization function.  Note that we cannot return
1934 * error because we have compiled-in VFS hooks.  So an (unlikely) failure here
1935 * must result in panic().
1936 */
1937static int __init fanotify_user_setup(void)
1938{
1939	struct sysinfo si;
1940	int max_marks;
1941
1942	si_meminfo(&si);
1943	/*
1944	 * Allow up to 1% of addressable memory to be accounted for per user
1945	 * marks limited to the range [8192, 1048576]. mount and sb marks are
1946	 * a lot cheaper than inode marks, but there is no reason for a user
1947	 * to have many of those, so calculate by the cost of inode marks.
1948	 */
1949	max_marks = (((si.totalram - si.totalhigh) / 100) << PAGE_SHIFT) /
1950		    INODE_MARK_COST;
1951	max_marks = clamp(max_marks, FANOTIFY_OLD_DEFAULT_MAX_MARKS,
1952				     FANOTIFY_DEFAULT_MAX_USER_MARKS);
1953
1954	BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
1955	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 13);
1956	BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 11);
1957
1958	fanotify_mark_cache = KMEM_CACHE(fanotify_mark,
1959					 SLAB_PANIC|SLAB_ACCOUNT);
1960	fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
1961					       SLAB_PANIC);
1962	fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
1963						SLAB_PANIC);
1964	if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
1965		fanotify_perm_event_cachep =
1966			KMEM_CACHE(fanotify_perm_event, SLAB_PANIC);
1967	}
1968
1969	fanotify_max_queued_events = FANOTIFY_DEFAULT_MAX_EVENTS;
1970	init_user_ns.ucount_max[UCOUNT_FANOTIFY_GROUPS] =
1971					FANOTIFY_DEFAULT_MAX_GROUPS;
1972	init_user_ns.ucount_max[UCOUNT_FANOTIFY_MARKS] = max_marks;
1973	fanotify_sysctls_init();
1974
1975	return 0;
1976}
1977device_initcall(fanotify_user_setup);