audit_watch.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* audit_watch.c -- watching inodes
 *
 * Copyright 2003-2009 Red Hat, Inc.
 * Copyright 2005 Hewlett-Packard Development Company, L.P.
 * Copyright 2005 IBM Corporation
 */

#include <linux/file.h>
#include <linux/kernel.h>
#include <linux/audit.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/fsnotify_backend.h>
#include <linux/namei.h>
#include <linux/netlink.h>
#include <linux/refcount.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/security.h>
#include "audit.h"

/*
 * Reference counting:
 *
 * audit_parent: lifetime is from audit_init_parent() to receipt of an FS_IGNORED
 * 	event.  Each audit_watch holds a reference to its associated parent.
 *
 * audit_watch: if added to lists, lifetime is from audit_init_watch() to
 * 	audit_remove_watch().  Additionally, an audit_watch may exist
 * 	temporarily to assist in searching existing filter data.  Each
 * 	audit_krule holds a reference to its associated watch.
 */

struct audit_watch {
	refcount_t		count;	/* reference count */
	dev_t			dev;	/* associated superblock device */
	char			*path;	/* insertion path */
	unsigned long		ino;	/* associated inode number */
	struct audit_parent	*parent; /* associated parent */
	struct list_head	wlist;	/* entry in parent->watches list */
	struct list_head	rules;	/* anchor for krule->rlist */
};

struct audit_parent {
	struct list_head	watches; /* anchor for audit_watch->wlist */
	struct fsnotify_mark mark; /* fsnotify mark on the inode */
};

/* fsnotify handle. */
static struct fsnotify_group *audit_watch_group;

/* fsnotify events we care about. */
#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\
			FS_MOVE_SELF | FS_UNMOUNT)

static void audit_free_parent(struct audit_parent *parent)
{
	WARN_ON(!list_empty(&parent->watches));
	kfree(parent);
}

static void audit_watch_free_mark(struct fsnotify_mark *entry)
{
	struct audit_parent *parent;

	parent = container_of(entry, struct audit_parent, mark);
	audit_free_parent(parent);
}