audit: convert audit watches to use fsnotify instead of inotify

				   FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\

				   FS_DELETE)

#define FS_MOVE			(FS_MOVED_FROM | FS_MOVED_TO)

/* listeners that hard code group numbers near the top */

#define DNOTIFY_GROUP_NUM	UINT_MAX

#define INOTIFY_GROUP_NUM	(DNOTIFY_GROUP_NUM-1)

#define AUDIT_WATCH_GROUP_NUM  (DNOTIFY_GROUP_NUM-1)

#define INOTIFY_GROUP_NUM      (AUDIT_WATCH_GROUP_NUM-1)

struct fsnotify_group;

struct fsnotify_event;

#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/sched.h>

#include <linux/slab.h>

#include <linux/inotify.h>

#include <linux/security.h>

#include "audit.h"

/*

 * Reference counting:

 *

 * audit_parent: lifetime is from audit_init_parent() to receipt of an IN_IGNORED

 * 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

struct audit_parent {

	struct list_head	ilist;	/* tmp list used to free parents */

	struct list_head	watches; /* anchor for audit_watch->wlist */

	struct inotify_watch	wdata;	/* inotify watch data */

	struct fsnotify_mark_entry mark; /* fsnotify mark on the inode */

	unsigned		flags;	/* status flags */

};

/* Inotify handle. */

struct inotify_handle *audit_ih;

/* fsnotify handle. */

struct fsnotify_group *audit_watch_group;

/*

 * audit_parent status flags:

 *

 * AUDIT_PARENT_INVALID - set anytime rules/watches are auto-removed due to

 * a filesystem event to ensure we're adding audit watches to a valid parent.

 * Technically not needed for IN_DELETE_SELF or IN_UNMOUNT events, as we cannot

 * receive them while we have nameidata, but must be used for IN_MOVE_SELF which

 * Technically not needed for FS_DELETE_SELF or FS_UNMOUNT events, as we cannot

 * receive them while we have nameidata, but must be used for FS_MOVE_SELF which

 * we can receive while holding nameidata.

 */

#define AUDIT_PARENT_INVALID	0x001

/* Inotify events we care about. */

#define AUDIT_IN_WATCH IN_MOVE|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF

/* fsnotify events we care about. */

#define AUDIT_FS_WATCH (FS_MOVE | FS_CREATE | FS_DELETE | FS_DELETE_SELF |\

			FS_MOVE_SELF | FS_EVENT_ON_CHILD)

static void audit_free_parent(struct audit_parent *parent)

{

	kfree(parent);

}

static void audit_destroy_watch(struct inotify_watch *i_watch)

static void audit_watch_free_mark(struct fsnotify_mark_entry *entry)

{

	struct audit_parent *parent;

	parent = container_of(i_watch, struct audit_parent, wdata);

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

	audit_free_parent(parent);

}

static void audit_get_parent(struct audit_parent *parent)

{

	if (likely(parent))

		fsnotify_get_mark(&parent->mark);

}

static void audit_put_parent(struct audit_parent *parent)

{

	if (likely(parent))

		fsnotify_put_mark(&parent->mark);

}

/*

 * Find and return the audit_parent on the given inode.  If found a reference

 * is taken on this parent.

 */

static inline struct audit_parent *audit_find_parent(struct inode *inode)

{

	struct audit_parent *parent = NULL;

	struct fsnotify_mark_entry *entry;

	spin_lock(&inode->i_lock);

	entry = fsnotify_find_mark_entry(audit_watch_group, inode);

	spin_unlock(&inode->i_lock);

	if (entry)

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

	return parent;

}

void audit_get_watch(struct audit_watch *watch)

{

	atomic_inc(&watch->count);

void audit_remove_watch(struct audit_watch *watch)

{

	list_del(&watch->wlist);

	put_inotify_watch(&watch->parent->wdata);

	audit_put_parent(watch->parent);

	watch->parent = NULL;

	audit_put_watch(watch); /* match initial get */

}

/* Initialize a parent watch entry. */

static struct audit_parent *audit_init_parent(struct nameidata *ndp)

{

	struct inode *inode = ndp->path.dentry->d_inode;

	struct audit_parent *parent;

	s32 wd;

	int ret;

	parent = kzalloc(sizeof(*parent), GFP_KERNEL);

	if (unlikely(!parent))

	INIT_LIST_HEAD(&parent->watches);

	parent->flags = 0;

	inotify_init_watch(&parent->wdata);

	/* grab a ref so inotify watch hangs around until we take audit_filter_mutex */

	get_inotify_watch(&parent->wdata);

	wd = inotify_add_watch(audit_ih, &parent->wdata,

			       ndp->path.dentry->d_inode, AUDIT_IN_WATCH);

	if (wd < 0) {

	fsnotify_init_mark(&parent->mark, audit_watch_free_mark);

	parent->mark.mask = AUDIT_FS_WATCH;

	/* grab a ref so fsnotify mark hangs around until we take audit_filter_mutex */

	audit_get_parent(parent);

	ret = fsnotify_add_mark(&parent->mark, audit_watch_group, inode);

	if (ret < 0) {

		audit_free_parent(parent);

		return ERR_PTR(wd);

		return ERR_PTR(ret);

	}

	return parent;

{

	struct audit_watch *watch;

	if (!audit_ih)

	if (!audit_watch_group)

		return -EOPNOTSUPP;

	if (path[0] != '/' || path[len-1] == '/' ||

	new->dev = old->dev;

	new->ino = old->ino;

	get_inotify_watch(&old->parent->wdata);

	audit_get_parent(old->parent);

	new->parent = old->parent;

out:

		audit_remove_watch(w);

	}

	mutex_unlock(&audit_filter_mutex);

	fsnotify_destroy_mark_by_entry(&parent->mark);

}

/* Unregister inotify watches for parents on in_list.

 * Generates an IN_IGNORED event. */

 * Generates an FS_IGNORED event. */

void audit_watch_inotify_unregister(struct list_head *in_list)

{

	struct audit_parent *p, *n;

	list_for_each_entry_safe(p, n, in_list, ilist) {

		list_del(&p->ilist);

		inotify_rm_watch(audit_ih, &p->wdata);

		/* the unpin matching the pin in audit_remove_watch_rule() */

		unpin_inotify_watch(&p->wdata);

		fsnotify_destroy_mark_by_entry(&p->mark);

		/* matches the get in audit_remove_watch_rule() */

		audit_put_parent(p);

	}

}

	}

}

/* Associate the given rule with an existing parent inotify_watch.

/* Associate the given rule with an existing parent.

 * Caller must hold audit_filter_mutex. */

static void audit_add_to_parent(struct audit_krule *krule,

				struct audit_parent *parent)

	struct audit_watch *w, *watch = krule->watch;

	int watch_found = 0;

	BUG_ON(!mutex_is_locked(&audit_filter_mutex));

	list_for_each_entry(w, &parent->watches, wlist) {

		if (strcmp(watch->path, w->path))

			continue;

	}

	if (!watch_found) {

		get_inotify_watch(&parent->wdata);

		audit_get_parent(parent);

		watch->parent = parent;

		list_add(&watch->wlist, &parent->watches);

int audit_add_watch(struct audit_krule *krule, struct list_head **list)

{

	struct audit_watch *watch = krule->watch;

	struct inotify_watch *i_watch;

	struct audit_parent *parent;

	struct nameidata *ndp = NULL, *ndw = NULL;

	int h, ret = 0;

	 * inotify watch is found, inotify_find_watch() grabs a reference before

	 * returning.

	 */

	if (inotify_find_watch(audit_ih, ndp->path.dentry->d_inode,

			       &i_watch) < 0) {

	parent = audit_find_parent(ndp->path.dentry->d_inode);

	if (!parent) {

		parent = audit_init_parent(ndp);

		if (IS_ERR(parent)) {

			/* caller expects mutex locked */

			ret = PTR_ERR(parent);

			goto error;

		}

	} else

		parent = container_of(i_watch, struct audit_parent, wdata);

	}

	mutex_lock(&audit_filter_mutex);

	else

		audit_add_to_parent(krule, parent);

	/* match get in audit_init_parent or inotify_find_watch */

	put_inotify_watch(&parent->wdata);

	/* match get in audit_find_parent or audit_init_parent */

	audit_put_parent(parent);

	h = audit_hash_ino((u32)watch->ino);

	*list = &audit_inode_hash[h];

		audit_remove_watch(watch);

		if (list_empty(&parent->watches)) {

			/* Put parent on the inotify un-registration

			 * list.  Grab a reference before releasing

			/* Put parent on the un-registration list.

			 * Grab a reference before releasing

			 * audit_filter_mutex, to be released in

			 * audit_inotify_unregister().

			 * audit_watch_inotify_unregister().

			 * If filesystem is going away, just leave

			 * the sucker alone, eviction will take

			 * care of it. */

			if (pin_inotify_watch(&parent->wdata))

			audit_get_parent(parent);

			list_add(&parent->ilist, list);

		}

	}

}

/* Update watch data in audit rules based on inotify events. */

static void audit_handle_ievent(struct inotify_watch *i_watch, u32 wd, u32 mask,

			 u32 cookie, const char *dname, struct inode *inode)

static bool audit_watch_should_send_event(struct fsnotify_group *group, struct inode *inode, __u32 mask)

{

	struct fsnotify_mark_entry *entry;

	bool send;

	spin_lock(&inode->i_lock);

	entry = fsnotify_find_mark_entry(group, inode);

	spin_unlock(&inode->i_lock);

	if (!entry)

		return false;

	mask = (mask & ~FS_EVENT_ON_CHILD);

	send = (entry->mask & mask);

	/* find took a reference */

	fsnotify_put_mark(entry);

	return send;

}

/* Update watch data in audit rules based on fsnotify events. */

static int audit_watch_handle_event(struct fsnotify_group *group, struct fsnotify_event *event)

{

	struct inode *inode;

	__u32 mask = event->mask;

	const char *dname = event->file_name;

	struct audit_parent *parent;

	parent = container_of(i_watch, struct audit_parent, wdata);

	BUG_ON(group != audit_watch_group);

	parent = audit_find_parent(event->to_tell);

	if (unlikely(!parent))

		return 0;

	switch (event->data_type) {

	case (FSNOTIFY_EVENT_PATH):

		inode = event->path.dentry->d_inode;

		break;

	case (FSNOTIFY_EVENT_INODE):

		inode = event->inode;

		break;

	default:

		BUG();

		inode = NULL;

		break;

	};

	if (mask & (IN_CREATE|IN_MOVED_TO) && inode)

	if (mask & (FS_CREATE|FS_MOVED_TO) && inode)

		audit_update_watch(parent, dname, inode->i_sb->s_dev, inode->i_ino, 0);

	else if (mask & (IN_DELETE|IN_MOVED_FROM))

	else if (mask & (FS_DELETE|FS_MOVED_FROM))

		audit_update_watch(parent, dname, (dev_t)-1, (unsigned long)-1, 1);

	/* inotify automatically removes the watch and sends IN_IGNORED */

	else if (mask & (IN_DELETE_SELF|IN_UNMOUNT))

	else if (mask & (FS_DELETE_SELF|FS_UNMOUNT|FS_MOVE_SELF))

		audit_remove_parent_watches(parent);

	/* inotify does not remove the watch, so remove it manually */

	else if(mask & IN_MOVE_SELF) {

		audit_remove_parent_watches(parent);

		inotify_remove_watch_locked(audit_ih, i_watch);

	} else if (mask & IN_IGNORED)

		put_inotify_watch(i_watch);

	/* moved put_inotify_watch to freeing mark */

	/* matched the ref taken by audit_find_parent */

	audit_put_parent(parent);

	return 0;

}

static void audit_watch_freeing_mark(struct fsnotify_mark_entry *entry, struct fsnotify_group *group)

{

	struct audit_parent *parent;

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

	/* taken from audit_handle_ievent & FS_IGNORED please figure out what I match... */

	audit_put_parent(parent);

}

static const struct inotify_operations audit_inotify_ops = {

	.handle_event   = audit_handle_ievent,

	.destroy_watch  = audit_destroy_watch,

static const struct fsnotify_ops audit_watch_fsnotify_ops = {

	.should_send_event = 	audit_watch_should_send_event,

	.handle_event = 	audit_watch_handle_event,

	.free_group_priv = 	NULL,

	.freeing_mark = 	audit_watch_freeing_mark,

	.free_event_priv = 	NULL,

};

static int __init audit_watch_init(void)

{

	audit_ih = inotify_init(&audit_inotify_ops);

	if (IS_ERR(audit_ih))

		audit_panic("cannot initialize inotify handle");

	audit_watch_group = fsnotify_obtain_group(AUDIT_WATCH_GROUP_NUM, AUDIT_FS_WATCH,

						  &audit_watch_fsnotify_ops);

	if (IS_ERR(audit_watch_group)) {

		audit_watch_group = NULL;

		audit_panic("cannot create audit fsnotify group");

	}

	return 0;

}

subsys_initcall(audit_watch_init);