mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-19 02:04:19 +08:00
ff57cd5863
Commit 7053aee26a "fsnotify: do not share events between notification
groups" used overflow event statically allocated in a group with the
size of the generic notification event. This causes problems because
some code looks at type specific parts of event structure and gets
confused by a random data it sees there and causes crashes.
Fix the problem by allocating overflow event with type corresponding to
the group type so code cannot get confused.
Signed-off-by: Jan Kara <jack@suse.cz>
119 lines
3.1 KiB
C
119 lines
3.1 KiB
C
/*
|
|
* Copyright (C) 2008 Red Hat, Inc., Eric Paris <eparis@redhat.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2, or (at your option)
|
|
* any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; see the file COPYING. If not, write to
|
|
* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
#include <linux/list.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/srcu.h>
|
|
#include <linux/rculist.h>
|
|
#include <linux/wait.h>
|
|
|
|
#include <linux/fsnotify_backend.h>
|
|
#include "fsnotify.h"
|
|
|
|
#include <linux/atomic.h>
|
|
|
|
/*
|
|
* Final freeing of a group
|
|
*/
|
|
void fsnotify_final_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
if (group->ops->free_group_priv)
|
|
group->ops->free_group_priv(group);
|
|
|
|
kfree(group);
|
|
}
|
|
|
|
/*
|
|
* Trying to get rid of a group. Remove all marks, flush all events and release
|
|
* the group reference.
|
|
* Note that another thread calling fsnotify_clear_marks_by_group() may still
|
|
* hold a ref to the group.
|
|
*/
|
|
void fsnotify_destroy_group(struct fsnotify_group *group)
|
|
{
|
|
/* clear all inode marks for this group */
|
|
fsnotify_clear_marks_by_group(group);
|
|
|
|
synchronize_srcu(&fsnotify_mark_srcu);
|
|
|
|
/* clear the notification queue of all events */
|
|
fsnotify_flush_notify(group);
|
|
|
|
/*
|
|
* Destroy overflow event (we cannot use fsnotify_destroy_event() as
|
|
* that deliberately ignores overflow events.
|
|
*/
|
|
if (group->overflow_event)
|
|
group->ops->free_event(group->overflow_event);
|
|
|
|
fsnotify_put_group(group);
|
|
}
|
|
|
|
/*
|
|
* Get reference to a group.
|
|
*/
|
|
void fsnotify_get_group(struct fsnotify_group *group)
|
|
{
|
|
atomic_inc(&group->refcnt);
|
|
}
|
|
|
|
/*
|
|
* Drop a reference to a group. Free it if it's through.
|
|
*/
|
|
void fsnotify_put_group(struct fsnotify_group *group)
|
|
{
|
|
if (atomic_dec_and_test(&group->refcnt))
|
|
fsnotify_final_destroy_group(group);
|
|
}
|
|
|
|
/*
|
|
* Create a new fsnotify_group and hold a reference for the group returned.
|
|
*/
|
|
struct fsnotify_group *fsnotify_alloc_group(const struct fsnotify_ops *ops)
|
|
{
|
|
struct fsnotify_group *group;
|
|
|
|
group = kzalloc(sizeof(struct fsnotify_group), GFP_KERNEL);
|
|
if (!group)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/* set to 0 when there a no external references to this group */
|
|
atomic_set(&group->refcnt, 1);
|
|
atomic_set(&group->num_marks, 0);
|
|
|
|
mutex_init(&group->notification_mutex);
|
|
INIT_LIST_HEAD(&group->notification_list);
|
|
init_waitqueue_head(&group->notification_waitq);
|
|
group->max_events = UINT_MAX;
|
|
|
|
mutex_init(&group->mark_mutex);
|
|
INIT_LIST_HEAD(&group->marks_list);
|
|
|
|
group->ops = ops;
|
|
|
|
return group;
|
|
}
|
|
|
|
int fsnotify_fasync(int fd, struct file *file, int on)
|
|
{
|
|
struct fsnotify_group *group = file->private_data;
|
|
|
|
return fasync_helper(fd, file, on, &group->fsn_fa) >= 0 ? 0 : -EIO;
|
|
}
|