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authorJan Kara <jack@suse.cz>2016-09-20 00:44:30 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-09-20 01:36:17 +0300
commit96d41019e3ac55f6f0115b0ce97e4f24a3d636d2 (patch)
tree4178f8feee6258da1c08f27de55af8de3f2b5af2 /fs/notify/notification.c
parent12703dbfeb15402260e7554d32a34ac40c233990 (diff)
downloadlinux-96d41019e3ac55f6f0115b0ce97e4f24a3d636d2.tar.xz
fanotify: fix list corruption in fanotify_get_response()
fanotify_get_response() calls fsnotify_remove_event() when it finds that group is being released from fanotify_release() (bypass_perm is set). However the event it removes need not be only in the group's notification queue but it can have already moved to access_list (userspace read the event before closing the fanotify instance fd) which is protected by a different lock. Thus when fsnotify_remove_event() races with fanotify_release() operating on access_list, the list can get corrupted. Fix the problem by moving all the logic removing permission events from the lists to one place - fanotify_release(). Fixes: 5838d4442bd5 ("fanotify: fix double free of pending permission events") Link: http://lkml.kernel.org/r/1473797711-14111-3-git-send-email-jack@suse.cz Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Miklos Szeredi <mszeredi@redhat.com> Tested-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/notify/notification.c')
-rw-r--r--fs/notify/notification.c15
1 files changed, 0 insertions, 15 deletions
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 3d76e65ff84f..e455e83ceeeb 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -132,21 +132,6 @@ queue:
}
/*
- * Remove @event from group's notification queue. It is the responsibility of
- * the caller to destroy the event.
- */
-void fsnotify_remove_event(struct fsnotify_group *group,
- struct fsnotify_event *event)
-{
- mutex_lock(&group->notification_mutex);
- if (!list_empty(&event->list)) {
- list_del_init(&event->list);
- group->q_len--;
- }
- mutex_unlock(&group->notification_mutex);
-}
-
-/*
* Remove and return the first event from the notification list. It is the
* responsibility of the caller to destroy the obtained event
*/