From 5838d4442bd5971687b72221736222637e03140d Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 6 Aug 2014 16:03:28 -0700 Subject: fanotify: fix double free of pending permission events Commit 85816794240b ("fanotify: Fix use after free for permission events") introduced a double free issue for permission events which are pending in group's notification queue while group is being destroyed. These events are freed from fanotify_handle_event() but they are not removed from groups notification queue and thus they get freed again from fsnotify_flush_notify(). Fix the problem by removing permission events from notification queue before freeing them if we skip processing access response. Also expand comments in fanotify_release() to explain group shutdown in detail. Fixes: 85816794240b9659e66e4d9b0df7c6e814e5f603 Signed-off-by: Jan Kara Reported-by: Douglas Leeder Tested-by: Douglas Leeder Reported-by: Heinrich Schuchard Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/fsnotify_backend.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/fsnotify_backend.h') diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index a6e899943363..ca060d7c4fa6 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -326,6 +326,8 @@ extern int fsnotify_add_event(struct fsnotify_group *group, struct fsnotify_event *event, int (*merge)(struct list_head *, struct fsnotify_event *)); +/* Remove passed event from groups notification queue */ +extern void fsnotify_remove_event(struct fsnotify_group *group, struct fsnotify_event *event); /* true if the group notification queue is empty */ extern bool fsnotify_notify_queue_is_empty(struct fsnotify_group *group); /* return, but do not dequeue the first event on the notification queue */ -- cgit v1.2.1