diff options
| author | Jan Kara <jack@suse.cz> | 2016-09-19 14:44:30 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-30 10:18:37 +0200 |
| commit | 6e67de3922f25ae43fc86be362d740d88167ae7f (patch) | |
| tree | 012cf4cc3267befa270b04035e7157ca6dd444e9 /include | |
| parent | af426ec184a38d257457a22554542d4f9bb7eecd (diff) | |
fanotify: fix list corruption in fanotify_get_response()
commit 96d41019e3ac55f6f0115b0ce97e4f24a3d636d2 upstream.
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/fsnotify_backend.h | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h index 5dfba9a8a7be..850d8822e8ff 100644 --- a/include/linux/fsnotify_backend.h +++ b/include/linux/fsnotify_backend.h @@ -180,7 +180,6 @@ struct fsnotify_group { spinlock_t access_lock; struct list_head access_list; wait_queue_head_t access_waitq; - atomic_t bypass_perm; #endif /* CONFIG_FANOTIFY_ACCESS_PERMISSIONS */ int f_flags; unsigned int max_marks; @@ -323,8 +322,6 @@ 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 */ |