Commit a4f9a9a6 authored by Naohiro Aota's avatar Naohiro Aota Committed by Al Viro

fsnotify: handle subfiles' perm events

Recently I'm working on fanotify and found the following strange
behaviors.

I wrote a program to set fanotify_mark on "/tmp/block" and FAN_DENY
all events notified.

fanotify_mask = FAN_ALL_EVENTS | FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD:
$ cd /tmp/block; cat foo
cat: foo: Operation not permitted

Operation on the file is blocked as expected.

But,

fanotify_mask = FAN_ALL_PERM_EVENTS | FAN_EVENT_ON_CHILD:
$ cd /tmp/block; cat foo
aaa

It's not blocked anymore.  This is confusing behavior.  Also reading
commit "fsnotify: call fsnotify_parent in perm events", it seems like
fsnotify should handle subfiles' perm events as well as the other notify
events.

With this patch, regardless of FAN_ALL_EVENTS set or not:
$ cd /tmp/block; cat foo
cat: foo: Operation not permitted

Operation on the file is now blocked properly.

FS_OPEN_PERM and FS_ACCESS_PERM are not listed on FS_EVENTS_POSS_ON_CHILD.
 Due to fsnotify_inode_watches_children() check, if you only specify only
these events as fsnotify_mask, you don't get subfiles' perm events
notified.

This patch add the events to FS_EVENTS_POSS_ON_CHILD to get them notified
even if only these events are specified to fsnotify_mask.
Signed-off-by: default avatarNaohiro Aota <naota@elisp.net>
Cc: Eric Paris <eparis@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 799243a3
...@@ -60,7 +60,7 @@ ...@@ -60,7 +60,7 @@
#define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\ #define FS_EVENTS_POSS_ON_CHILD (FS_ACCESS | FS_MODIFY | FS_ATTRIB |\
FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\ FS_CLOSE_WRITE | FS_CLOSE_NOWRITE | FS_OPEN |\
FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\ FS_MOVED_FROM | FS_MOVED_TO | FS_CREATE |\
FS_DELETE) FS_DELETE | FS_OPEN_PERM | FS_ACCESS_PERM)
#define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO) #define FS_MOVE (FS_MOVED_FROM | FS_MOVED_TO)
......
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