Commit b3c1030d authored by Suzuki K. Poulose's avatar Suzuki K. Poulose Committed by Linus Torvalds

fanotify: fix event filtering with FAN_ONDIR set

With FAN_ONDIR set, the user can end up getting events, which it hasn't
marked.  This was revealed with fanotify04 testcase failure on
Linux-4.0-rc1, and is a regression from 3.19, revealed with 66ba93c0
("fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask").

   # /opt/ltp/testcases/bin/fanotify04
   [ ... ]
  fanotify04    7  TPASS  :  event generated properly for type 100000
  fanotify04    8  TFAIL  :  fanotify04.c:147: got unexpected event 30
  fanotify04    9  TPASS  :  No event as expected

The testcase sets the adds the following marks : FAN_OPEN | FAN_ONDIR for
a fanotify on a dir.  Then does an open(), followed by close() of the
directory and expects to see an event FAN_OPEN(0x20).  However, the
fanotify returns (FAN_OPEN|FAN_CLOSE_NOWRITE(0x10)).  This happens due to
the flaw in the check for event_mask in fanotify_should_send_event() which
does:

	if (event_mask & marks_mask & ~marks_ignored_mask)
		return true;

where, event_mask == (FAN_ONDIR | FAN_CLOSE_NOWRITE),
       marks_mask == (FAN_ONDIR | FAN_OPEN),
       marks_ignored_mask == 0

Fix this by masking the outgoing events to the user, as we already take
care of FAN_ONDIR and FAN_EVENT_ON_CHILD.
Signed-off-by: default avatarSuzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: default avatarLino Sanfilippo <LinoSanfilippo@gmx.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5b8bf307
......@@ -143,7 +143,8 @@ static bool fanotify_should_send_event(struct fsnotify_mark *inode_mark,
!(marks_mask & FS_ISDIR & ~marks_ignored_mask))
return false;
if (event_mask & marks_mask & ~marks_ignored_mask)
if (event_mask & FAN_ALL_OUTGOING_EVENTS & marks_mask &
~marks_ignored_mask)
return true;
return false;
......
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