WSL2-Linux-Kernel/fs/notify/fanotify
Suzuki K. Poulose b3c1030d50 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 66ba93c0d7
("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: Suzuki K. Poulose <suzuki.poulose@arm.com>
Tested-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Eric Paris <eparis@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-12 18:46:08 -07:00
..
Kconfig treewide: fix typo of "suport" in various comments and Kconfig 2012-11-19 14:16:09 +01:00
Makefile fanotify: fanotify_init syscall declaration 2010-07-28 09:58:55 -04:00
fanotify.c fanotify: fix event filtering with FAN_ONDIR set 2015-03-12 18:46:08 -07:00
fanotify.h fanotify: use fanotify event structure for permission response processing 2014-04-03 16:20:51 -07:00
fanotify_user.c fanotify: don't set FAN_ONDIR implicitly on a marks ignored mask 2015-02-10 14:30:28 -08:00