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SubjectRe: [PATCH] fanotify: Fix event filtering with FAN_ONDIR set
On Fri 27-02-15 11:40:39, Suzuki K. Poulose wrote:
> From: "Suzuki K. Poulose" <suzuki.poulose@arm.com>
>
> 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 commit (66ba93c0d7fe6: 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.
>
> Cc: Lino Sanfilippo <LinoSanfilippo@gmx.de>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Eric Paris <eparis@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Will Deacon <will.deacon@arm.com>
> Signed-off-by: Suzuki K. Poulose <suzuki.poulose@arm.com>
Thanks for the fix. I should have run LTP myself. You can add:
Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> fs/notify/fanotify/fanotify.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
> index 9a66ff7..d2f97ec 100644
> --- a/fs/notify/fanotify/fanotify.c
> +++ b/fs/notify/fanotify/fanotify.c
> @@ -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;
> --
> 1.7.9.5
>
>
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR


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