Re: [PATCH 4.4] fanotify: fix logic of events on child

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Sun, Apr 22, 2018 at 03:14:06AM -0700, Nathan Chancellor wrote:
> From: Amir Goldstein <amir73il@gmail.com>
> 
> commit 54a307ba8d3cd00a3902337ffaae28f436eeb1a4 upstream.
> 
> When event on child inodes are sent to the parent inode mark and
> parent inode mark was not marked with FAN_EVENT_ON_CHILD, the event
> will not be delivered to the listener process. However, if the same
> process also has a mount mark, the event to the parent inode will be
> delivered regadless of the mount mark mask.
> 
> This behavior is incorrect in the case where the mount mark mask does
> not contain the specific event type. For example, the process adds
> a mark on a directory with mask FAN_MODIFY (without FAN_EVENT_ON_CHILD)
> and a mount mark with mask FAN_CLOSE_NOWRITE (without FAN_ONDIR).
> 
> A modify event on a file inside that directory (and inside that mount)
> should not create a FAN_MODIFY event, because neither of the marks
> requested to get that event on the file.
> 
> Fixes: 1968f5eed54c ("fanotify: use both marks when possible")
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> Signed-off-by: Jan Kara <jack@suse.cz>
> [natechancellor: Fix small conflict due to lack of 3cd5eca8d7a2f]
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
>  fs/notify/fanotify/fanotify.c | 34 +++++++++++++++-------------------
>  1 file changed, 15 insertions(+), 19 deletions(-)

Thanks for this, now queued up to 4.9.y, 4.4.y, and 3.18.y

greg k-h