On Mon, Feb 04, 2019 at 12:48:00PM +0200, Amir Goldstein wrote:
On Mon, Feb 4, 2019 at 12:44 PM Greg Kroah-Hartman gregkh@linuxfoundation.org wrote:
4.9-stable review patch. If anyone has any objections, please let me know.
From: Amir Goldstein amir73il@gmail.com
commit b469e7e47c8a075cc08bcd1e85d4365134bdcdd5 upstream.
When an event is reported on a sub-directory and the parent inode has a mark mask with FS_EVENT_ON_CHILD|FS_ISDIR, the event will be sent to fsnotify() even if the event type is not in the parent mark mask (e.g. FS_OPEN).
Further more, if that event happened on a mount or a filesystem with a mount/sb mark that does have that event type in their mask, the "on child" event will be reported on the mount/sb mark. That is not desired, because user will get a duplicate event for the same action.
Note that the event reported on the victim inode is never merged with the event reported on the parent inode, because of the check in should_merge(): old_fsn->inode == new_fsn->inode.
Fix this by looking for a match of an actual event type (i.e. not just FS_ISDIR) in parent's inode mark mask and by not reporting an "on child" event to group if event type is only found on mount/sb marks.
[backport hint: The bug seems to have always been in fanotify, but this patch will only apply cleanly to v4.19.y]
Same comment about this backport hint being misleading in the context of the backport patch.
I try to leave the text in the changelog identical to what is upstream to make it easier to track things.
thanks,
greg k-h