From: Amir Goldstein amir73il@gmail.com
[ Upstream commit 2f02fd3fa13e51713b630164f8a8e5b42de8283b ]
The comments in fanotify_group_event_mask() say:
"If the event is on dir/child and this mark doesn't care about events on dir/child, don't send it!"
Specifically, mount and filesystem marks do not care about events on child, but they can still specify an ignore mask for those events. For example, a group that has: - A mount mark with mask 0 and ignore_mask FAN_OPEN - An inode mark on a directory with mask FAN_OPEN | FAN_OPEN_EXEC with flag FAN_EVENT_ON_CHILD
A child file open for exec would be reported to group with the FAN_OPEN event despite the fact that FAN_OPEN is in ignore mask of mount mark, because the mark iteration loop skips over non-inode marks for events on child when calculating the ignore mask.
Move ignore mask calculation to the top of the iteration loop block before excluding marks for events on dir/child.
Link: https://lore.kernel.org/r/20200524072441.18258-1-amir73il@gmail.com Reported-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/linux-fsdevel/20200521162443.GA26052@quack2.suse.cz/ Fixes: 55bf882c7f13 "fanotify: fix merging marks masks with FAN_ONDIR" Fixes: b469e7e47c8a "fanotify: fix handling of events on child..." Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Jan Kara jack@suse.cz Signed-off-by: Sasha Levin sashal@kernel.org --- fs/notify/fanotify/fanotify.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index c18459cea6f4..29a9de57c34c 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -232,6 +232,10 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, if (!fsnotify_iter_should_report_type(iter_info, type)) continue; mark = iter_info->marks[type]; + + /* Apply ignore mask regardless of ISDIR and ON_CHILD flags */ + marks_ignored_mask |= mark->ignored_mask; + /* * If the event is on dir and this mark doesn't care about * events on dir, don't send it! @@ -249,7 +253,6 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, continue;
marks_mask |= mark->mask; - marks_ignored_mask |= mark->ignored_mask; }
test_mask = event_mask & marks_mask & ~marks_ignored_mask;