From: Amir Goldstein amir73il@gmail.com
commit 55bf882c7f13dda8bbe624040c6d5b4fbb812d16 upstream.
Change the logic of FAN_ONDIR in two ways that are similar to the logic of FAN_EVENT_ON_CHILD, that was fixed in commit 54a307ba8d3c ("fanotify: fix logic of events on child"):
1. The flag is meaningless in ignore mask 2. The flag refers only to events in the mask of the mark where it is set
This is what the fanotify_mark.2 man page says about FAN_ONDIR: "Without this flag, only events for files are created." It doesn't say anything about setting this flag in ignore mask to stop getting events on directories nor can I think of any setup where this capability would be useful.
Currently, when marks masks are merged, the FAN_ONDIR flag set in one mark affects the events that are set in another mark's mask and this behavior causes unexpected results. For example, a user adds a mark on a directory with mask FAN_ATTRIB | FAN_ONDIR and a mount mark with mask FAN_OPEN (without FAN_ONDIR). An opendir() of that directory (which is inside that mount) generates a FAN_OPEN event even though neither of the marks requested to get open events on directories.
Link: https://lore.kernel.org/r/20200319151022.31456-10-amir73il@gmail.com Signed-off-by: Amir Goldstein amir73il@gmail.com Signed-off-by: Jan Kara jack@suse.cz Cc: Rachel Sibley rasibley@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/notify/fanotify/fanotify.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
--- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -172,6 +172,13 @@ static u32 fanotify_group_event_mask(str continue; mark = iter_info->marks[type]; /* + * If the event is on dir and this mark doesn't care about + * events on dir, don't send it! + */ + if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR)) + continue; + + /* * If the event is for a child and this mark doesn't care about * events on a child, don't send it! */ @@ -203,10 +210,6 @@ static u32 fanotify_group_event_mask(str user_mask &= ~FAN_ONDIR; }
- if (event_mask & FS_ISDIR && - !(marks_mask & FS_ISDIR & ~marks_ignored_mask)) - return 0; - return test_mask & user_mask; }