On Sun, Dec 2, 2018 at 1:38 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> When setting up an fanotify listener, user may request to get fid
> information in event instead of an open file descriptor.
>
> The fid obtained with event on a watched object contains the file
> handle returned by name_to_handle_at(2) and fsid returned by statfs(2).
>
> When setting a mark, we need to make sure that the filesystem
> supports encoding file handles with name_to_handle_at(2) and that
> statfs(2) encodes a non-zero fsid.
>
Jan,
On a discussion with Matthew about tests he is writing for FAN_REPORT_TID,
the issue of permission events came up.
Since I am not aware of any specific benefit that FAN_REPORT_TID could
bring to users of permission events, I think the best course of action is to
limit the use of FAN_REPORT_TID to group with priority FAN_CLASS_NOTIF.
That would simplify tests and man page and if we ever see a use case for
anything else, we can add that in the future.
If you agree, we should add something like this to this patch:
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -768,6 +768,10 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int,
flags, unsigned int, event_f_flags)
return -EINVAL;
}
+ if ((flags & FAN_REPORT_FID) &&
+ (flags & FANOTIFY_CLASS_BITS) != FAN_CLASS_NOTIF)
+ return -EINVAL;
+
user = get_current_user();
if (atomic_read(&user->fanotify_listeners) >
FANOTIFY_DEFAULT_MAX_LISTENERS) {
free_uid(user);
Thanks,
Amir.
