netdev - Bridge port userspace events broken?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 14 Oct 2019 22:33:22 +0200
From:   Richard Weinberger <richard.weinberger@...il.com>
To:     netdev@...r.kernel.org
Cc:     Roopa Prabhu <roopa@...ulusnetworks.com>,
        nikolay@...ulusnetworks.com, bridge@...ts.linux-foundation.org,
        Greg KH <gregkh@...uxfoundation.org>
Subject: Bridge port userspace events broken?

Hi!

My userspace needs /sys/class/net/eth0/brport/group_fwd_mask, so I set
up udev rules
to wait for the sysfs file.
Without luck.
Also "udevadm monitor" does not show any event related to
/sys/class/net/eth0/brport when I assign eth0 to a bridge.

First I thought that the bridge code just misses to emit some events but
br_add_if() calls kobject_uevent() which is good.

Greg gave me the hint that the bridge code might not use the kobject model
correctly.

Enabling kobjekt debugging shows that all events are dropped:
[   36.904602] device eth0 entered promiscuous mode
[   36.904786] kobject: 'brport' (0000000028a47e33): kobject_uevent_env
[   36.904789] kobject: 'brport' (0000000028a47e33):
kobject_uevent_env: filter function caused the event to drop!

If I understood Greg correctly this is because the bridge code uses
plain kobjects which
have a parent object. Therefore all events are dropped.

Shouldn't brport be a kset just like net_device->queues_kset?

-- 
Thanks,
//richard