[Pkg-utopia-maintainers] Bug#939294: network-manager: After upgrade to 1.20.0-1, mac address of wlan0 is randomized

[Jörn Heissler]

On Tue, Sep 03, 2019 at 00:55:59 +0200, Michael Biebl wrote:
> network-manager did always randomize the mac, unless you have a package
> explicitly overriding this behaviour.

After a reboot it worked again.
I had a closer looks at the logs: It appears like NM always changes mac address
before scanning:

device (wlan0): set-hw-addr: set MAC address to 7E:83:4F:92:E9:72 (scanning)

And changing it back when connecting:

device (wlan0): set-hw-addr: reset MAC address to <---redacted---> (preserve)

I wasn't even aware of the feature, but it makes sense. That happened
before the upgrade too.


During the upgrade, NM started a scan for some reason and changed the address.
Then the NM process was terminated. The new instance of NM assumed wrongly
that the current mac address is the real one.

Logs looked like:

device (wlan0): set-hw-addr: set MAC address to C6:E8:D3:FB:55:4B (scanning)
exiting (success)
---
NetworkManager (version 1.20.0) is starting... (after a restart)
device (wlan0): set-hw-addr: set MAC address to 52:8C:79:7C:65:5E (scanning)
device (wlan0): set-hw-addr: reset MAC address to C6:E8:D3:FB:55:4B (preserve)


The flaw can be triggered easily:

# systemctl restart wpa_supplicant.service; sleep 1.5; systemctl restart NetworkManager.service

Restart of wpa_supplicant.service causes a rescan which appears to take
about 3 seconds. During rescan, NM is restarted. Afterwards the MAC
address is wrong.

A workaround without reboot is to stop NM, change the mac adress
manually (ip link set dev wlan0 down; ip link set dev wlan0 address zz:yy:xx:ww:vv:uu),
then start NM again.


So, I believe this is really a bug in NetworkManager which should be
fixed. But might well be an upstream bug.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://alioth-lists.debian.net/pipermail/pkg-utopia-maintainers/attachments/20190903/464c51c8/attachment.sig>