[Bug 1545302] Re: wpa-roam broken by fix for ifupdown #1337873

[Dariusz Gadomski]

Hello Paul,
I have identified the cause of the problem and prepared a fix.
My tests show that it solves the issue for Trusty and Wily (while Xenial does not require a fix since it's ifupdown has been synced with Debian to a version containing a fix already).

Could you please revert your wpasupplicant to the original state
(without your patches) and upgrade your ifupdown from the one available
in my ppa?

sudo add-apt-repository ppa:dgadomski/lp1545302
sudo apt-get update
sudo apt-get install ifupdown

In my understanding this should solve your problem. Please leave your
feedback and so we will be able to proceed with an official release.

Thank you.

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https://bugs.launchpad.net/bugs/1545302

Title:
  wpa-roam broken by fix for ifupdown #1337873

Status in wpa package in Ubuntu:
  Confirmed

Bug description:
  The following versions of ifupdown introduced a recursion check using "IFUPDOWN_<interface>" environment variables along with a new locking mechanism for ifup (see #1337873):
  0.7.47.2ubuntu4.2 (in Trusty)
  0.7.54ubuntu1.1 (in Wily)
  0.7.54ubuntu2 (in Xenial)

  This recursion check breaks the wpa-roam feature of wpasupplicant,
  preventing it from loading the logical interface specified by id_str
  after associating with an AP.  Specifically, after upgrading to one of
  the above ifupdown versions, the '/sbin/ifup -v --force
  "$WPA_IFACE=$WPA_LOGICAL_IFACE"' command run by wpa_action in
  functions.sh fails with an "ifup: recursion detected for parent
  interface wlan0 in post-up phase" error.

  To fix the issue, functions.sh needs to run `unset
  "IFDOWN_$WPA_IFACE"` before calling /sbin/ifup to prevent ifup from
  detecting the recursion.  The attached patch implements this change.

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