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

[Launchpad Bug Tracker]

You have been subscribed to a public bug:

[Impact]

 * In some configurations recurrent ifup/down calls are broken due to a
false-positive recursion detection.

 * In certain situations it leaves interfaces unconfigured (in this
case: WLAN interface connected to WiFi network, but dhcp fails).

[Test Case]

 * Setup wpa-roam configuration based on what is in comment #6
 
 * Wait until wpa_supplicant connects to a wifi network

 * Run ifconfig to check if the WLAN interface received dhcp info

 * Expected result: WLAN is fully configured according to dhcp settings
 
 * Actual result: WLAN is connected to WiFi but not configured

[Regression Potential]

 * Fixed upstream, fix present in Xenial.

 * Debdiffs contain a backport of an upstream fix.

[Other Info]
 
 * Original 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.

** Affects: ifupdown (Ubuntu)
     Importance: High
     Assignee: Dariusz Gadomski (dgadomski)
         Status: Fix Released

** Affects: ifupdown (Ubuntu Trusty)
     Importance: High
     Assignee: Dariusz Gadomski (dgadomski)
         Status: In Progress

** Affects: ifupdown (Ubuntu Wily)
     Importance: High
     Assignee: Dariusz Gadomski (dgadomski)
         Status: In Progress


** Tags: patch regression-update sts
-- 
wpa-roam broken by fix for ifupdown #1337873
https://bugs.launchpad.net/bugs/1545302
You received this bug notification because you are a member of Ubuntu Foundations Bugs, which is subscribed to ifupdown in Ubuntu.