NetworkManager leaves garbage in essid after disconnect

[Craig Ringer]

Binary package hint: network-manager

NetworkManager appears to fill the essid with garbage when it disconnects from a network as part of disabling networking (ie: right click on nm applet, uncheck "enable networking").

craig@ayaki:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu lucid (development branch)
Release: 10.04
Codename: lucid

craig@ayaki:~$ apt-cache policy network-manager
network-manager:
  Installed: 0.8-0ubuntu3
  Candidate: 0.8-0ubuntu3
  Version table:
 *** 0.8-0ubuntu3 0
        500 http://ftp.iinet.net.au/pub/ubuntu/ lucid/main Packages
        500 http://au.archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

craig@ayaki:~$ uname -a
Linux ayaki 2.6.32-20-generic #29-Ubuntu SMP Fri Apr 9 20:35:55 UTC 2010 i686 GNU/Linux

While connected to wifi, as normal:

root@ayaki:~# iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"madradish"
          Mode:Managed Frequency:2.437 GHz Access Point: 00:12:BF:09:E1:76
          Bit Rate=1 Mb/s Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Encryption key:3132-3334-35
          Power Management:off
          Link Quality=42/70 Signal level=-68 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

After disconnection, note the garbage essid:

root@ayaki:~# iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"p\xE9>\xA1A\xE1\xFCg>\x01~\x97\xEA\xDCk\x96\x8F8\*\xEC\xB0;\xFB2\xAF<T\xEC\x18\xDB\"
          Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated
          Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Encryption key:off
          Power Management:off

I never noticed this before upgrading to lucid (pre) and therefore from NM 0.7 to NM 0.8 . While that doesn't mean it wasn't happening, I tend to use iwconfig and would expect to have noticed.

[Craig Ringer (ringerc)]

It also happens if I disconnect from the wireless using the "Enable Wireless" check box.

craig@ayaki:~$ iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"\x02\x1A\xFEC\xFB\xFA\xAA:\xFB)\xD1\xE6\x05<|\x94u\xD8\xBEa\x89\xF9\\xBB\xA8\x99\x0F\x95\xB1\xEB\xF1\xB3"
          Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated
          Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off

.... or even leaving wireless enabled and using the "Disconnect" menu option:

craig@ayaki:~$ iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"\x05\xEF\xF7\x00\xE9\xA1:\xE5\xCA\x0B\xCB\xD0HGd\xBD\x1F#\x1E\xA8\x1C{d\xC5\x14sZ\xC5^Kyc"
          Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated
          Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off

I smell a string null termination bug...

[Craig Ringer (ringerc)]

Wifi card info:

0c:00.0 Network controller: Intel Corporation PRO/Wireless 4965 AG or AGN [Kedron] Network Connection (rev 61)
 Subsystem: Intel Corporation Device 1120

0c:00.0 0280: 8086:4229 (rev 61)
 Subsystem: 8086:1120
 Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx+
 Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 0, Cache Line Size: 64 bytes
 Interrupt: pin A routed to IRQ 30
 Region 0: Memory at f1ffe000 (64-bit, non-prefetchable) [size=8K]
 Capabilities: <access denied>
 Kernel driver in use: iwlagn
 Kernel modules: iwlagn

craig@ayaki:~$ modinfo iwlagn
filename: /lib/modules/2.6.32-20-generic/kernel/drivers/net/wireless/iwlwifi/iwlagn.ko
alias: iwl4965
license: GPL
author: Copyright(c) 2003-2009 Intel Corporation <email address hidden>
version: 1.3.27k
description: Intel(R) Wireless WiFi Link AGN driver for Linux
firmware: iwlwifi-4965-2.ucode
firmware: iwlwifi-5150-2.ucode
firmware: iwlwifi-5000-2.ucode
firmware: iwlwifi-6050-4.ucode
firmware: iwlwifi-6000-4.ucode
srcversion: 9B8B8B62434B92B6793FD7A

[Craig Ringer (ringerc)]

Re-tested with current (as of five minutes ago) lucid, post-alpha-2. Problem still exists.

craig@ayaki:~$ iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"aloe"
          Mode:Managed Frequency:2.437 GHz Access Point: 00:13:46:27:6B:41
          Bit Rate=1 Mb/s Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off
          Link Quality=64/70 Signal level=-46 dBm
          Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
          Tx excessive retries:0 Invalid misc:0 Missed beacon:0

craig@ayaki:~$ iwconfig wlan0
wlan0 IEEE 802.11abgn ESSID:"g\xC6isQ\xFFJ\xEC)\xCD\xBA\xAB\xF2\xFB\xE3F|\xC2T\xF8\x1B\xE8\xE7\x8DvZ.c3\x9F\xC9\x9A"
          Mode:Managed Frequency:2.437 GHz Access Point: Not-Associated
          Tx-Power=14 dBm
          Retry long limit:7 RTS thr:off Fragment thr:off
          Power Management:off

Linux ayaki 2.6.32-21-generic #32-Ubuntu SMP Fri Apr 16 08:10:02 UTC 2010 i686 GNU/Linux

craig@ayaki:~$ apt-cache policy network-manager
network-manager:
  Installed: 0.8-0ubuntu3
  Candidate: 0.8-0ubuntu3
  Version table:
 *** 0.8-0ubuntu3 0
        500 http://ftp.iinet.net.au/pub/ubuntu/ lucid/main Packages
        500 http://au.archive.ubuntu.com/ubuntu/ lucid/main Packages
        100 /var/lib/dpkg/status

[Craig Ringer (ringerc)]

Note that this bug doesn't seem to actually cause any kind of breakage. It's just ugly, and may indicate useof unitialized/freed memory or an improperly terminated string somewhere in the nm code, which may become a problem later.

[Thomas Hood (jdthood)]

@Craig: Is this bug still present in Ubuntu 12.04?

[Craig Ringer (ringerc)]

NFI, I haven't used Ubuntu for a good year now. The fact that there haven't been any recent "affects me too" additions and there's been no comment activity suggests it's probably gone into the mists of wherever unloved bugs go to die.

[Launchpad Janitor (janitor)]

[Expired for network-manager (Ubuntu) because there has been no activity for 60 days.]