dhcp3-client can't set IP address due to insufficient rights

[Hadmut Danisch]

Binary package hint: dhcp3-client

Hi,

strange problem: On my notebook computer with WLAN I can't get DHCP addresses.

Trace of the problem:

dhclient3 properly receives an IP address from the server.

dhclient3 then calls /sbin/dhclient-script to actually perform the configuration, e.g. use ifconfig to put the IP address received from the server on the interface, something like

   ifconfig wlan0 inet 1.2.3.4 netmask 255.255.255.0 broadcast 1.2.3.255

which fails. A trace showed that it fails with PERMISSION DENIED because of insufficient rights. dhclient3 performs a
setuid and setgid to the user and group "dhcp" before calling the script /sbin/dhclient-script.

Since this script is then run without root privileges, the ifconfig fails with EPERM.

How was this intended to work?

regards
Hadmut

[Jeroen Roovers (jer-gentoo)]

As first noted in https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/329105/comments/7

network-manager successfully starts dhclient, but dhclient never returns and doesn't set up the network interface:

/var/log/daemon.log after selecting a connection in nm-applet:
Feb 21 02:54:11 patricia NetworkManager: <info> Activation (ra0) Stage 3 of 5 (IP Configure Start) complete.
Feb 21 02:54:11 patricia dhclient: Internet Systems Consortium DHCP Client V3.1.1
Feb 21 02:54:11 patricia dhclient: Copyright 2004-2008 Internet Systems Consortium.
Feb 21 02:54:11 patricia dhclient: All rights reserved.
Feb 21 02:54:11 patricia dhclient: For info, please visit http://www.isc.org/sw/dhcp/
Feb 21 02:54:11 patricia dhclient:
Feb 21 02:54:11 patricia dhclient: Listening on LPF/ra0/00:22:43:5d:4b:d4
Feb 21 02:54:11 patricia dhclient: Sending on LPF/ra0/00:22:43:5d:4b:d4
Feb 21 02:54:11 patricia dhclient: Sending on Socket/fallback
Feb 21 02:54:14 patricia dhclient: DHCPDISCOVER on ra0 to 255.255.255.255 port 67 interval 4
Feb 21 02:54:14 patricia dhclient: DHCPOFFER of 172.16.24.220 from 172.16.27.1
Feb 21 02:54:14 patricia dhclient: DHCPREQUEST of 172.16.24.220 on ra0 to 255.255.255.255 port 67
Feb 21 02:54:14 patricia dhclient: DHCPACK of 172.16.24.220 from 172.16.27.1
Feb 21 02:54:14 patricia dhclient: bound to 172.16.24.220 -- renewal in 3431 seconds.
Feb 21 02:54:57 patricia NetworkManager: <info> Device 'ra0' DHCP transaction took too long (>45s), stopping it.
Feb 21 02:54:57 patricia NetworkManager: <info> ra0: canceled DHCP transaction, dhcp client pid 7290
Feb 21 02:54:57 patricia NetworkManager: <info> Activation (ra0) Stage 4 of 5 (IP Configure Timeout) scheduled...
Feb 21 02:54:57 patricia NetworkManager: <info> Activation (ra0) Stage 4 of 5 (IP Configure Timeout) started...
Feb 21 02:54:57 patricia NetworkManager: <info> (ra0): device state change: 7 -> 9
Feb 21 02:54:57 patricia NetworkManager: <info> Activation (ra0) failed for access point (orxnet)
Feb 21 02:54:57 patricia NetworkManager: <info> Marking connection 'ORXNET' invalid.
Feb 21 02:54:57 patricia NetworkManager: <info> Activation (ra0) failed.
Feb 21 02:54:57 patricia NetworkManager: <info> Activation (ra0) Stage 4 of 5 (IP Configure Timeout) complete.
Feb 21 02:54:57 patricia NetworkManager: <info> (ra0): device state change: 9 -> 3
Feb 21 02:54:57 patricia NetworkManager: <info> (ra0): deactivating device (reason: 0)

ra0 shows some traffic but never goes up. I see the same consistent misbehaviour with eth0. Both interfaces work fine when started without using network-manager or dhclient.

The attached strace of dhclient3 shows that dhclient is not allowed to run /sbin/dhclient-script.

[Jeroen Roovers (jer-gentoo)]

Cannot confirm this any longer - switching to the jaunty kernel 2.6.28 made the problem disappear instantly.

[Jamie Strandboge (jdstrand)]

Closing per user's comments.