Difference between revisions of "Client Authentication:Fedora"

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Haven't tested the pam password configuration to see if password changes are handled correctly.
 
Haven't tested the pam password configuration to see if password changes are handled correctly.
  
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[[Category:Howto]]
 
[[Category:Howto]]
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[[Category:Administration]]

Revision as of 21:33, 11 May 2010

Warning.png Warning:
This is based upon limited testing and a small number of users via a VirtualBox virtual machine installation of Fedora. YMMV


Fedora 11

Introduction

The following details the setup of Fedora 11 as a desktop to authenticate users against SME 7.4 using Samba and Winbind. The method has been tested using Fedora installed in a VirtualBox virtual machine on a Windows XP host. It assumes login is via the gui interface.

Install Fedora

  • Download the Fedora .iso and install. The initial install process asks for a root password and the hostname (which defaults to localhost.localdomain). Change this to a hostname of your choice and your domain name.
<HOSTNAME>.<yourdomain>.<yourtld>
Information.png Tip:
Make sure you set the <HOSTNAME> to something less than 15 characters.


  • When the install has finished you need to remove the media and reboot. A gui Welcome startup process then completes the setup and installation. During this process you will be asked for a username and password to set up the first user, and also the date/time configuration.
Information.png Tip:
When prompted for a user name to log in with, give a non-SME user such as 'administrator', as this first user effectively becomes a local user for Gnome login. Root is not allowed to login at the Gnome GDM prompt. You can login as this user, open an 'Applications - System - Terminal' cli and 'su' to root to carry out most of the authentication setup later.

You can also Enable Network Time Protocol and add the SME server ip to the list of NTP servers


Warning.png Warning:
On the Create User setup screen do not select the 'Use Network Login' button. This will not work yet due to missing packages etc, and will just complicate the setup below


  • Complete install, login and apply all updates. Logout and Restart.
Important.png Note:
There may be a lot of updates so apply the security fixes as a minimum.

For VirtualBox VM installation only, install the 'Guest Additions'. See section below for details.


Additional Packages

Use the 'System - Administration - Add/Remove Software' or yum to install additional packages

Windows file server (Note this is a group of packages under Package Collections or yum groupinstall)
pam_mount
libtalloc (this needs to be updated if you haven't run all the updates, else samba and the domain join don't work)

Firewall Modifications

Open the 'System - Administration - Firewall' and tick

samba
samba-client

as Trusted Services. Don't forget to 'Apply'

SELinux Administration

Open 'Systems - Administration - SELinux Administration' and set 'System Default Enforcing Mode' to 'Disabled

Samba Modifications

  • Open 'System - Administration - Services' and enable 'smb'
  • Open 'System - Administration - Authentication'. This will open an 'Authentication Configuration' dialogue.
Information.png Tip:
Do not press the 'Join Domain' button until you have completed the changes below on all three of the dialogue tabs


  • On the 'User Information' tab tick 'Enable Winbind Support' and press the 'Configure Winbind ' button.
A 'Winbind Configuration' dialogue opens. Complete the boxes with the relevant information and press OK
Winbind Domain             - this is the Windows Workgroup name for your SME Server
Security                   - set this to domain
Winbind Domain Controllers - this is the ip address of your SME server
Template Shell             - set this to /bin/bash
Allow Offline Login        - tick
  • Change to the 'Authentication' tab. Tick 'Enable Winbind Support' and press the 'Configure Winbind' button.
A 'Winbind Settings' dialogue opens. Check the values are the same as above and press OK.
  • Change to the Options tab and check the following are ticked or set
Use Shadow Passwords
Password Hashing Algorithym - MD5
Local Authorization is sufficient for local users
Create Home directories on first login
  • Now change back to the 'User Information' tab, press 'Configure Winbind' and then 'Join Domain'. Save the configuration when prompted. Enter 'admin' as the Domain Administrator and the SME server 'admin' password when prompted. Click 'OK' until the application closes.
  • Open an 'Applications - Accessories - Terminal' cli and 'su' to root
  • Open and edit /etc/samba/smb.conf. Under [global] there will be a section commented as having been generated by authconfig. Check this section is as below. Some lines may not exist and may need to be added.
Replace <WORKGROUP> and below with the 'Windows workgroup' name of your SME server. Replace <ip of sme server> below with the internal network ip address of your SME server.
workgroup = <WORKGROUP>
password server = <ip of sme server>
security = domain
idmap uid = <whatever range is set>
idmap gid = <whatever range is set>
template shell = /bin/bash
winbind use default domain = yes             (you will probably need to change this from false)
winbind offline logon = true 
wins server = <ip of sme server>
name resolve order = wins host lmhosts bcast
socket options = TCP_NODELAY
template homedir = /home/%D/%U
winbind enum users = yes
winbind enum groups = yes
winbind cache time = 10
obey pam restrictions = yes
pam password change = yes
hostname lookups = yes 
Important.png Note:
If you run the 'System - Administration - Authentication' tool again your amendments will be lost


  • To check validation of smb.conf, run
testparm
  • The 'Join Domain' above should also have worked so to list users, groups and available shares respectively from the SME server, test with
wbinfo -u
wbinfo -g
smbtree
If it doesn't appear to have worked then run
net rpc join -D <WORKGROUP> -U admin
Enter the admin password for the SME server when prompted and you should get a message,
Joined domain <WORKGROUP>

Authentication Modifications

Warning.png Warning:
Altering the pam system authentication files can seriously effect your ability to login in to the system. Take a backup of the /etc/pam.d directory and /etc/nsswitch.conf. Have a live CD available to give access and re-apply the backup files if you make a mistake and/or get locked out


  • Open, check and edit as necessary /etc/nsswitch.conf . Close and Save
hosts: files wins dns
group:  files winbind
passwd: files winbind
shadow: files winbind
  • Open and edit the /etc/pam.d/system-auth file, and amend as below
#%PAM-1.0
# This file is auto-generated.
# User changes will be destroyed the next time authconfig is run.
auth        required      pam_env.so
auth        sufficient    pam_fprintd.so
auth        sufficient    pam_unix.so nullok try_first_pass
#auth        requisite     pam_succeed_if.so uid >= 500 quiet
auth        optional      pam_winbind.so use_first_pass
auth	    optional      pam_mount.so enable_pam_password
#auth        required      pam_deny.so

account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 500 quiet
account     [default=bad success=ok user_unknown=ignore] pam_winbind.so use_first_pass
account     required      pam_permit.so

#password    requisite     pam_cracklib.so try_first_pass retry=3
password    sufficient    pam_unix.so md5 shadow nullok 
password    sufficient    pam_winbind.so use_first_pass use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
session     optional      pam_mkhomedir.so skel=/etc/skel umask=0022
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_winbind.so
session     optional      pam_mount.so enable_pam_password
  • Open and edit the /etc/pam.d/password-auth file, and amend as below
#%PAM-1.0
# This file is auto-generated.
# User changes will be destroyed the next time authconfig is run.
auth        required      pam_env.so
auth        sufficient    pam_unix.so nullok try_first_pass
#auth        requisite     pam_succeed_if.so uid >= 500 quiet
auth        optional      pam_winbind.so use_first_pass
auth        optional      pam_mount.so enable_pam_password
#auth        required      pam_deny.so

account     required      pam_unix.so broken_shadow
account     sufficient    pam_localuser.so
account     sufficient    pam_succeed_if.so uid < 500 quiet
account     [default=bad success=ok user_unknown=ignore] pam_winbind.so use_first_pass
account     required      pam_permit.so

#password    requisite     pam_cracklib.so try_first_pass retry=3
password    sufficient    pam_unix.so md5 shadow nullok 
password    sufficient    pam_winbind.so use_first_pass use_authtok
password    required      pam_deny.so

session     optional      pam_keyinit.so revoke
session     required      pam_limits.so
session     optional      pam_mkhomedir.so skel=/etc/skel umask=0022
session     [success=1 default=ignore] pam_succeed_if.so service in crond quiet use_uid
session     required      pam_unix.so
session     optional      pam_winbind.so
session     optional      pam_mount.so enable_pam_password

Automount User Home Directories at Login

  • Open and edit /etc/security/pam_mount.conf.xml file. Find the 'Volume Definitions' section. Add a volume line below the header
<!-- Volume Definitions --> 
<volume fstype="cifs" server="<SMESERVER>" path="homes" mountpoint="~/nethome" options="nosuid,nodev" />
  • Replace <SMESERVER> above with the samba name of your SME server. This will mount the users 'home' directory from SME into a directory called 'nethome' in their local home directory.

Login and Test

  • Exit the Terminal cli
  • Logout, and Restart Fedora.
  • Login as a valid SME server user on your system, just giving username and password. No need for DOMAIN\user as samba configured above to use the default Windows Workgroup
  • Authentication against SME should proceed and the user log in. A home directory on the local machine should be created as /home/DOMAIN/user, and a sub directory to that called 'nethome' mounted to the users home directory on the SME server. The mount point should also appear on the users gui desktop.

VirtualBox Guest Additions Installation

Important.png Note:
This section is only applicable if you have installed Fedora in a VirtualBox Virtual Machine. It should be carried out immediately after installation and before setting up the rest of the authentication features


  • The autorun.sh script on the VirtualBox Guest Additions media does not run on Fedora as it requires gksu which doesn't appear to be available as a standard RedHat package. You will need to add the following packages therefore either through the 'System - Adminsitration - Add/Remove Software' or with yum at a Terminal cli command prompt
gcc
kernel-headers
kernel-devel
  • Change to the mounted Virtual Box Guest Additions CDROM, for example
cd /media/VBOXADDITIONS_3.0.10_54097
  • Run the relevant script for your processor type, for example for i386 processors
sh ./VBoxLinuxAdditions-x86.run
  • The script should run, build and install the guest additions. Logout and restart to complete the installation.
Important.png Note:
You may want to remove gcc at this point for security reasons


Issues / ToDo

The above was tested on a VirtualBox virtual machine. The login appears to stall after username and password entered due to the mount of the home directory, but this does complete after a little while. Appears to be due to NAT traversal and WINS lookup as VM is using NAT and a different subnet. Couldn't get bridged mode to work, and haven't installed on a dedicated machine on the same subnet to confirm. Login is a little slow therefore using the VM. Perhaps someone could confirm its OK when on proper subnet.

Haven't tested the pam password configuration to see if password changes are handled correctly.