【指导】LDAP 与 linux login users 集成

源自：https://www.digitalocean.com/community/tutorials/how-to-authenticate-client-computers-using-ldap-on-an-ubuntu-12-04-vps

In this article, we will discuss how to configure a client machine to remotely authenticate with that server for various services.

Install Client Packages

On the client machine, you will needs to install a few packages to make authentication function correctly with an LDAP server:

sudo apt-get update
sudo apt-get install libpam-ldap nscd

You will be asked a variety of questions similar to the those asked when you were installing the server components.

• LDAP server Uniform Resource Identifier: ldap://LDAP-server-IP-Address

  • Change the initial string from "ldapi:///" to "ldap://" before inputing your server's information

• Distinguished name of the search base:

  • This should match the value you put in your LDAP server's /etc/phpldapadmin/config.php file.
  • Search for: " 'server','base',array " within the file.
  • Our example was "dc=test,dc=com"

• LDAP version to use: 3

• Make local root Database admin: Yes

• Does the LDAP database require login? No

• LDAP account for root:

  • This should also match the value in your /etc/phpldapadmin/config.php.
  • Search for: " 'login','bind_id' " within the file
  • Our example was "cn=admin,dc=test,dc=com"

• LDAP root account password: Your-LDAP-root-password

If you make a mistake and need to change a value, you can go through the menu again by issuing this command:

sudo dpkg-reconfigure ldap-auth-config

Configure Client Software

We have to adjust a few files to tell our authentication files that they can look to our LDAP server for authentication information.

First, edit the /etc/nsswitch.conf file. This will allow us to specify that the LDAP credentials should be modified when users issue authentication change commands.

sudo nano /etc/nsswitch.conf

The three lines we are interested in are the "passwd", "group", and "shadow" definitions. Modify them to look like this:

passwd:         ldap compat
group:          ldap compat
shadow:         ldap compat

Next, we will add a value to our PAM configuration.

PAM, or Pluggable Authentication Modules, is a system that connects applications that can provide authentication to applications that require authentication.

PAM is already implemented on most computers, and works behind the scenes without needing user interaction. When we installed and configured our LDAP PAM module, most of the needed information was added to the configuration files.

Edit the /etc/pam.d/common-session file:

sudo nano /etc/pam.d/common-session

Add a line to the bottom of the configuration that reads:

session required    pam_mkhomedir.so skel=/etc/skel umask=0022

This will create a home directory on the client machine when an LDAP user logs in who does not have a home directory.

We have to restart a service for these changes to be implemented:

sudo /etc/init.d/nscd restart

Permissions

During the LDAP server configuration, we created a group called "admin". This was not chosen at random. It coincides with the "admin" group that is created by default on Ubuntu machines.

The LDAP users that you added to the "admin" group will have access to the sudo command.

This is because we have a line that gives members of the "admin" group sudo access within the/etc/sudoers file. Edit the file by issuing this command:

sudo visudo

There is a line that reads:

%admin ALL=(ALL) ALL

Entries that begin with a percentage sign (%) specify a group instead of a user. If you wish to disable this functionality, or only grant specific users this functionality, comment out this line:

#%admin ALL=(ALL) ALL

Log In as an LDAP User

We have now configured our client machine enough to be able to log in as one of our LDAP users. This user does not have to exist on the client machine.

In a new terminal window (it is best to keep your original terminal window logged in, in case of a configuration mistake), ssh into the client machine using an LDAP user's credentials:

ssh LDAP_user@LDAP_client_IP_Address

You should be able to log in as if your user had been created locally. Issue the print working directory command:

pwd

You should see that the home directory you selected for your user on the LDAP server is being used on this machine. It has been created on-demand to serve the LDAP user.

If you log out and log in with a different LDAP user, you can see that there will be two home directory entries:

ls /home

user1  user2

If your user is part of the "admin" group and you didn't disable the ability in the previous section, you will have normal sudo access, otherwise, you will not.

If you issue the passwd command to change your password, you can see that it will be modifying your LDAP credentials:

passwd

Enter login(LDAP) password: