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LDAP installation so we can use space-wide logins instead of seperate logins for every computer/server. | LDAP installation so we can use space-wide logins instead of seperate logins for every computer/server. | ||
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Latest revision as of 16:31, 22 April 2023
Project: LDAP | |
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State | Active |
Members | Stuiterveer |
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Description | LDAP server for central logins using passwords or keypairs |
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LDAP installation so we can use space-wide logins instead of seperate logins for every computer/server.
Contents
Server
Server IP is 192.168.1.177. The server uses an installation of OpenLDAP with phpLDAPAdmin. The following settings were applied:
OpenLDAP
- DNS domain name: ackspace.nl ("dc=ackspace,dc=nl")
- Database backend: HDB
phpLDAPAdmin
/etc/phpldapadmin/config.php
The following values were set/changed in /etc/phpldapadmin/config.php:
$servers->setValue('server','host','0.0.0.0'); $servers->setValue('server','base',array('dc=ackspace,dc=nl')); $config->custom->appearance['hide_template_warning'] = true; $servers->setValue('login','bind_id','cn=admin,dc=ackspace,dc=nl');
SSH keys
A field to insert SSH keys for users is not present in OpenLDAP/phpLDAPAdmin by default, for this I created a file called openssh-lpk.ldif with the following content:
dn: cn=openssh-lpk,cn=schema,cn=config objectClass: olcSchemaConfig cn: openssh-lpk olcAttributeTypes: ( 1.3.6.1.4.1.24552.500.1.1.1.13 NAME 'sshPublicKey' DESC 'MANDATORY: OpenSSH Public key' EQUALITY octetStringMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.40 ) olcObjectClasses: ( 1.3.6.1.4.1.24552.500.1.1.2.0 NAME 'ldapPublicKey' SUP top AUXILIARY DESC 'MANDATORY: OpenSSH LPK objectclass' MAY ( sshPublicKey $ uid ) )
The following command was then used to add support (make sure ldapscripts is installed):
ldapadd -Y EXTERNAL -H ldapi:/// -f openssh-lpk.ldif
/etc/phpldapadmin/templates/creation/posixAccount.xml
Finally the User Account creation template was changed to add an SSH public key input field to the form by default. For this, /etc/phpldapadmin/templates/creation/posixAccount.xml was changed to the following:
<?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE template SYSTEM "template.dtd"> <template> <askcontainer>1</askcontainer> <description>New User Account</description> <icon>ldap-user.png</icon> <invalid>0</invalid> <rdn>cn</rdn> <title>Generic: User Account</title> <visible>1</visible> <objectClasses> <objectClass id="inetOrgPerson"></objectClass> <objectClass id="posixAccount"></objectClass> <objectClass id="ldapPublicKey"></objectClass> </objectClasses> <attributes> <attribute id="givenName"> <display>First name</display> <icon>ldap-uid.png</icon> <onchange>=autoFill(cn;%givenName% %sn%)</onchange> <onchange>=autoFill(uid;%givenName|0-1/l%%sn/l%)</onchange> <order>1</order> <page>1</page> </attribute> <attribute id="sn"> <display>Last name</display> <onchange>=autoFill(cn;%givenName% %sn%)</onchange> <onchange>=autoFill(uid;%givenName|0-1/l%%sn/l%)</onchange> <order>2</order> <page>1</page> </attribute> <attribute id="cn"> <display>Common Name</display> <order>3</order> <page>1</page> </attribute> <attribute id="uid"> <display>User ID</display> <onchange>=autoFill(homeDirectory;/home/users/%uid%)</onchange> <order>4</order> <page>1</page> <spacer>1</spacer> </attribute> <attribute id="homeDirectory"> <display>Home directory</display> <order>8</order> <page>1</page> </attribute> <attribute id="uidNumber"> <display>UID Number</display> <icon>terminal.png</icon> <order>6</order> <page>1</page> <readonly>1</readonly> <value>=php.GetNextNumber(/;uidNumber)</value> </attribute> <attribute id="gidNumber"> <display>GID Number</display> <order>7</order> <page>1</page> <value><![CDATA[=php.PickList(/;(&(objectClass=posixGroup));gidNumber;%cn%;;;;cn)]]></value> </attribute> <attribute id="loginShell"> <display>Login shell</display> <order>9</order> <page>1</page> <type>select</type> <value id="/bin/bash">/bin/bash</value> <value id="/bin/sh">/bin/sh</value> <value id="/bin/csh">/bin/csh</value> <value id="/bin/tsh">/bin/tsh</value> </attribute> <attribute id="userPassword"> <display>Password</display> <icon>lock.png</icon> <order>5</order> <page>1</page> <post>=php.PasswordEncrypt(%enc%;%userPassword%)</post> <spacer>1</spacer> <verify>1</verify> </attribute> <attribute id="sshPublicKey"> <display>SSH public key</display> <icon>lock.png</icon> <order>10</order> <page>1</page> </attribute> </attributes> </template>
Sudoers
Sudo roles are not included in LDAP by default. For this we need to create a few files.
/etc/ldap/schema/sudo.schema
First of all, a schema was added called /etc/ldap/schema/sudo.schema. It contains the following:
attributetype ( 1.3.6.1.4.1.15953.9.1.1 NAME 'sudoUser' DESC 'User(s) who may run sudo' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.2 NAME 'sudoHost' DESC 'Host(s) who may run sudo' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.3 NAME 'sudoCommand' DESC 'Command(s) to be executed by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.4 NAME 'sudoRunAs' DESC 'User(s) impersonated by sudo (deprecated)' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.5 NAME 'sudoOption' DESC 'Options(s) followed by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.6 NAME 'sudoRunAsUser' DESC 'User(s) impersonated by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.7 NAME 'sudoRunAsGroup' DESC 'Group(s) impersonated by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) attributetype ( 1.3.6.1.4.1.15953.9.1.8 NAME 'sudoNotBefore' DESC 'Start of time interval for which the entry is valid' EQUALITY generalizedTimeMatch ORDERING generalizedTimeOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 ) attributetype ( 1.3.6.1.4.1.15953.9.1.9 NAME 'sudoNotAfter' DESC 'End of time interval for which the entry is valid' EQUALITY generalizedTimeMatch ORDERING generalizedTimeOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 ) attributeTypes ( 1.3.6.1.4.1.15953.9.1.10 NAME 'sudoOrder' DESC 'an integer to order the sudoRole entries' EQUALITY integerMatch ORDERING integerOrderingMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 ) objectclass ( 1.3.6.1.4.1.15953.9.2.1 NAME 'sudoRole' SUP top STRUCTURAL DESC 'Sudoer Entries' MUST ( cn ) MAY ( sudoUser $ sudoHost $ sudoCommand $ sudoRunAs $ sudoRunAsUser $ sudoRunAsGroup $ sudoOption $ sudoOrder $ sudoNotBefore $ sudoNotAfter $ description ) )
/etc/ldap/slapd.conf
If /etc/ldap/slapd.conf exists, make sure you place the following at the top (where you find other includes as well):
include /etc/ldap/schema/sudo.schema
Note that slapd.conf is deprecated and should be replaced by the use of slapd-config[1].
Restart service
Restart the slapd service to make sure the schema is loaded.
LDIF file
Last, a file was created called sudo.ldif that contains the following:
dn: cn=sudo,cn=schema,cn=config objectClass: olcSchemaConfig cn: sudo olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.1 NAME 'sudoUser' DESC 'User(s) who may run sudo' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.2 NAME 'sudoHost' DESC 'Host(s) who may run sudo' EQUALITY caseExactIA5Match SUBSTR caseExactIA5SubstringsMatch SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.3 NAME 'sudoCommand' DESC 'Command(s) to be executed by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.4 NAME 'sudoRunAs' DESC 'User(s) impersonated by sudo (deprecated)' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.5 NAME 'sudoOption' DESC 'Options(s) followed by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.6 NAME 'sudoRunAsUser' DESC 'User(s) impersonated by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcAttributeTypes: ( 1.3.6.1.4.1.15953.9.1.7 NAME 'sudoRunAsGroup' DESC 'Group(s) impersonated by sudo' EQUALITY caseExactIA5Match SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 ) olcObjectClasses: ( 1.3.6.1.4.1.15953.9.2.1 NAME 'sudoRole' SUP top STRUCTURAL DESC 'Sudoer Entries' MUST ( cn ) MAY ( sudoUser $ sudoHost $ sudoCommand $ sudoRunAs $ sudoRunAsUser $ sudoRunAsGroup $ sudoOption $ description ) )
You can import this file to LDAP using:
ldapadd -Y EXTERNAL -H ldapi:/// -f sudo.ldif
Client
PAM
To use LDAP to sign in to Linux, install libpam-ldapd. When asked, fill in the details mentioned in LDAP#OpenLDAP.
/etc/nsswitch.conf
Make sure LDAP is enabled for passwd, group and shadow. To verify, check to see if the following is present (edit the existing entries if needed) in /etc/nsswitch.conf:
passwd: ldap compat group: ldap compat shadow: ldap compat
This will first check LDAP for entries, otherwise it will check locally. If preferred, you can switch around compat and ldap to first check locally and revert to LDAP on failure.
Home folder creation
If you want to make sure a user folder is created upon login, add the following to the end of /etc/pam.d/common-session:
session required pam_mkhomedir.so skel=/etc/skel umask=0022
SSH key login
Create a file that has the following content:
#!/bin/bash ldapsearch -h 192.168.1.177 -b "dc=ackspace,dc=nl" -x '(&(objectClass=posixAccount)(uid='"$1"'))' 'sshPublicKey' | sed -n '/^ /{H;d};/sshPublicKey:/x;$g;s/\n *//g;s/sshPublicKey: //gp'
Make sure the file and all folders above it are owned by root:root and have umask 022.[2]
Then edit sshd_config to include the following:
AuthorizedKeysCommand /path/to/file AuthorizedKeysCommandUser nobody
Sudoers
In order to make sure you can use LDAP for sudoers, make sure your installation of sudo has support for LDAP. If it doesn't you can try installing sudo-ldap which will replace the existing sudo installation.
/etc/ldap.conf
If /etc/ldap.conf doesn't exist yet, create it. Make sure it has at least the following lines in it:
URI ldap://192.168.1.177 sudoers_base ou=sudoers,dc=ackspace,dc=nl
/etc/nsswitch.conf
Make sure /etc/nssswitch.conf has the following line in it:
sudoers: ldap files
Be aware that any matches found in LDAP will be overwritten if they are found in the regular files.
Restart services
When you restart the nscd and ssh services you will be up and running. Sign in to the computer/VM with your LDAP account to verify that it works.
Account
To obtain a user on the LDAP server, contact Stuiterveer.
Reset password
To reset your password, visit 192.168.1.177 in the browser. Fill in the following credentials:
- Login DN: cn=YOUR_USERNAME,ou=users,dc=ackspace,dc=nl (replace YOUR_USERNAME with your own LDAP username)
- Password: your LDAP password
Select your user on the left and fill in the new password in the "password" field. Select "Update Object" when you're done.