17 KiB
ldapdock
a configurable container running openLDAP
Step by step approach on how to setup and run the openLDAP server on a classic systemd-less Docker image container
note about the dockerfile and running the generated image container on FG (foreground) or BG (background): by default the dockerfile generates an image to be run in FG, it expects to be run into it and launch slapd (openLDAP server) manually; to run the image container in BG and start slapd automatically without any user intervention, uncomment the line number 31 of the dockerfile.
Creating the ldapdock image container
build ldapdock
> docker build -t ldapdock /path/to/dockerfile
after build, check the docker image has been created properly with the given REPOSITORY name
> docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
ldapdock latest 0e4a1521b346 6 hours ago 138MB
If you just want to jump in the container and right now don't care saving the configuration or directories, you can run it with this command:
> docker run -h example.com -i -t ldapdock /bin/bash
If you wish (and it is recommended in development) to save the configuration and LDAP directory structure (also called LDAP database) outside of the container, run this command instead:
> docker run -h example.com -i -t -v ldap_data:/var/lib/ldap -v ldap_config:/etc/ldap/slapd.d ldapdock /bin/bash
Parameters explanation:with -h we are specifying the name of the host, we are using example.com, this is very important. -i tells docker to run in an interactive way instead of running the container in the background. -t goes in hand with -i, and allocates a tty (terminal) so we can run commands. -v mounts a volume to save information (we use one to save the data and another one to save the configuration).
Explaining DN, parentDN, CN, and DC as parameters
One of the key configuration of LDAP is our "DC" or "parent DN" and other terms, which to explain it in a pure pragmatic way, we will use some examples: we use per defect example.com as our domain, so the DC (Distinguished Name) that we would use it is "dc=example,dc=com", instead, if our domain would be for example "ideas.lab.com", the parent DN would be "dc=ideas,dc=lab,dc=com". This configuration it's very often passed with the CN (Common Name) in concatenation with the DN (Distinguished Name), and the result it's very simple, in the case of the domain example.com, it is DN: "cn=config,dn=example,dn=com", or for ideas.lab.com DN: "cn=config,dn=ideas,dn=lab,dn=com".
Inside the ldapdock image container
Use the following command to start openLDAP
root@example:/# slapd -h "ldap:/// ldapi:///" -g openldap -u openldap -F /etc/ldap/slapd.d
It's always a good idea to test connectivity to slapd the first times
root@example:/# ldapsearch -x -H ldap://localhost -b "dc=example,dc=com" -s base "(objectclass=*)"
# extended LDIF
#
# LDAPv3
# base <dc=example,dc=com> with scope baseObject
...
Create an Administrator account
In order to create users with different attributes and permits, we need to create a new admin account besides the root one that comes with slapd by default.
We will refer to the LDAP Administrator account as admin or administrative account, and to the root account simply the one sat by default.
When running any Administrative task that requires the usage of either the admin or root account, like creating an Organizational Unit (ou) or a new user, both accounts will have set the same privileges, meaning both will work, but it is strongly recommended to use the admin or administrative one created here. An easy way to differentiate them it's setting different passwords for each one, as we will see...
Generate a password hash for our administrator user, 1234 here being the password
root@example:/# slappasswd -s 1234 # Change 1234 to your desired password
{SSHA}yxIgYTzcuRRdlesjfWkIN6K97/8jOrZF
Create the .ldif file that will create the admin user, editing the userPassword attribute with our password hash
root@example:/# vim create_admin.ldif
dn: cn=admin,dc=example,dc=com
changetype: add
objectClass: organizationalRole
objectClass: simpleSecurityObject
cn: admin
userPassword: {SSHA}yxIgYTzcuRRdlesjfWkIN6K97/8jOrZF # Replace with the hash of your password
description: LDAP administrator
Execute create_admin.ldif using the root password (which is the default container's: admin)
root@example:/etc/ldap# ldapadd -x -H ldap:/// -D "cn=admin,dc=example,dc=com" -w admin -f create_admin.ldif
adding new entry "cn=admin,dc=example,dc=com"
Check the attributes of our new administrator user of our domain (parentDN)
root@example:/# ldapsearch -x -H ldap:/// -D "cn=admin,dc=example,dc=com" -w 1234 -b "cn=admin,dc=example,dc=com" "(objectclass=*)"
# extended LDIF
#
# LDAPv3
# base <cn=admin,dc=example,dc=com> with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#
# admin, example.com
dn: cn=admin,dc=example,dc=com
objectClass: organizationalRole
objectClass: simpleSecurityObject
cn: admin
userPassword:: e1NTSEF9eXhJZ1lUemN1UlJkbGVzamZXa0lONks5Ny84ak9yWkY=
description: LDAP administrator
...
That's all, our administrator user was properly done.
First administrative tasks
Create our first Organizational Unit (ou) with a new user
Prepare a new LDAP directory (ou) called Supergirls with the following data
root@example:/# vim add_ou.ldif
dn: ou=Supergirls,dc=example,dc=com
objectClass: organizationalUnit
ou: Supergirls
Execute the .ldif file to create it in the LDAP server, and when asked for the root password, remember in the dockerfile by default is admin
root@example:/# ldapadd -x -D "cn=admin,dc=example,dc=com" -W -f add_ou.ldif
Enter LDAP Password:
adding new entry "ou=Supergirls,dc=example,dc=com"
verify the entry in the LDAP server
root@example:/# ldapsearch -x -LLL -b "dc=example,dc=com" "(ou=Supergirls)" dn
dn: ou=Supergirls,dc=example,dc=com
create a new LDAP password to manage our new directory, annotate both the entered plain password and the result hashed password
root@example:/# slappasswd
New password:
Re-enter new password:
{SSHA}hashedpasswd
create a .ldif file with the necessary attributes to insert in our Supergirls directory
root@example:/# vim add_user_supergirls.ldif
dn: uid=marisa,ou=Supergirls,dc=example,dc=com
objectClass: inetOrgPerson
objectClass: posixAccount
cn: Marisa
sn: Kirisame
givenName: Marisa
displayName: Marisa Kirisame
uid: marisa
uidNumber: 1001
gidNumber: 5000
homeDirectory: /home/marisa
loginShell: /bin/bash
userPassword: {SSHA}hashedpasswd
mail: marisa@example.com
insert the new user (marisa) in our Supergirls directory (LDAP OU), still using the root password admin
root@example:/# ldapadd -x -D "cn=admin,dc=example,dc=com" -W -f add_user_supergirls.ldif
Enter LDAP Password:
adding new entry "uid=marisa,ou=Supergirls,dc=example,dc=com"
verify the user (marisa) has been added to the Supergirls OU
root@example:/# ldapsearch -x -LLL -b "dc=example,dc=com" "(uid=marisa)" dn
dn: uid=marisa,ou=Supergirls,dc=example,dc=com
Modify users attributes
create a new .ldif file with the attributes we want to change
in this case we want to modify the mail marisa@example.com of the user (uid) marisa from the group (ou) Supergirls
root@example:/home# vim modify_user.ldif
dn: uid=marisa,ou=Supergirls,dc=example,dc=com
changetype: modify
replace: mail
mail: marisa.kirisame@example.com
run the modify file, when asked for the root password, remember in the dockerfile by default is admin
root@example:/home# ldapmodify -x -D "cn=admin,dc=example,dc=com" -W -f modify_user.ldif
Enter LDAP Password:
modifying entry "uid=marisa,ou=Supergirls,dc=example,dc=com"
verify the mail attribute of the user marisa has been changed to marisa.kirisame@example.com
root@example:/home# ldapsearch -x -LLL -b "dc=example,dc=com" "(uid=marisa)" mail
dn: uid=marisa,ou=Engineering,dc=example,dc=com
mail: marisa.kirisame@example.com
Modify user password
In this examples, we are changing the special attribute password of the user marisa from ou Supergirls, using the old password.
In order to change the password interactively (writing in the prompt when asked), we can run this command:
root@example:/etc/ldap# ldappasswd -H ldap:/// -x -D "uid=marisa,ou=Supergirls,dc=example,dc=com" -W -S "uid=marisa,ou=Supergirls,dc=example,dc=com"
New password: newpasswd
Re-enter new password: newpasswd
Enter LDAP Password: oldpasswd
newpasswd being the new password we want to use, and oldpasswd, the last password we were using for the user uid marisa.
To change the password in an non interactive (sending the password directly via the command), we can run this:
root@example:/etc/ldap# ldappasswd -H ldap:/// -x -D "uid=marisa,ou=Supergirls,dc=example,dc=com" -w newpasswd "uid=marisa,ou=Supergirls,dc=example,dc=com"
New password: 6vUj/2lE
newpasswd being the new password we want to use. We can also notice the hashed output of our new password is not a typical LDAP SSHA hash, this is due to security implementations.
Reset user password
In the likely common event that we forgot the old password of an specific user, we need to reset it.
In this example we forgot the password of the user uid marisa, we can reset it with this command:
root@example:/etc/ldap# ldappasswd -H ldap:/// -x -D "cn=admin,dc=example,dc=com" -W -S "uid=marisa,ou=Supergirls,dc=example,dc=com"
New password: newpasswd
Re-enter new password: newpasswd
Enter LDAP Password: admin
Note we need to use the root password (admin by default) in the last query ("Enter LDAP Password") to reset an user's password.
Query as an specific user
we already created the user (uid) marisa, and established the user's own password using slappasswd
now we are gonna query our LDAP server using the user (uid) marisa credentials, and the password we entered during slappasswd, called plain password (plainpasswd)
root@example:/etc/ldap# ldapsearch -D uid=marisa,ou=Supergirls,dc=example,dc=com -b "dc=example,dc=com" -w plainpasswd
# extended LDIF
#
# LDAPv3
# base <dc=example,dc=com> with scope subtree
# filter: (objectclass=*)
# requesting: ALL
#
# example.com
dn: dc=example,dc=com
objectClass: top
objectClass: dcObject
objectClass: organization
o: nodomain
dc: example
# Supergirls, example.com
dn: ou=Supergirls,dc=example,dc=com
...
we can narrow this search to get only specific attributes of the user marisa, remember we are using the plainpasswd when asked
root@example:/etc/ldap# ldapsearch -D uid=marisa,ou=Supergirls,dc=example,dc=com -b "dc=example,dc=com" -w plainpasswd givenName uidNumber gidNumber homeDirectory
# extended LDIF
#
# LDAPv3
# base <dc=example,dc=com> with scope subtree
# filter: (objectclass=*)
# requesting: givenName uidNumber gidNumber homeDirectory
#
# example.com
dn: dc=example,dc=com
# Supergirls, example.com
dn: ou=Supergirls,dc=example,dc=com
# marisa, Supergirls, example.com
dn: uid=marisa,ou=Supergirls,dc=example,dc=com
givenName: Marisa
uidNumber: 1001
gidNumber: 5000
homeDirectory: /home/marisa
Reset root password
Build line by line, the .ldif file we will need to reset root password, starting with the following command:
root@example:/# ldapsearch -Q -LLL -Y EXTERNAL -H ldapi:/// -b cn=config '(olcSuffix=dc=example,dc=com)' dn > rootpw.ldif
which writes to the rootpw.ldif file, the current rootDN (Distinguised Name): dn: olcDatabase={1}mdb,cn=config
The next command will add the 'changetype' (modify, add, etc.) and what object are we working with:
root@example:/# echo -e 'changetype: modify\nreplace: olcRootPW: ' >> rootpw.ldif
root@example:/etc/ldap# cat rootpw.ldif
dn: olcDatabase={1}mdb,cn=config
changetype: modify
replace: olcRootPW
We run a simple sed command to delete blank lines
root@example:/# sed '/^$/d' rootpw.ldif > chrootpw.ldif
root@example:/# cat chrootpw.ldif
dn: olcDatabase={1}mdb,cn=config
changetype: modify
replace: olcRootPW
It's time to write our new password (newpasswd):
root@example:/# slappasswd -s 1234
{SSHA}2xbd33S4ZumAZW4Oks0GJidBFJYEVBPz
The last line it's our password 1234 hashed in SSHA cryptography. We will need to copy and paste it in the following command:
root@example:/# echo "olcRootPW: {SSHA}2xbd33S4ZumAZW4Oks0GJidBFJYEVBPz" >> chrootpw.ldif
The file that describes the variables needed to change our root password, chrootpw.ldif should be ready, we finally run:
root@example:/etc/ldap# ldapmodify -Q -Y EXTERNAL -H ldapi:/// -f chrootpw.ldif
modifying entry "olcDatabase={1}mdb,cn=config"
If successful, the output will show the modified entry.
Password schemas
Since no policy overlays are loaded in slapd in the container, we need to load our own.
In the next command, notice we are using the -Q and -Y EXTERNAL -H ldapi:///, meaning SASL EXTERNAL authentication over the -x -H ldap:/// socket, which we usually use for binding as the root account. Using -Q -Y EXTERNAL -H ldapi:/// works because it binds as the openldap user and has sufficient permissions for cn=config.
Run the following command to query our loaded modules list
root@example:/# ldapsearch -Q -Y EXTERNAL -H ldapi:/// -D "cn=admin,dc=example,dc=com" -b cn=config "(objectclass=olcModuleList)"
# extended LDIF
#
# LDAPv3
# base <cn=config> with scope subtree
# filter: (objectclass=olcModuleList)
# requesting: ALL
#
# module{0}, config
dn: cn=module{0},cn=config
objectClass: olcModuleList
cn: module{0}
olcModulePath: /usr/lib/ldap
olcModuleLoad: {0}back_mdb
Reading the output in detail, means we are only loading the default backend (olcModuleLoad: {0}back_mdb) that comes by default with LDAP to load basic schemas such as directories (OU) creation.
Run the following command:
root@example:/# ls /usr/lib/ldap/ppolicy*
/usr/lib/ldap/ppolicy-2.5.so.0 /usr/lib/ldap/ppolicy-2.5.so.0.1.14 /usr/lib/ldap/ppolicy.la /usr/lib/ldap/ppolicy.so
Our LDAP server may not come loaded with the policies we need to apply features such as passwords schemas and ACLs (Access Control Lists), but the modules exists inside the container image. We need to make use of schemas, which in large part exists in /usr/lib/ppolicy.so -since the module exists, we are going to create modify_ppolicy_module.ldif to be able to make use of it:
root@example:/# vim modify_ppolicy_module.ldif
dn: cn=module{0},cn=config
changetype: modify
add: olcModuleLoad
olcModuleLoad: ppolicy.so
Run modify_ppolicy_module.ldif
root@example:/# ldapmodify -Q -Y EXTERNAL -H ldapi:/// -f modify_ppolicy_module.ldif
modifying entry "cn=module{0},cn=config"
Now we run the exact same command as before to check if the policy overlay was loaded
root@example:/# ldapsearch -Q -Y EXTERNAL -H ldapi:/// -D "cn=admin,dc=example,dc=com" -b cn=config "(objectclass=olcModuleList)"
# extended LDIF
#
# LDAPv3
# base <cn=config> with scope subtree
# filter: (objectclass=olcModuleList)
# requesting: ALL
#
# module{0}, config
dn: cn=module{0},cn=config
objectClass: olcModuleList
cn: module{0}
olcModulePath: /usr/lib/ldap
olcModuleLoad: {0}back_mdb
olcModuleLoad: {1}ppolicy.so
Notice the addition of olcModuleLoad: {1}ppolicy.so. If we get a different result from the last command, we won't be able to enable the schemas or ACLs we need, and should check that we did input the right commands to reach this point, from the commands to run the container, if we started slapd with the right parameters, to the correct creation of the user administrator.