Cookbook
Here in this cookbook, you’ll find some recipes for various use case of ldap2pg.
If you struggle to find a way to setup ldap2pg for your needs, please file an issue so that we can update Cookbook with new recipes! Your contribution is welcome!
Configure pg_hba.conf
with LDAP¶
ldap2pg does NOT configure PostgreSQL for you. You should carefully read
PostgreSQL LDAP documentation for this point. Having PostgreSQL properly
configured before writing ldap2pg.yaml
is a good start. Here is the steps
to setup PostgreSQL with LDAP in the best order:
- Write the LDAP search and test it with
ldapsearch(1)
. This way, you can also check how you connect to your LDAP directory. - In PostgreSQL cluster, manually create a single role having its password in LDAP directory.
- Edit
pg_hba.conf
following PostgreSQL LDAP documentation until you can effectively login with the single role and the password from LDAP.
Once you have LDAP authentication configured in PostgreSQL cluster, you can move to automate role creation from the LDAP directory using ldap2pg:
- Write a simple
ldap2pg.yaml
with only one LDAP search just to setup ldap2pg connection parameters for PostgreSQL and LDAP connection. ldap2pg always run in dry mode by default, so you can safely loop ldap2pg execution until you get it right. - Then, complete
ldap2pg.yaml
to fit your needs following ldap2pg documentation. Run ldap2pg for real and check that ldap2pg maintain your single test role, and that you can still connect to the cluster with it. - Finally, you must decide when and how you want to trigger synchronization: a regular cron tab ? An ansible task ? Manually ? Other ? Ensure ldap2pg execution is frequent, on purpose and notified.
Configure Postgres Connection¶
The simplest case is to save the connection settings in ldap2pg.yaml
, section
postgres
:
ldap2pg checks for file mode and refuse to read password in world readable files. Ensure it is not world readable by setting a proper file mode:
ldap2pg will warn about Empty synchronization map and ends with Comparison complete. ldap2pg suggests to drop everything. Go on and write the synchronization map to tell ldap2pg the required roles for the cluster.
Search LDAP Directory¶
The first step is to search your LDAP server with ldapsearch(1), the CLI tool from OpenLDAP. Like this:
$ ldapsearch -H ldaps://ldap.ldap2pg.docker -U testsasl -W -b dc=ldap,dc=ldap2pg,dc=docker
Enter LDAP Password:
SASL/DIGEST-MD5 authentication started
SASL username: testsasl
SASL SSF: 128
SASL data security layer installed.
# extended LDIF
#
# LDAPv3
...
# search result
search: 4
result: 0 Success
# numResponses: 16
# numEntries: 15
$
Now save the settings in ldaprc
:
And in environment: LDAPPASSWORD=secret
Next, update your ldapsearch(1) to properly match role entries in LDAP server:
$ ldapsearch -H ldaps://ldap.ldap2pg.docker -U testsasl -W -b cn=dba,ou=groups,dc=ldap,dc=ldap2pg,dc=docker '' member
...
# dba, groups, ldap.ldap2pg.docker
dn: cn=dba,ou=groups,dc=ldap,dc=ldap2pg,dc=docker
member: cn=Alan,ou=people,dc=ldap,dc=ldap2pg,dc=docker
member: cn=albert,ou=people,dc=ldap,dc=ldap2pg,dc=docker
member: cn=ALICE,ou=people,dc=ldap,dc=ldap2pg,dc=docker
# search result
search: 4
result: 0 Success
...
$
Now translate the query in ldap2pg.yaml
and associate a role mapping to
produce roles from each values of each entries returned by the LDAP search:
- ldapsearch:
base: cn=dba,ou=groups,dc=ldap,dc=ldap2pg,dc=docker
role:
name: '{member.cn}'
options: LOGIN SUPERUSER
Test it:
$ ldap2pg
...
Querying LDAP cn=dba,ou=groups,dc=ldap,dc=ldap2pg,dc=docker...
Would create alan.
Would create albert.
Would update options of alice.
...
Comparison complete.
$
Read further on how to control role creation from LDAP entry in
Configuration. Once you’re satisfied with the comparison output, go
real with --real
.
Using LDAP High-Availability¶
ldap2pg supports LDAP HA out of the box just like any openldap client. Use a space separated list of URI to tells all servers.
See [ldap.conf(5)] for further details.
Running as non-superuser¶
Since Postgres provide a CREATEROLE
role option, you can manage roles without
superuser privileges. Security-wise, it’s a good idea to manage roles without
super privileges.
ldap2pg supports this case. However, you must be careful about the limitations.
Let’s call the non-super role creating other roles creator
.
- You can’t manage some roles options like
SUPERUSER
,BYPASSRLS
andREPLICATION
. Thus you wont be able to detect spurious superusers. - Ensure
creator
can revoke all grants of managed users. creator
should own database and other objects if you wantcreator
to grant privileges on this. This includepublic
schema.- Granting
CREATE
on schema requires to grant write access topg_catalog
. That’s tricky to give such privileges tocreator
.
Revoking privileges¶
There is no explicit revoke in ldap2pg. ldap2pg inspects SQL grants, ldap2pg.yml tells what privileges should be granted. Every unexpected grant is revoked. This is called implicit revoke.
ldap2pg don’t require any YAML grant
to trigger inspection of Postgres for SQL
GRANT
, and thus revoke. You just declare a privilege with an inspect
query.
Of course, you’ll need a revoke
query too.
The following YAML is enough to revoke CONNECT ON DATABASE
from public
role:
privileges:
mypriv:
type: datacl
inspect: |
SELECT NULL, 'public';
revoke: |
REVOKE CONNECT ON DATABASE {database} FROM {role};
The bug here, is that inspect does not truly inspect Postgres and always
returns the same result. ldap2pg will always execute the revoke query, thinking
mypriv
is granted to public
, whatever the actual state of the cluster. It’s
up to you to dig in pg_catalog.pg_database.datacl
to find SQL GRANT.
Inherit Unmanaged Role¶
You may want to grand a local role, not managed by ldap2pg, to managed users. This is tricky because ldap2pg can’t manage members of a role without managing its own privileges and other options. The solution is to isolate managed membership in a preexisting sub-role.
Say you have a local_readers
roles with custom privileges and custom members.
You want ldap2pg to add member of this role from directory.
Prior to running ldap2pg, create a local_readers_managed_members
role, member of local_readers
:
=# CREATE ROLE local_readers;
=# CREATE ROLE local_readers_managed_members;
=# GRANT local_readers TO local_readers_managed_members;
Now, in ldap2pg.yml
, declare local_readers_managed_members
and add members:
Ensure that local_readers
is not returned by managed_roles_query
to prevent any modifications by ldap2pg.
Now run ldap2pg as usual.
You’ll see the message add missing local_readers_managed_members members.
That’s it, ldap2pg will never touch local_readers
privileges or direct members, but managed roles can inherit from it.
Removing All Roles¶
If ever you want to clean all roles in a PostgreSQL cluster, ldap2pg could be
helpful. You must explicitly define an empty sync_map
.
$ echo 'sync_map: []' | ldap2pg --config - --real
...
Empty synchronization map. All roles will be dropped!
...
In this example, default blacklist applies. ldap2pg never drop its connect role.
ldap2pg as Docker container¶
Already familiar with Docker and willing to save the setup time? You’re at the right place.
To run the container simply use the command:
The Docker image of ldap2pg use the same configuration options as explained in the cli and ldap2pg.yml sections. You can mount the ldap2pg.yml configuration file.
You can also export some environmnent variables with the -e option:
$ docker run --rm -v ${PWD}/ldap2pg.yml:/workspace/ldap2pg.yml -e PGDSN=postgres://postgres@localhost:5432/ -e LDAPURI=ldaps://localhost -e LDAPBINDDN=cn=you,dc=entreprise,dc=fr -e LDAPPASSWORD=pasglop dalibo/ldap2pg
Make sure your container can resolve the hostname your pointing to. If you use some internal name resolution be sure to add the –dns= option to your command pointing to your internal DNS server. More info