Configure saslauthd

saslauthd is a daemon process that handles plaintext authentication requests on behalf of the SASL library.

In LDAP authentication, the saslauthd process handles authentication requests on behalf of Couchbase Server while the LDAP protocol is used to connect to the LDAP server.

Note that remote authentication with the LDAP server requires proper configuration of the saslauthd agent, which must be installed and configured on each Couchbase Server node.

Supported Packages

Install your Unix operating system with the saslauthd package that is supported for LDAP integration.

Make sure that you have the prerequisites for the LDAP software you are installing, such as OpenLDAP libraries. On RPM-based distros, installation packages are a part of cyrus-sasl rpm, so make sure that it is installed.

CentOS 6: saslauthd 2.1.23 or higher
CentOS 7: saslauthd 2.1.26 or higher
Ubuntu: saslauthd 2.1.25 or higher
SUSE: saslauthd 2.1.23 or higher

Preparation

Make sure your LDAP setup is working, by running a test ldapsearch as follows:

ldapsearch -LLL -H ldap://ldapserver:389 -D cn=someuser,ou=users,dc=mydomain,dc=com -w Passw0rd -x -bou=users,dc=mydomain,dc=com cn=someuser

Install `saslauthd`

Install the saslauthd package on your operating system. On Ubuntu, install saslauthd with the following command:

sudo apt-get install sasl2-bin

Determine mux File Location

To communicate with the LDAP server, Couchbase Server makes use of the mux file provided by the saslauthd package. The location of the mux file varies, according to distribution. Couchbase Server checks for the file at two locations, which are /var/run/sasl2/mux and /var/run/saslauthd/mux.

Debian/Ubuntu: By default, the file is located at /var/run/sasl2/mux.
RHEL/CentOS 6: By default, the file is located at at /var/run/saslauthd/mux.
RHEL/CentOS 7: By default, the file is located at /run/saslauthd/mux; but a symlink from /var/run to /run/ allows Couchbase Server to access the file at /var/run/saslauthd/mux.

If, on your system, the location of the mux file is neither /var/run/sasl2/mux nor /var/run/saslauthd/mux, set the CBAUTH_SOCKPATH environment variable to the mux file’s actual location. Couchbase Server will attempt to access the mux file there.

Getting Started with saslauthd and LDAP

Ensure that the Couchbase Cluster is running. Then, enable external authentication on the cluster, using the Couchbase CLI setting-ldap command: specifying server IP-address and port number, username and password:
```
 $ couchbase-cli setting-ldap -c 10.142.170.101:8091 -u Administrator -p passw0rd --ldap-enabled 1
```
Note that --ldap-enabled 1 enables external authentication, and --ldap-enabled 0 disables. See cli:cbcli/couchbase-cli-setting-ldap.adoc for further information. When successfully executed, the command provides the following notification: SUCCESS: LDAP settings modified.
Configure the MECHANISMS option for ldap.

Red Hat Enterprise Linux, CentOS, and Amazon Linux AMI edit /etc/sysconfig/saslauthd (/etc/default/saslauthd on Debian/Ubuntu) to set the mechanism MECH to ldap:
```
MECH=ldap
```
Ubuntu and Debian edit /etc/default/saslauthd, setting MECHANISMS option to ldap:
```
MECHANISMS=ldap
```
On Debian and Ubuntu, you should also add Couchbase to the sasl group:
```
sudo adduser couchbase sasl
```
The default configuration file used to obtain the LDAP configuration parameters is located at /usr/local/etc/saslauthd.conf. Open this in your editor of choice.
Set up ldap_servers

Specify URIs of the LDAP servers used for authentication, such as ldap:///10.1.1.11/, ldap://10.1.1.12/. Multiple LDAP servers can be specified in the list, which is then tested to find out whether one of the servers is offline. If you install OpenLDAP on the local host machine, you can specify the value ldap://localhost:389.

If using LDAP over SSL, you can specify the value ldaps://localhost:636.
```
ldap_servers: ldaps://10.1.1.25 ldaps://10.1.1.15
```
Set up ldap_search_base

Specify the distinguished name to which the search is relative. The search includes the base or objects below.

It also includes Domain Components (dc) such as in dc=company and dc=com.

The administrative users created in LDAP with the attribute uid are placed under the user’s organizational unit ou under the two domain components (example and com).
```
ldap_search_base: ou=Users,dc=company,dc=com
```
Set up ldap_filter

Specify the search filter. The values for these configuration options correspond to the values specific to the test. For example, to filter on email specify ldap_filter: (mail=%n).
```
ldap_filter: (uid=%u)
```
Configure LDAP options /etc/saslauthd.conf:
```
ldap_servers: ldaps://ad.example.net
ldap_search_base: ou=Users,dc=example,dc=com
ldap_filter: (uid=%u)
```
Running automatically

For sasld to run automatically on start up, you’ll need to change the START value to YES.
```
START = yes
```

Test yoursaslauthdset-up.

If the connection is properly working, the user couchbase must have access to /var/run/saslauthd/mux (or the appropriate alternate directory for SUSE), in order to communicate to saslauthd.

Start the saslauthd service (or set it to start automatically with chkconfig).

service saslauthd restart
Stopping saslauthd:                             [  OK  ]
Starting saslauthd:                             [  OK  ]

chkconfig  saslauthd on
chkconfig --list saslauthd
saslauthd   	0:off   1:off   2:on	3:on	4:on	5:on	6:off

Test saslauthd by using the testsaslauth script to test LDAP authentication:

sudo -u couchbase /usr/sbin/testsaslauthd -u <username> \
-p mypassword -f /var/run/saslauthd/mux
0: OK "Success."

Restart the Couchbase service, to allow authentication through the changed configuration.
```
$ sudo service couchbase-server restart
```

Example

Putting the above steps into typical configuration files:

cat /etc/saslauthd.conf
# ldap_servers: ldap:<URI>:<PORT> or ldaps:<URI>:<PORT> for TLS protected connection
ldap_servers: ldap://my.company.com:389
# The administrative users created in LDAP with the attribute uid are placed under the user's
# organizational unit ou under the two domain components (example and com).
OU=InteractiveUsers,DC=my,DC=company,DC=com
# Specifies the search filter. The values for these configuration options correspond to the
# values specific to the test
ldap_filter: uid=%u
# Optional: specify a user to perform ldap queries
ldap_bind_dn: CN=user_ldap,OU=Users,DC=my,DC=company,DC=com
# Optional: specify ldap user’s password
ldap_password: -sEcReTp#AssWoRd!

cat /etc/sysconfig/saslauthd
# Just keep the default
SOCKETDIR=/var/run/saslauthd
# Make sure MECH is set to ldap (pam is default)
MECH=ldap
# Include the config file described above
FLAGS="-O /etc/saslauthd.conf"

Configuring `saslauthd` with Windows Active Directory

A common requirement is to delegate some or all authentication to another LDAP server. Here is a sample saslauthd configuration that uses Microsoft Active Directory (AD) as the LDAP server:

Here is a sample saslauthd configuration with Microsoft Active Directory (AD):

ldap_servers: ldap://dc1.example.com:<port>
ldap_search_base: cn=Users,DC=ad,DC=example,DC=com
ldap_filter: sAMAccountName=%u
ldap_bind_dn: cn=saslauthd,cn=Users,DC=ad,DC=example,DC=com
ldap_password: secret

Troubleshooting LDAP Settings

After you set up the LDAP server, saslauthd, and LDAP administrators, likely causes of problems include:

Firewall ports are not open for LDAP.
The Proxy did not start or has started with an inappropriate protocol or hostname.
The configuration of saslauthd is incorrect (look at /etc/sysconfig/saslauthd or /etc/saslauthd.conf)
The LDAP filters are not correct.
You can also encounter error messages from the system. These errors belong either to issues caused by saslauthd or the LDAP server.