mongoldap

Synopsis

MongoDB Enterprise provides mongoldap for testing MongoDB's LDAP configuration options against a running LDAP server or set of servers.

To validate the LDAP options in the configuration file, set the mongoldap --config option to the configuration file's path.

To test the LDAP configuration options, you must specify a --user and --password. mongoldap simulates authentication to a MongoDB server running with the provided configuration options and credentials.

mongoldap returns a report that includes the success or failure of any step in the LDAP authentication or authorization procedure. Error messages include information on specific errors encountered and potential advice for resolving the error.

When configuring options related to LDAP authorization, mongoldap executes an LDAP query constructed using the provided configuration options and username, and returns a list of roles on the admin database which the user is authorized for.

You can use this information when configuring LDAP authorization roles for user access control. For example, use mongoldap to ensure your configuration allows privileged users to gain the necessary roles to perform their expected tasks. Similarly, use mongoldap to ensure your configuration disallows non-privileged users from gaining roles for accessing the MongoDB server, or performing unauthorized actions.

When configuring options related to LDAP authentication, use mongoldap to ensure that the authentication operation works as expected.

Run mongoldap from the system command line, not in the mongosh.

This document provides a complete overview of all command line options for mongoldap.

Installation

The mongoldap tool is part of the MongoDB Database Tools Extra package, and can be installed with the MongoDB Server or as a standalone installation.

Usage

Consider the following sample configuration file, designed to support LDAP authentication and authorization via Active Directory:

security:
   authorization: "enabled"
   ldap:
      servers: "activedirectory.example.net"
      bind:
         queryUser: "mongodbadmin@dba.example.com"
         queryPassword: "secret123"
      userToDNMapping:
         '[
            {
               match : "(.+)",
               ldapQuery: "DC=example,DC=com??sub?(userPrincipalName={0})"
            }
         ]'
      authz:
         queryTemplate: "DC=example,DC=com??sub?(&(objectClass=group)(member:1.2.840.113556.1.4.1941:={USER}))"
setParameter:
   authenticationMechanisms: "PLAIN"

You can use mongoldap to validate the configuration file, which returns a report of the procedure. You must specify a username and password for mongoldap.

mongoldap --config=<path-to-config> --user="bob@dba.example.com" --password="secret123"

If the provided credentials are valid, and the LDAP options in the configuration files are valid, the output might be as follows:

Checking that an LDAP server has been specified...
[OK] LDAP server found
Connecting to LDAP server...
[OK] Connected to LDAP server
Parsing MongoDB to LDAP DN mappings..
[OK] MongoDB to LDAP DN mappings appear to be valid
Attempting to authenticate against the LDAP server...
[OK] Successful authentication performed
Checking if LDAP authorization has been enabled by configuration...
[OK] LDAP authorization enabled
Parsing LDAP query template..
[OK] LDAP query configuration template appears valid
Executing query against LDAP server...
[OK] Successfully acquired the following roles:
...

Behavior

Starting in MonogoDB 5.1, mongoldap supports prefixing LDAP server with srv: and srv_raw:.

If your connection string specifies "srv:<DNS_NAME>", mongoldap verifies that "_ldap._tcp.gc._msdcs.<DNS_NAME>" exists for SRV to support Active Directory. If not found, it verifies "_ldap._tcp.<DNS_NAME>" exists for SRV. If an SRV record cannot be found, mongoldap warns you to use "srv_raw:<DNS_NAME>" instead. mongoldap does the reverse check for "srv_raw:<DNS_NAME>" by checking for "_ldap._tcp.<DNS NAME>".

Options

--config=<filename>, -f=<filename>

Specifies a configuration file for runtime configuration options. The options are equivalent to the command-line configuration options. See Configuration File Options for more information.

mongoldap uses any configuration options related to LDAP Proxy Authentication or LDAP Authorization for testing LDAP authentication or authorization.

Requires specifying --user. May accept --password for testing LDAP authentication.

Ensure the configuration file uses ASCII encoding. The mongoldap instance does not support configuration files with non-ASCII encoding, including UTF-8.

--user=<string>

Username for mongoldap to use when attempting LDAP authentication or authorization.

--password=<string>

Password of the --user for mongoldap to use when attempting LDAP authentication. Not required for LDAP authorization.

--ldapServers=<host1>:<port>,<host2>:<port>,...,<hostN>:<port>

The LDAP server against which the mongoldap authenticates users or determines what actions a user is authorized to perform on a given database. If the LDAP server specified has any replicated instances, you may specify the host and port of each replicated server in a comma-delimited list.

If your LDAP infrastructure partitions the LDAP directory over multiple LDAP servers, specify one LDAP server or any of its replicated instances to --ldapServers. MongoDB supports following LDAP referrals as defined in RFC 4511 4.1.10. Do not use --ldapServers for listing every LDAP server in your infrastructure.

If unset, mongoldap cannot use LDAP authentication or authorization.

--ldapQueryUser=<string>

Available in MongoDB Enterprise only.

The identity with which mongoldap binds as, when connecting to or performing queries on an LDAP server.

Only required if any of the following are true:

• Using LDAP authorization.

• Using an LDAP query for username transformation.

• The LDAP server disallows anonymous binds

You must use --ldapQueryUser with --ldapQueryPassword.

If unset, mongoldap will not attempt to bind to the LDAP server.

Note

Windows MongoDB deployments can use --ldapBindWithOSDefaults instead of --ldapQueryUser and --ldapQueryPassword. You cannot specify both --ldapQueryUser and --ldapBindWithOSDefaults at the same time.

--ldapQueryPassword=<string | array>

Available in MongoDB Enterprise only.

The password used to bind to an LDAP server when using --ldapQueryUser. You must use --ldapQueryPassword with --ldapQueryUser.

If not set, mongoldap does not attempt to bind to the LDAP server.

You can configure this setting on a running mongoldap using setParameter.

Starting in MongoDB 4.4, the ldapQueryPassword setParameter command accepts either a string or an array of strings. If ldapQueryPassword is set to an array, MongoDB tries each password in order until one succeeds. Use a password array to roll over the LDAP account password without downtime.

--ldapBindWithOSDefaults=<bool>

Default: false

Available in MongoDB Enterprise for the Windows platform only.

Allows mongoldap to authenticate, or bind, using your Windows login credentials when connecting to the LDAP server.

Only required if:

• Using LDAP authorization.

• Using an LDAP query for username transformation.

• The LDAP server disallows anonymous binds

Use --ldapBindWithOSDefaults to replace --ldapQueryUser and --ldapQueryPassword.

--ldapBindMethod=<string>

Default: simple

Available in MongoDB Enterprise only.

The method mongoldap uses to authenticate to an LDAP server. Use with --ldapQueryUser and --ldapQueryPassword to connect to the LDAP server.

--ldapBindMethod supports the following values:

Value	Description
simple	mongoldap uses simple authentication.
sasl	mongoldap uses SASL protocol for authentication.

If you specify sasl, you can configure the available SASL mechanisms using --ldapBindSaslMechanisms. mongoldap defaults to using DIGEST-MD5 mechanism.

--ldapBindSaslMechanisms=<string>

Default: DIGEST-MD5

Available in MongoDB Enterprise only.

A comma-separated list of SASL mechanisms mongoldap can use when authenticating to the LDAP server. The mongoldap and the LDAP server must agree on at least one mechanism. The mongoldap dynamically loads any SASL mechanism libraries installed on the host machine at runtime.

Install and configure the appropriate libraries for the selected SASL mechanism(s) on both the mongoldap host and the remote LDAP server host. Your operating system may include certain SASL libraries by default. Defer to the documentation associated with each SASL mechanism for guidance on installation and configuration.

If using the GSSAPI SASL mechanism for use with Kerberos Authentication, verify the following for the mongoldap host machine:

Linux

• The KRB5_CLIENT_KTNAME environment variable resolves to the name of the client Linux Keytab Files for the host machine. For more on Kerberos environment variables, please defer to the Kerberos documentation.

• The client keytab includes a User Principal for the mongoldap to use when connecting to the LDAP server and execute LDAP queries.

Windows

If connecting to an Active Directory server, the Windows Kerberos configuration automatically generates a Ticket-Granting-Ticket when the user logs onto the system. Set --ldapBindWithOSDefaults to true to allow mongoldap to use the generated credentials when connecting to the Active Directory server and execute queries.

Set --ldapBindMethod to sasl to use this option.

Note

For a complete list of SASL mechanisms see the IANA listing. Defer to the documentation for your LDAP or Active Directory service for identifying the SASL mechanisms compatible with the service.

MongoDB is not a source of SASL mechanism libraries, nor is the MongoDB documentation a definitive source for installing or configuring any given SASL mechanism. For documentation and support, defer to the SASL mechanism library vendor or owner.

For more information on SASL, defer to the following resources:

• For Linux, please see the Cyrus SASL documentation.

• For Windows, please see the Windows SASL documentation.

--ldapTransportSecurity=<string>

Default: tls

Available in MongoDB Enterprise only.

By default, mongoldap creates a TLS/SSL secured connection to the LDAP server.

For Linux deployments, you must configure the appropriate TLS Options in /etc/openldap/ldap.conf file. Your operating system's package manager creates this file as part of the MongoDB Enterprise installation, via the libldap dependency. See the documentation for TLS Options in the ldap.conf OpenLDAP documentation for more complete instructions.

For Windows deployment, you must add the LDAP server CA certificates to the Windows certificate management tool. The exact name and functionality of the tool may vary depending on operating system version. Please see the documentation for your version of Windows for more information on certificate management.

Set --ldapTransportSecurity to none to disable TLS/SSL between mongoldap and the LDAP server.

Warning

Setting --ldapTransportSecurity to none transmits plaintext information and possibly credentials between mongoldap and the LDAP server.

--ldapTimeoutMS=<long>

Default: 10000

Available in MongoDB Enterprise only.

The amount of time in milliseconds mongoldap should wait for an LDAP server to respond to a request.

Increasing the value of --ldapTimeoutMS may prevent connection failure between the MongoDB server and the LDAP server, if the source of the failure is a connection timeout. Decreasing the value of --ldapTimeoutMS reduces the time MongoDB waits for a response from the LDAP server.

--ldapUserToDNMapping=<string>

Available in MongoDB Enterprise only.

Maps the username provided to mongoldap for authentication to a LDAP Distinguished Name (DN). You may need to use --ldapUserToDNMapping to transform a username into an LDAP DN in the following scenarios:

• Performing LDAP authentication with simple LDAP binding, where users authenticate to MongoDB with usernames that are not full LDAP DNs.

• Using an LDAP authorization query template that requires a DN.

• Transforming the usernames of clients authenticating to Mongo DB using different authentication mechanisms (e.g. x.509, kerberos) to a full LDAP DN for authorization.

--ldapUserToDNMapping expects a quote-enclosed JSON-string representing an ordered array of documents. Each document contains a regular expression match and either a substitution or ldapQuery template used for transforming the incoming username.

Each document in the array has the following form:

{
  match: "<regex>"
  substitution: "<LDAP DN>" | ldapQuery: "<LDAP Query>"
}

Field	Description	Example
match	An ECMAScript-formatted regular expression (regex) to match against a provided username. Each parenthesis-enclosed section represents a regex capture group used by substitution or ldapQuery.	"(.+)ENGINEERING" "(.+)DBA"
substitution	An LDAP distinguished name (DN) formatting template that converts the authentication name matched by the match regex into a LDAP DN. Each curly bracket-enclosed numeric value is replaced by the corresponding regex capture group extracted from the authentication username via the match regex. The result of the substitution must be an RFC4514 escaped string.	"cn={0},ou=engineering, dc=example,dc=com"
ldapQuery	A LDAP query formatting template that inserts the authentication name matched by the match regex into an LDAP query URI encoded respecting RFC4515 and RFC4516. Each curly bracket-enclosed numeric value is replaced by the corresponding regex capture group extracted from the authentication username via the match expression. mongoldap executes the query against the LDAP server to retrieve the LDAP DN for the authenticated user. mongoldap requires exactly one returned result for the transformation to be successful, or mongoldap skips this transformation.	"ou=engineering,dc=example, dc=com??one?(user={0})"

Note

An explanation of RFC4514, RFC4515, RFC4516, or LDAP queries is out of scope for the MongoDB Documentation. Please review the RFC directly or use your preferred LDAP resource.

For each document in the array, you must use either substitution or ldapQuery. You cannot specify both in the same document.

When performing authentication or authorization, mongoldap steps through each document in the array in the given order, checking the authentication username against the match filter. If a match is found, mongoldap applies the transformation and uses the output for authenticating the user. mongoldap does not check the remaining documents in the array.

If the given document does not match the provided authentication name, mongoldap continues through the list of documents to find additional matches. If no matches are found in any document, or the transformation the document describes fails, mongoldap returns an error.

Starting in MongoDB 4.4, mongoldap also returns an error if one of the transformations cannot be evaluated due to networking or authentication failures to the LDAP server. mongoldap rejects the connection request and does not check the remaining documents in the array.

Starting in MongoDB 5.0, --ldapUserToDNMapping accepts an empty string "" or empty array [ ] in place of a mapping documnent. If providing an empty string or empty array to --ldapUserToDNMapping, MongoDB will map the authenticated username as the LDAP DN. Previously, providing an empty mapping document would cause mapping to fail.

Example

The following shows two transformation documents. The first document matches against any string ending in @ENGINEERING, placing anything preceeding the suffix into a regex capture group. The second document matches against any string ending in @DBA, placing anything preceeding the suffix into a regex capture group.

Important

You must pass the array to --ldapUserToDNMapping as a string.

"[
   {
      match: "(.+)@ENGINEERING.EXAMPLE.COM",
      substitution: "cn={0},ou=engineering,dc=example,dc=com"
   },
   {
      match: "(.+)@DBA.EXAMPLE.COM",
      ldapQuery: "ou=dba,dc=example,dc=com??one?(user={0})"
   }
]"

A user with username alice@ENGINEERING.EXAMPLE.COM matches the first document. The regex capture group {0} corresponds to the string alice. The resulting output is the DN "cn=alice,ou=engineering,dc=example,dc=com".

A user with username bob@DBA.EXAMPLE.COM matches the second document. The regex capture group {0} corresponds to the string bob. The resulting output is the LDAP query "ou=dba,dc=example,dc=com??one?(user=bob)". mongoldap executes this query against the LDAP server, returning the result "cn=bob,ou=dba,dc=example,dc=com".

If --ldapUserToDNMapping is unset, mongoldap applies no transformations to the username when attempting to authenticate or authorize a user against the LDAP server.

--ldapAuthzQueryTemplate=<string>

Available in MongoDB Enterprise only.

A relative LDAP query URL formatted conforming to RFC4515 and RFC4516 that mongoldap executes to obtain the LDAP groups to which the authenticated user belongs to. The query is relative to the host or hosts specified in --ldapServers.

In the URL, you can use the following substituion tokens:

Substitution Token	Description
{USER}	Substitutes the authenticated username, or the transformed username if a username mapping is specified.
{PROVIDED_USER}	Substitutes the supplied username, i.e. before either authentication or LDAP transformation. New in version 4.2.

When constructing the query URL, ensure that the order of LDAP parameters respects RFC4516:

[ dn  [ ? [attributes] [ ? [scope] [ ? [filter] [ ? [Extensions] ] ] ] ] ]

If your query includes an attribute, mongoldap assumes that the query retrieves a the DNs which this entity is member of.

If your query does not include an attribute, mongoldap assumes the query retrieves all entities which the user is member of.

For each LDAP DN returned by the query, mongoldap assigns the authorized user a corresponding role on the admin database. If a role on the on the admin database exactly matches the DN, mongoldap grants the user the roles and privileges assigned to that role. See the db.createRole() method for more information on creating roles.

Example

This LDAP query returns any groups listed in the LDAP user object's memberOf attribute.

"{USER}?memberOf?base"

Your LDAP configuration may not include the memberOf attribute as part of the user schema, may possess a different attribute for reporting group membership, or may not track group membership through attributes. Configure your query with respect to your own unique LDAP configuration.

If unset, mongoldap cannot authorize users using LDAP.

Note

An explanation of RFC4515, RFC4516 or LDAP queries is out of scope for the MongoDB Documentation. Please review the RFC directly or use your preferred LDAP resource.