feat(authentication): ldap memberof

Signed-off-by: James Elliott <james-d-elliott@users.noreply.github.com>

config.template.yml

@@ -317,7 +317,7 @@ authentication_backend:
   ## because it allows Authelia to offload the stateful operations
   ## onto the LDAP service.
   # ldap:
-    ## The address of the LDAP server to connect to in the address common syntax.
+    ## The address of the directory server to connect to in the address common syntax.
     ## Format: [<scheme>://]<hostname>[:<port>].
     ## Square brackets indicate optional portions of the format. Scheme must be 'ldap', 'ldaps', or 'ldapi`.
     ## The default scheme is 'ldapi' if the address is an absolute path otherwise it's 'ldaps'.
@@ -403,16 +403,6 @@ authentication_backend:
     ## See also: additional_users_dn, additional_groups_dn.
     # base_dn: 'dc=example,dc=com'
 
-    ## The attribute holding the username of the user. This attribute is used to populate the username in the session
-    ## information. For your information, Microsoft Active Directory usually uses 'sAMAccountName' and OpenLDAP usually
-    ## uses 'uid'. Beware that this attribute holds the unique identifiers for the users binding the user and the
-    ## configuration stored in database. Therefore only single value attributes are allowed and the value must never be
-    ## changed once attributed to a user otherwise it would break the configuration for that user. Technically,
-    ## non-unique attributes like 'mail' can also be used but we don't recommend using them, we instead advise to use
-    ## a filter to perform alternative lookups and the attributes mentioned above (sAMAccountName and uid) to
-    ## follow https://datatracker.ietf.org/doc/html/rfc2307.
-    # username_attribute: 'uid'
-
     ## The additional_users_dn is prefixed to base_dn and delimited by a comma when searching for users.
     ## i.e. with this set to OU=Users and base_dn set to DC=a,DC=com; OU=Users,DC=a,DC=com is searched for users.
     # additional_users_dn: 'ou=users'
@@ -443,15 +433,9 @@ authentication_backend:
     ##    (&(uniqueMember={dn})(objectClass=groupOfUniqueNames))
     # groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
 
-    ## The attribute holding the name of the group.
-    # group_name_attribute: 'cn'
-
-    ## The attribute holding the mail address of the user. If multiple email addresses are defined for a user, only the
-    ## first one returned by the LDAP server is used.
-    # mail_attribute: 'mail'
-
-    ## The attribute holding the display name of the user. This will be used to greet an authenticated user.
-    # display_name_attribute: 'displayName'
+    ## The group search mode to use. Options are 'filter' or 'memberof'. It's essential to read the docs if you wish to
+    ## use 'memberof'. Also 'filter' is the best choice for most use cases.
+    # group_search_mode: 'filter'
 
     ## Follow referrals returned by the server.
     ## This is especially useful for environments where read-only servers exist. Only implemented for write operations.
@@ -462,6 +446,37 @@ authentication_backend:
     ## Password can also be set using a secret: https://www.authelia.com/c/secrets
     # password: 'password'
 
+    ## The attributes for users and objects from the directory server.
+    # attributes:
+
+      ## The distinguished name attribute if your directory server supports it. Users should read the docs before
+      ## configuring. Only used for the 'memberof' group search mode.
+      # distinguished_name: ''
+
+      ## The attribute holding the username of the user. This attribute is used to populate the username in the session
+      ## information. For your information, Microsoft Active Directory usually uses 'sAMAccountName' and OpenLDAP
+      ## usually uses 'uid'. Beware that this attribute holds the unique identifiers for the users binding the user and
+      ## the configuration stored in database; therefore only single value attributes are allowed and the value must
+      ## never be changed once attributed to a user otherwise it would break the configuration for that user.
+      ## Technically non-unique attributes like 'mail' can also be used but we don't recommend using them, we instead
+      ## advise to use a filter to perform alternative lookups and the attributes mentioned above
+      ## (sAMAccountName and uid) to follow https://datatracker.ietf.org/doc/html/rfc2307.
+      # username: 'uid'
+
+      ## The attribute holding the display name of the user. This will be used to greet an authenticated user.
+      # display_name: 'displayName'
+
+      ## The attribute holding the mail address of the user. If multiple email addresses are defined for a user, only
+      ## the first one returned by the directory server is used.
+      # mail: 'mail'
+
+      ## The attribute which provides distinguished names of groups an object is a member of.
+      ## Only used for the 'memberof' group search mode.
+      # member_of: 'memberOf'
+
+      ## The attribute holding the name of the group.
+      # group_name: 'cn'
+
   ##
   ## File (Authentication Provider)
   ##

docs/content/en/configuration/first-factor/ldap.md

@@ -101,16 +101,20 @@ authentication_backend:
     base_dn: 'DC=example,DC=com'
     additional_users_dn: 'OU=users'
     users_filter: '(&({username_attribute}={input})(objectClass=person))'
-    username_attribute: 'uid'
-    mail_attribute: 'mail'
-    display_name_attribute: 'displayName'
     additional_groups_dn: 'OU=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
+    group_search_mode: 'filter'
     permit_referrals: false
     permit_unauthenticated_bind: false
     user: 'CN=admin,DC=example,DC=com'
     password: 'password'
+    attributes:
+      distinguished_name: 'distinguishedName'
+      username: 'uid'
+      display_name: 'displayName'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 ```
 
 ## Options
@@ -209,66 +213,33 @@ The LDAP filter to narrow down which users are valid. This is important to set c
 The default value is dependent on the [implementation](#implementation), refer to the
 [attribute defaults](../../reference/guides/ldap.md#attribute-defaults) for more information.
 
-### username_attribute
-
-{{< confkey type="string" required="situational" >}}
-
-*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
-default negating this requirement. Refer to the [attribute defaults](../../reference/guides/ldap.md#attribute-defaults)
-for more information.*
-
-The LDAP attribute that maps to the username in *Authelia*. This must contain the `{username_attribute}`
-[placeholder](../../reference/guides/ldap.md#users-filter-replacements).
-
-### mail_attribute
-
-{{< confkey type="string" required="situational" >}}
-
-*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
-default negating this requirement. Refer to the [attribute defaults](../../reference/guides/ldap.md#attribute-defaults)
-for more information.*
-
-The attribute to retrieve which contains the users email addresses. This is important for the device registration and
-password reset processes. The user must have an email address in order for Authelia to perform identity verification
-when a user attempts to reset their password or register a second factor device.
-
-### display_name_attribute
-
-{{< confkey type="string" required="situational" >}}
-
-*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
-default negating this requirement. Refer to the [attribute defaults](#attribute-defaults) for more information.*
-
-The attribute to retrieve which is shown on the Web UI to the user when they log in.
-
 ### additional_groups_dn
 
 {{< confkey type="string" required="no" >}}
 
-Similar to [additional_users_dn](#additional_users_dn) but it applies to group searches.
+Similar to [additional_users_dn](#additionalusersdn) but it applies to group searches.
 
 ### groups_filter
 
 {{< confkey type="string" required="situational" >}}
 
 *__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
-default negating this requirement. Refer to the [filter defaults](#filter-defaults) for more information.*
+default negating this requirement. Refer to the [filter defaults](../../reference/guides/ldap.md#filter-defaults) for
+more information.*
 
-Similar to [users_filter](#users_filter) but it applies to group searches. In order to include groups the member is not
+Similar to [users_filter](#usersfilter) but it applies to group searches. In order to include groups the member is not
 a direct member of, but is a member of another group that is a member of those (i.e. recursive groups), you may try
 using the following filter which is currently only tested against Microsoft Active Directory:
 
 `(&(member:1.2.840.113556.1.4.1941:={dn})(objectClass=group)(objectCategory=group))`
 
-### group_name_attribute
+### group_search_mode
 
-{{< confkey type="string" required="situational" >}}
+{{< confkey type="string" default="filter" required="no" >}}
 
-*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
-default negating this requirement. Refer to the [attribute defaults](#attribute-defaults) for more
-information.*
-
-The LDAP attribute that is used by Authelia to determine the group name.
+The group search mode controls how user groups are discovered. The default of `filter` directly uses the filter to
+determine the result. The `memberof` experimental mode does another special filtered search. See the
+[Reference Documentation](../../reference/guides/ldap.md#group-search-modes) for more information.
 
 ### permit_referrals
 
@@ -313,6 +284,71 @@ It's __strongly recommended__ this is a
 [Random Alphanumeric String](../../reference/guides/generating-secure-values.md#generating-a-random-alphanumeric-string) with 64 or more
 characters and the user password is changed to this value.
 
+### attributes
+
+The following options configure The directory server attribute mappings.
+
+#### distinguished_name
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically not required however it is required when using the group search mode
+`memberof` replacement `{memberof:dn}`.*
+
+The directory server attribute which contains the distinguished name, primarily used to perform filtered searches. There
+is a clear distinction between the actual distinguished name and a distinguished name attribute, all directories have
+distinguished names for objects, but not all have an attribute representing this that can be searched on.
+
+The only known support at this time is with Active Directory.
+
+#### username
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
+default negating this requirement. Refer to the [attribute defaults] for more information.*
+
+The directory server attribute that maps to the username in *Authelia*. This must contain the `{username_attribute}` [placeholder].
+
+#### display_name
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
+default negating this requirement. Refer to the [attribute defaults] for more information.*
+
+The directory server attribute to retrieve which is shown on the Web UI to the user when they log in.
+
+#### mail
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
+default negating this requirement. Refer to the [attribute defaults] for more information.*
+
+The directory server attribute to retrieve which contains the users email addresses. This is important for the device
+registration and password reset processes. The user must have an email address in order for Authelia to perform
+identity verification when a user attempts to reset their password or register a second factor device.
+
+#### member_of
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
+default negating this requirement. Refer to the [attribute defaults] for more information.*
+
+The directory server attribute which contains the groups a user is a member of. This is currently only used for the
+`memberof` group search mode.
+
+#### group_name
+
+{{< confkey type="string" required="situational" >}}
+
+*__Note:__ This option is technically required however the [implementation](#implementation) option can implicitly set a
+default negating this requirement. Refer to the [attribute defaults] for more information.*
+
+The directory server attribute that is used by Authelia to determine the group name.
+
 ## Refresh Interval
 
 It's recommended you either use the default [refresh interval](introduction.md#refreshinterval) or configure this to
@@ -332,6 +368,8 @@ for your users.
 
 - [LDAP Reference Guide](../../reference/guides/ldap.md)
 
-[username attribute]: #usernameattribute
+[username attribute]: #username
 [TechNet wiki]: https://social.technet.microsoft.com/wiki/contents/articles/5392.active-directory-ldap-syntax-filters.aspx
 [RFC2307]: https://datatracker.ietf.org/doc/html/rfc2307
+[attribute defaults]: ../../reference/guides/ldap.md#attribute-defaults
+[placeholder]: ../../reference/guides/ldap.md#users-filter-replacements

docs/content/en/configuration/miscellaneous/server-endpoints-authz.md

@@ -24,16 +24,24 @@ server:
     authz:
       forward-auth:
         implementation: 'ForwardAuth'
-        authn_strategies: []
+        authn_strategies:
+          - name: 'HeaderProxyAuthorization'
+          - name: 'CookieSession'
       ext-authz:
         implementation: 'ExtAuthz'
-        authn_strategies: []
+        authn_strategies:
+          - name: 'HeaderProxyAuthorization'
+          - name: 'CookieSession'
       auth-request:
         implementation: 'AuthRequest'
-        authn_strategies: []
+        authn_strategies:
+          - name: 'HeaderAuthRequestProxyAuthorization'
+          - name: 'CookieSession'
       legacy:
         implementation: 'Legacy'
-        authn_strategies: []
+        authn_strategies:
+          - name: 'HeaderLegacy'
+          - name: 'CookieSession'
 ```
 
 ## Name

docs/content/en/integration/deployment/docker.md

@@ -92,35 +92,35 @@ Use this [Standalone Example](#standalone-example) if you want to use
 version: "3.8"
 secrets:
   JWT_SECRET:
-    file: ${PWD}/data/authelia/secrets/JWT_SECRET
+    file: '${PWD}/data/authelia/secrets/JWT_SECRET'
   SESSION_SECRET:
-    file: ${PWD}/data/authelia/secrets/SESSION_SECRET
+    file: '${PWD}/data/authelia/secrets/SESSION_SECRET'
   STORAGE_PASSWORD:
-    file: ${PWD}/data/authelia/secrets/STORAGE_PASSWORD
+    file: '${PWD}/data/authelia/secrets/STORAGE_PASSWORD'
   STORAGE_ENCRYPTION_KEY:
-    file: ${PWD}/data/authelia/secrets/STORAGE_ENCRYPTION_KEY
+    file: '${PWD}/data/authelia/secrets/STORAGE_ENCRYPTION_KEY'
 services:
   authelia:
-    container_name: authelia
-    image: docker.io/authelia/authelia:latest
-    restart: unless-stopped
+    container_name: 'authelia'
+    image: 'docker.io/authelia/authelia:latest'
+    restart: 'unless-stopped'
     networks:
       net:
         aliases: []
     expose:
       - 9091
-    secrets: [JWT_SECRET, SESSION_SECRET, STORAGE_PASSWORD, STORAGE_ENCRYPTION_KEY]
+    secrets: ['JWT_SECRET', 'SESSION_SECRET', 'STORAGE_PASSWORD', 'STORAGE_ENCRYPTION_KEY']
     environment:
-      AUTHELIA_JWT_SECRET_FILE: /run/secrets/JWT_SECRET
-      AUTHELIA_SESSION_SECRET_FILE: /run/secrets/SESSION_SECRET
-      AUTHELIA_STORAGE_POSTGRES_PASSWORD_FILE: /run/secrets/STORAGE_PASSWORD
-      AUTHELIA_STORAGE_ENCRYPTION_KEY_FILE: /run/secrets/STORAGE_ENCRYPTION_KEY
+      AUTHELIA_JWT_SECRET_FILE: '/run/secrets/JWT_SECRET'
+      AUTHELIA_SESSION_SECRET_FILE: '/run/secrets/SESSION_SECRET'
+      AUTHELIA_STORAGE_POSTGRES_PASSWORD_FILE: '/run/secrets/STORAGE_PASSWORD'
+      AUTHELIA_STORAGE_ENCRYPTION_KEY_FILE: '/run/secrets/STORAGE_ENCRYPTION_KEY'
     volumes:
-      - ${PWD}/data/authelia/config:/config
+      - '${PWD}/data/authelia/config:/config'
 networks:
   net:
     external: true
-    name: net
+    name: 'net'
 ...
 ```
 {{< /details >}}
@@ -136,26 +136,26 @@ Use this [Standalone Example](#standalone-example) if you want to use a standard
 version: "3.8"
 services:
   authelia:
-    container_name: authelia
-    image: docker.io/authelia/authelia:latest
-    restart: unless-stopped
+    container_name: 'authelia'
+    image: 'docker.io/authelia/authelia:latest'
+    restart: 'unless-stopped'
     networks:
       net:
         aliases: []
     expose:
       - 9091
     environment:
-      AUTHELIA_JWT_SECRET_FILE: /secrets/JWT_SECRET
-      AUTHELIA_SESSION_SECRET_FILE: /secrets/SESSION_SECRET
-      AUTHELIA_STORAGE_POSTGRES_PASSWORD_FILE: /secrets/STORAGE_PASSWORD
-      AUTHELIA_STORAGE_ENCRYPTION_KEY_FILE: /secrets/STORAGE_ENCRYPTION_KEY
+      AUTHELIA_JWT_SECRET_FILE: '/secrets/JWT_SECRET'
+      AUTHELIA_SESSION_SECRET_FILE: '/secrets/SESSION_SECRET'
+      AUTHELIA_STORAGE_POSTGRES_PASSWORD_FILE: '/secrets/STORAGE_PASSWORD'
+      AUTHELIA_STORAGE_ENCRYPTION_KEY_FILE: '/secrets/STORAGE_ENCRYPTION_KEY'
     volumes:
-      - ${PWD}/data/authelia/config:/config
-      - ${PWD}/data/authelia/secrets:/secrets
+      - '${PWD}/data/authelia/config:/config'
+      - '${PWD}/data/authelia/secrets:/secrets'
 networks:
   net:
     external: true
-    name: net
+    name: 'net'
 ```
 ...
 {{< /details >}}

docs/content/en/integration/ldap/introduction.md

@@ -55,14 +55,16 @@ In your Authelia configuration you will need to enter and update the following v
     base_dn: DC=example,DC=com
     additional_users_dn: OU=users
     users_filter: (&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person))
-    username_attribute: uid
-    mail_attribute: mail
-    display_name_attribute: displayName
     additional_groups_dn: OU=groups
     groups_filter: (&(member=UID={input},OU=users,DC=example,DC=com)(objectClass=groupOfNames))
-    group_name_attribute: cn
     user: UID=authelia,OU=service accounts,DC=example,DC=com
     password: "SUPER_COMPLEX_PASSWORD"
+    attributes:
+      distinguished_name: 'distinguishedName'
+      username: 'uid'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 ```
 Following this, restart Authelia, and you should be able to begin using LDAP integration for your user logins, with
 Authelia taking the email attribute for users straight from the 'mail' attribute within the LDAP object.
@@ -100,16 +102,18 @@ In your Authelia configuration you will need to enter and update the following v
       skip_verify: true
       minimum_version: TLS1.2
     base_dn: dc=example,DC=com
-    username_attribute: uid
     additional_users_dn: CN=users,CN=accounts
     users_filter: (&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person))
     additional_groups_dn: OU=groups
     groups_filter: (&(member=UID={input},CN=users,CN=accounts,DC=example,DC=com)(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
-    display_name_attribute: displayName
     user: UID=authelia,CN=users,CN=accounts,DC=example,DC=com
     password: "SUPER_COMPLEX_PASSWORD"
+    attributes:
+      distinguished_name: 'distinguishedName'
+      username: 'uid'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 ```
 Following this, restart Authelia, and you should be able to begin using LDAP integration for your user logins, with
 Authelia taking the email attribute for users straight from the 'mail' attribute within the LDAP object.
@@ -139,19 +143,21 @@ ldap:
     timeout: 5s
     start_tls: false
     base_dn: dc=example,DC=com
-    username_attribute: uid
     additional_users_dn: OU=people
     # To allow sign in both with username and email, one can use a filter like
     # (&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person))
     users_filter: (&({username_attribute}={input})(objectClass=person))
     additional_groups_dn: OU=groups
     groups_filter: (member={dn})
-    group_name_attribute: cn
-    mail_attribute: mail
-    display_name_attribute: displayName
     # The username and password of the admin or service user.
     user: UID=authelia,OU=people,DC=example,DC=com
     password: "SUPER_COMPLEX_PASSWORD"
+    attributes:
+      distinguished_name: 'distinguishedName'
+      username: 'uid'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 ```
 Following this, restart Authelia, and you should be able to begin using lldap integration for your user logins, with
 Authelia taking the email attribute for users straight from the 'mail' attribute within the LDAP object.

docs/content/en/reference/guides/ldap.md

@@ -75,6 +75,32 @@ The following implementations exist:
 [GLAuth]: https://glauth.github.io/
 [RFC2307bis]: https://datatracker.ietf.org/doc/html/draft-howard-rfc2307bis-02
 
+### Group Search Modes
+
+There are currently two group search modes that exist.
+
+#### Search Mode: filter
+
+The `filter` search mode is the default search mode. Generally this is recommended.
+
+#### Search Mode: memberof
+
+The `memberof` search mode is a special search mode. Generally this is discouraged and is currently experimental.
+
+Some systems provide a `memberOf` attribute which may include additional groups that the user is a member of. This
+search mode allows using this attribute as a method to determine their groups. How it works is the search is performed
+against the base with the subtree scope and the groups filter must include one of the `{memberof:*}` replacements, and
+the distinguished names of the results from the search are compared (case-insensitive) against the users `memberOf`
+attribute to determine if they are members.
+
+This means:
+
+1. The groups still must be in the search base that you have configured.
+2. The `memberOf` attribute *__MUST__* include the distinguished name of the group.
+3. If the `{memberof:dn}` replacement is used:
+   1. The distinguished name *__MUST__* be searchable by your directory server.
+3. The first relative distinguished name of the distinguished name *__MUST__* be search
+
 ### Filter replacements
 
 Various replacements occur in the user and groups filter. The replacements either occur at startup or upon an LDAP
@@ -85,25 +111,65 @@ is ever established. In addition to this, during the startup phase we purposeful
 phase replacements exist so we only have to check if the replacement is necessary once, and we don't needlessly perform
 every possible replacement on every search regardless of if it's needed or not.
 
+#### General filter replacements
+
+|          Placeholder           |  Phase  |                 Replacement                 |
+|:------------------------------:|:-------:|:-------------------------------------------:|
+| {distinguished_name_attribute} | startup | The configured distinguished name attribute |
+|      {username_attribute}      | startup |      The configured username attribute      |
+|        {mail_attribute}        | startup |        The configured mail attribute        |
+|    {display_name_attribute}    | startup |    The configured display name attribute    |
+|     {member_of_attribute}      | startup |     The configured member of attribute      |
+|            {input}             | search  |      The input into the username field      |
+
 #### Users filter replacements
 
-|       Placeholder        |  Phase  |                                                   Replacement                                                    |
-|:------------------------:|:-------:|:----------------------------------------------------------------------------------------------------------------:|
-|   {username_attribute}   | startup |                                        The configured username attribute                                         |
-|     {mail_attribute}     | startup |                                          The configured mail attribute                                           |
-| {display_name_attribute} | startup |                                      The configured display name attribute                                       |
-|         {input}          | search  |                                        The input into the username field                                         |
-| {date-time:generalized}  | search  |          The current UTC time formatted as a LDAP generalized time in the format of `20060102150405.0Z`          |
-|     {date-time:unix}     | search  |                                    The current time formatted as a Unix epoch                                    |
-| {date-time:microsoft-nt} | search  | The current time formatted as a Microsoft NT epoch which is used by some Microsoft [Active Directory] attributes |
+|          Placeholder           |  Phase  |                                                   Replacement                                                    |
+|:------------------------------:|:-------:|:----------------------------------------------------------------------------------------------------------------:|
+|    {date-time:generalized}     | search  |          The current UTC time formatted as a LDAP generalized time in the format of `20060102150405.0Z`          |
+|        {date-time:unix}        | search  |                                    The current time formatted as a Unix epoch                                    |
+|    {date-time:microsoft-nt}    | search  | The current time formatted as a Microsoft NT epoch which is used by some Microsoft [Active Directory] attributes |
 
 #### Groups filter replacements
 
-| Placeholder | Phase  |                                Replacement                                |
-|:-----------:|:------:|:-------------------------------------------------------------------------:|
-|   {input}   | search |                     The input into the username field                     |
-| {username}  | search | The username from the profile lookup obtained from the username attribute |
-|    {dn}     | search |              The distinguished name from the profile lookup               |
+|  Placeholder   | Phase  |                                                                     Replacement                                                                      |
+|:--------------:|:------:|:----------------------------------------------------------------------------------------------------------------------------------------------------:|
+|   {username}   | search |                                      The username from the profile lookup obtained from the username attribute                                       |
+|      {dn}      | search |                                                    The distinguished name from the profile lookup                                                    |
+| {memberof:dn}  | search |                                                            See the detailed section below                                                            |
+| {memberof:rdn} | search | Only allowed with the `memberof` search method and contains the first relative distinguished name of every `memberOf` entry a use has in parenthesis |
+
+##### memberof:dn
+
+Requirements:
+
+1. Must be using the `memberof` search mode.
+2. Must have the distinguished name attribute configured in Authelia.
+3. Directory server must support searching by the distinguished name attribute (many directory services *__DO NOT__*
+   have a distinguished name attribute).
+
+##### memberof:rdn
+
+Requirements:
+
+1. Must be using the `memberof` search mode.
+2. Directory server must support searching by the first relative distinguished name as an attribute.
+
+Splits every `memberOf` value to obtain th e first relative distinguished name and joins all of those after surrounding
+them in parenthesis. This makes the general suggested filter pattern for this particular replacement
+`(|{memberof:rdn})`. The format of this value is as follows:
+
+```text
+(<RDN>)
+```
+
+For example if the user has the following distinguished names in their object:
+
+- CN=abc,OU=groups,DC=example,DC=com
+- CN=xyz,OU=groups,DC=example,DC=com
+
+The value will be replaced with `(CN=abc)(CN=xyz)` which using the suggested pattern for the filter becomes
+`(|(CN=abc)(CN=xyz))` which will then return any user that as a `CN` of `abc` or `xyz`.
 
 ### Defaults
 
@@ -122,14 +188,14 @@ The following set defaults for the `additional_users_dn` and `additional_groups_
 This table describes the attribute defaults for each implementation. i.e. the username_attribute is described by the
 Username column.
 
-| Implementation  |    Username    | Display Name | Mail | Group Name |
-|:---------------:|:--------------:|:------------:|:----:|:----------:|
-|     custom      |      N/A       | displayName  | mail |     cn     |
-| activedirectory | sAMAccountName | displayName  | mail |     cn     |
-|   rfc2307bis    |      uid       | displayName  | mail |     cn     |
-|     freeipa     |      uid       | displayName  | mail |     cn     |
-|      lldap      |      uid       |      cn      | mail |     cn     |
-|     glauth      |       cn       | description  | mail |     cn     |
+| Implementation  |    Username    | Display Name | Mail | Group Name | Distinguished Name | Member Of |
+|:---------------:|:--------------:|:------------:|:----:|:----------:|:------------------:|:---------:|
+|     custom      |      N/A       | displayName  | mail |     cn     |        N/A         |    N/A    |
+| activedirectory | sAMAccountName | displayName  | mail |     cn     | distinguishedName  | memberOf  |
+|   rfc2307bis    |      uid       | displayName  | mail |     cn     |        N/A         | memberOf  |
+|     freeipa     |      uid       | displayName  | mail |     cn     |        N/A         | memberOf  |
+|      lldap      |      uid       |      cn      | mail |     cn     |        N/A         |    N/A    |
+|     glauth      |       cn       | description  | mail |     cn     |        N/A         |    N/A    |
 
 #### Filter defaults
 

internal/authentication/const.go

@@ -72,12 +72,19 @@ const (
 )
 
 const (
-	ldapPlaceholderInput                        = "{input}"
-	ldapPlaceholderDistinguishedName            = "{dn}"
-	ldapPlaceholderUsername                     = "{username}"
-	ldapPlaceholderDateTimeGeneralized          = "{date-time:generalized}"
-	ldapPlaceholderDateTimeMicrosoftNTTimeEpoch = "{date-time:microsoft-nt}"
-	ldapPlaceholderDateTimeUnixEpoch            = "{date-time:unix}"
+	ldapPlaceholderInput                             = "{input}"
+	ldapPlaceholderDistinguishedName                 = "{dn}"
+	ldapPlaceholderMemberOfDistinguishedName         = "{memberof:dn}"
+	ldapPlaceholderMemberOfRelativeDistinguishedName = "{memberof:rdn}"
+	ldapPlaceholderUsername                          = "{username}"
+	ldapPlaceholderDateTimeGeneralized               = "{date-time:generalized}"
+	ldapPlaceholderDateTimeMicrosoftNTTimeEpoch      = "{date-time:microsoft-nt}"
+	ldapPlaceholderDateTimeUnixEpoch                 = "{date-time:unix}"
+	ldapPlaceholderDistinguishedNameAttribute        = "{distinguished_name_attribute}"
+	ldapPlaceholderUsernameAttribute                 = "{username_attribute}"
+	ldapPlaceholderDisplayNameAttribute              = "{display_name_attribute}"
+	ldapPlaceholderMailAttribute                     = "{mail_attribute}"
+	ldapPlaceholderMemberOfAttribute                 = "{member_of_attribute}"
 )
 
 const (

internal/authentication/ldap_user_provider.go

@@ -8,7 +8,7 @@ import (
 	"strconv"
 	"strings"
 
-	"github.com/go-ldap/ldap/v3"
+	ldap "github.com/go-ldap/ldap/v3"
 	"github.com/sirupsen/logrus"
 
 	"github.com/authelia/authelia/v4/internal/configuration/schema"
@@ -40,11 +40,13 @@ type LDAPUserProvider struct {
 	usersFilterReplacementDateTimeMicrosoftNTTimeEpoch bool
 
 	// Dynamically generated groups values.
-	groupsBaseDN                    string
-	groupsAttributes                []string
-	groupsFilterReplacementInput    bool
-	groupsFilterReplacementUsername bool
-	groupsFilterReplacementDN       bool
+	groupsBaseDN                        string
+	groupsAttributes                    []string
+	groupsFilterReplacementInput        bool
+	groupsFilterReplacementUsername     bool
+	groupsFilterReplacementDN           bool
+	groupsFilterReplacementsMemberOfDN  bool
+	groupsFilterReplacementsMemberOfRDN bool
 }
 
 // NewLDAPUserProvider creates a new instance of LDAPUserProvider with the ProductionLDAPClientFactory.
@@ -86,6 +88,7 @@ func NewLDAPUserProviderWithFactory(config schema.LDAPAuthenticationBackend, dis
 
 	provider.parseDynamicUsersConfiguration()
 	provider.parseDynamicGroupsConfiguration()
+	provider.parseDynamicConfiguration()
 
 	return provider
 }
@@ -134,38 +137,11 @@ func (p *LDAPUserProvider) GetDetails(username string) (details *UserDetails, er
 	}
 
 	var (
-		request *ldap.SearchRequest
-		result  *ldap.SearchResult
+		groups []string
 	)
 
-	// Search for the users groups.
-	request = ldap.NewSearchRequest(
-		p.groupsBaseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
-		0, 0, false, p.resolveGroupsFilter(username, profile), p.groupsAttributes, nil,
-	)
-
-	p.log.
-		WithField("base_dn", request.BaseDN).
-		WithField("filter", request.Filter).
-		WithField("attr", request.Attributes).
-		WithField("scope", request.Scope).
-		WithField("deref", request.DerefAliases).
-		Trace("Performing group search")
-
-	if result, err = p.search(client, request); err != nil {
-		return nil, fmt.Errorf("unable to retrieve groups of user '%s'. Cause: %w", username, err)
-	}
-
-	groups := make([]string, 0)
-
-	for _, res := range result.Entries {
-		if len(res.Attributes) == 0 {
-			p.log.Warningf("No groups retrieved from LDAP for user %s", username)
-			break
-		}
-
-		// Append all values of the document. Normally there should be only one per document.
-		groups = append(groups, res.Attributes[0].Values...)
+	if groups, err = p.getUserGroups(client, username, profile); err != nil {
+		return nil, err
 	}
 
 	return &UserDetails{
@@ -275,6 +251,8 @@ func (p *LDAPUserProvider) search(client LDAPClient, request *ldap.SearchRequest
 			} else {
 				result.Referrals = append(result.Referrals, referral)
 			}
+		} else {
+			return nil, err
 		}
 	}
 
@@ -357,6 +335,11 @@ func (p *LDAPUserProvider) getUserProfile(client LDAPClient, username string) (p
 		return nil, fmt.Errorf("there were %d users found when searching for '%s' but there should only be 1", len(result.Entries), username)
 	}
 
+	return p.getUserProfileResultToProfile(username, result)
+}
+
+//nolint:gocyclo // Not overly complex.
+func (p *LDAPUserProvider) getUserProfileResultToProfile(username string, result *ldap.SearchResult) (profile *ldapUserProfile, err error) {
 	userProfile := ldapUserProfile{
 		DN: result.Entries[0].DN,
 	}
@@ -364,35 +347,50 @@ func (p *LDAPUserProvider) getUserProfile(client LDAPClient, username string) (p
 	for _, attr := range result.Entries[0].Attributes {
 		attrs := len(attr.Values)
 
-		if attr.Name == p.config.UsernameAttribute {
+		switch attr.Name {
+		case p.config.Attributes.Username:
 			switch attrs {
 			case 1:
 				userProfile.Username = attr.Values[0]
+
+				if attr.Name == p.config.Attributes.DisplayName && userProfile.DisplayName == "" {
+					userProfile.DisplayName = attr.Values[0]
+				}
+
+				if attr.Name == p.config.Attributes.Mail && len(userProfile.Emails) == 0 {
+					userProfile.Emails = []string{attr.Values[0]}
+				}
 			case 0:
 				return nil, fmt.Errorf("user '%s' must have value for attribute '%s'",
-					username, p.config.UsernameAttribute)
+					username, p.config.Attributes.Username)
 			default:
 				return nil, fmt.Errorf("user '%s' has %d values for for attribute '%s' but the attribute must be a single value attribute",
-					username, attrs, p.config.UsernameAttribute)
+					username, attrs, p.config.Attributes.Username)
+			}
+		case p.config.Attributes.Mail:
+			if attrs == 0 {
+				continue
 			}
-		}
 
-		if attrs == 0 {
-			continue
-		}
-
-		if attr.Name == p.config.MailAttribute {
 			userProfile.Emails = attr.Values
-		}
+		case p.config.Attributes.DisplayName:
+			if attrs == 0 {
+				continue
+			}
 
-		if attr.Name == p.config.DisplayNameAttribute {
 			userProfile.DisplayName = attr.Values[0]
+		case p.config.Attributes.MemberOf:
+			if attrs == 0 {
+				continue
+			}
+
+			userProfile.MemberOf = attr.Values
 		}
 	}
 
 	if userProfile.Username == "" {
 		return nil, fmt.Errorf("user '%s' must have value for attribute '%s'",
-			username, p.config.UsernameAttribute)
+			username, p.config.Attributes.Username)
 	}
 
 	if userProfile.DN == "" {
@@ -402,6 +400,124 @@ func (p *LDAPUserProvider) getUserProfile(client LDAPClient, username string) (p
 	return &userProfile, nil
 }
 
+func (p *LDAPUserProvider) getUserGroups(client LDAPClient, username string, profile *ldapUserProfile) (groups []string, err error) {
+	request := ldap.NewSearchRequest(
+		p.groupsBaseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
+		0, 0, false, p.resolveGroupsFilter(username, profile), p.groupsAttributes, nil,
+	)
+
+	p.log.
+		WithField("base_dn", request.BaseDN).
+		WithField("filter", request.Filter).
+		WithField("attributes", request.Attributes).
+		WithField("scope", request.Scope).
+		WithField("deref", request.DerefAliases).
+		WithField("mode", p.config.GroupSearchMode).
+		Trace("Performing group search")
+
+	switch p.config.GroupSearchMode {
+	case "", "filter":
+		return p.getUserGroupsRequestFilter(client, username, profile, request)
+	case "memberof":
+		return p.getUserGroupsRequestMemberOf(client, username, profile, request)
+	default:
+		return nil, fmt.Errorf("could not perform group search with mode '%s' as it's unknown", p.config.GroupSearchMode)
+	}
+}
+
+func (p *LDAPUserProvider) getUserGroupsRequestFilter(client LDAPClient, username string, _ *ldapUserProfile, request *ldap.SearchRequest) (groups []string, err error) {
+	var result *ldap.SearchResult
+
+	if result, err = p.search(client, request); err != nil {
+		return nil, fmt.Errorf("unable to retrieve groups of user '%s'. Cause: %w", username, err)
+	}
+
+	for _, entry := range result.Entries {
+	attributes:
+		for _, attr := range entry.Attributes {
+			switch attr.Name {
+			case p.config.Attributes.GroupName:
+				switch n := len(attr.Values); n {
+				case 0:
+					continue
+				case 1:
+					groups = append(groups, attr.Values[0])
+				default:
+					fmt.Println(attr.Name, n, attr.Values)
+					return nil, fmt.Errorf("unable to retrieve groups of user '%s': Cause: the group '%s' attribute '%s' (group name attribute) has more than one value", username, entry.DN, p.config.Attributes.GroupName)
+				}
+
+				break attributes
+			}
+		}
+	}
+
+	return groups, nil
+}
+
+func (p *LDAPUserProvider) getUserGroupsRequestMemberOf(client LDAPClient, username string, profile *ldapUserProfile, request *ldap.SearchRequest) (groups []string, err error) {
+	var result *ldap.SearchResult
+
+	if result, err = p.search(client, request); err != nil {
+		return nil, fmt.Errorf("unable to retrieve groups of user '%s'. Cause: %w", username, err)
+	}
+
+	for _, entry := range result.Entries {
+		if len(entry.Attributes) == 0 {
+			p.log.
+				WithField("dn", entry.DN).
+				WithField("attributes", request.Attributes).
+				WithField("mode", "memberof").
+				Trace("Skipping Group as the server did not return any requested attributes")
+
+			continue
+		}
+
+		if !utils.IsStringInSliceFold(entry.DN, profile.MemberOf) {
+			p.log.
+				WithField("dn", entry.DN).
+				WithField("mode", "memberof").
+				Trace("Skipping Group as it doesn't match the users memberof entries")
+
+			continue
+		}
+
+	attributes:
+		for _, attr := range entry.Attributes {
+			switch attr.Name {
+			case p.config.Attributes.GroupName:
+				switch len(attr.Values) {
+				case 0:
+					p.log.
+						WithField("dn", entry.DN).
+						WithField("attribute", attr.Name).
+						Trace("Group skipped as the server returned a null attribute")
+				case 1:
+					switch len(attr.Values[0]) {
+					case 0:
+						p.log.
+							WithField("dn", entry.DN).
+							WithField("attribute", attr.Name).
+							Trace("Skipping group as the configured group name attribute had no value")
+
+					default:
+						groups = append(groups, attr.Values[0])
+					}
+				default:
+					p.log.
+						WithField("dn", entry.DN).
+						WithField("attribute", attr.Name).
+						Trace("Group skipped as the server returned a multi-valued attribute but it should be a single-valued attribute")
+				}
+
+				break attributes
+			}
+		}
+	}
+
+	return groups, nil
+}
+
 func (p *LDAPUserProvider) resolveUsersFilter(input string) (filter string) {
 	filter = p.config.UsersFilter
 
@@ -445,6 +561,27 @@ func (p *LDAPUserProvider) resolveGroupsFilter(input string, profile *ldapUserPr
 		}
 	}
 
+	if p.groupsFilterReplacementsMemberOfDN {
+		sep := fmt.Sprintf(")(%s=", p.config.Attributes.DistinguishedName)
+		values := make([]string, len(profile.MemberOf))
+
+		for i, memberof := range profile.MemberOf {
+			values[i] = ldap.EscapeFilter(memberof)
+		}
+
+		filter = strings.ReplaceAll(filter, ldapPlaceholderMemberOfDistinguishedName, fmt.Sprintf("(%s=%s)", p.config.Attributes.DistinguishedName, strings.Join(values, sep)))
+	}
+
+	if p.groupsFilterReplacementsMemberOfRDN {
+		values := make([]string, len(profile.MemberOf))
+
+		for i, memberof := range profile.MemberOf {
+			values[i] = ldap.EscapeFilter(strings.SplitN(memberof, ",", 2)[0])
+		}
+
+		filter = strings.ReplaceAll(filter, ldapPlaceholderMemberOfRelativeDistinguishedName, fmt.Sprintf("(%s)", strings.Join(values, ")(")))
+	}
+
 	p.log.Tracef("Computed groups filter is %s", filter)
 
 	return filter

internal/authentication/ldap_user_provider_startup.go

@@ -37,11 +37,6 @@ func (p *LDAPUserProvider) StartupCheck() (err error) {
 			"LDAP Server.")
 	}
 
-	if !p.features.Extensions.TLS && p.config.StartTLS {
-		p.log.Info("Your LDAP Server does not appear to support TLS but you enabled StartTLS which may result " +
-			"in an error.")
-	}
-
 	return nil
 }
 
@@ -90,22 +85,24 @@ func (p *LDAPUserProvider) getServerSupportedFeatures(client LDAPClient) (featur
 }
 
 func (p *LDAPUserProvider) parseDynamicUsersConfiguration() {
-	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, "{username_attribute}", p.config.UsernameAttribute)
-	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, "{mail_attribute}", p.config.MailAttribute)
-	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, "{display_name_attribute}", p.config.DisplayNameAttribute)
+	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, ldapPlaceholderDistinguishedNameAttribute, p.config.Attributes.DistinguishedName)
+	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, ldapPlaceholderUsernameAttribute, p.config.Attributes.Username)
+	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, ldapPlaceholderDisplayNameAttribute, p.config.Attributes.DisplayName)
+	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, ldapPlaceholderMailAttribute, p.config.Attributes.Mail)
+	p.config.UsersFilter = strings.ReplaceAll(p.config.UsersFilter, ldapPlaceholderMemberOfAttribute, p.config.Attributes.MemberOf)
 
 	p.log.Tracef("Dynamically generated users filter is %s", p.config.UsersFilter)
 
-	if !utils.IsStringInSlice(p.config.UsernameAttribute, p.usersAttributes) {
-		p.usersAttributes = append(p.usersAttributes, p.config.UsernameAttribute)
+	if len(p.config.Attributes.Username) != 0 && !utils.IsStringInSlice(p.config.Attributes.Username, p.usersAttributes) {
+		p.usersAttributes = append(p.usersAttributes, p.config.Attributes.Username)
 	}
 
-	if !utils.IsStringInSlice(p.config.MailAttribute, p.usersAttributes) {
-		p.usersAttributes = append(p.usersAttributes, p.config.MailAttribute)
+	if len(p.config.Attributes.Mail) != 0 && !utils.IsStringInSlice(p.config.Attributes.Mail, p.usersAttributes) {
+		p.usersAttributes = append(p.usersAttributes, p.config.Attributes.Mail)
 	}
 
-	if !utils.IsStringInSlice(p.config.DisplayNameAttribute, p.usersAttributes) {
-		p.usersAttributes = append(p.usersAttributes, p.config.DisplayNameAttribute)
+	if len(p.config.Attributes.DisplayName) != 0 && !utils.IsStringInSlice(p.config.Attributes.DisplayName, p.usersAttributes) {
+		p.usersAttributes = append(p.usersAttributes, p.config.Attributes.DisplayName)
 	}
 
 	if p.config.AdditionalUsersDN != "" {
@@ -137,8 +134,14 @@ func (p *LDAPUserProvider) parseDynamicUsersConfiguration() {
 }
 
 func (p *LDAPUserProvider) parseDynamicGroupsConfiguration() {
-	p.groupsAttributes = []string{
-		p.config.GroupNameAttribute,
+	p.config.GroupsFilter = strings.ReplaceAll(p.config.GroupsFilter, ldapPlaceholderDistinguishedNameAttribute, p.config.Attributes.DistinguishedName)
+	p.config.GroupsFilter = strings.ReplaceAll(p.config.GroupsFilter, ldapPlaceholderUsernameAttribute, p.config.Attributes.Username)
+	p.config.GroupsFilter = strings.ReplaceAll(p.config.GroupsFilter, ldapPlaceholderDisplayNameAttribute, p.config.Attributes.DisplayName)
+	p.config.GroupsFilter = strings.ReplaceAll(p.config.GroupsFilter, ldapPlaceholderMailAttribute, p.config.Attributes.Mail)
+	p.config.GroupsFilter = strings.ReplaceAll(p.config.GroupsFilter, ldapPlaceholderMemberOfAttribute, p.config.Attributes.MemberOf)
+
+	if len(p.config.Attributes.GroupName) != 0 && !utils.IsStringInSlice(p.config.Attributes.GroupName, p.groupsAttributes) {
+		p.groupsAttributes = append(p.groupsAttributes, p.config.Attributes.GroupName)
 	}
 
 	if p.config.AdditionalGroupsDN != "" {
@@ -161,5 +164,25 @@ func (p *LDAPUserProvider) parseDynamicGroupsConfiguration() {
 		p.groupsFilterReplacementDN = true
 	}
 
+	if strings.Contains(p.config.GroupsFilter, ldapPlaceholderMemberOfDistinguishedName) {
+		p.groupsFilterReplacementsMemberOfDN = true
+	}
+
+	if strings.Contains(p.config.GroupsFilter, ldapPlaceholderMemberOfRelativeDistinguishedName) {
+		p.groupsFilterReplacementsMemberOfRDN = true
+	}
+
 	p.log.Tracef("Detected group filter replacements that need to be resolved per lookup are: input=%v, username=%v, dn=%v", p.groupsFilterReplacementInput, p.groupsFilterReplacementUsername, p.groupsFilterReplacementDN)
 }
+
+func (p *LDAPUserProvider) parseDynamicConfiguration() {
+	if len(p.config.Attributes.MemberOf) != 0 {
+		if !utils.IsStringInSlice(p.config.Attributes.MemberOf, p.usersAttributes) {
+			p.usersAttributes = append(p.usersAttributes, p.config.Attributes.MemberOf)
+		}
+
+		if !utils.IsStringInSlice(p.config.Attributes.MemberOf, p.groupsAttributes) {
+			p.groupsAttributes = append(p.groupsAttributes, p.config.Attributes.MemberOf)
+		}
+	}
+}

internal/authentication/types.go

@@ -83,6 +83,7 @@ type ldapUserProfile struct {
 	Emails      []string
 	DisplayName string
 	Username    string
+	MemberOf    []string
 }
 
 // LDAPSupportedFeatures represents features which a server may support which are implemented in code.

internal/configuration/config.template.yml

@@ -317,7 +317,7 @@ authentication_backend:
   ## because it allows Authelia to offload the stateful operations
   ## onto the LDAP service.
   # ldap:
-    ## The address of the LDAP server to connect to in the address common syntax.
+    ## The address of the directory server to connect to in the address common syntax.
     ## Format: [<scheme>://]<hostname>[:<port>].
     ## Square brackets indicate optional portions of the format. Scheme must be 'ldap', 'ldaps', or 'ldapi`.
     ## The default scheme is 'ldapi' if the address is an absolute path otherwise it's 'ldaps'.
@@ -403,16 +403,6 @@ authentication_backend:
     ## See also: additional_users_dn, additional_groups_dn.
     # base_dn: 'dc=example,dc=com'
 
-    ## The attribute holding the username of the user. This attribute is used to populate the username in the session
-    ## information. For your information, Microsoft Active Directory usually uses 'sAMAccountName' and OpenLDAP usually
-    ## uses 'uid'. Beware that this attribute holds the unique identifiers for the users binding the user and the
-    ## configuration stored in database. Therefore only single value attributes are allowed and the value must never be
-    ## changed once attributed to a user otherwise it would break the configuration for that user. Technically,
-    ## non-unique attributes like 'mail' can also be used but we don't recommend using them, we instead advise to use
-    ## a filter to perform alternative lookups and the attributes mentioned above (sAMAccountName and uid) to
-    ## follow https://datatracker.ietf.org/doc/html/rfc2307.
-    # username_attribute: 'uid'
-
     ## The additional_users_dn is prefixed to base_dn and delimited by a comma when searching for users.
     ## i.e. with this set to OU=Users and base_dn set to DC=a,DC=com; OU=Users,DC=a,DC=com is searched for users.
     # additional_users_dn: 'ou=users'
@@ -443,15 +433,9 @@ authentication_backend:
     ##    (&(uniqueMember={dn})(objectClass=groupOfUniqueNames))
     # groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
 
-    ## The attribute holding the name of the group.
-    # group_name_attribute: 'cn'
-
-    ## The attribute holding the mail address of the user. If multiple email addresses are defined for a user, only the
-    ## first one returned by the LDAP server is used.
-    # mail_attribute: 'mail'
-
-    ## The attribute holding the display name of the user. This will be used to greet an authenticated user.
-    # display_name_attribute: 'displayName'
+    ## The group search mode to use. Options are 'filter' or 'memberof'. It's essential to read the docs if you wish to
+    ## use 'memberof'. Also 'filter' is the best choice for most use cases.
+    # group_search_mode: 'filter'
 
     ## Follow referrals returned by the server.
     ## This is especially useful for environments where read-only servers exist. Only implemented for write operations.
@@ -462,6 +446,37 @@ authentication_backend:
     ## Password can also be set using a secret: https://www.authelia.com/c/secrets
     # password: 'password'
 
+    ## The attributes for users and objects from the directory server.
+    # attributes:
+
+      ## The distinguished name attribute if your directory server supports it. Users should read the docs before
+      ## configuring. Only used for the 'memberof' group search mode.
+      # distinguished_name: ''
+
+      ## The attribute holding the username of the user. This attribute is used to populate the username in the session
+      ## information. For your information, Microsoft Active Directory usually uses 'sAMAccountName' and OpenLDAP
+      ## usually uses 'uid'. Beware that this attribute holds the unique identifiers for the users binding the user and
+      ## the configuration stored in database; therefore only single value attributes are allowed and the value must
+      ## never be changed once attributed to a user otherwise it would break the configuration for that user.
+      ## Technically non-unique attributes like 'mail' can also be used but we don't recommend using them, we instead
+      ## advise to use a filter to perform alternative lookups and the attributes mentioned above
+      ## (sAMAccountName and uid) to follow https://datatracker.ietf.org/doc/html/rfc2307.
+      # username: 'uid'
+
+      ## The attribute holding the display name of the user. This will be used to greet an authenticated user.
+      # display_name: 'displayName'
+
+      ## The attribute holding the mail address of the user. If multiple email addresses are defined for a user, only
+      ## the first one returned by the directory server is used.
+      # mail: 'mail'
+
+      ## The attribute which provides distinguished names of groups an object is a member of.
+      ## Only used for the 'memberof' group search mode.
+      # member_of: 'memberOf'
+
+      ## The attribute holding the name of the group.
+      # group_name: 'cn'
+
   ##
   ## File (Authentication Provider)
   ##

internal/configuration/deprecation.go

@@ -261,4 +261,36 @@ var deprecations = map[string]Deprecation{
 		MapFunc: nil,
 		ErrFunc: nil,
 	},
+	"authentication_backend.ldap.username_attribute": {
+		Version: model.SemanticVersion{Major: 4, Minor: 38},
+		Key:     "authentication_backend.ldap.username_attribute",
+		NewKey:  "authentication_backend.ldap.attributes.username",
+		AutoMap: true,
+		MapFunc: nil,
+		ErrFunc: nil,
+	},
+	"authentication_backend.ldap.mail_attribute": {
+		Version: model.SemanticVersion{Major: 4, Minor: 38},
+		Key:     "authentication_backend.ldap.mail_attribute",
+		NewKey:  "authentication_backend.ldap.attributes.mail",
+		AutoMap: true,
+		MapFunc: nil,
+		ErrFunc: nil,
+	},
+	"authentication_backend.ldap.display_name_attribute": {
+		Version: model.SemanticVersion{Major: 4, Minor: 38},
+		Key:     "authentication_backend.ldap.display_name_attribute",
+		NewKey:  "authentication_backend.ldap.attributes.display_name",
+		AutoMap: true,
+		MapFunc: nil,
+		ErrFunc: nil,
+	},
+	"authentication_backend.ldap.group_name_attribute": {
+		Version: model.SemanticVersion{Major: 4, Minor: 38},
+		Key:     "authentication_backend.ldap.group_name_attribute",
+		NewKey:  "authentication_backend.ldap.attributes.group_name",
+		AutoMap: true,
+		MapFunc: nil,
+		ErrFunc: nil,
+	},
 }

internal/configuration/schema/authentication.go

@@ -108,11 +108,9 @@ type LDAPAuthenticationBackend struct {
 
 	AdditionalGroupsDN string `koanf:"additional_groups_dn"`
 	GroupsFilter       string `koanf:"groups_filter"`
+	GroupSearchMode    string `koanf:"group_search_mode"`
 
-	GroupNameAttribute   string `koanf:"group_name_attribute"`
-	UsernameAttribute    string `koanf:"username_attribute"`
-	MailAttribute        string `koanf:"mail_attribute"`
-	DisplayNameAttribute string `koanf:"display_name_attribute"`
+	Attributes LDAPAuthenticationAttributes `koanf:"attributes"`
 
 	PermitReferrals               bool `koanf:"permit_referrals"`
 	PermitUnauthenticatedBind     bool `koanf:"permit_unauthenticated_bind"`
@@ -122,6 +120,16 @@ type LDAPAuthenticationBackend struct {
 	Password string `koanf:"password"`
 }
 
+// LDAPAuthenticationAttributes represents the configuration related to LDAP server attributes.
+type LDAPAuthenticationAttributes struct {
+	DistinguishedName string `koanf:"distinguished_name"`
+	Username          string `koanf:"username"`
+	DisplayName       string `koanf:"display_name"`
+	Mail              string `koanf:"mail"`
+	MemberOf          string `koanf:"member_of"`
+	GroupName         string `koanf:"group_name"`
+}
+
 // DefaultPasswordConfig represents the default configuration related to Argon2id hashing.
 var DefaultPasswordConfig = Password{
 	Algorithm: argon2,
@@ -175,11 +183,14 @@ var DefaultCIPasswordConfig = Password{
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationCustom represents the default LDAP config.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationCustom = LDAPAuthenticationBackend{
-	UsernameAttribute:    ldapAttrUserID,
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrDisplayName,
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	GroupSearchMode: ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		Username:    ldapAttrUserID,
+		DisplayName: ldapAttrDisplayName,
+		Mail:        ldapAttrMail,
+		GroupName:   ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},
@@ -187,13 +198,18 @@ var DefaultLDAPAuthenticationBackendConfigurationImplementationCustom = LDAPAuth
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory represents the default LDAP config for the LDAPImplementationActiveDirectory Implementation.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory = LDAPAuthenticationBackend{
-	UsersFilter:          "(&(|({username_attribute}={input})({mail_attribute}={input}))(sAMAccountType=805306368)(!(userAccountControl:1.2.840.113556.1.4.803:=2))(!(pwdLastSet=0))(|(!(accountExpires=*))(accountExpires=0)(accountExpires>={date-time:microsoft-nt})))",
-	UsernameAttribute:    "sAMAccountName",
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrDisplayName,
-	GroupsFilter:         "(&(member={dn})(|(sAMAccountType=268435456)(sAMAccountType=536870912)))",
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	UsersFilter:     "(&(|({username_attribute}={input})({mail_attribute}={input}))(sAMAccountType=805306368)(!(userAccountControl:1.2.840.113556.1.4.803:=2))(!(pwdLastSet=0))(|(!(accountExpires=*))(accountExpires=0)(accountExpires>={date-time:microsoft-nt})))",
+	GroupsFilter:    "(&(member={dn})(|(sAMAccountType=268435456)(sAMAccountType=536870912)))",
+	GroupSearchMode: ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		DistinguishedName: ldapAttrDistinguishedName,
+		Username:          ldapAttrSAMAccountName,
+		DisplayName:       ldapAttrDisplayName,
+		Mail:              ldapAttrMail,
+		MemberOf:          ldapAttrMemberOf,
+		GroupName:         ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},
@@ -201,13 +217,17 @@ var DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory =
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis represents the default LDAP config for the LDAPImplementationRFC2307bis Implementation.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis = LDAPAuthenticationBackend{
-	UsersFilter:          "(&(|({username_attribute}={input})({mail_attribute}={input}))(|(objectClass=inetOrgPerson)(objectClass=organizationalPerson)))",
-	UsernameAttribute:    ldapAttrUserID,
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrDisplayName,
-	GroupsFilter:         "(&(|(member={dn})(uniqueMember={dn}))(|(objectClass=groupOfNames)(objectClass=groupOfUniqueNames)(objectClass=groupOfMembers)))",
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	UsersFilter:     "(&(|({username_attribute}={input})({mail_attribute}={input}))(|(objectClass=inetOrgPerson)(objectClass=organizationalPerson)))",
+	GroupsFilter:    "(&(|(member={dn})(uniqueMember={dn}))(|(objectClass=groupOfNames)(objectClass=groupOfUniqueNames)(objectClass=groupOfMembers)))",
+	GroupSearchMode: ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		Username:    ldapAttrUserID,
+		DisplayName: ldapAttrDisplayName,
+		Mail:        ldapAttrMail,
+		MemberOf:    ldapAttrMemberOf,
+		GroupName:   ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},
@@ -215,13 +235,17 @@ var DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis = LDAP
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA represents the default LDAP config for the LDAPImplementationFreeIPA Implementation.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA = LDAPAuthenticationBackend{
-	UsersFilter:          "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person)(!(nsAccountLock=TRUE))(krbPasswordExpiration>={date-time:generalized})(|(!(krbPrincipalExpiration=*))(krbPrincipalExpiration>={date-time:generalized})))",
-	UsernameAttribute:    ldapAttrUserID,
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrDisplayName,
-	GroupsFilter:         "(&(member={dn})(objectClass=groupOfNames))",
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	UsersFilter:     "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person)(!(nsAccountLock=TRUE))(krbPasswordExpiration>={date-time:generalized})(|(!(krbPrincipalExpiration=*))(krbPrincipalExpiration>={date-time:generalized})))",
+	GroupsFilter:    "(&(member={dn})(objectClass=groupOfNames))",
+	GroupSearchMode: ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		Username:    ldapAttrUserID,
+		DisplayName: ldapAttrDisplayName,
+		Mail:        ldapAttrMail,
+		MemberOf:    ldapAttrMemberOf,
+		GroupName:   ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},
@@ -229,15 +253,18 @@ var DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA = LDAPAut
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP represents the default LDAP config for the LDAPImplementationLLDAP Implementation.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP = LDAPAuthenticationBackend{
-	AdditionalUsersDN:    "OU=people",
-	AdditionalGroupsDN:   "OU=groups",
-	UsersFilter:          "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person))",
-	UsernameAttribute:    ldapAttrUserID,
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrCommonName,
-	GroupsFilter:         "(&(member={dn})(objectClass=groupOfUniqueNames))",
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	AdditionalUsersDN:  "OU=people",
+	AdditionalGroupsDN: "OU=groups",
+	UsersFilter:        "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person))",
+	GroupsFilter:       "(&(member={dn})(objectClass=groupOfUniqueNames))",
+	GroupSearchMode:    ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		Username:    ldapAttrUserID,
+		DisplayName: ldapAttrCommonName,
+		Mail:        ldapAttrMail,
+		GroupName:   ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},
@@ -245,13 +272,16 @@ var DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP = LDAPAuthe
 
 // DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth represents the default LDAP config for the LDAPImplementationGLAuth Implementation.
 var DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth = LDAPAuthenticationBackend{
-	UsersFilter:          "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=posixAccount)(!(accountStatus=inactive)))",
-	UsernameAttribute:    ldapAttrCommonName,
-	MailAttribute:        ldapAttrMail,
-	DisplayNameAttribute: ldapAttrDescription,
-	GroupsFilter:         "(&(uniqueMember={dn})(objectClass=posixGroup))",
-	GroupNameAttribute:   ldapAttrCommonName,
-	Timeout:              time.Second * 5,
+	UsersFilter:     "(&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=posixAccount)(!(accountStatus=inactive)))",
+	GroupsFilter:    "(&(uniqueMember={dn})(objectClass=posixGroup))",
+	GroupSearchMode: ldapGroupSearchModeFilter,
+	Attributes: LDAPAuthenticationAttributes{
+		Username:    ldapAttrCommonName,
+		DisplayName: ldapAttrDescription,
+		Mail:        ldapAttrMail,
+		GroupName:   ldapAttrCommonName,
+	},
+	Timeout: time.Second * 5,
 	TLS: &TLSConfig{
 		MinimumVersion: TLSVersion{tls.VersionTLS12},
 	},

internal/configuration/schema/const.go

@@ -78,6 +78,14 @@ const (
 	LDAPImplementationGLAuth = "glauth"
 )
 
+const (
+	// LDAPGroupSearchModeFilter is the string for the filter group search mode.
+	LDAPGroupSearchModeFilter = "filter"
+
+	// LDAPGroupSearchModeMemberOf is the string for the memberOf group search mode.
+	LDAPGroupSearchModeMemberOf = "memberof"
+)
+
 // TOTP Algorithm.
 const (
 	TOTPAlgorithmSHA1   = "SHA1"
@@ -121,11 +129,18 @@ const (
 )
 
 const (
-	ldapAttrMail        = "mail"
-	ldapAttrUserID      = "uid"
-	ldapAttrDisplayName = "displayName"
-	ldapAttrDescription = "description"
-	ldapAttrCommonName  = "cn"
+	ldapGroupSearchModeFilter = "filter"
+)
+
+const (
+	ldapAttrDistinguishedName = "distinguishedName"
+	ldapAttrMail              = "mail"
+	ldapAttrUserID            = "uid"
+	ldapAttrSAMAccountName    = "sAMAccountName"
+	ldapAttrDisplayName       = "displayName"
+	ldapAttrDescription       = "description"
+	ldapAttrCommonName        = "cn"
+	ldapAttrMemberOf          = "memberOf"
 )
 
 // Address Schemes.

internal/configuration/schema/keys.go

@@ -118,10 +118,13 @@ var Keys = []string{
 	"authentication_backend.ldap.users_filter",
 	"authentication_backend.ldap.additional_groups_dn",
 	"authentication_backend.ldap.groups_filter",
-	"authentication_backend.ldap.group_name_attribute",
-	"authentication_backend.ldap.username_attribute",
-	"authentication_backend.ldap.mail_attribute",
-	"authentication_backend.ldap.display_name_attribute",
+	"authentication_backend.ldap.group_search_mode",
+	"authentication_backend.ldap.attributes.distinguished_name",
+	"authentication_backend.ldap.attributes.username",
+	"authentication_backend.ldap.attributes.display_name",
+	"authentication_backend.ldap.attributes.mail",
+	"authentication_backend.ldap.attributes.member_of",
+	"authentication_backend.ldap.attributes.group_name",
 	"authentication_backend.ldap.permit_referrals",
 	"authentication_backend.ldap.permit_unauthenticated_bind",
 	"authentication_backend.ldap.permit_feature_detection_failure",

internal/configuration/test_resources/config.deprecated.alt.yml

@@ -66,14 +66,15 @@ authentication_backend:
         1YjCJ36UpTsLre2f8nOSLtNmRfDPtbOE2mkOoO9dD9UU0XZwnvn9xw==
         -----END RSA PRIVATE KEY-----
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&({username_attribute}={input})(objectCategory=person)(objectClass=user))
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
     user: cn=admin,dc=example,dc=com
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: deny

internal/configuration/test_resources/config.deprecated.yml

@@ -66,14 +66,15 @@ authentication_backend:
         1YjCJ36UpTsLre2f8nOSLtNmRfDPtbOE2mkOoO9dD9UU0XZwnvn9xw==
         -----END RSA PRIVATE KEY-----
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&({username_attribute}={input})(objectCategory=person)(objectClass=user))
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
     user: cn=admin,dc=example,dc=com
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: deny

internal/configuration/test_resources/config.durations.yml

@@ -66,14 +66,15 @@ authentication_backend:
         1YjCJ36UpTsLre2f8nOSLtNmRfDPtbOE2mkOoO9dD9UU0XZwnvn9xw==
         -----END RSA PRIVATE KEY-----
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config.filtered.yml

@@ -47,14 +47,15 @@ authentication_backend:
         1YjCJ36UpTsLre2f8nOSLtNmRfDPtbOE2mkOoO9dD9UU0XZwnvn9xw==
         -----END RSA PRIVATE KEY-----
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&({username_attribute}={input})(objectCategory=person)(objectClass=user))
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
     user: cn=admin,dc=example,dc=com
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: deny

internal/configuration/test_resources/config.yml

@@ -66,14 +66,15 @@ authentication_backend:
         1YjCJ36UpTsLre2f8nOSLtNmRfDPtbOE2mkOoO9dD9UU0XZwnvn9xw==
         -----END RSA PRIVATE KEY-----
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_alt.yml

@@ -18,14 +18,16 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
+
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      mail: 'mail'
+      group_name: 'cn'
+      username: 'uid'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_bad_keys.yml

@@ -19,14 +19,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_domain_bad_regex.yml

@@ -18,14 +18,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_domain_regex.yml

@@ -18,13 +18,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
+    attributes:
+      group_name: 'cn'
+      mail: 'mail'
+      username: 'uid'
+
     user: 'cn=admin,dc=example,dc=com'
 
 access_control:

internal/configuration/test_resources/config_oidc.yml

@@ -18,14 +18,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_smtp_sender_blank.yml

@@ -18,14 +18,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_smtp_sender_invalid.yml

@@ -18,14 +18,15 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
 
 access_control:
   default_policy: 'deny'

internal/configuration/test_resources/config_with_secret.yml

@@ -20,14 +20,16 @@ authentication_backend:
   ldap:
     address: 'ldap://127.0.0.1'
     base_dn: 'dc=example,dc=com'
-    username_attribute: 'uid'
     additional_users_dn: 'ou=users'
     users_filter: '(&({username_attribute}={input})(objectCategory=person)(objectClass=user))'
     additional_groups_dn: 'ou=groups'
     groups_filter: '(&(member={dn})(objectClass=groupOfNames))'
-    group_name_attribute: 'cn'
-    mail_attribute: 'mail'
     user: 'cn=admin,dc=example,dc=com'
+    attributes:
+      username: 'uid'
+      group_name: 'cn'
+      mail: 'mail'
+
 
 access_control:
   default_policy: 'deny'

internal/configuration/validator/authentication.go

@@ -364,7 +364,7 @@ func validateLDAPAuthenticationBackendImplementation(config *schema.Authenticati
 	case schema.LDAPImplementationGLAuth:
 		implementation = &schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth
 	default:
-		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendImplementation, strJoinOr(validLDAPImplementations), config.LDAP.Implementation))
+		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendOptionMustBeOneOf, "implementation", strJoinOr(validLDAPImplementations), config.LDAP.Implementation))
 	}
 
 	tlsconfig := &schema.TLSConfig{}
@@ -394,32 +394,44 @@ func setDefaultImplementationLDAPAuthenticationBackendProfileAttributes(config *
 		config.AdditionalUsersDN = implementation.AdditionalUsersDN
 	}
 
-	if ldapImplementationShouldSetStr(config.AdditionalGroupsDN, implementation.AdditionalGroupsDN) {
-		config.AdditionalGroupsDN = implementation.AdditionalGroupsDN
-	}
-
 	if ldapImplementationShouldSetStr(config.UsersFilter, implementation.UsersFilter) {
 		config.UsersFilter = implementation.UsersFilter
 	}
 
-	if ldapImplementationShouldSetStr(config.UsernameAttribute, implementation.UsernameAttribute) {
-		config.UsernameAttribute = implementation.UsernameAttribute
-	}
-
-	if ldapImplementationShouldSetStr(config.DisplayNameAttribute, implementation.DisplayNameAttribute) {
-		config.DisplayNameAttribute = implementation.DisplayNameAttribute
-	}
-
-	if ldapImplementationShouldSetStr(config.MailAttribute, implementation.MailAttribute) {
-		config.MailAttribute = implementation.MailAttribute
+	if ldapImplementationShouldSetStr(config.AdditionalGroupsDN, implementation.AdditionalGroupsDN) {
+		config.AdditionalGroupsDN = implementation.AdditionalGroupsDN
 	}
 
 	if ldapImplementationShouldSetStr(config.GroupsFilter, implementation.GroupsFilter) {
 		config.GroupsFilter = implementation.GroupsFilter
 	}
 
-	if ldapImplementationShouldSetStr(config.GroupNameAttribute, implementation.GroupNameAttribute) {
-		config.GroupNameAttribute = implementation.GroupNameAttribute
+	if ldapImplementationShouldSetStr(config.GroupSearchMode, implementation.GroupSearchMode) {
+		config.GroupSearchMode = implementation.GroupSearchMode
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.DistinguishedName, implementation.Attributes.DistinguishedName) {
+		config.Attributes.DistinguishedName = implementation.Attributes.DistinguishedName
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.Username, implementation.Attributes.Username) {
+		config.Attributes.Username = implementation.Attributes.Username
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.DisplayName, implementation.Attributes.DisplayName) {
+		config.Attributes.DisplayName = implementation.Attributes.DisplayName
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.Mail, implementation.Attributes.Mail) {
+		config.Attributes.Mail = implementation.Attributes.Mail
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.MemberOf, implementation.Attributes.MemberOf) {
+		config.Attributes.MemberOf = implementation.Attributes.MemberOf
+	}
+
+	if ldapImplementationShouldSetStr(config.Attributes.GroupName, implementation.Attributes.GroupName) {
+		config.Attributes.GroupName = implementation.Attributes.GroupName
 	}
 }
 
@@ -486,4 +498,32 @@ func validateLDAPRequiredParameters(config *schema.AuthenticationBackend, valida
 	} else if !strings.HasPrefix(config.LDAP.GroupsFilter, "(") || !strings.HasSuffix(config.LDAP.GroupsFilter, ")") {
 		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendFilterEnclosingParenthesis, "groups_filter", config.LDAP.GroupsFilter, config.LDAP.GroupsFilter))
 	}
+
+	validateLDAPGroupFilter(config, validator)
+}
+
+func validateLDAPGroupFilter(config *schema.AuthenticationBackend, validator *schema.StructValidator) {
+	if config.LDAP.GroupSearchMode == "" {
+		config.LDAP.GroupSearchMode = schema.LDAPGroupSearchModeFilter
+	}
+
+	if !utils.IsStringInSlice(config.LDAP.GroupSearchMode, validLDAPGroupSearchModes) {
+		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendOptionMustBeOneOf, "group_search_mode", strJoinOr(validLDAPGroupSearchModes), config.LDAP.GroupSearchMode))
+	}
+
+	pMemberOfDN, pMemberOfRDN := strings.Contains(config.LDAP.GroupsFilter, "{memberof:dn}"), strings.Contains(config.LDAP.GroupsFilter, "{memberof:rdn}")
+
+	if config.LDAP.GroupSearchMode == schema.LDAPGroupSearchModeMemberOf {
+		if !pMemberOfDN && !pMemberOfRDN {
+			validator.Push(fmt.Errorf(errFmtLDAPAuthBackendFilterMissingPlaceholderGroupSearchMode, "groups_filter", strJoinOr([]string{"{memberof:rdn}", "{memberof:dn}"}), config.LDAP.GroupSearchMode))
+		}
+	}
+
+	if pMemberOfDN && config.LDAP.Attributes.DistinguishedName == "" {
+		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendFilterMissingAttribute, "distinguished_name", strJoinOr([]string{"{memberof:dn}"})))
+	}
+
+	if (pMemberOfDN || pMemberOfRDN) && config.LDAP.Attributes.MemberOf == "" {
+		validator.Push(fmt.Errorf(errFmtLDAPAuthBackendFilterMissingAttribute, "member_of", strJoinOr([]string{"{memberof:rdn}", "{memberof:dn}"})))
+	}
 }

internal/configuration/validator/authentication_test.go

@@ -577,7 +577,7 @@ func (suite *LDAPAuthenticationBackendSuite) SetupTest() {
 	suite.config.LDAP.User = testLDAPUser
 	suite.config.LDAP.Password = testLDAPPassword
 	suite.config.LDAP.BaseDN = testLDAPBaseDN
-	suite.config.LDAP.UsernameAttribute = "uid"
+	suite.config.LDAP.Attributes.Username = "uid"
 	suite.config.LDAP.UsersFilter = "({username_attribute}={input})"
 	suite.config.LDAP.GroupsFilter = "(cn={input})"
 }
@@ -591,12 +591,12 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldValidateCompleteConfigura
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldValidateDefaultImplementationAndUsernameAttribute() {
 	suite.config.LDAP.Implementation = ""
-	suite.config.LDAP.UsernameAttribute = ""
+	suite.config.LDAP.Attributes.Username = ""
 	ValidateAuthenticationBackend(&suite.config, suite.validator)
 
 	suite.Equal(schema.LDAPImplementationCustom, suite.config.LDAP.Implementation)
 
-	suite.Equal(suite.config.LDAP.UsernameAttribute, schema.DefaultLDAPAuthenticationBackendConfigurationImplementationCustom.UsernameAttribute)
+	suite.Equal(suite.config.LDAP.Attributes.Username, schema.DefaultLDAPAuthenticationBackendConfigurationImplementationCustom.Attributes.Username)
 	suite.Len(suite.validator.Warnings(), 0)
 	suite.Len(suite.validator.Errors(), 0)
 }
@@ -743,7 +743,7 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldRaiseOnEmptyUsersFilter()
 }
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldNotRaiseOnEmptyUsernameAttribute() {
-	suite.config.LDAP.UsernameAttribute = ""
+	suite.config.LDAP.Attributes.Username = ""
 
 	ValidateAuthenticationBackend(&suite.config, suite.validator)
 
@@ -793,7 +793,7 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultGroupNameAttrib
 	suite.Len(suite.validator.Warnings(), 0)
 	suite.Len(suite.validator.Errors(), 0)
 
-	suite.Equal("cn", suite.config.LDAP.GroupNameAttribute)
+	suite.Equal("cn", suite.config.LDAP.Attributes.GroupName)
 }
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultMailAttribute() {
@@ -802,7 +802,7 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultMailAttribute()
 	suite.Len(suite.validator.Warnings(), 0)
 	suite.Len(suite.validator.Errors(), 0)
 
-	suite.Equal("mail", suite.config.LDAP.MailAttribute)
+	suite.Equal("mail", suite.config.LDAP.Attributes.Mail)
 }
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultDisplayNameAttribute() {
@@ -811,7 +811,7 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultDisplayNameAttr
 	suite.Len(suite.validator.Warnings(), 0)
 	suite.Len(suite.validator.Errors(), 0)
 
-	suite.Equal("displayName", suite.config.LDAP.DisplayNameAttribute)
+	suite.Equal("displayName", suite.config.LDAP.Attributes.DisplayName)
 }
 
 func (suite *LDAPAuthenticationBackendSuite) TestShouldSetDefaultRefreshInterval() {
@@ -890,6 +890,64 @@ func (suite *LDAPAuthenticationBackendSuite) TestShouldNotAllowSSL30() {
 	suite.EqualError(suite.validator.Errors()[0], "authentication_backend: ldap: tls: option 'minimum_version' is invalid: minimum version is TLS1.0 but SSL3.0 was configured")
 }
 
+func (suite *LDAPAuthenticationBackendSuite) TestShouldErrorOnBadSearchMode() {
+	suite.config.LDAP.GroupSearchMode = "memberOF"
+
+	ValidateAuthenticationBackend(&suite.config, suite.validator)
+
+	suite.Len(suite.validator.Warnings(), 0)
+	suite.Require().Len(suite.validator.Errors(), 1)
+
+	suite.EqualError(suite.validator.Errors()[0], "authentication_backend: ldap: option 'group_search_mode' must be one of 'filter' or 'memberof' but it's configured as 'memberOF'")
+}
+
+func (suite *LDAPAuthenticationBackendSuite) TestShouldNoErrorOnPlaceholderSearchMode() {
+	suite.config.LDAP.GroupSearchMode = memberof
+	suite.config.LDAP.GroupsFilter = filterMemberOfRDN
+	suite.config.LDAP.Attributes.MemberOf = memberOf
+
+	ValidateAuthenticationBackend(&suite.config, suite.validator)
+
+	suite.Len(suite.validator.Warnings(), 0)
+	suite.Len(suite.validator.Errors(), 0)
+}
+
+func (suite *LDAPAuthenticationBackendSuite) TestShouldErrorOnMissingPlaceholderSearchMode() {
+	suite.config.LDAP.GroupSearchMode = memberof
+
+	ValidateAuthenticationBackend(&suite.config, suite.validator)
+
+	suite.Len(suite.validator.Warnings(), 0)
+	suite.Require().Len(suite.validator.Errors(), 1)
+
+	suite.EqualError(suite.validator.Errors()[0], "authentication_backend: ldap: option 'groups_filter' must contain one of the '{memberof:rdn}' or '{memberof:dn}' placeholders when using a group_search_mode of 'memberof' but they're absent")
+}
+
+func (suite *LDAPAuthenticationBackendSuite) TestShouldErrorOnMissingDistinguishedNameDN() {
+	suite.config.LDAP.Attributes.DistinguishedName = ""
+	suite.config.LDAP.GroupsFilter = "(|({memberof:dn}))"
+
+	ValidateAuthenticationBackend(&suite.config, suite.validator)
+
+	suite.Len(suite.validator.Warnings(), 0)
+	suite.Require().Len(suite.validator.Errors(), 2)
+
+	suite.EqualError(suite.validator.Errors()[0], "authentication_backend: ldap: attributes: option 'distinguished_name' must be provided when using the '{memberof:dn}' placeholder but it's absent")
+	suite.EqualError(suite.validator.Errors()[1], "authentication_backend: ldap: attributes: option 'member_of' must be provided when using the '{memberof:rdn}' or '{memberof:dn}' placeholder but it's absent")
+}
+
+func (suite *LDAPAuthenticationBackendSuite) TestShouldErrorOnMissingMemberOfRDN() {
+	suite.config.LDAP.Attributes.DistinguishedName = ""
+	suite.config.LDAP.GroupsFilter = filterMemberOfRDN
+
+	ValidateAuthenticationBackend(&suite.config, suite.validator)
+
+	suite.Len(suite.validator.Warnings(), 0)
+	suite.Require().Len(suite.validator.Errors(), 1)
+
+	suite.EqualError(suite.validator.Errors()[0], "authentication_backend: ldap: attributes: option 'member_of' must be provided when using the '{memberof:rdn}' or '{memberof:dn}' placeholder but it's absent")
+}
+
 func (suite *LDAPAuthenticationBackendSuite) TestShouldNotAllowTLSVerMinGreaterThanVerMax() {
 	suite.config.LDAP.TLS = &schema.TLSConfig{
 		MinimumVersion: schema.TLSVersion{Value: tls.VersionTLS13},
@@ -951,32 +1009,39 @@ func (suite *ActiveDirectoryAuthenticationBackendSuite) TestShouldSetActiveDirec
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.Equal(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(memberOf, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("distinguishedName", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *ActiveDirectoryAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManuallyConfigured() {
 	suite.config.LDAP.Timeout = time.Second * 2
 	suite.config.LDAP.UsersFilter = "(&({username_attribute}={input})(objectCategory=person)(objectClass=user)(!userAccountControl:1.2.840.113556.1.4.803:=2))"
-	suite.config.LDAP.UsernameAttribute = "cn"
-	suite.config.LDAP.MailAttribute = "userPrincipalName"
-	suite.config.LDAP.DisplayNameAttribute = "name"
+	suite.config.LDAP.Attributes.Username = "cn"
+	suite.config.LDAP.Attributes.Mail = "userPrincipalName"
+	suite.config.LDAP.Attributes.DisplayName = "name"
 	suite.config.LDAP.GroupsFilter = "(&(member={dn})(objectClass=group)(objectCategory=group))"
-	suite.config.LDAP.GroupNameAttribute = "distinguishedName"
+	suite.config.LDAP.Attributes.GroupName = "distinguishedName"
 	suite.config.LDAP.AdditionalUsersDN = "OU=test"
 	suite.config.LDAP.AdditionalGroupsDN = "OU=grps"
+	suite.config.LDAP.Attributes.MemberOf = member
+	suite.config.LDAP.GroupSearchMode = memberof
+	suite.config.LDAP.Attributes.DistinguishedName = "objectGUID"
 
 	ValidateAuthenticationBackend(&suite.config, suite.validator)
 
@@ -993,20 +1058,24 @@ func (suite *ActiveDirectoryAuthenticationBackendSuite) TestShouldOnlySetDefault
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.NotEqual(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationActiveDirectory.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(member, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("objectGUID", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(memberof, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *ActiveDirectoryAuthenticationBackendSuite) TestShouldRaiseErrorOnInvalidURLWithHTTP() {
@@ -1059,32 +1128,38 @@ func (suite *RFC2307bisAuthenticationBackendSuite) TestShouldSetDefaults() {
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.Equal(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(memberOf, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *RFC2307bisAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManuallyConfigured() {
 	suite.config.LDAP.Timeout = time.Second * 2
 	suite.config.LDAP.UsersFilter = "(&({username_attribute}={input})(objectClass=Person))"
-	suite.config.LDAP.UsernameAttribute = "o"
-	suite.config.LDAP.MailAttribute = "Email"
-	suite.config.LDAP.DisplayNameAttribute = "Given"
+	suite.config.LDAP.Attributes.Username = "o"
+	suite.config.LDAP.Attributes.Mail = "Email"
+	suite.config.LDAP.Attributes.DisplayName = "Given"
 	suite.config.LDAP.GroupsFilter = "(&(member={dn})(objectClass=posixGroup)(objectClass=top))"
-	suite.config.LDAP.GroupNameAttribute = "gid"
+	suite.config.LDAP.Attributes.GroupName = "gid"
+	suite.config.LDAP.Attributes.MemberOf = member
 	suite.config.LDAP.AdditionalUsersDN = "OU=users,OU=OpenLDAP"
 	suite.config.LDAP.AdditionalGroupsDN = "OU=groups,OU=OpenLDAP"
+	suite.config.LDAP.GroupSearchMode = memberof
 
 	ValidateAuthenticationBackend(&suite.config, suite.validator)
 
@@ -1104,20 +1179,24 @@ func (suite *RFC2307bisAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNo
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.NotEqual(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationRFC2307bis.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(member, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(memberof, suite.config.LDAP.GroupSearchMode)
 }
 
 func TestRFC2307bisAuthenticationBackend(t *testing.T) {
@@ -1161,30 +1240,35 @@ func (suite *FreeIPAAuthenticationBackendSuite) TestShouldSetDefaults() {
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.Equal(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(memberOf, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *FreeIPAAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManuallyConfigured() {
 	suite.config.LDAP.Timeout = time.Second * 2
 	suite.config.LDAP.UsersFilter = "(&({username_attribute}={input})(objectClass=person)(!(nsAccountLock=TRUE)))"
-	suite.config.LDAP.UsernameAttribute = "dn"
-	suite.config.LDAP.MailAttribute = "email"
-	suite.config.LDAP.DisplayNameAttribute = "gecos"
+	suite.config.LDAP.Attributes.Username = "dn"
+	suite.config.LDAP.Attributes.Mail = "email"
+	suite.config.LDAP.Attributes.DisplayName = "gecos"
 	suite.config.LDAP.GroupsFilter = "(&(member={dn})(objectClass=posixgroup))"
-	suite.config.LDAP.GroupNameAttribute = "groupName"
+	suite.config.LDAP.Attributes.GroupName = "groupName"
+	suite.config.LDAP.Attributes.MemberOf = member
 	suite.config.LDAP.AdditionalUsersDN = "OU=people"
 	suite.config.LDAP.AdditionalGroupsDN = "OU=grp"
 
@@ -1203,20 +1287,24 @@ func (suite *FreeIPAAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotMa
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.NotEqual(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationFreeIPA.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal(member, suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func TestFreeIPAAuthenticationBackend(t *testing.T) {
@@ -1260,30 +1348,34 @@ func (suite *LLDAPAuthenticationBackendSuite) TestShouldSetDefaults() {
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.Equal(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal("", suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *LLDAPAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManuallyConfigured() {
 	suite.config.LDAP.Timeout = time.Second * 2
 	suite.config.LDAP.UsersFilter = "(&({username_attribute}={input})(objectClass=Person)(!(nsAccountLock=TRUE)))"
-	suite.config.LDAP.UsernameAttribute = "username"
-	suite.config.LDAP.MailAttribute = "m"
-	suite.config.LDAP.DisplayNameAttribute = "fn"
+	suite.config.LDAP.Attributes.Username = "username"
+	suite.config.LDAP.Attributes.Mail = "m"
+	suite.config.LDAP.Attributes.DisplayName = "fn"
 	suite.config.LDAP.GroupsFilter = "(&(member={dn})(!(objectClass=posixGroup)))"
-	suite.config.LDAP.GroupNameAttribute = "grpz"
+	suite.config.LDAP.Attributes.GroupName = "grpz"
 	suite.config.LDAP.AdditionalUsersDN = "OU=no"
 	suite.config.LDAP.AdditionalGroupsDN = "OU=yes"
 
@@ -1305,20 +1397,24 @@ func (suite *LLDAPAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManu
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.NotEqual(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationLLDAP.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal("", suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func TestLLDAPAuthenticationBackend(t *testing.T) {
@@ -1362,30 +1458,34 @@ func (suite *GLAuthAuthenticationBackendSuite) TestShouldSetDefaults() {
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.Equal(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.Equal(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal("", suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func (suite *GLAuthAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotManuallyConfigured() {
 	suite.config.LDAP.Timeout = time.Second * 2
 	suite.config.LDAP.UsersFilter = "(&({username_attribute}={input})(objectClass=Person)(!(accountStatus=inactive)))"
-	suite.config.LDAP.UsernameAttribute = "description"
-	suite.config.LDAP.MailAttribute = "sender"
-	suite.config.LDAP.DisplayNameAttribute = "given"
+	suite.config.LDAP.Attributes.Username = "description"
+	suite.config.LDAP.Attributes.Mail = "sender"
+	suite.config.LDAP.Attributes.DisplayName = "given"
 	suite.config.LDAP.GroupsFilter = "(&(member={dn})(objectClass=posixGroup))"
-	suite.config.LDAP.GroupNameAttribute = "grp"
+	suite.config.LDAP.Attributes.GroupName = "grp"
 	suite.config.LDAP.AdditionalUsersDN = "OU=users,OU=GlAuth"
 	suite.config.LDAP.AdditionalGroupsDN = "OU=groups,OU=GLAuth"
 
@@ -1407,20 +1507,24 @@ func (suite *GLAuthAuthenticationBackendSuite) TestShouldOnlySetDefaultsIfNotMan
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.UsersFilter,
 		suite.config.LDAP.UsersFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.UsernameAttribute,
-		suite.config.LDAP.UsernameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.Username,
+		suite.config.LDAP.Attributes.Username)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.DisplayNameAttribute,
-		suite.config.LDAP.DisplayNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.DisplayName,
+		suite.config.LDAP.Attributes.DisplayName)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.MailAttribute,
-		suite.config.LDAP.MailAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.Mail,
+		suite.config.LDAP.Attributes.Mail)
 	suite.NotEqual(
 		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.GroupsFilter,
 		suite.config.LDAP.GroupsFilter)
 	suite.NotEqual(
-		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.GroupNameAttribute,
-		suite.config.LDAP.GroupNameAttribute)
+		schema.DefaultLDAPAuthenticationBackendConfigurationImplementationGLAuth.Attributes.GroupName,
+		suite.config.LDAP.Attributes.GroupName)
+
+	suite.Equal("", suite.config.LDAP.Attributes.MemberOf)
+	suite.Equal("", suite.config.LDAP.Attributes.DistinguishedName)
+	suite.Equal(schema.LDAPGroupSearchModeFilter, suite.config.LDAP.GroupSearchMode)
 }
 
 func TestGLAuthAuthenticationBackend(t *testing.T) {

internal/configuration/validator/const.go

@@ -98,9 +98,9 @@ const (
 	errFmtLDAPAuthBackendUnauthenticatedBindWithPassword     = "authentication_backend: ldap: option 'permit_unauthenticated_bind' can't be enabled when a password is specified"
 	errFmtLDAPAuthBackendUnauthenticatedBindWithResetEnabled = "authentication_backend: ldap: option 'permit_unauthenticated_bind' can't be enabled when password reset is enabled"
 
-	errFmtLDAPAuthBackendMissingOption    = "authentication_backend: ldap: option '%s' is required"
-	errFmtLDAPAuthBackendTLSConfigInvalid = "authentication_backend: ldap: tls: %w"
-	errFmtLDAPAuthBackendImplementation   = "authentication_backend: ldap: option 'implementation' " +
+	errFmtLDAPAuthBackendMissingOption     = "authentication_backend: ldap: option '%s' is required"
+	errFmtLDAPAuthBackendTLSConfigInvalid  = "authentication_backend: ldap: tls: %w"
+	errFmtLDAPAuthBackendOptionMustBeOneOf = "authentication_backend: ldap: option '%s' " +
 		errSuffixMustBeOneOf
 	errFmtLDAPAuthBackendFilterReplacedPlaceholders = "authentication_backend: ldap: option " +
 		"'%s' has an invalid placeholder: '%s' has been removed, please use '%s' instead"
@@ -109,6 +109,10 @@ const (
 		"'%s' must contain enclosing parenthesis: '%s' should probably be '(%s)'"
 	errFmtLDAPAuthBackendFilterMissingPlaceholder = "authentication_backend: ldap: option " +
 		"'%s' must contain the placeholder '{%s}' but it's absent"
+	errFmtLDAPAuthBackendFilterMissingPlaceholderGroupSearchMode = "authentication_backend: ldap: option " +
+		"'%s' must contain one of the %s placeholders when using a group_search_mode of '%s' but they're absent"
+	errFmtLDAPAuthBackendFilterMissingAttribute = "authentication_backend: ldap: attributes: option " +
+		"'%s' must be provided when using the %s placeholder but it's absent"
 )
 
 // TOTP Error constants.
@@ -371,17 +375,6 @@ const (
 	operatorNotPattern = "not pattern"
 )
 
-var (
-	validLDAPImplementations = []string{
-		schema.LDAPImplementationCustom,
-		schema.LDAPImplementationActiveDirectory,
-		schema.LDAPImplementationRFC2307bis,
-		schema.LDAPImplementationFreeIPA,
-		schema.LDAPImplementationLLDAP,
-		schema.LDAPImplementationGLAuth,
-	}
-)
-
 const (
 	legacy                      = "legacy"
 	authzImplementationLegacy   = "Legacy"
@@ -397,6 +390,22 @@ var (
 	validAuthzAuthnStrategies = []string{"CookieSession", "HeaderAuthorization", "HeaderProxyAuthorization", "HeaderAuthRequestProxyAuthorization", "HeaderLegacy"}
 )
 
+var (
+	validLDAPImplementations = []string{
+		schema.LDAPImplementationCustom,
+		schema.LDAPImplementationActiveDirectory,
+		schema.LDAPImplementationRFC2307bis,
+		schema.LDAPImplementationFreeIPA,
+		schema.LDAPImplementationLLDAP,
+		schema.LDAPImplementationGLAuth,
+	}
+
+	validLDAPGroupSearchModes = []string{
+		schema.LDAPGroupSearchModeFilter,
+		schema.LDAPGroupSearchModeMemberOf,
+	}
+)
+
 var (
 	validArgon2Variants    = []string{"argon2id", "id", "argon2i", "i", "argon2d", "d"}
 	validSHA2CryptVariants = []string{digestSHA256, digestSHA512}

internal/configuration/validator/const_test.go

@@ -13,6 +13,11 @@ const (
 	testLDAPURL       = "ldap://ldap"
 	testLDAPUser      = "user"
 	testEncryptionKey = "a_not_so_secure_encryption_key"
+
+	member            = "member"
+	memberof          = "memberof"
+	memberOf          = "memberOf"
+	filterMemberOfRDN = "(|({memberof:rdn}))"
 )
 
 const (

internal/suites/HighAvailability/configuration.yml

@@ -21,16 +21,19 @@ authentication_backend:
   ldap:
     address: 'ldap://openldap'
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&({username_attribute}={input})(objectClass=person))
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
-    display_name_attribute: displayName
     user: cn=admin,dc=example,dc=com
     password: password
+    attributes:
+      distinguished_name: 'distinguishedName'
+      username: 'uid'
+      display_name: 'displayName'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 
 access_control:
   default_policy: deny

internal/suites/LDAP/configuration.yml

@@ -22,16 +22,19 @@ authentication_backend:
     tls:
       skip_verify: true
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&(|({username_attribute}={input})({mail_attribute}={input}))(objectClass=person)(objectClass=inetOrgPerson))  # yamllint disable-line rule:line-length
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
-    display_name_attribute: displayName
     user: cn=pwmanager,dc=example,dc=com
     password: password
+    attributes:
+      distinguished_name: ''
+      username: 'uid'
+      display_name: 'displayName'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 
 session:
   secret: unsecure_session_secret

internal/suites/example/kube/authelia/configs/configuration.yml

@@ -20,15 +20,18 @@ authentication_backend:
     tls:
       skip_verify: true
     base_dn: dc=example,dc=com
-    username_attribute: uid
     additional_users_dn: ou=users
     users_filter: (&({username_attribute}={input})(objectClass=person))
     additional_groups_dn: ou=groups
     groups_filter: (&(member={dn})(objectClass=groupOfNames))
-    group_name_attribute: cn
-    mail_attribute: mail
-    display_name_attribute: displayName
     user: cn=admin,dc=example,dc=com
+    attributes:
+      distinguished_name: ''
+      username: 'uid'
+      display_name: 'displayName'
+      mail: 'mail'
+      member_of: 'memberOf'
+      group_name: 'cn'
 
 access_control:
   default_policy: deny