MinIO provides a custom STS API that allows integration with LDAP
based corporate environments. The flow is as follows:
MinIO provides a custom STS API that allows integration with LDAP based corporate environments. The flow is as follows:
1. User provides their AD/LDAP username and password to the STS API.
2. MinIO logs-in to the AD/LDAP server as the user - if the login
succeeds the user is authenticated.
3. MinIO then queries the AD/LDAP server for a list of groups that the
user is a member of.
2. MinIO logs-in to the AD/LDAP server as the user - if the login succeeds the user is authenticated.
3. MinIO then queries the AD/LDAP server for a list of groups that the user is a member of.
- This is done via a customizable AD/LDAP search query.
4. MinIO then generates temporary credentials for the user storing the
list of groups in a cryptographically secure session token. The
temporary access key, secret key and session token are returned to
the user.
5. The user can now use these credentials to make requests to the
MinIO server.
The administrator will associate IAM access policies with each group
and if required with the user too. The MinIO server then evaluates
applicable policies on a user (these are the policies associated with
the groups along with the policy on the user if any) to check if the
request should be allowed or denied.
4. MinIO then generates temporary credentials for the user storing the list of groups in a cryptographically secure session token. The temporary access key, secret key and session token are returned to the user.
5. The user can now use these credentials to make requests to the MinIO server.
The administrator will associate IAM access policies with each group and if required with the user too. The MinIO server then evaluates applicable policies on a user (these are the policies associated with the groups along with the policy on the user if any) to check if the request should be allowed or denied.
## Configuring AD/LDAP on MinIO
LDAP configuration is designed to be simple for the MinIO administrator.
The full path of a user DN (Distinguished Name)
(e.g. `uid=johnwick,cn=users,cn=accounts,dc=minio,dc=io`) is
configured as a format string in the
**MINIO_IDENTITY_LDAP_USERNAME_FORMAT** environment variable. This
allows an AD/LDAP user to not specify this whole string in the AD/LDAP STS
API. Instead the user only needs to specify the username portion
(i.e. `johnwick` in this example) that will be substituted into the
format string configured on the server.
MinIO can be configured to find the groups of a user from AD/LDAP by
specifying the **MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER** and
variables. When a user logs in via the STS API, the MinIO server
queries the AD/LDAP server with the given search filter and extracts the
given attribute from the search results. These values represent the
groups that the user is a member of. On each access MinIO applies the
IAM policies attached to these groups in MinIO.
LDAP configuration is designed to be simple for the MinIO administrator. The full path of a user DN (Distinguished Name) (e.g. `uid=johnwick,cn=users,cn=accounts,dc=minio,dc=io`) is configured as a format string in the **MINIO_IDENTITY_LDAP_USERNAME_FORMAT** environment variable. This allows an AD/LDAP user to not specify this whole string in the AD/LDAP STS API. Instead the user only needs to specify the username portion (i.e. `johnwick` in this example) that will be substituted into the format string configured on the server.
MinIO can be configured to find the groups of a user from AD/LDAP by specifying the **MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER** and **MINIO_IDENTITY_LDAP_GROUP_NAME_ATTRIBUTE** environment variables. When a user logs in via the STS API, the MinIO server queries the AD/LDAP server with the given search filter and extracts the given attribute from the search results. These values represent the groups that the user is a member of. On each access MinIO applies the IAM policies attached to these groups in MinIO.
LDAP is configured via the following environment variables:
@ -56,9 +29,7 @@ LDAP is configured via the following environment variables:
### Variable substitution in AD/LDAP configuration strings
In the configuration values described above, some values support
runtime substitutions. The substitution syntax is simply
`${variable}` - this substring is replaced with the (string) value of
`variable`. The following substitutions will be available:
In the configuration values described above, some values support runtime substitutions. The substitution syntax is simply `${variable}` - this substring is replaced with the (string) value of `variable`. The following substitutions will be available:
| Variable | Example Runtime Value | Description |
| *username* | "james" | The AD/LDAP username of a user. |
| *usernamedn* | "uid=james,cn=accounts,dc=myldapserver,dc=com" | The AD/LDAP username DN of a user. This is constructed from the AD/LDAP user DN format string provided to the server and the actual AD/LDAP username. |
The **MINIO_IDENTITY_LDAP_USERNAME_FORMAT** environment variable
supports substitution of the *username* variable only.
The **MINIO_IDENTITY_LDAP_USERNAME_FORMAT** environment variable supports substitution of the *username* variable only.
The **MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER** and
support substitution of the *username* and *usernamedn* variables
only.
The **MINIO_IDENTITY_LDAP_GROUP_SEARCH_FILTER** and **MINIO_IDENTITY_LDAP_GROUP_SEARCH_BASE_DN** environment variables support substitution of the *username* and *usernamedn* variables only.
## Notes on configuring with Microsoft Active Directory (AD)
The LDAP STS API also works with Microsoft AD and can be configured
as above. The following are some notes on determining the values of
the configuration parameters described above.
The LDAP STS API also works with Microsoft AD and can be configured as above. The following are some notes on determining the values of the configuration parameters described above.
Once LDAP over TLS is enabled on AD, test access to LDAP works by running a
sample search query with the `ldapsearch` utility from
[OpenLDAP](https://openldap.org/):
Once LDAP over TLS is enabled on AD, test access to LDAP works by running a sample search query with the `ldapsearch` utility from [OpenLDAP](https://openldap.org/):
The lines with "..." represent skipped content not shown here from brevity.
Based on the output above, we see that the username format variable looks like
`cn=${username},cn=users,dc=minioad,dc=local`.
The lines with "..." represent skipped content not shown here from brevity. Based on the output above, we see that the username format variable looks like `cn=${username},cn=users,dc=minioad,dc=local`.
The group search filter looks like
`(&(objectclass=group)(member=${usernamedn}))` and the group name attribute is
clearly `cn`.
The group search filter looks like `(&(objectclass=group)(member=${usernamedn}))` and the group name attribute is clearly `cn`.
Thus the key configuration parameters look like:
@ -234,32 +189,24 @@ $ go run ldap.go -u foouser -p foopassword
## Managing User/Group Access Policy
Access policies may be configured on a group or on a user directly. Access
policies are first defined on the MinIO server using IAM policy JSON syntax. The
`mc` tool is used to issue the necessary commands.
Access policies may be configured on a group or on a user directly. Access policies are first defined on the MinIO server using IAM policy JSON syntax. The `mc` tool is used to issue the necessary commands.
**Note that by default no policy is set on a user**. Thus even if they
successfully authenticate with AD/LDAP credentials, they have no access to
object storage as the default access policy is to deny all access.
**Note that by default no policy is set on a user**. Thus even if they successfully authenticate with AD/LDAP credentials, they have no access to object storage as the default access policy is to deny all access.
To define a new policy, you can use the [AWS policy
generator](https://awspolicygen.s3.amazonaws.com/policygen.html). Copy the
policy into a text file `mypolicy.json` and issue the command like so:
To define a new policy, you can use the [AWS policy generator](https://awspolicygen.s3.amazonaws.com/policygen.html). Copy the policy into a text file `mypolicy.json` and issue the command like so:
```shell
```sh
mc admin policy add myminio mypolicy mypolicy.json
```
To assign the policy to a user or group, use:
```shell
```sh
mc admin policy set myminio mypolicy user=james
```
```sh
mc admin policy set myminio mypolicy group=bigdatausers
```
**Please note that when AD/LDAP is configured, MinIO will not support long term
users defined internally.** Only AD/LDAP users are allowed. In addition to this,
the server will not support operations on users or groups using `mc admin user`
or `mc admin group` commands. This is because users and groups are defined
externally in AD/LDAP.
**Please note that when AD/LDAP is configured, MinIO will not support long term users defined internally.** Only AD/LDAP users are allowed. In addition to this, the server will not support operations on users or groups using `mc admin user` or `mc admin group` commands except `mc admin user info` and `mc admin group info` to list set policies for users and groups. This is because users and groups are defined externally in AD/LDAP.
Harshavardhana
5 years ago
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