LDAP
Authenticate requests against membership information that is stored in a Lightweight Directory Access Protocol (LDAP) server.
About LDAP
The Lightweight Directory Access Protocol (LDAP) is an open protocol that you can use to store and retrieve hierarchically structured data over a network. Many enterprises use LDAP to centrally store and secure organizational information. In particular, LDAP is often used for membership directories. You might set up LDAP to store information such as the following:
- User details like name and email
- Group membership details for each user
- Permissions for each group
You can deploy an LDAP server to your Kubernetes cluster. Then, use a Gloo Gateway external auth policy to authenticate users and control access based on their group membership details in the LDAP server.
Want to learn more about LDAP? Try out this LDAP tutorial by Digital Ocean.
LDAP in Gloo Gateway
Upon receiving an authentication request that uses LDAP, Gloo Gateway performs the following steps.
Gloo Gateway looks for a Basic Authentication header on the request to extract the username (
uid) and credentials (userPassword).If the header is not present, a
401response is returned.If the header is present, Gloo Gateway tries to perform a BIND operation in one of the following ways:
User binding: Gloo Gateway extracts the username from the basic auth header. Then, it builds the distinguished name (DN) for the user entry by substituting the username from the header for the
%splaceholder in the LDAPuserDnTemplatesetting.To prevent injection attacks, special characters are removed from the username before continuing to the next bind step.Service account binding: Instead of giving each user access to the group membership information, you can use an LDAP service account to look up this information on behalf of the user. To authenticate with the LDAP server, you must store the LDAP service account credentials in a Kubernetes secret in your cluster. Then, you reference that secret in your AuthConfig resource. Note that you can only verify the user’s group membership in the LDAP server with the service account.
If the
BINDoperation fails, a401response is returned. This response means that the user could not be found or the credentials are incorrect.Gloo Gateway issues a search operation for the user entry (with a
basescope). In the user entry, Gloo Gateway looks for an attribute with a name equal tomembershipAttributeName.Gloo Gateway checks if one of the values for the attribute matches one of the
allowedGroupsin the policy. If so, Gloo Gateway completes the request. Otherwise, Gloo Gateway returns a403response. This response means that although the user can be authenticated, the user does not have the appropriate permissions to complete the request.
Before you begin
Follow the Get started guide to install Gloo Gateway, set up a gateway resource, and deploy the httpbin sample app.
Get the external address of the gateway and save it in an environment variable.
Deploy an LDAP server
Before you can create an LDAP external auth policy, you must have an LDAP server. The following example configures a simple set of users and groups, and deploys the LDAP server to your cluster.
Download the sample LDAP setup script.
Review what the sample LDAP setup script does. For in-depth information, see About the LDAP setup script. In short, the script sets up LDAP users and groups, as well as creates the following Kubernetes resources:
- A
configmapwith the LDAP server setup configuration. - A
deploymentto run OpenLDAP. - A
serviceto provide access to the deployment.
- A
Make the downloaded script executable.
chmod +x setup-ldap.shRun the LDAP setup script. The script accepts an optional string argument to specify the namespace to create the resources in. Otherwise, you can omit the argument to create the resources in the
defaultnamespace../setup-ldap.shExample output:
No namespace provided, using default namespace Creating configmap with LDAP server bootstrap config... configmap/ldap created Creating LDAP service and deployment... deployment.apps/ldap created service/ldap createdEnable port-forwarding on the deployment so that you can test the LDAP server.
kubectl port-forward deployment/ldap 8088:389In a new tab in your terminal, search for the distinguished names (DNs) of all entries in the
soloandiodomain components (DCs). For more information about this command, see the LDAP docs.ldapsearch -H ldap://localhost:8088 -D "cn=admin,dc=solo,dc=io" -w "solopwd" -b "dc=solo,dc=io" -LLL dnExample output:
dn: dc=solo,dc=io dn: cn=admin,dc=solo,dc=io dn: ou=people,dc=solo,dc=io dn: uid=marco,ou=people,dc=solo,dc=io dn: uid=rick,ou=people,dc=solo,dc=io dn: uid=scottc,ou=people,dc=solo,dc=io dn: ou=groups,dc=solo,dc=io dn: cn=developers,ou=groups,dc=solo,dc=io dn: cn=sales,ou=groups,dc=solo,dc=io dn: cn=managers,ou=groups,dc=solo,dc=io
Good job, now you have an LDAP server running! Continue to Set up LDAP auth.
About the LDAP setup script
The LDAP setup script sets up a basic LDAP server with a few different users and groups. This setup includes the Kubernetes resources to create in the cluster.
#!/usr/bin/env bash
####################################################################################################
# This script is used to deploy an LDAP server with sample user/group configuration to Kubernetes #
####################################################################################################
set -e
if [ -z "$1" ]; then
echo "No namespace provided, using default namespace"
NAMESPACE='default'
else
NAMESPACE=$1
fi
echo "Creating configmap with LDAP server bootstrap config..."
kubectl apply -n "${NAMESPACE}" -f - <<EOF
apiVersion: v1
kind: ConfigMap
metadata:
name: ldap
data:
01_overlay.ldif: |-
######################################################################
# Create a 'memberof' overlay for 'groupOfNames' entries.
#
# This will cause the 'memberOf' attribute to be automatically added
# to user entries when they are referenced in a group entry.
######################################################################
dn: olcOverlay={1}memberof,olcDatabase={1}mdb,cn=config
objectClass: olcOverlayConfig
objectClass: olcMemberOf
olcOverlay: {1}memberof
olcMemberOfDangling: ignore
olcMemberOfRefInt: TRUE
olcMemberOfGroupOC: groupOfNames
olcMemberOfMemberAD: member
olcMemberOfMemberOfAD: memberOf
02_acl.ldif: |-
dn: olcDatabase={1}mdb,cn=config
changeType: modify
######################################################################
# Delete default ACLs that come with Docker image
######################################################################
delete: olcAccess
olcAccess: to attrs=userPassword,shadowLastChange by self write by dn="cn=admin,dc=solo,dc=io" write by anonymous auth by * none
-
delete: olcAccess
olcAccess: to * by self read by dn="cn=admin,dc=solo,dc=io" write by * none
-
######################################################################
# Control access to People
######################################################################
add: olcAccess
olcAccess: to dn.subtree="ou=people,dc=solo,dc=io"
by dn="cn=admin,dc=solo,dc=io" write
by group.exact="cn=managers,ou=groups,dc=solo,dc=io" write
by group.exact="cn=developers,ou=groups,dc=solo,dc=io" read
by group.exact="cn=sales,ou=groups,dc=solo,dc=io" read
by anonymous auth
-
######################################################################
# Control access to Groups
######################################################################
add: olcAccess
olcAccess: to dn.subtree="ou=groups,dc=solo,dc=io"
by dn="cn=admin,dc=solo,dc=io" write
by group.exact="cn=managers,ou=groups,dc=solo,dc=io" write
by group.exact="cn=developers,ou=groups,dc=solo,dc=io" write
-
######################################################################
# This policy applies to the 'userPassword' attribute only
# 'self write' grants only the owner of the entry write permission to this attribute
# 'anonymous auth' grants an anonymous user access to this attribute only for authentication purposes (required for BIND)
# 'developers' group members can update any user's password
######################################################################
add: olcAccess
olcAccess: to attrs=userPassword
by self write
by anonymous auth
by dn="cn=admin,dc=solo,dc=io"
by group.exact="cn=developers,ou=groups,dc=solo,dc=io" write
by * none
-
######################################################################
# This policy applies to all entries under the "dc=solo,dc=io" subtree
# 'managers' have read access at all the organization's information
######################################################################
add: olcAccess
olcAccess: to dn.subtree="dc=solo,dc=io"
by self write
by dn="cn=admin,dc=solo,dc=io" write
by group.exact="cn=managers,ou=groups,dc=solo,dc=io" read
by * none
03_people.ldif: |
# Create a parent 'people' entry
dn: ou=people,dc=solo,dc=io
objectClass: organizationalUnit
ou: people
description: All solo.io people
# Add 'marco'
dn: uid=marco,ou=people,dc=solo,dc=io
objectClass: inetOrgPerson
cn: Marco Schwarz
sn: Schwarz
uid: marco
userPassword: marcopwd
mail: marco.schwarz@solo.io
# Add 'rick'
dn: uid=rick,ou=people,dc=solo,dc=io
objectClass: inetOrgPerson
cn: Rick Duke
sn: Duke
uid: rick
userPassword: rickpwd
mail: rick.duke@solo.io
# Add 'scottc'
dn: uid=scottc,ou=people,dc=solo,dc=io
objectClass: inetOrgPerson
cn: Scott Crawley
sn: Crawley
uid: scottc
userPassword: scottcpwd
mail: scott.crawley@solo.io
04_groups.ldif: |+
# Create top level 'group' entry
dn: ou=groups,dc=solo,dc=io
objectClass: organizationalUnit
ou: groups
description: Generic parent entry for groups
# Create the 'developers' entry under 'groups'
dn: cn=developers,ou=groups,dc=solo,dc=io
objectClass: groupOfNames
cn: developers
description: Developers group
member: uid=marco,ou=people,dc=solo,dc=io
member: uid=rick,ou=people,dc=solo,dc=io
member: uid=scottc,ou=people,dc=solo,dc=io
# Create the 'sales' entry under 'groups'
dn: cn=sales,ou=groups,dc=solo,dc=io
objectClass: groupOfNames
cn: sales
description: Sales group
member: uid=scottc,ou=people,dc=solo,dc=io
# Create the 'managers' entry under 'groups'
dn: cn=managers,ou=groups,dc=solo,dc=io
objectClass: groupOfNames
cn: managers
description: Managers group
member: uid=rick,ou=people,dc=solo,dc=io
EOF
echo "Creating LDAP service and deployment..."
kubectl apply -n "${NAMESPACE}" -f - <<EOF
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: ldap
name: ldap
spec:
selector:
matchLabels:
app: ldap
replicas: 1
template:
metadata:
labels:
app: ldap
spec:
volumes:
- name: config
emptyDir: {}
- name: configmap
configMap:
name: ldap
# We need this intermediary step because when Kubernetes mounts a configMap to a directory,
# it generates additional files that the LDAP server tries to load, causing it to fail.
initContainers:
- name: copy-config
image: busybox
command: ['sh', '-c', 'cp /configmap/*.ldif /config']
volumeMounts:
- name: configmap
mountPath: /configmap
# This is the volume that will be mounted to the LDAP container
- name: config
mountPath: /config
containers:
- image: osixia/openldap:1.2.5
name: openldap
args: ["--copy-service", "--loglevel", "debug"]
env:
- name: LDAP_ORGANISATION
value: "Solo.io"
- name: LDAP_DOMAIN
value: "solo.io"
- name: LDAP_ADMIN_PASSWORD
value: "solopwd"
ports:
- containerPort: 389
name: ldap
- containerPort: 636
name: ldaps
volumeMounts:
- mountPath: /container/service/slapd/assets/config/bootstrap/ldif/custom
name: config
---
apiVersion: v1
kind: Service
metadata:
name: ldap
labels:
app: ldap
spec:
ports:
- port: 389
protocol: TCP
selector:
app: ldap
EOF
About the LDAP users and groups
The root of the LDAP directory hierarchy is the dc=solo,dc=io entry, which has two child entries for users and groups.
Summary of LDAP credentials
The user credentials and memberships are summarized in the following table.
| Username | Password | Member of developers | Member of sales | Member of managers |
|---|---|---|---|---|
| marco | marcopwd | ✅ | ❌ | ❌ |
| rick | rickpwd | ✅ | ❌ | ✅ |
| scott | scottpwd | ✅ | ✅ | ❌ |
Set up LDAP auth
Create an AuthConfig resource and add your external authentication rules.
Create a RouteOption resource and reference the AuthConfig resource that you just created.
kubectl apply -f- <<EOF apiVersion: gateway.solo.io/v1 kind: RouteOption metadata: name: ldap-auth namespace: httpbin spec: options: extauth: configRef: name: ldap-auth namespace: httpbin EOFCreate an HTTPRoute resource for the httpbin app that requires authentication for requests on the
extauth.exampledomain.kubectl apply -f- <<EOF apiVersion: gateway.networking.k8s.io/v1beta1 kind: HTTPRoute metadata: name: httpbin-ldap-auth namespace: httpbin spec: parentRefs: - name: http namespace: gloo-system hostnames: - extauth.example rules: - filters: - type: ExtensionRef extensionRef: group: gateway.solo.io kind: RouteOption name: ldap-auth backendRefs: - name: httpbin port: 8000 EOF
Test LDAP auth
To test the LDAP policy, make a series of requests as different users. The following table is based off the users that you created in your LDAP config map. The username and password are encoded to base 64 in the format username:password so that you can pass them in a basic auth header.
| Username | Password | Basic auth header | Notes |
|---|---|---|---|
| marco | marcopwd | Authorization: Basic bWFyY286bWFyY29wd2Q= | Member of developers group |
| rick | rickpwd | Authorization: Basic cmljazpyaWNrcHdk | Member of developers and managers groups |
| john | doe | Authorization: Basic am9objpkb2U= | Unknown user, not a member of any group |
Send a request to the httpbin app on the
extauth.exampledomain without a user. Verify that your request is denied and that you get back a 401 HTTP response code.Example output:
* Mark bundle as not supporting multiuse < HTTP/1.1 401 Unauthorized < www-authenticate: Basic realm="gloo" < date: Fri, 19 Apr 2024 17:41:01 GMT < server: envoy < content-length: 0Send another request to the httpbin app. This time, you include the credentials of the unknown member,
john. Verify that the request is blocked and that you get back a 401 HTTP response code.Example output:
* Mark bundle as not supporting multiuse < HTTP/1.1 401 Unauthorized < www-authenticate: Basic realm="gloo" < date: Fri, 19 Apr 2024 17:41:01 GMT < server: envoy < content-length: 0Send another request to the httpbin app. This time, you use the credentials of the known member,
marco. This user is a member of thedevelopersgroup, but the LDAP policy only grants permission to members of themanagersgroup. The request is blocked, but this time with a 403 Forbidden response to indicate the lack of permissions.Example output:
* Mark bundle as not supporting multiuse < HTTP/1.1 403 Forbidden < date: Tue, 04 Jun 2024 19:52:55 GMT < server: envoy < content-length: 0Finally, send another request with the credentials of the
rick, who is a member of themanagersgroup and meets the LDAP policy requirements. Verify that you get back a 200 HTTP response code.Example output:
* Mark bundle as not supporting multiuse < HTTP/1.1 200 OK < access-control-allow-credentials: true < access-control-allow-origin: * < date: Tue, 04 Jun 2024 19:53:19 GMT < content-length: 0 < x-envoy-upstream-service-time: 1 < server: envoy
Cleanup
You can optionally remove the resources that you created in this guide.
kubectl delete authconfig ldap-auth -n httpbin
kubectl delete routeoption ldap-auth -n httpbin
kubectl delete httproute httpbin-ldap-auth -n httpbin
kubectl delete secret ldapcredentials -n httpbin
kubectl delete configmap ldap
kubectl delete deployment ldap
kubectl delete service ldap