Teleport

Teleport Mattermost Plugin Setup

This guide will explain how to set up Teleport with Mattermost, an open source messaging platform. Teleport's Mattermost integration allows teams to approve or deny Teleport Access Requests using Mattermost.

Example Mattermost request

Setup

Prerequisites

This guide assumes that you have:

A running Teleport Cluster
Admin privileges with access to tctl
A Mattermost account with admin privileges. This plugin has been tested with Mattermost 5.x

Teleport Cloud requires that plugins connect through the Proxy Service (mytenant.teleport.sh:443). Open Source and Enterprise installations can connect to the Auth Service (auth.example.com:3025) directly.

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=teleport.example.com [email protected]
tctl status
Cluster  teleport.example.com
Version  10.1.2
CA pin   sha256:abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678abdc1245efgh5678

You can run subsequent tctl commands in this guide on your local machine.

For full privileges, you can also run tctl commands on your Auth Service host.

To connect to Teleport, log in to your cluster using tsh, then use tctl remotely:

tsh login --proxy=myinstance.teleport.sh [email protected]
tctl status
Cluster  myinstance.teleport.sh
Version  9.3.10
CA pin   sha256:sha-hash-here

You must run subsequent tctl commands in this guide on your local machine.

Setting up Mattermost to work with the bot

In Mattermost, go to System Console → Integrations → Enable Bot Account Creation → Set to True. This will allow you to create a new bot account that the Teleport bot will use.

Go back to your team, then Integrations → Bot Accounts → Add Bot Account.

The new bot account will need Post All permission.

App Icon: Download Teleport Bot Icon

Create an OAuth 2.0 application

In Mattermost, go to System Console → Integrations → OAuth 2.0 Applications.

Set Callback URLs to the location of your Teleport Proxy

The confirmation screen after you've created the bot will give you the access token. We'll use this in the config later.

Create User and Role resources for access

Teleport's Access Request plugins authenticate to your Teleport cluster as a user with permissions to list, read, and update Access Requests. This way, plugins can retrieve Access Requests from the Teleport Auth Service, present them to reviewers, and modify them after a review.

Define a user and role called access-plugin by adding the following content to a file called access-plugin.yaml:

kind: role
version: v5
metadata:
  name: access-plugin
spec:
  allow:
    rules:
      - resources: ['access_request']
        verbs: ['list', 'read', 'update']
      - resources: ['access_plugin_data']
        verbs: ['update']
---
kind: user
metadata:
  name: access-plugin
spec:
  roles: ['access-plugin']
version: v2

Create the user and role:

tctl create -f access-plugin.yaml

As with all Teleport users, the Teleport Auth Service authenticates the access-plugin user by issuing short-lived TLS credentials. In this case, we will need to request the credentials manually by impersonating the access-plugin role and user.

If you are using tctl from the Auth Service host, you will already have impersonation privileges.

To grant your user impersonation privileges for access-plugin, define a role called access-plugin-impersonator by pasting the following YAML document into a file called access-plugin-impersonator.yaml:

kind: role
version: v5
metadata:
  name: access-plugin-impersonator
spec:
  allow:
    impersonate:
      roles:
      - access-plugin
      users:
      - access-plugin

Create the access-plugin-impersonator role:

tctl create -f access-plugin-impersonator.yaml

Retrieve your user definition:

TELEPORT_USER=$(tsh status --format=json | jq -r .active.username)
tctl get users/${TELEPORT_USER?} > myuser.yaml

Edit myuser.yaml to include the role you just created:

  roles:
   - access
   - auditor
   - editor
+  - access-plugin-impersonator

Apply your changes:

tctl create -f myuser.yaml

Log out of your Teleport cluster and log in again. You will now be able to generate signed certificates for the access-plugin role and user.

Export access-plugin Certificate

Like all Teleport users, access-plugin needs signed credentials in order to connect to your Teleport cluster. You will use the tctl auth sign command to request these credentials for your plugin.

The format of the credentials depends on whether you have set up your network to give the plugin direct access to the Teleport Auth Service, or if all Teleport clients and services connect to the Teleport Proxy Service instead.

The following tctl auth sign command impersonates the access-plugin user, generates signed credentials, and writes an identity file to the local directory:

tctl auth sign --user=access-plugin --out=auth.pem

Teleport's Access Request plugins listen for new and updated Access Requests by connecting to the Teleport Auth Service's gRPC endpoint over TLS.

The identity file, auth.pem, includes both TLS and SSH credentials. Your Access Request plugin uses the SSH credentials to connect to the Proxy Service, which establishes a reverse tunnel connection to the Auth Service. The plugin uses this reverse tunnel, along with your TLS credentials, to connect to the Auth Service's gRPC endpoint.

You will refer to this file later when configuring the plugin.

If your network allows your plugin to access the Auth Service directly, e.g., you are running the plugin on the Auth Service host, the plugin uses TLS credentials to connect to the Auth Service's gRPC endpoint and listen for new and updated Access Requests.

You can generate TLS credentials with the following command:

tctl auth sign --format=tls --user=access-plugin --out=auth

This command should result in three PEM-encoded files: auth.crt, auth.key, and auth.cas (certificate, private key, and CA certs respectively). Later, you will configure the plugin to use these credentials to connect to the Auth Service directly.

Certificate Lifetime

By default, tctl auth sign produces certificates with a relatively short lifetime. For production deployments, you can use the --ttl flag to ensure a more practical certificate lifetime, e.g., --ttl=8760h to export a one-year certificate.

We'll reference these files later when configuring the plugins.

Downloading and installing the plugin

We recommend installing the Teleport Plugins alongside the Teleport Proxy. This is an ideal location as plugins have a low memory footprint, and will require both public internet access and Teleport Auth Service access.

curl -L -O https://get.gravitational.com/teleport-access-mattermost-v10.1.2-linux-amd64-bin.tar.gz
tar -xzf teleport-access-mattermost-v10.1.2-linux-amd64-bin.tar.gz
cd teleport-access-mattermost
./install

To install from source you need git and go installed. If you do not have Go installed, visit the Go downloads page.

Checkout teleport-plugins
git clone https://github.com/gravitational/teleport-plugins.git
cd teleport-plugins/access/mattermost
make

Run ./install from teleport-mattermost or place the executable in the appropriate /usr/bin or /usr/local/bin on the server installation.

docker pull quay.io/gravitational/teleport-plugin-mattermost:10.1.2

Configuring Mattermost bot

Mattermost Bot uses a config file in TOML format. Generate a boilerplate config by running the following command:

teleport-mattermost configure > teleport-mattermost.toml
sudo mv teleport-mattermost.toml /etc

Then, edit the config as needed.

# example mattermost configuration TOML file
[teleport]
auth_server = "example.com:3025"                             # Teleport Auth Server GRPC API address
client_key = "/var/lib/teleport/plugins/mattermost/auth.key" # Teleport GRPC client secret key
client_crt = "/var/lib/teleport/plugins/mattermost/auth.crt" # Teleport GRPC client certificate
root_cas = "/var/lib/teleport/plugins/mattermost/auth.cas"   # Teleport cluster CA certs

[mattermost]
url = "https://mattermost.example.com" # Mattermost Server URL
team = "team-name"                     # Mattermost team in which the channel resides.
channel = "channel-name"               # Mattermost Channel name to post requests to
token = "api-token"                    # Mattermost Bot OAuth token
secret = "signing-secret-value"        # Mattermost API signing Secret

[http]
public_addr = "example.com" # URL on which callback server is accessible externally, e.g. [https://]teleport-mattermost.example.com
# listen_addr = ":8081" # Network address in format [addr]:port on which callback server listens, e.g. 0.0.0.0:443
https_key_file = "/var/lib/teleport/plugins/mattermost/server.key"  # TLS private key
https_cert_file = "/var/lib/teleport/plugins/mattermost/server.crt" # TLS certificate

[log]
output = "stderr" # Logger output. Could be "stdout", "stderr" or "/var/lib/teleport/mattermost.log"
severity = "INFO" # Logger severity. Could be "INFO", "ERROR", "DEBUG" or "WARN".

# example mattermost configuration TOML file
[teleport]
auth_server = "myinstance.teleport.sh:443"                   # Teleport Cloud proxy HTTPS address
identity = "/var/lib/teleport/plugins/mattermost/auth.pem"   # Identity file path

[mattermost]
url = "https://mattermost.example.com" # Mattermost Server URL
team = "team-name"                     # Mattermost team in which the channel resides.
channel = "channel-name"               # Mattermost Channel name to post requests to
token = "api-token"                    # Mattermost Bot OAuth token
secret = "signing-secret-value"        # Mattermost API signing Secret

[http]
public_addr = "example.com" # URL on which callback server is accessible externally, e.g. [https://]teleport-mattermost.example.com
# listen_addr = ":8081" # Network address in format [addr]:port on which callback server listens, e.g. 0.0.0.0:443
https_key_file = "/var/lib/teleport/plugins/mattermost/server.key"  # TLS private key
https_cert_file = "/var/lib/teleport/plugins/mattermost/server.crt" # TLS certificate

[log]
output = "stderr" # Logger output. Could be "stdout", "stderr" or "/var/lib/teleport/mattermost.log"
severity = "INFO" # Logger severity. Could be "INFO", "ERROR", "DEBUG" or "WARN".

Testing the plugin

With the config above, you should be able to run the bot invoking teleport-mattermost start -d. The will provide some debug information to make sure the bot can connect to Mattermost.

teleport-mattermost start -d
DEBU   DEBUG logging enabled logrus/exported.go:117
INFO   Starting Teleport Access Mattermost Bot 10.1.2-dev.1: mattermost/main.go:140
DEBU   Checking Teleport server version mattermost/main.go:234
DEBU   Starting a request watcher... mattermost/main.go:296
DEBU   Starting Mattermost API health check... mattermost/main.go:186
DEBU   Starting secure HTTPS server on :8081 utils/http.go:146
DEBU   Watcher connected mattermost/main.go:260
DEBU   Mattermost API health check finished ok mattermost/main.go:19

Set up with SystemD

In production, we recommend starting the Teleport plugin daemon via an init system like systemd. Here's the recommended Teleport plugin service unit file for systemd:

[Unit]
Description=Teleport Mattermost Plugin
After=network.target

[Service]
Type=simple
Restart=on-failure
ExecStart=/usr/local/bin/teleport-mattermost start --config=/etc/teleport-mattermost.toml
ExecReload=/bin/kill -HUP $MAINPID
PIDFile=/run/teleport-mattermost.pid

[Install]
WantedBy=multi-user.target

Save this as teleport-mattermost.service.

Audit log

The plugin will let anyone with access to the Mattermost channel requests so it's important to review Teleport's audit log.

Feedback

If you have any issues with this plugin please create an issue here.

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