[SSO, API] Add Matrix auth API (https://monsterware.dev/monsterpit/matrix-synapse-rest-password-provider)

3 files changed, 154 insertions, 1 deletions

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 8154924b9..5e12e89c8 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -45,7 +45,7 @@ class ApplicationController < ActionController::Base
   private
 
   def https_enabled?
-    Rails.env.production? && !request.path.start_with?('/health')
+    Rails.env.production? && !request.path.start_with?('/health', '/_matrix-internal/')
   end
 
   def authorized_fetch_mode?
diff --git a/app/controllers/matrix/base_controller.rb b/app/controllers/matrix/base_controller.rb
new file mode 100644
index 000000000..5922501ec
--- /dev/null
+++ b/app/controllers/matrix/base_controller.rb
@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+class Matrix::BaseController < ApplicationController
+  include RateLimitHeaders
+
+  skip_before_action :store_current_location
+  skip_before_action :require_functional!
+
+  before_action :set_cache_headers
+
+  protect_from_forgery with: :null_session
+
+  skip_around_action :set_locale
+
+  rescue_from ActiveRecord::RecordInvalid, Mastodon::ValidationError do |e|
+    render json: { success: false, error: e.to_s }, status: 422
+  end
+
+  rescue_from ActiveRecord::RecordNotUnique do
+    render json: { success: false, error: 'Duplicate record' }, status: 422
+  end
+
+  rescue_from ActiveRecord::RecordNotFound do
+    render json: { success: false, error: 'Record not found' }, status: 404
+  end
+
+  rescue_from HTTP::Error, Mastodon::UnexpectedResponseError do
+    render json: { success: false, error: 'Remote data could not be fetched' }, status: 503
+  end
+
+  rescue_from OpenSSL::SSL::SSLError do
+    render json: { success: false, error: 'Remote SSL certificate could not be verified' }, status: 503
+  end
+
+  rescue_from Mastodon::NotPermittedError do
+    render json: { success: false, error: 'This action is not allowed' }, status: 403
+  end
+
+  rescue_from Mastodon::RaceConditionError do
+    render json: { success: false, error: 'There was a temporary problem serving your request, please try again' }, status: 503
+  end
+
+  rescue_from Mastodon::RateLimitExceededError do
+    render json: { auth: { success: false }, success: false, error: I18n.t('errors.429') }, status: 429
+  end
+
+  rescue_from ActionController::ParameterMissing do |e|
+    render json: { success: false, error: e.to_s }, status: 400
+  end
+
+  def doorkeeper_unauthorized_render_options(error: nil)
+    { json: { success: false, error: (error.try(:description) || 'Not authorized') } }
+  end
+
+  def doorkeeper_forbidden_render_options(*)
+    { json: { success: false, error: 'This action is outside the authorized scopes' } }
+  end
+
+  protected
+
+  def current_resource_owner
+    @current_user ||= User.find(doorkeeper_token.resource_owner_id) if doorkeeper_token
+  end
+
+  def current_user
+    current_resource_owner || super
+  rescue ActiveRecord::RecordNotFound
+    nil
+  end
+
+  def require_authenticated_user!
+    render json: { success: false, error: 'This method requires an authenticated user' }, status: 401 unless current_user
+  end
+
+  def require_user!
+    if !current_user
+      render json: { success: false, error: 'This method requires an authenticated user' }, status: 422
+    elsif current_user.disabled?
+      render json: { success: false, error: 'Your login is currently disabled' }, status: 403
+    elsif !current_user.confirmed?
+      render json: { success: false, error: 'Your login is missing a confirmed e-mail address' }, status: 403
+    elsif !current_user.approved?
+      render json: { success: false, error: 'Your login is currently pending approval' }, status: 403
+    else
+      set_user_activity
+    end
+  end
+
+  def render_empty
+    render json: {}, status: 200
+  end
+
+  def authorize_if_got_token!(*scopes)
+    doorkeeper_authorize!(*scopes) if doorkeeper_token
+  end
+
+  def set_cache_headers
+    response.headers['Cache-Control'] = 'no-cache, no-store, max-age=0, must-revalidate'
+  end
+end
diff --git a/app/controllers/matrix/identity/v1/check_credentials_controller.rb b/app/controllers/matrix/identity/v1/check_credentials_controller.rb
new file mode 100644
index 000000000..1969d354b
--- /dev/null
+++ b/app/controllers/matrix/identity/v1/check_credentials_controller.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+class Matrix::Identity::V1::CheckCredentialsController < Matrix::BaseController
+  def create
+    matrix_profile = matrix_profile_json
+    return render json: fail_json, status: 403 if matrix_profile.blank?
+
+    render json: matrix_profile
+  rescue ActionController::ParameterMissing, ActiveRecord::RecordNotFound
+    render json: fail_json, status: 403
+  end
+
+  private
+
+  def resource_params
+    params.require(:user).permit(:id, :password)
+  end
+
+  def matrix_domains
+    ENV.fetch('MATRIX_AUTH_DOMAINS', '').delete(',').split.to_set
+  end
+
+  def matrix_profile_json
+    user_params = resource_params
+    return unless user_params[:id].present? && user_params[:password].present? && user_params[:id][0] == '@'
+
+    (username, domain) = user_params[:id].downcase.split(':', 2)
+    return unless matrix_domains.include?(domain)
+
+    user = User.find_by_lower_username!(username[1..-1])
+    return unless user.valid_password?(user_params[:password])
+
+    {
+      auth: {
+        success: true,
+        mxid: user_params[:id],
+        profile: {
+          display_name: user.account.display_name.presence || user.username,
+          three_pids: [
+            {
+              medium: 'email',
+              address: user.email,
+            },
+          ]
+        }
+      }
+    }
+  end
+
+  def fail_json
+    { auth: { success: false } }
+  end
+end