gitlab-ce/app/controllers/projects/git_http_client_controller.rb

# This file should be identical in GitLab Community Edition and Enterprise Edition

class Projects::GitHttpClientController < Projects::ApplicationController
  include ActionController::HttpAuthentication::Basic
  include KerberosSpnegoHelper

  attr_reader :actor, :authentication_abilities

  # Git clients will not know what authenticity token to send along
  skip_before_action :verify_authenticity_token
  skip_before_action :repository
  before_action :authenticate_user
  before_action :ensure_project_found!

  private

  def authenticate_user
    if project && project.public? && download_request?
      return # Allow access
    end

    if allow_basic_auth? && basic_auth_provided?
      login, password = user_name_and_password(request)

      if handle_basic_authentication(login, password)
        return # Allow access
      end
    elsif allow_kerberos_spnego_auth? && spnego_provided?
      @actor = find_kerberos_user

      if actor
        send_final_spnego_response
        return # Allow access
      end
    end

    send_challenges
    render plain: "HTTP Basic: Access denied\n", status: 401
  rescue Gitlab::Auth::MissingPersonalTokenError
    render_missing_personal_token
  end

  def basic_auth_provided?
    has_basic_credentials?(request)
  end

  def send_challenges
    challenges = []
    challenges << 'Basic realm="GitLab"' if allow_basic_auth?
    challenges << spnego_challenge if allow_kerberos_spnego_auth?
    headers['Www-Authenticate'] = challenges.join("\n") if challenges.any?
  end

  def ensure_project_found!
    render_not_found if project.blank?
  end

  def project
    return @project if defined?(@project)

    project_id, _ = project_id_with_suffix
    if project_id.blank?
      @project = nil
    else
      @project = Project.find_with_namespace("#{params[:namespace_id]}/#{project_id}")
    end
  end

  # This method returns two values so that we can parse
  # params[:project_id] (untrusted input!) in exactly one place.
  def project_id_with_suffix
    id = params[:project_id] || ''

    %w[.wiki.git .git].each do |suffix|
      if id.end_with?(suffix)
        # Be careful to only remove the suffix from the end of 'id'.
        # Accidentally removing it from the middle is how security
        # vulnerabilities happen!
        return [id.slice(0, id.length - suffix.length), suffix]
      end
    end

    # Something is wrong with params[:project_id]; do not pass it on.
    [nil, nil]
  end

  def render_missing_personal_token
    render plain: "HTTP Basic: Access denied\n" \
                  "You have 2FA enabled, please use a personal access token for Git over HTTP.\n" \
                  "You can generate one at #{profile_personal_access_tokens_url}",
           status: 401
  end

  def repository
    _, suffix = project_id_with_suffix
    if suffix == '.wiki.git'
      project.wiki.repository
    else
      project.repository
    end
  end

  def render_not_found
    render plain: 'Not Found', status: :not_found
  end

  def ci?
    @ci
  end

  def user
    @actor
  end

  def handle_basic_authentication(login, password)
    auth_result = Gitlab::Auth.find_for_git_client(login, password, project: project, ip: request.ip)

    case auth_result.type
    when :ci
      if auth_result.project == project && download_request?
        @ci = true
      else
        return false
      end
    when :oauth
      if download_request?
        @actor = auth_result.actor
        @authentication_abilities = auth_result.authentication_abilities
      else
        return false
      end
    when :lfs_deploy_token
      if download_request?
        @lfs_deploy_key = true
        @actor = auth_result.actor
        @authentication_abilities = auth_result.authentication_abilities
      else
        return false
      end
    when :lfs_token, :personal_token, :gitlab_or_ldap, :build
      @actor = auth_result.actor
      @authentication_abilities = auth_result.authentication_abilities
    else
      # Not allowed
      return false
    end

    true
  end

  def lfs_deploy_key?
    @lfs_deploy_key && actor && actor.projects.include?(project)
  end

  def has_authentication_ability?(capability)
    @authentication_abilities.include?(capability)
  end

  def verify_workhorse_api!
    Gitlab::Workhorse.verify_api_request!(request.headers)
  end
end