NXD: access token should be valid for project and namespace

when doing git clone https://gitlab-ci-token:RUNNER_TOKEN@GITLAB_URL/NAMESPACE/PROJECT.git
user is always gitlab-ci-token and cannot be used to identify the project, runner token
is not unique per project.

If two projects in the namespace has the same token and the wrong project is returned by
`build_access_token_check` method, gitlab will simply return 404.

`build_access_token_check` now take namespace_id as parameter so that we can ensure that
we authenticate on the right project.

app/controllers/jwt_controller.rb

@@ -23,7 +23,9 @@ class JwtController < ApplicationController
     @authentication_result = Gitlab::Auth::Result.new(nil, nil, :none, Gitlab::Auth.read_authentication_abilities)
 
     authenticate_with_http_basic do |login, password|
-      @authentication_result = Gitlab::Auth.find_for_git_client(login, password, project: nil, ip: request.ip)
+      @authentication_result = Gitlab::Auth.find_for_git_client(
+        login, password, project: nil, ip: request.ip,
+        namespace_id: params[:namespace_id])
 
       render_unauthorized unless @authentication_result.success? &&
           (@authentication_result.actor.nil? || @authentication_result.actor.is_a?(User))

app/controllers/projects/git_http_client_controller.rb

@@ -125,7 +125,8 @@ class Projects::GitHttpClientController < Projects::ApplicationController
 
   def handle_basic_authentication(login, password)
     @authentication_result = Gitlab::Auth.find_for_git_client(
-      login, password, project: project, ip: request.ip)
+      login, password, project: project, ip: request.ip,
+      namespace_id: params[:namespace_id])
 
     return false unless @authentication_result.success?
 

lib/gitlab/auth.rb

@@ -7,7 +7,7 @@ module Gitlab
     OPTIONAL_SCOPES = SCOPES - DEFAULT_SCOPES
 
     class << self
-      def find_for_git_client(login, password, project:, ip:)
+      def find_for_git_client(login, password, project:, ip:, namespace_id:)
         raise "Must provide an IP for rate limiting" if ip.nil?
 
         # `user_with_password_for_git` should be the last check
@@ -15,7 +15,7 @@ module Gitlab
         # is enabled.
         result =
           service_request_check(login, password, project) ||
-          build_access_token_check(login, password) ||
+          build_access_token_check(login, password, namespace_id: namespace_id) ||
           lfs_token_check(login, password) ||
           oauth_access_token_check(login, password) ||
           personal_access_token_check(login, password) ||
@@ -151,14 +151,18 @@ module Gitlab
         end
       end
 
-      def build_access_token_check(login, password)
+      def build_access_token_check(login, password, namespace_id:)
         return unless login == 'gitlab-ci-token'
         return unless password
 
         # XXX-nxd: we also accept runners_token if enabled on projects
-        project = Project.with_builds_enabled.find_by(runners_token: password)
+        namespace = Namespace.find_by_path_or_name(namespace_id)
+        if namespace
+          # find for project in the given namespace
+          project = Project.with_builds_enabled.find_by(runners_token: password, namespace_id: namespace.id)
           if project
             Gitlab::Auth::Result.new(nil, project, :ci, build_authentication_abilities)
+          end
         else
           build = ::Ci::Build.running.find_by_token(password)
           return unless build