refactor: apply "require 2FA" to all subgroup and ancestor group members, when changing

app/models/group.rb

@@ -423,7 +423,7 @@ class Group < Namespace
   def update_two_factor_requirement
     return unless saved_change_to_require_two_factor_authentication? || saved_change_to_two_factor_grace_period?
 
-    User.from_union([users_with_descendants, project_users_with_descendants]).find_each(&:update_two_factor_requirement)
+    direct_and_indirect_members.find_each(&:update_two_factor_requirement)
   end
 
   def path_changed_hook

app/models/user.rb

@@ -728,8 +728,7 @@ class User < ApplicationRecord
   end
 
   def expanded_groups_requiring_two_factor_authentication
-    Group.from_union([all_expanded_groups.where(require_two_factor_authentication: true),
-                      authorized_groups.where(require_two_factor_authentication: true)])
+    all_expanded_groups.where(require_two_factor_authentication: true)
   end
 
   # rubocop: disable CodeReuse/ServiceClass

changelogs/unreleased/feature-require-2fa-for-all-entities-in-group.yml

----
-title: Apply the group setting "require 2FA" to be inherited across all subgroups
-  and descendant projects of the group where it was set. (This works only for postgresql
-  databases, not for mysql/mariadb)
+title: Apply the group setting "require 2FA" across all subgroup and ancestor group members as well when changing the group setting
 merge_request: 24965
 author: rroger
 type: changed

doc/security/two_factor_authentication.md

@@ -39,8 +39,26 @@ If you want to enforce 2FA only for certain groups, you can:
 
 To change this setting, you need to be administrator or owner of the group.
 
-If there are multiple 2FA requirements (i.e. group + all users, or multiple
-groups) the shortest grace period will be used.
+> [From](https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24965) GitLab 12.0, 2FA settings for a group are also applied to subgroups.
+
+If you want to enforce 2FA only for certain groups, you can enable it in the
+group settings and specify a grace period as above. To change this setting you
+need to be administrator or owner of the group.
+
+The following are important notes about 2FA:
+
+- Projects belonging to a 2FA-enabled group that
+  [is shared](../user/project/members/share_project_with_groups.md) 
+  with a 2FA-disabled group will *not* require members of the 2FA-disabled group to use
+  2FA for the project. For example, if project *P* belongs to 2FA-enabled group *A* and 
+  is shared with 2FA-disabled group *B*, members of group *B* can access project *P*
+  without 2FA. To ensure this scenario doesn't occur, 
+  [prevent sharing of projects](../user/group/index.md#share-with-group-lock)
+  for the 2FA-enabled group.
+- If you add additional members to a project within a group or subgroup that has
+  2FA enabled, 2FA is **not** required for those individually added members.
+- If there are multiple 2FA requirements (for example, group + all users, or multiple
+  groups) the shortest grace period will be used.
 
 ## Disabling 2FA for everyone
 

spec/models/group_spec.rb

@@ -603,6 +603,7 @@ describe Group do
   describe '#update_two_factor_requirement' do
     let(:user) { create(:user) }
 
+    context 'group membership' do
       before do
         group.add_user(user, GroupMember::OWNER)
       end
@@ -625,7 +626,10 @@ describe Group do
         group.update!(description: 'foobar')
       end
 
-    def expects_other_user_to_require_two_factors(expected_calls_mysql_db = 1)
+      it 'calls #update_two_factor_requirement on each group member' do
+        other_user = create(:user)
+        group.add_user(other_user, GroupMember::OWNER)
+
         calls = 0
         allow_any_instance_of(User).to receive(:update_two_factor_requirement) do
           calls += 1
@@ -633,43 +637,62 @@ describe Group do
 
         group.update!(require_two_factor_authentication: true, two_factor_grace_period: 23)
 
-      if Group.supports_nested_objects?
         expect(calls).to eq 2
-      else
-        expect(calls).to eq expected_calls_mysql_db
       end
     end
 
-    it 'calls #update_two_factor_requirement on each group member' do
-      other_user = create(:user)
-      group.add_user(other_user, GroupMember::OWNER)
+    context 'sub groups and projects', :nested_groups do
+      it 'enables two_factor_requirement for group member' do
+        group.add_user(user, GroupMember::OWNER)
+
+        group.update!(require_two_factor_authentication: true)
 
-      expects_other_user_to_require_two_factors(2)
+        expect(user.reload.require_two_factor_authentication_from_group).to be_truthy
       end
 
-    it 'calls #update_two_factor_requirement on each subgroup member' do
+      context 'expanded group members', :nested_groups do
+        let(:indirect_user) { create(:user) }
+
+        it 'enables two_factor_requirement for subgroup member' do
           subgroup = create(:group, :nested, parent: group)
-      subgroup_user = create(:user)
-      subgroup.add_user(subgroup_user, GroupMember::OWNER)
+          subgroup.add_user(indirect_user, GroupMember::OWNER)
+
+          group.update!(require_two_factor_authentication: true)
 
-      expects_other_user_to_require_two_factors
+          expect(indirect_user.reload.require_two_factor_authentication_from_group).to be_truthy
         end
 
-    it 'calls #update_two_factor_requirement on each child project member' do
+        it 'enables two_factor_requirement for ancestor group member' do
+          ancestor_group = create(:group)
+          ancestor_group.add_user(indirect_user, GroupMember::OWNER)
+          group.update!(parent: ancestor_group)
+
+          group.update!(require_two_factor_authentication: true)
+
+          expect(indirect_user.reload.require_two_factor_authentication_from_group).to be_truthy
+        end
+      end
+
+      context 'project members' do
+        it 'does not enable two_factor_requirement for child project member' do
           project = create(:project, group: group)
-      project_user = create(:user)
-      project.add_developer(project_user)
+          project.add_maintainer(user)
 
-      expects_other_user_to_require_two_factors(2)
+          group.update!(require_two_factor_authentication: true)
+
+          expect(user.reload.require_two_factor_authentication_from_group).to be_falsey
         end
 
-    it 'calls #update_two_factor_requirement on each subgroups child project member' do
+        it 'does not enable two_factor_requirement for subgroup child project member', :nested_groups do
           subgroup = create(:group, :nested, parent: group)
           project = create(:project, group: subgroup)
-      project_user = create(:user)
-      project.add_developer(project_user)
+          project.add_maintainer(user)
+
+          group.update!(require_two_factor_authentication: true)
 
-      expects_other_user_to_require_two_factors
+          expect(user.reload.require_two_factor_authentication_from_group).to be_falsey
+        end
+      end
     end
   end
 

spec/models/user_spec.rb

@@ -2655,9 +2655,9 @@ describe User do
       end
     end
 
-    context 'with 2FA requirement on nested parent group', :nested_groups do
+    context 'with 2FA requirement from expanded groups', :nested_groups do
       let!(:group1) { create :group, require_two_factor_authentication: true }
-      let!(:group1a) { create :group, require_two_factor_authentication: false, parent: group1 }
+      let!(:group1a) { create :group, parent: group1 }
 
       before do
         group1a.add_user(user, GroupMember::OWNER)
@@ -2685,6 +2685,27 @@ describe User do
       end
     end
 
+    context "with 2FA requirement from shared project's group" do
+      let!(:group1) { create :group, require_two_factor_authentication: true }
+      let!(:group2) { create :group }
+      let(:shared_project) { create(:project, namespace: group1) }
+
+      before do
+        shared_project.project_group_links.create!(
+          group: group2,
+          group_access: ProjectGroupLink.default_access
+        )
+
+        group2.add_user(user, GroupMember::OWNER)
+      end
+
+      it 'does not require 2FA' do
+        user.update_two_factor_requirement
+
+        expect(user.require_two_factor_authentication_from_group).to be false
+      end
+    end
+
     context 'without 2FA requirement on groups' do
       let(:group) { create :group }