Fix readable_by? method

- Check if the user is a member of the project
if the issue is confidential
- Add specs to cover moved issues

Add specs for ReferenceRedactorFilter

Add check for project access

- When the issue checked in #readable_by?
is confidential the assignee or author should
be able to access the project to view it.

Refactor #readable_by?

- Refactor Issue specs to cover all cases
in readable_by? conditions

Refactor reference_redactor_filter_spec

-  Change empty lines to apply Four-Phase
test pattern

Add specs in IssuePolicy to test moved issue case

app/models/issue.rb

@@ -327,9 +327,7 @@ class Issue < ApplicationRecord
       true
     elsif project.owner == user
       true
-    elsif confidential?
-      author == user ||
-        assignees.include?(user) ||
+    elsif confidential? && !assignee_or_author?(user)
       project.team.member?(user, Gitlab::Access::REPORTER)
     else
       project.public? ||

changelogs/unreleased/security-120026-redact-notes-in-moved-confidential-issues.yml

+---
+title: Redact notes in moved confidential issues
+merge_request:
+author:
+type: security

spec/lib/banzai/filter/reference_redactor_filter_spec.rb

@@ -20,8 +20,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
   it 'skips when the skip_redaction flag is set' do
     user = create(:user)
     project = create(:project)
-
     link = reference_link(project: project.id, reference_type: 'test')
+
     doc = filter(link, current_user: user, skip_redaction: true)
 
     expect(doc.css('a').length).to eq 1
@@ -51,8 +51,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         user = create(:user)
         project = create(:project)
         project.add_maintainer(user)
-
         link = reference_link(project: project.id, reference_type: 'test')
+
         doc = filter(link, current_user: user)
 
         expect(doc.css('a').length).to eq 1
@@ -69,8 +69,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
       it 'removes unpermitted references' do
         user = create(:user)
         project = create(:project)
-
         link = reference_link(project: project.id, reference_type: 'test')
+
         doc = filter(link, current_user: user)
 
         expect(doc.css('a').length).to eq 0
@@ -90,8 +90,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         non_member = create(:user)
         project = create(:project, :public)
         issue = create(:issue, :confidential, project: project)
-
         link = reference_link(project: project.id, issue: issue.id, reference_type: 'issue')
+
         doc = filter(link, current_user: non_member)
 
         expect(doc.css('a').length).to eq 0
@@ -124,8 +124,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         assignee = create(:user)
         project = create(:project, :public)
         issue = create(:issue, :confidential, project: project, assignees: [assignee])
-
         link = reference_link(project: project.id, issue: issue.id, reference_type: 'issue')
+
         doc = filter(link, current_user: assignee)
 
         expect(doc.css('a').length).to eq 1
@@ -136,8 +136,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         project = create(:project, :public)
         project.add_developer(member)
         issue = create(:issue, :confidential, project: project)
-
         link = reference_link(project: project.id, issue: issue.id, reference_type: 'issue')
+
         doc = filter(link, current_user: member)
 
         expect(doc.css('a').length).to eq 1
@@ -147,20 +147,62 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         admin = create(:admin)
         project = create(:project, :public)
         issue = create(:issue, :confidential, project: project)
-
         link = reference_link(project: project.id, issue: issue.id, reference_type: 'issue')
+
         doc = filter(link, current_user: admin)
 
         expect(doc.css('a').length).to eq 1
       end
+
+      context "when a confidential issue is moved from a public project to a private one" do
+        let(:public_project) { create(:project, :public) }
+        let(:private_project) { create(:project, :private) }
+
+        it 'removes references for author' do
+          author = create(:user)
+          issue = create(:issue, :confidential, project: public_project, author: author)
+          issue.update!(project: private_project) # move issue to private project
+          link = reference_link(project: private_project.id, issue: issue.id, reference_type: 'issue')
+
+          doc = filter(link, current_user: author)
+
+          expect(doc.css('a').length).to eq 0
+        end
+
+        it 'removes references for assignee' do
+          assignee = create(:user)
+          issue = create(:issue, :confidential, project: public_project, assignees: [assignee])
+          issue.update!(project: private_project) # move issue to private project
+          link = reference_link(project: private_project.id, issue: issue.id, reference_type: 'issue')
+
+          doc = filter(link, current_user: assignee)
+
+          expect(doc.css('a').length).to eq 0
+        end
+
+        it 'allows references for project members' do
+          member = create(:user)
+          project = create(:project, :public)
+          project_2 = create(:project, :private)
+          project.add_developer(member)
+          project_2.add_developer(member)
+          issue = create(:issue, :confidential, project: project)
+          issue.update!(project: project_2) # move issue to private project
+          link = reference_link(project: project_2.id, issue: issue.id, reference_type: 'issue')
+
+          doc = filter(link, current_user: member)
+
+          expect(doc.css('a').length).to eq 1
+        end
+      end
     end
 
     it 'allows references for non confidential issues' do
       user = create(:user)
       project = create(:project, :public)
       issue = create(:issue, project: project)
-
       link = reference_link(project: project.id, issue: issue.id, reference_type: 'issue')
+
       doc = filter(link, current_user: user)
 
       expect(doc.css('a').length).to eq 1
@@ -172,8 +214,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
       it 'removes unpermitted Group references' do
         user = create(:user)
         group = create(:group, :private)
-
         link = reference_link(group: group.id, reference_type: 'user')
+
         doc = filter(link, current_user: user)
 
         expect(doc.css('a').length).to eq 0
@@ -183,8 +225,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
         user = create(:user)
         group = create(:group, :private)
         group.add_developer(user)
-
         link = reference_link(group: group.id, reference_type: 'user')
+
         doc = filter(link, current_user: user)
 
         expect(doc.css('a').length).to eq 1
@@ -200,8 +242,8 @@ describe Banzai::Filter::ReferenceRedactorFilter do
     context 'with data-user' do
       it 'allows any User reference' do
         user = create(:user)
-
         link = reference_link(user: user.id, reference_type: 'user')
+
         doc = filter(link)
 
         expect(doc.css('a').length).to eq 1

spec/policies/issue_policy_spec.rb

@@ -103,12 +103,24 @@ describe IssuePolicy do
         expect(permissions(author, confidential_issue_no_assignee)).to be_disallowed(:read_issue, :read_issue_iid, :update_issue, :admin_issue)
       end
 
+      it 'does not allow issue author to read or update confidential issue moved to an private project' do
+        confidential_issue.project = build(:project, :private)
+
+        expect(permissions(author, confidential_issue)).to be_disallowed(:read_issue, :read_issue_iid, :update_issue)
+      end
+
       it 'allows issue assignees to read and update their confidential issues' do
         expect(permissions(assignee, confidential_issue)).to be_allowed(:read_issue, :read_issue_iid, :update_issue)
         expect(permissions(assignee, confidential_issue)).to be_disallowed(:admin_issue)
 
         expect(permissions(assignee, confidential_issue_no_assignee)).to be_disallowed(:read_issue, :read_issue_iid, :update_issue, :admin_issue)
       end
+
+      it 'does not allow issue assignees to read or update confidential issue moved to an private project' do
+        confidential_issue.project = build(:project, :private)
+
+        expect(permissions(assignee, confidential_issue)).to be_disallowed(:read_issue, :read_issue_iid, :update_issue)
+      end
     end
   end