ImportExport::ExportService to require admin_project permission

It only requires admin_project for actual exports. Creating project from
template also uses ImportExport::ExportService but users usually do not
have admin_project on the template source and it should not be required.

app/models/project.rb

@@ -2339,6 +2339,10 @@ class Project < ApplicationRecord
     end
   end
 
+  def template_source?
+    false
+  end
+
   private
 
   def closest_namespace_setting(name)

app/services/projects/import_export/export_service.rb

@@ -4,6 +4,12 @@ module Projects
   module ImportExport
     class ExportService < BaseService
       def execute(after_export_strategy = nil, options = {})
+        unless project.template_source? || can?(current_user, :admin_project, project)
+          raise ::Gitlab::ImportExport::Error.new(
+            "User with ID: %s does not have permission to Project %s with ID: %s." %
+              [current_user.id, project.name, project.id])
+        end
+
         @shared = project.import_export_shared
 
         save_all!

changelogs/unreleased/security-project_export_service_permission_check.yml

+---
+title: ImportExport::ExportService to require admin_project permission
+merge_request:
+author:
+type: security

ee/app/models/ee/project.rb

@@ -728,6 +728,13 @@ module EE
       strong_memoize(:license_compliance) { SCA::LicenseCompliance.new(self) }
     end
 
+    override :template_source?
+    def template_source?
+      return true if namespace_id == ::Gitlab::CurrentSettings.current_application_settings.custom_project_templates_group_id
+
+      ::Project.with_groups_level_repos_templates.exists?(id)
+    end
+
     private
 
     def set_override_pull_mirror_available

ee/spec/models/project_spec.rb

@@ -2417,4 +2417,36 @@ describe Project do
       project.expire_caches_before_rename('foo')
     end
   end
+
+  describe '#template_source?' do
+    let_it_be(:group) { create(:group, :private) }
+    let_it_be(:subgroup) { create(:group, :private, parent: group) }
+    let_it_be(:project_template) { create(:project, group: subgroup) }
+
+    context 'when project is not template source' do
+      it 'returns false' do
+        expect(project.template_source?).to be_falsey
+      end
+    end
+
+    context 'instance-level custom project templates' do
+      before do
+        stub_ee_application_setting(custom_project_templates_group_id: subgroup.id)
+      end
+
+      it 'returns true' do
+        expect(project_template.template_source?).to be_truthy
+      end
+    end
+
+    context 'group-level custom project templates' do
+      before do
+        group.update(custom_project_templates_group_id: subgroup.id)
+      end
+
+      it 'returns true' do
+        expect(project_template.template_source?).to be_truthy
+      end
+    end
+  end
 end

ee/spec/services/projects/import_export/export_service_spec.rb

@@ -5,15 +5,55 @@ require 'spec_helper'
 describe Projects::ImportExport::ExportService do
   describe '#execute' do
     let_it_be(:user) { create(:user) }
+
+    context 'user can admin project' do
       let_it_be(:project) { create(:project) }
       let(:shared) { project.import_export_shared }
-    let(:service) { described_class.new(project, user) }
-    let!(:after_export_strategy) { Gitlab::ImportExport::AfterExportStrategies::DownloadNotificationStrategy.new }
+
+      subject { described_class.new(project, user).execute }
+
+      before do
+        project.add_maintainer(user)
+      end
 
       it 'saves the design repo' do
         expect(Gitlab::ImportExport::DesignRepoSaver).to receive(:new).and_call_original
 
-      service.execute
+        subject
+      end
+    end
+
+    context 'project templates' do
+      let_it_be(:group) { create(:group, :private) }
+      let_it_be(:subgroup) { create(:group, :private, parent: group) }
+      let_it_be(:project_template) { create(:project, group: subgroup) }
+      let(:shared) { project_template.import_export_shared }
+
+      subject { described_class.new(project_template, user).execute }
+
+      context 'instance-level custom project templates' do
+        before do
+          stub_ee_application_setting(custom_project_templates_group_id: subgroup.id)
+        end
+
+        it 'succeeds' do
+          expect(Gitlab::ImportExport::Saver).to receive(:save).with(exportable: project_template, shared: shared)
+
+          subject
+        end
+      end
+
+      context 'group-level custom project templates' do
+        before do
+          group.update(custom_project_templates_group_id: subgroup.id)
+        end
+
+        it 'succeeds' do
+          expect(Gitlab::ImportExport::Saver).to receive(:save).with(exportable: project_template, shared: shared)
+
+          subject
+        end
+      end
     end
   end
 end

spec/services/projects/import_export/export_service_spec.rb

@@ -10,6 +10,10 @@ describe Projects::ImportExport::ExportService do
     let(:service) { described_class.new(project, user) }
     let!(:after_export_strategy) { Gitlab::ImportExport::AfterExportStrategies::DownloadNotificationStrategy.new }
 
+    before do
+      project.add_maintainer(user)
+    end
+
     it 'saves the version' do
       expect(Gitlab::ImportExport::VersionSaver).to receive(:new).and_call_original
 
@@ -133,5 +137,18 @@ describe Projects::ImportExport::ExportService do
         expect(service).not_to receive(:execute_after_export_action)
       end
     end
+
+    context 'when user does not have admin_project permission' do
+      let!(:another_user) { create(:user) }
+
+      subject(:service) { described_class.new(project, another_user) }
+
+      it 'fails' do
+        expected_message =
+          "User with ID: %s does not have permission to Project %s with ID: %s." %
+            [another_user.id, project.name, project.id]
+        expect { service.execute }.to raise_error(Gitlab::ImportExport::Error).with_message(expected_message)
+      end
+    end
   end
 end