Prevent API access for unconfirmed users

- Add feature flag to disable `unconfirmed` condition.

app/policies/base_policy.rb

@@ -21,6 +21,14 @@ class BasePolicy < DeclarativePolicy::Base
   with_options scope: :user, score: 0
   condition(:deactivated) { @user&.deactivated? }
 
+  desc "User email is unconfirmed or user account is locked"
+  with_options scope: :user, score: 0
+  condition(:inactive) do
+    Feature.enabled?(:inactive_policy_condition, default_enabled: true) &&
+      @user &&
+      !@user&.active_for_authentication?
+  end
+
   with_options scope: :user, score: 0
   condition(:external_user) { @user.nil? || @user.external? }
 

app/policies/global_policy.rb

@@ -36,6 +36,13 @@ class GlobalPolicy < BasePolicy
     enable :use_slash_commands
   end
 
+  rule { inactive }.policy do
+    prevent :log_in
+    prevent :access_api
+    prevent :access_git
+    prevent :use_slash_commands
+  end
+
   rule { blocked | internal }.policy do
     prevent :log_in
     prevent :access_api

changelogs/unreleased/security-email-confirmation-bypass-via-api-ee.yml

+---
+title: Prevent API access for unconfirmed users
+merge_request:
+author:
+type: security

spec/policies/global_policy_spec.rb

@@ -141,6 +141,34 @@ describe GlobalPolicy do
         it { is_expected.to be_allowed(:access_api) }
       end
     end
+
+    context 'inactive user' do
+      before do
+        current_user.update!(confirmed_at: nil, confirmation_sent_at: 5.days.ago)
+      end
+
+      context 'when within the confirmation grace period' do
+        before do
+          allow(User).to receive(:allow_unconfirmed_access_for).and_return(10.days)
+        end
+
+        it { is_expected.to be_allowed(:access_api) }
+      end
+
+      context 'when confirmation grace period is expired' do
+        before do
+          allow(User).to receive(:allow_unconfirmed_access_for).and_return(2.days)
+        end
+
+        it { is_expected.not_to be_allowed(:access_api) }
+      end
+
+      it 'when `inactive_policy_condition` feature flag is turned off' do
+        stub_feature_flags(inactive_policy_condition: false)
+
+        is_expected.to be_allowed(:access_api)
+      end
+    end
   end
 
   describe 'receive notifications' do
@@ -202,6 +230,20 @@ describe GlobalPolicy do
       it { is_expected.not_to be_allowed(:access_git) }
     end
 
+    describe 'inactive user' do
+      before do
+        current_user.update!(confirmed_at: nil)
+      end
+
+      it { is_expected.not_to be_allowed(:access_git) }
+
+      it 'when `inactive_policy_condition` feature flag is turned off' do
+        stub_feature_flags(inactive_policy_condition: false)
+
+        is_expected.to be_allowed(:access_git)
+      end
+    end
+
     context 'when terms are enforced' do
       before do
         enforce_terms
@@ -298,6 +340,20 @@ describe GlobalPolicy do
       it { is_expected.not_to be_allowed(:use_slash_commands) }
     end
 
+    describe 'inactive user' do
+      before do
+        current_user.update!(confirmed_at: nil)
+      end
+
+      it { is_expected.not_to be_allowed(:use_slash_commands) }
+
+      it 'when `inactive_policy_condition` feature flag is turned off' do
+        stub_feature_flags(inactive_policy_condition: false)
+
+        is_expected.to be_allowed(:use_slash_commands)
+      end
+    end
+
     context 'when access locked' do
       before do
         current_user.lock_access!

spec/requests/api/oauth_tokens_spec.rb

@@ -30,26 +30,40 @@ describe 'OAuth tokens' do
       end
     end
 
-    context "when user is blocked" do
-      it "does not create an access token" do
-        user = create(:user)
+    shared_examples 'does not create an access token' do
+      let(:user) { create(:user) }
+
+      it { expect(response).to have_gitlab_http_status(401) }
+    end
+
+    context 'when user is blocked' do
+      before do
         user.block
 
         request_oauth_token(user)
-
-        expect(response).to have_gitlab_http_status(401)
       end
+
+      include_examples 'does not create an access token'
     end
 
-    context "when user is ldap_blocked" do
-      it "does not create an access token" do
-        user = create(:user)
+    context 'when user is ldap_blocked' do
+      before do
         user.ldap_block
 
         request_oauth_token(user)
+      end
 
-        expect(response).to have_gitlab_http_status(401)
+      include_examples 'does not create an access token'
+    end
+
+    context 'when user account is not confirmed' do
+      before do
+        user.update!(confirmed_at: nil)
+
+        request_oauth_token(user)
       end
+
+      include_examples 'does not create an access token'
     end
   end
 end