Require a fresh second factor for user management

Administrative actions are gated behind a 30-minute elevation window:
creating and retiring accounts, editing roles, clearing a second factor.
Reading the list is not gated, and content work is untouched.

elevated? is tied to is_admin?, so losing the role closes the window at
once. The window opens when the second factor verifies at login, so an
admin heading straight for user management is already elevated, and closes
on logout with the other session state. Five wrong codes end the session,
mirroring the login challenge.

users#update carries no elevation filter, since self-service reaches it;
the role field is gated in user_params instead and fails closed.

1 files changed, 44 insertions, 0 deletions

diff --git a/app/controllers/elevations_controller.rb b/app/controllers/elevations_controller.rb
new file mode 100644
index 00000000..804b8f95
--- /dev/null
+++ b/app/controllers/elevations_controller.rb
@@ -0,0 +1,44 @@
+# Step-up authentication for janitorial work. Mirrors the two-step login's
+# attempt cap: verify_otp! guards replay but not rate, and an attacker with a
+# stolen cookie would otherwise have unlimited tries at a six-digit code.
+class ElevationsController < ApplicationController
+  include RoleRequired
+
+  layout 'admin'
+
+  before_action :login_required
+  before_action :require_admin
+
+  MAX_ATTEMPTS = 5
+
+  def new
+    redirect_to admin_path if elevated?
+  end
+
+  def create
+    return render(:new) unless current_user.otp_enrolled?
+
+    session[:elevation_attempts] = session[:elevation_attempts].to_i + 1
+    if session[:elevation_attempts] > MAX_ATTEMPTS
+      logout_killing_session!
+      flash[:error] = t("flash.otp.too_many_attempts")
+      return redirect_to(login_path)
+    end
+
+    if current_user.verify_otp!(params[:code])
+      session.delete(:elevation_attempts)
+      elevate!
+      redirect_to safe_return_to(session.delete(:elevation_return_to),
+                                 :default => users_path)
+    else
+      flash.now[:error] = t("flash.otp.code_mismatch")
+      render :new
+    end
+  end
+
+  def destroy
+    drop_elevation!
+    flash[:notice] = t("flash.elevation.dropped")
+    redirect_to admin_path
+  end
+end