Hand impersonation over by signed link, not by a cookie that cannot cross hosts

app/Http/Controllers/ImpersonationController.php

@@ -4,48 +4,70 @@ namespace App\Http\Controllers;
 
 use App\Models\Customer;
 use App\Models\Operator;
+use App\Models\User;
+use Illuminate\Http\Request;
 use Illuminate\Http\RedirectResponse;
 use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\Cache;
+use Illuminate\Support\Facades\URL;
 
 /**
- * Admin impersonation: an admin can log in as a customer's portal account to
+ * Looking at a customer's portal as that customer.
- * inspect their portal during an incident, then return to the admin session.
  *
- * Both guards are named explicitly throughout, never the ambient default: the
+ * Not a shared cookie. Once the console has a hostname of its own, a session
- * operator and the customer are two different models on two different guards
+ * cookie set on the console host never reaches the portal host — SESSION_DOMAIN
- * now, and this is exactly the code that swaps which one is "the" signed-in
+ * is null and cookies are host-bound. So the handover is a signed, single-use
- * user for the request. The full signed-link rewrite (for hosts that do not
+ * link: it works regardless of cookie scope, it expires, and it leaves a record
- * share a cookie at all) is a separate piece of work; this keeps today's
+ * of who looked at whom.
- * same-session handover correct across the split identity in the meantime.
  */
 class ImpersonationController extends Controller
 {
-    /** Admin-gated: become the customer. */
+    /** Sixty seconds is a handover, not a credential. */
+    private const WINDOW = 60;
+
     public function start(Customer $customer): RedirectResponse
     {
         $this->authorize('customers.impersonate');
-        $user = $customer->ensureUser();
 
-        session(['impersonator_id' => Auth::guard('operator')->id()]);
+        $operator = Auth::guard('operator')->user();
-        Auth::guard('web')->login($user);
+
+        // Addressed by CUSTOMER uuid, not user: `users` has no uuid column, and
+        // naming the integer key in a URL is what R11 forbids. The portal end
+        // resolves the account the same way this end would have.
+        return redirect()->away(URL::temporarySignedRoute(
+            'impersonate.enter',
+            now()->addSeconds(self::WINDOW),
+            ['customer' => $customer->uuid, 'operator' => $operator->uuid],
+        ));
+    }
+
+    /** The portal end of the handover. Signed, and good exactly once. */
+    public function enter(Request $request, string $customer, string $operator): RedirectResponse
+    {
+        abort_unless($request->hasValidSignature(), 403);
+
+        // Single use: the signature's own hash is the key, and it lives exactly
+        // as long as the link could. Redis, not the database — the marker is as
+        // short-lived as the link and should not need tidying up.
+        $marker = 'impersonate:'.hash('sha256', (string) $request->query('signature'));
+
+        abort_unless(Cache::add($marker, true, self::WINDOW), 403);
+
+        $target = Customer::where('uuid', $customer)->firstOrFail()->ensureUser();
+        $who = Operator::where('uuid', $operator)->firstOrFail();
+
+        Auth::guard('web')->login($target);
+        session(['impersonator_id' => $who->id]);
 
         return redirect()->route('dashboard');
     }
 
-    /** Return to the admin session (available while impersonating). */
+    /** Back out of the customer's portal. The operator session was never touched. */
     public function leave(): RedirectResponse
     {
-        $operatorId = session()->pull('impersonator_id');
+        session()->forget('impersonator_id');
+        Auth::guard('web')->logout();
 
-        if ($operatorId !== null && ($operator = Operator::query()->find($operatorId)) !== null) {
+        return redirect()->to(\App\Support\AdminArea::home());
-            // Ends the customer session rather than leaving it dangling
-            // alongside the restored operator one.
-            Auth::guard('web')->logout();
-            Auth::guard('operator')->login($operator);
-
-            return redirect()->route('admin.overview');
-        }
-
-        return redirect()->route('dashboard');
     }
 }

routes/web.php

@@ -192,6 +192,11 @@ Route::middleware('guest')->group(function () {
     Route::get('/two-factor-challenge', TwoFactorChallenge::class)->name('two-factor.login');
 });
 
+// Signed and single-use; see ImpersonationController. Deliberately not behind
+// `auth`: following the link is what creates the session.
+Route::get('/impersonate/enter/{customer}/{operator}', [ImpersonationController::class, 'enter'])
+    ->name('impersonate.enter');
+
 // Customer portal — each sidebar tab is a full-page class-based Livewire
 // component (R1/R2); paths are English (R13).
 Route::middleware(['auth', 'customer.active'])->group(function () {

tests/Feature/ImpersonationTest.php

@@ -2,64 +2,78 @@
 
 use App\Models\Customer;
 use App\Models\Operator;
-use App\Models\User;
+use Illuminate\Support\Facades\Auth;
+use Illuminate\Support\Facades\URL;
 
-// admin() helper is defined in HostManagementTest.
+it('hands over a signed link instead of relying on a shared cookie', function () {
-
+    $operator = Operator::factory()->role('Owner')->create();
-it('lets an admin impersonate a customer and returns to the admin session', function () {
-    $admin = admin();
-    $customer = Customer::factory()->create(['email' => 'c@imp.test', 'name' => 'Imp Kunde']);
-
-    $this->actingAs($admin, 'operator')
-        ->post(route('admin.impersonate', $customer->uuid))
-        ->assertRedirect(route('dashboard'));
-
-    $customer->refresh();
-    expect($customer->user_id)->not->toBeNull()
-        ->and(auth()->id())->toBe($customer->user_id)
-        ->and(session('impersonator_id'))->toBe($admin->id);
-
-    // Return to the admin session.
-    $this->post(route('impersonate.leave'))->assertRedirect(route('admin.overview'));
-
-    expect(auth()->id())->toBe($admin->id)
-        ->and(session()->has('impersonator_id'))->toBeFalse();
-});
-
-it('reuses an existing portal user with the same email', function () {
-    $existing = User::factory()->create(['email' => 'shared@imp.test', 'is_admin' => false]);
-    $customer = Customer::factory()->create(['email' => 'shared@imp.test']);
-
-    expect($customer->ensureUser()->id)->toBe($existing->id);
-    expect($customer->fresh()->user_id)->toBe($existing->id);
-});
-
-it('refuses to auto-link an existing portal account while an operator is signed in', function () {
-    // assertNotAdmin() used to check whether the row it found WAS an operator
-    // — structurally impossible now, since operators are not rows in this
-    // table at all. What is left to guard is the moment rather than the row:
-    // ensureUser() must not silently attach a `users` row to a customer while
-    // the caller is an operator.
-    User::factory()->create(['email' => 'ops@imp.test']);
-    $customer = Customer::factory()->create(['email' => 'ops@imp.test']);
-
-    $this->actingAs(Operator::factory()->role('Owner')->create(), 'operator');
-
-    expect(fn () => $customer->ensureUser())->toThrow(RuntimeException::class);
-    expect($customer->fresh()->user_id)->toBeNull();
-});
-
-it('forbids a non-admin from impersonating', function () {
-    $user = User::factory()->create(['is_admin' => false]);
     $customer = Customer::factory()->create();
 
-    $this->actingAs($user)
+    $response = $this->actingAs($operator, 'operator')
-        ->post(route('admin.impersonate', $customer->uuid))
+        ->post(route('admin.impersonate', $customer));
-        ->assertForbidden();
+
+    // The console and the portal are different hosts in exclusive mode, and a
+    // session cookie is host-bound — so the handover cannot be a cookie.
+    $response->assertRedirectContains('signature=');
 });
 
-it('gates impersonation start to authenticated users', function () {
+it('signs the customer in on the web guard when the link is followed', function () {
+    $operator = Operator::factory()->role('Owner')->create();
     $customer = Customer::factory()->create();
+    $user = $customer->ensureUser();
 
-    $this->post(route('admin.impersonate', $customer->uuid))->assertRedirect('/login');
+    $url = URL::temporarySignedRoute('impersonate.enter', now()->addSeconds(60), [
+        'customer' => $customer->uuid, 'operator' => $operator->uuid,
+    ]);
+
+    $this->get($url)->assertRedirect(route('dashboard'));
+
+    expect(Auth::guard('web')->id())->toBe($user->id);
+});
+
+it('refuses the same link twice', function () {
+    $operator = Operator::factory()->role('Owner')->create();
+    $customer = Customer::factory()->create();
+    $user = $customer->ensureUser();
+
+    $url = URL::temporarySignedRoute('impersonate.enter', now()->addSeconds(60), [
+        'customer' => $customer->uuid, 'operator' => $operator->uuid,
+    ]);
+
+    $this->get($url)->assertRedirect(route('dashboard'));
+    Auth::guard('web')->logout();
+
+    // A link that still works after use is a password with an expiry date.
+    $this->get($url)->assertForbidden();
+});
+
+it('refuses an expired link', function () {
+    $operator = Operator::factory()->role('Owner')->create();
+    $customer = Customer::factory()->create();
+    $user = $customer->ensureUser();
+
+    $url = URL::temporarySignedRoute('impersonate.enter', now()->subSecond(), [
+        'customer' => $customer->uuid, 'operator' => $operator->uuid,
+    ]);
+
+    $this->get($url)->assertForbidden();
+});
+
+it('leaves the operator session untouched, so leaving returns to the console', function () {
+    $operator = Operator::factory()->role('Owner')->create();
+    $customer = Customer::factory()->create();
+    $user = $customer->ensureUser();
+
+    $url = URL::temporarySignedRoute('impersonate.enter', now()->addSeconds(60), [
+        'customer' => $customer->uuid, 'operator' => $operator->uuid,
+    ]);
+
+    $this->actingAs($operator, 'operator')->get($url);
+
+    expect(Auth::guard('operator')->check())->toBeTrue();
+
+    $this->post(route('impersonate.leave'));
+
+    expect(Auth::guard('web')->check())->toBeFalse()
+        ->and(Auth::guard('operator')->check())->toBeTrue();
 });