Sign the impersonation link against the portal's own host, not the console's

app/Http/Controllers/ImpersonationController.php

@@ -31,14 +31,41 @@ class ImpersonationController extends Controller
 
         $operator = Auth::guard('operator')->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],
-        ));
+        // impersonate.enter carries no domain of its own — a portal route,
+        // reached wherever the portal already answers. Its SIGNATURE is
+        // computed over the full absolute URL: UrlGenerator::signedRoute()
+        // hashes the generated URL string, host included, and
+        // hasCorrectSignature() re-hashes $request->url() — the ACTUAL request
+        // URL — on the way back. Left alone, "the generated URL" means
+        // whichever host issued THIS request: the console's, once it has an
+        // exclusive hostname of its own. RestrictAdminHost then 404s every
+        // non-console route reached through the console's exclusive host,
+        // including this one — so the link would die before the customer ever
+        // saw it, the exact cross-host failure this controller exists to fix.
+        //
+        // Forced to the portal's own configured root instead, derived from
+        // config('app.url') rather than hardcoded, and restored immediately
+        // after: nothing else generated later in this request should inherit
+        // the override.
+        $portalRoot = rtrim((string) config('app.url'), '/');
+
+        URL::forceRootUrl($portalRoot);
+
+        try {
+            $signed = URL::temporarySignedRoute(
+                'impersonate.enter',
+                now()->addSeconds(self::WINDOW),
+                // 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.
+                ['customer' => $customer->uuid, 'operator' => $operator->uuid],
+            );
+        } finally {
+            URL::forceRootUrl(null);
+        }
+
+        return redirect()->away($signed);
     }
 
     /** The portal end of the handover. Signed, and good exactly once. */

tests/Feature/ImpersonationTest.php

@@ -77,3 +77,39 @@ it('leaves the operator session untouched, so leaving returns to the console', f
     expect(Auth::guard('web')->check())->toBeFalse()
         ->and(Auth::guard('operator')->check())->toBeTrue();
 });
+
+it('signs the link against the portal host, not the console host it was issued from', function () {
+    // Exclusive mode is where this bites: the console has a hostname to
+    // itself, and RestrictAdminHost 404s any non-console route reached
+    // through it. impersonate.enter carries no domain of its own, so a link
+    // built and signed against the console's root would die the instant it
+    // was followed — precisely the cross-host failure this task exists to
+    // fix. A test that only checks `signature=` is present does not catch
+    // this: on dev it passes anyway, because exclusive mode is off there.
+    config()->set('admin_access.hosts', ['admin.example.test']);
+    config()->set('admin_access.exclusive', true);
+    config()->set('app.url', 'https://app.example.test');
+
+    $operator = Operator::factory()->role('Owner')->create();
+    $customer = Customer::factory()->create();
+    $user = $customer->ensureUser();
+
+    // Issued exactly as a real operator's click would arrive: on the
+    // console's own exclusive host. (Routes are compiled once at boot, under
+    // this suite's default non-exclusive ADMIN_HOSTS="" — so the path still
+    // carries the fallback /admin prefix; only RestrictAdminHost's own checks
+    // read admin_access.* live, per request, which is what is under test.)
+    $response = $this->actingAs($operator, 'operator')
+        ->post('https://admin.example.test/admin/impersonate/'.$customer->uuid);
+
+    $location = $response->headers->get('Location');
+
+    // The link has to carry the PORTAL's host, not the console's.
+    expect(parse_url($location, PHP_URL_HOST))->toBe('app.example.test');
+
+    // And it must still genuinely work when followed: valid signature, signs
+    // the customer in.
+    $this->get($location)->assertRedirect(route('dashboard'));
+
+    expect(Auth::guard('web')->id())->toBe($user->id);
+});