feat(auth): require signed NIP-42 event for Nostr login

Closes a security flaw where the server trusted any pubkey the client sent. The frontend now signs a per-session, time-bound challenge (kind-22242 event) that the backend verifies with swentel/nostr-php before establishing the session. - NostrAuth: issueChallenge() + loginWithSignedEvent() with full schnorr/id verification, TTL window, and idempotent re-entry for concurrent Livewire listeners. - auth-button: mounts a fresh challenge, exposes it via data-attribute + requestNostrChallenge() fallback, renders a full-viewport AAA-style loading overlay while the wallet signs. - NostrSessionGuard: override logout() to drop the cookie-jar dep so programmatic logout works in any context.
2026-05-23 13:15:36 +00:00 · 2026-05-20 01:09:20 +02:00
parent 532199fe15
commit 6bb7d93d1d
9 changed files with 501 additions and 77 deletions
@@ -0,0 +1,155 @@
+<?php
+
+use App\Support\NostrAuth;
+use Illuminate\Support\Facades\Session;
+use Illuminate\Validation\ValidationException;
+use swentel\nostr\Event\Event as NostrEvent;
+use swentel\nostr\Key\Key as NostrKey;
+use swentel\nostr\Sign\Sign as NostrSign;
+
+/**
+ * Build a NIP-42-style kind-22242 login event signed with a freshly generated
+ * keypair. Returns the signed event as the plain array that the frontend
+ * dispatches to Livewire (post-JSON round-trip), plus the pubkey for assertions.
+ *
+ * @return array{event: array<string, mixed>, pubkey: string, privkey: string}
+ */
+function makeSignedLoginEvent(string $challenge, ?int $createdAt = null): array
+{
+    $key = new NostrKey;
+    $privkey = $key->generatePrivateKey();
+    $pubkey = $key->getPublicKey($privkey);
+
+    $event = new NostrEvent;
+    $event->setKind(22242);
+    $event->setCreatedAt($createdAt ?? time());
+    $event->setTags([['challenge', $challenge]]);
+    $event->setContent('');
+
+    (new NostrSign)->signEvent($event, $privkey);
+
+    $array = $event->toArray();
+
+    // Match the shape produced by JSON.parse(JSON.stringify(signedEvent)) in
+    // nostrLogin.js — plain arrays, integer kind/created_at, string sig/id.
+    return [
+        'event' => [
+            'id' => $array['id'],
+            'pubkey' => $array['pubkey'],
+            'created_at' => $array['created_at'],
+            'kind' => $array['kind'],
+            'tags' => $array['tags'],
+            'content' => $array['content'],
+            'sig' => $array['sig'],
+        ],
+        'pubkey' => $pubkey,
+        'privkey' => $privkey,
+    ];
+}
+
+it('issues a fresh hex challenge and persists it to the session', function () {
+    $challenge = NostrAuth::issueChallenge();
+
+    expect($challenge)->toMatch('/^[0-9a-f]{64}$/');
+    expect(Session::get('nostr_login_challenge'))->toBe($challenge);
+    expect(Session::get('nostr_login_challenge_expires_at'))->toBeGreaterThan(now()->timestamp);
+});
+
+it('logs in via a valid signed login event and consumes the challenge', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent, 'pubkey' => $pubkey] = makeSignedLoginEvent($challenge);
+
+    $returned = NostrAuth::loginWithSignedEvent($signedEvent);
+
+    expect($returned)->toBe($pubkey);
+    expect(NostrAuth::check())->toBeTrue();
+    expect(NostrAuth::pubkey())->toBe($pubkey);
+    expect(Session::has('nostr_login_challenge'))->toBeFalse();
+});
+
+it('rejects an event whose challenge does not match the session', function () {
+    NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent('deadbeef'.str_repeat('0', 56));
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});
+
+it('rejects an event of the wrong kind', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent($challenge);
+    $signedEvent['kind'] = 1; // text note, not auth
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});
+
+it('rejects an event whose created_at is outside the TTL window', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent($challenge, now()->subHour()->timestamp);
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});
+
+it('rejects an event with a tampered signature', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent($challenge);
+    // Flip the first byte of the signature to break the schnorr verification.
+    $signedEvent['sig'] = ($signedEvent['sig'][0] === '0' ? '1' : '0').substr($signedEvent['sig'], 1);
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});
+
+it('rejects an event with a tampered pubkey (sig no longer matches)', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent($challenge);
+    // Swap in an attacker-controlled pubkey while keeping the original sig.
+    $signedEvent['pubkey'] = str_repeat('a', 64);
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});
+
+it('rejects a non-array payload', function () {
+    NostrAuth::issueChallenge();
+
+    expect(fn () => NostrAuth::loginWithSignedEvent('not-an-event'))
+        ->toThrow(ValidationException::class);
+    expect(fn () => NostrAuth::loginWithSignedEvent(null))
+        ->toThrow(ValidationException::class);
+});
+
+it('is idempotent for repeated calls with the same event within one session', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent, 'pubkey' => $pubkey] = makeSignedLoginEvent($challenge);
+
+    NostrAuth::loginWithSignedEvent($signedEvent);
+    // Challenge is consumed after the first call. A sibling listener that
+    // receives the same dispatched event must still succeed.
+    $returned = NostrAuth::loginWithSignedEvent($signedEvent);
+
+    expect($returned)->toBe($pubkey);
+    expect(NostrAuth::pubkey())->toBe($pubkey);
+});
+
+it('does not allow a replay from a different (unauthenticated) session', function () {
+    $challenge = NostrAuth::issueChallenge();
+    ['event' => $signedEvent] = makeSignedLoginEvent($challenge);
+
+    NostrAuth::loginWithSignedEvent($signedEvent);
+
+    // Simulate a fresh session: no challenge, no authenticated user.
+    NostrAuth::logout();
+    Session::forget(['nostr_login_challenge', 'nostr_login_challenge_expires_at']);
+
+    expect(fn () => NostrAuth::loginWithSignedEvent($signedEvent))
+        ->toThrow(ValidationException::class);
+    expect(NostrAuth::check())->toBeFalse();
+});