Wipe keys before dispatching decrypt-failure events

src/Laravel/Factory.php

@@ -259,6 +259,13 @@ public function decryptMessage(string $secureMessageId, string $verificationCode
                 $record->save();
             }
 
+            // Wipe the keys before the secure message is handed to event listeners. Most failure paths
+            // already wipe the keys (the DecryptException constructor does so when it is given the secure
+            // message), but the paths that throw without it - a missing key file, a missing file blob or
+            // malformed stored ciphertext - would otherwise expose the decrypted keys on this instance to
+            // listeners (and to anything they serialize the event to, such as a queue).
+            $secureMessage->wipeKeysFromMemory();
+
             // Dispatch events.
             match ($exception::class) {
                 HitPointLimitReachedException::class => $this->event->dispatch(new HitPointLimitReached($secureMessage)),

tests/Laravel/FactoryTest.php

@@ -187,6 +187,13 @@ public function testDecryptMessageStorageKeyNotFound(): void
         $secureMessageFactoryMock->shouldReceive('setMetaKey')->withArgs(['metaKey'])->once()->andReturnSelf();
 
         $eventMock->shouldReceive('dispatch')->withArgs([\Mockery::on(function ($event) {
+            // The event must not expose any key material to listeners, even though this failure path
+            // throws without a secure message (so the DecryptException constructor never wiped it).
+            $this->assertNull($event->secureMessage->getDatabaseKey());
+            $this->assertNull($event->secureMessage->getStorageKey());
+            $this->assertNull($event->secureMessage->getMetaKey());
+            $this->assertNull($event->secureMessage->getVerificationCode());
+
             return $event::class === DecryptionFailed::class;
         })])->once();
 
@@ -489,6 +496,13 @@ public function testDecryptFileMessageBlobMissing(): void
         $secureMessageFactoryMock->shouldReceive('setMetaKey')->withArgs(['metaKey'])->once()->andReturnSelf();
 
         $eventMock->shouldReceive('dispatch')->withArgs([\Mockery::on(function ($event) {
+            // The event must not expose any key material to listeners, even though this failure path
+            // throws without a secure message (so the DecryptException constructor never wiped it).
+            $this->assertNull($event->secureMessage->getDatabaseKey());
+            $this->assertNull($event->secureMessage->getStorageKey());
+            $this->assertNull($event->secureMessage->getMetaKey());
+            $this->assertNull($event->secureMessage->getVerificationCode());
+
             return $event::class === DecryptionFailed::class;
         })])->once();