From c0aa5200f7a2a0cf8698d3f47e98f8bead9eef52 Mon Sep 17 00:00:00 2001
From: Joe Lambert <joe@rareloop.com>
Date: Wed, 4 Oct 2023 09:18:33 +0100
Subject: [PATCH] Gracefully handle encryption errors in session

---
 src/Session/EncryptedStore.php            | 15 +++++++++---
 tests/Unit/Session/EncryptedStoreTest.php | 30 +++++++++++++++++++++++
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/src/Session/EncryptedStore.php b/src/Session/EncryptedStore.php
index e731f1e..3a35953 100644
--- a/src/Session/EncryptedStore.php
+++ b/src/Session/EncryptedStore.php
@@ -2,16 +2,20 @@
 
 namespace Rareloop\Lumberjack\Session;
 
-use Rareloop\Lumberjack\Encrypter;
+use Exception;
 use SessionHandlerInterface;
+use Rareloop\Lumberjack\Encrypter;
+use Rareloop\Lumberjack\Exceptions\HandlerInterface;
 
 class EncryptedStore extends Store
 {
     protected $encrypter;
+    protected $exceptionHandler;
 
-    public function __construct($name, SessionHandlerInterface $handler, Encrypter $encrypter, $id = null)
+    public function __construct($name, SessionHandlerInterface $handler, Encrypter $encrypter, $id = null, HandlerInterface $exceptionHandler = null)
     {
         $this->encrypter = $encrypter;
+        $this->exceptionHandler = $exceptionHandler;
 
         parent::__construct($name, $handler, $id);
     }
@@ -23,6 +27,11 @@ protected function prepareForStorage($data)
 
     protected function prepareForUnserialize($data)
     {
-        return $this->encrypter->decrypt($data);
+        try {
+            return $this->encrypter->decrypt($data);
+        } catch (Exception $e) {
+            $this->exceptionHandler->report($e);
+            return null;
+        }
     }
 }
diff --git a/tests/Unit/Session/EncryptedStoreTest.php b/tests/Unit/Session/EncryptedStoreTest.php
index 5d80a46..fb2a324 100644
--- a/tests/Unit/Session/EncryptedStoreTest.php
+++ b/tests/Unit/Session/EncryptedStoreTest.php
@@ -6,6 +6,7 @@
 use Mockery;
 use PHPUnit\Framework\TestCase;
 use Rareloop\Lumberjack\Encrypter;
+use Rareloop\Lumberjack\Exceptions\HandlerInterface;
 use Rareloop\Lumberjack\Session\EncryptedStore;
 use Rareloop\Lumberjack\Session\Store;
 use Rareloop\Lumberjack\Test\Unit\Session\NullSessionHandler;
@@ -50,4 +51,33 @@ public function data_is_decrypted_before_it_is_loaded()
 
         $this->assertSame('bar', $store->get('foo'));
     }
+
+    /**
+     * @test
+     * @dataProvider unexpectedSessionData
+     */
+    public function unexpected_session_data_is_handled_gracefully($previousSessionValue)
+    {
+        $encryptionKey = 'encryption-key';
+
+        // Use a mock handler to fake a previously stored state
+        $handler = Mockery::mock(NullSessionHandler::class . '[read]');
+        $handler->shouldReceive('read')->andReturn($previousSessionValue);
+
+        $errorHandler = Mockery::mock(HandlerInterface::class);
+        $errorHandler->shouldReceive('report')->once();
+
+        $store = new EncryptedStore('session-name', $handler, new Encrypter($encryptionKey), 'session-id', $errorHandler);
+        $store->start();
+
+        $this->assertSame(null, $store->get('foo'));
+    }
+
+    private function unexpectedSessionData()
+    {
+        return [
+            [@serialize(['foo' => 'bar'])],
+            [''],
+        ];
+    }
 }