[HttpFoundation] [Session] Overwrite invalid session id

Author: peter17

Session/Storage/NativeSessionStorage.php

@@ -152,6 +152,12 @@ public function start()
             throw new \RuntimeException(sprintf('Failed to start the session because headers have already been sent by "%s" at line %d.', $file, $line));
         }
 
+        $sessionId = $_COOKIE[session_name()] ?? null;
+        if ($sessionId && !preg_match('/^[a-zA-Z0-9,-]{22,}$/', $sessionId)) {
+            // the session ID in the header is invalid, create a new one
+            session_id(session_create_id());
+        }
+
         // ok to try and start the session
         if (!session_start()) {
             throw new \RuntimeException('Failed to start the session.');

Tests/Session/Storage/NativeSessionStorageTest.php

@@ -293,4 +293,13 @@ public function testGetBagsOnceSessionStartedIsIgnored()
 
         $this->assertEquals($storage->getBag('flashes'), $bag);
     }
+
+    public function testRegenerateInvalidSessionId()
+    {
+        $_COOKIE[session_name()] = '&~[';
+        $started = (new NativeSessionStorage())->start();
+
+        $this->assertTrue($started);
+        $this->assertMatchesRegularExpression('/^[a-zA-Z0-9,-]{22,}$/', session_id());
+    }
 }