From 5a2390d4d6287f2ce35cadae4713b7dcd10fdc9b Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Wed, 4 Jan 2017 16:01:27 +0200 Subject: [ci skip] Protect CSRF verification from timing side-channel attacks --- system/core/Security.php | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'system/core') diff --git a/system/core/Security.php b/system/core/Security.php index d198b663b..585ed90ec 100644 --- a/system/core/Security.php +++ b/system/core/Security.php @@ -224,12 +224,9 @@ class CI_Security { } } - // Do the tokens exist in both the _POST and _COOKIE arrays? - if ( ! isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]) - OR $_POST[$this->_csrf_token_name] !== $_COOKIE[$this->_csrf_cookie_name]) // Do the tokens match? - { - $this->csrf_show_error(); - } + // Check CSRF token validity, but don't error on mismatch just yet - we'll want to regenerate + $valid = isset($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]) + && hash_equals($_POST[$this->_csrf_token_name], $_COOKIE[$this->_csrf_cookie_name]); // We kill this since we're done and we don't want to pollute the _POST array unset($_POST[$this->_csrf_token_name]); @@ -245,6 +242,11 @@ class CI_Security { $this->_csrf_set_hash(); $this->csrf_set_cookie(); + if ($valid !== TRUE) + { + $this->csrf_show_error(); + } + log_message('info', 'CSRF token verified'); return $this; } -- cgit v1.2.3-24-g4f1b