Updating the cookie driver to use HMAC authentication on all cookie data.
Signed-off-by: Pascal Kriete <pascal@pascalkriete.com>
diff --git a/system/libraries/Session/drivers/Session_cookie.php b/system/libraries/Session/drivers/Session_cookie.php
index 5bb1f7a..b44c833 100755
--- a/system/libraries/Session/drivers/Session_cookie.php
+++ b/system/libraries/Session/drivers/Session_cookie.php
@@ -372,27 +372,31 @@
return FALSE;
}
+ $len = strlen($session) - 40;
+
+ if ($len < 0)
+ {
+ log_message('debug', 'The session cookie was not signed.');
+ return FALSE;
+ }
+
+ // Check cookie authentication
+ $hmac = substr($session, $len);
+ $session = substr($session, 0, $len);
+
+ if ($hmac !== hash_hmac('sha1', $session, $this->encryption_key))
+ {
+ log_message('error', 'The session cookie data did not match what was expected. This could be a possible hacking attempt.');
+ $this->sess_destroy();
+ return FALSE;
+ }
+
// Check for encryption
if ($this->sess_encrypt_cookie === TRUE)
{
// Decrypt the cookie data
$session = $this->CI->encrypt->decode($session);
}
- else
- {
- // Encryption was not used, so we need to check the md5 hash in the last 32 chars
- $len = strlen($session)-32;
- $hash = substr($session, $len);
- $session = substr($session, 0, $len);
-
- // Does the md5 hash match? This is to prevent manipulation of session data in userspace
- if ($hash !== md5($session.$this->encryption_key))
- {
- log_message('error', 'The session cookie data did not match what was expected. This could be a possible hacking attempt.');
- $this->sess_destroy();
- return FALSE;
- }
- }
// Unserialize the session array
$session = $this->_unserialize($session);
@@ -658,10 +662,13 @@
// Serialize the userdata for the cookie
$cookie_data = $this->_serialize($cookie_data);
- $cookie_data = ($this->sess_encrypt_cookie === TRUE)
- ? $this->CI->encrypt->encode($cookie_data)
- // if encryption is not used, we provide an md5 hash to prevent userside tampering
- : $cookie_data.md5($cookie_data.$this->encryption_key);
+ if ($this->sess_encrypt_cookie === TRUE)
+ {
+ $this->CI->encrypt->encode($cookie_data);
+ }
+
+ // Require message authentication
+ $cookie_data .= hash_hmac('sha1', $cookie_data, $this->encryption_key);
$expire = ($this->sess_expire_on_close === TRUE) ? 0 : $this->sess_expiration + time();