8 files changed, 114 insertions, 4 deletions
diff --git a/system/libraries/Email.php b/system/libraries/Email.php
index a53e7e72a..cd74d6da1 100644
--- a/system/libraries/Email.php
+++ b/system/libraries/Email.php
@@ -1038,7 +1038,11 @@ class CI_Email {
 			$domain = defined('INTL_IDNA_VARIANT_UTS46')
 				? idn_to_ascii($domain, 0, INTL_IDNA_VARIANT_UTS46)
 				: idn_to_ascii($domain);
-			$email = $account.'@'.$domain;
+
+			if ($domain !== FALSE)
+			{
+				$email = $account.'@'.$domain;
+			}
 		}
 
 		return (bool) filter_var($email, FILTER_VALIDATE_EMAIL);
@@ -1859,7 +1863,11 @@ class CI_Email {
 			$domain = defined('INTL_IDNA_VARIANT_UTS46')
 				? idn_to_ascii($domain, 0, INTL_IDNA_VARIANT_UTS46)
 				: idn_to_ascii($domain);
-			$email = $account.'@'.$domain;
+
+			if ($domain !== FALSE)
+			{
+				$email = $account.'@'.$domain;
+			}
 		}
 
 		return (filter_var($email, FILTER_VALIDATE_EMAIL) === $email && preg_match('#\A[a-z0-9._+-]+@[a-z0-9.-]{1,253}\z#i', $email));
diff --git a/system/libraries/Form_validation.php b/system/libraries/Form_validation.php
index 6a97ee599..27187df2c 100644
--- a/system/libraries/Form_validation.php
+++ b/system/libraries/Form_validation.php
@@ -1234,7 +1234,11 @@ class CI_Form_validation {
 			$domain = defined('INTL_IDNA_VARIANT_UTS46')
 				? idn_to_ascii($matches[2], 0, INTL_IDNA_VARIANT_UTS46)
 				: idn_to_ascii($matches[2]);
-			$str = $matches[1].'@'.$domain;
+
+			if ($domain !== FALSE)
+			{
+				$str = $matches[1].'@'.$domain;
+			}
 		}
 
 		return (bool) filter_var($str, FILTER_VALIDATE_EMAIL);
diff --git a/system/libraries/Session/Session.php b/system/libraries/Session/Session.php
index 9e762745f..aa1fafb5b 100644
--- a/system/libraries/Session/Session.php
+++ b/system/libraries/Session/Session.php
@@ -604,7 +604,7 @@ class CI_Session {
 	// ------------------------------------------------------------------------
 
 	/**
-	 * Unmark flash
+	 * Unmark temp
 	 *
 	 * @param	mixed	$key	Session data key(s)
 	 * @return	void
diff --git a/system/libraries/Session/Session_driver.php b/system/libraries/Session/Session_driver.php
index bef5ee41f..2fe30b8a2 100644
--- a/system/libraries/Session/Session_driver.php
+++ b/system/libraries/Session/Session_driver.php
@@ -113,6 +113,23 @@ abstract class CI_Session_driver implements SessionHandlerInterface {
 	// ------------------------------------------------------------------------
 
 	/**
+	 * PHP 5.x validate ID
+	 *
+	 * Enforces session.use_strict_mode on PHP 5.x (7+ does it by itself)
+	 *
+	 * @return	void
+	 */
+	public function php5_validate_id()
+	{
+		if (PHP_VERSION_ID < 70000 && isset($_COOKIE[$this->_config['cookie_name']]) && ! $this->validateId($_COOKIE[$this->_config['cookie_name']]))
+		{
+			unset($_COOKIE[$this->_config['cookie_name']]);
+		}
+	}
+
+	// ------------------------------------------------------------------------
+
+	/**
 	 * Cookie destroy
 	 *
 	 * Internal method to force removal of a cookie by the client
diff --git a/system/libraries/Session/drivers/Session_database_driver.php b/system/libraries/Session/drivers/Session_database_driver.php
index ae7a1b4a1..074accfe7 100644
--- a/system/libraries/Session/drivers/Session_database_driver.php
+++ b/system/libraries/Session/drivers/Session_database_driver.php
@@ -133,6 +133,8 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 			return $this->_fail();
 		}
 
+		$this->php5_validate_id();
+
 		return $this->_success;
 	}
 
@@ -340,6 +342,30 @@ class CI_Session_database_driver extends CI_Session_driver implements SessionHan
 			: $this->_fail();
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate ID
+	 *
+	 * Checks whether a session ID record exists server-side,
+	 * to enforce session.use_strict_mode.
+	 *
+	 * @param	string	$id
+	 * @return	bool
+	 */
+	public function validateId($id)
+	{
+		// Prevent previous QB calls from messing with our queries
+		$this->_db->reset_query();
+
+		$this->_db->select('1')->from($this->_config['save_path'])->where('id', $id);
+		empty($this->_config['match_ip']) OR $this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
+		$result = $this->_db->get();
+		empty($result) OR $result = $result->row();
+
+		return ! empty($result);
+	}
+
 	// ------------------------------------------------------------------------
 
 	/**
diff --git a/system/libraries/Session/drivers/Session_files_driver.php b/system/libraries/Session/drivers/Session_files_driver.php
index c6d789aae..654f30010 100644
--- a/system/libraries/Session/drivers/Session_files_driver.php
+++ b/system/libraries/Session/drivers/Session_files_driver.php
@@ -148,6 +148,8 @@ class CI_Session_files_driver extends CI_Session_driver implements SessionHandle
 			.$name // we'll use the session cookie name as a prefix to avoid collisions
 			.($this->_config['match_ip'] ? md5($_SERVER['REMOTE_ADDR']) : '');
 
+		$this->php5_validate_id();
+
 		return $this->_success;
 	}
 
@@ -392,6 +394,22 @@ class CI_Session_files_driver extends CI_Session_driver implements SessionHandle
 	// --------------------------------------------------------------------
 
 	/**
+	 * Validate ID
+	 *
+	 * Checks whether a session ID record exists server-side,
+	 * to enforce session.use_strict_mode.
+	 *
+	 * @param	string	$id
+	 * @return	bool
+	 */
+	public function validateId($id)
+	{
+		return is_file($this->_file_path.$id);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
 	 * Byte-safe strlen()
 	 *
 	 * @param	string	$str
diff --git a/system/libraries/Session/drivers/Session_memcached_driver.php b/system/libraries/Session/drivers/Session_memcached_driver.php
index b109738c2..7d8e39022 100644
--- a/system/libraries/Session/drivers/Session_memcached_driver.php
+++ b/system/libraries/Session/drivers/Session_memcached_driver.php
@@ -145,6 +145,8 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 			return $this->_fail();
 		}
 
+		$this->php5_validate_id();
+
 		return $this->_success;
 	}
 
@@ -290,6 +292,23 @@ class CI_Session_memcached_driver extends CI_Session_driver implements SessionHa
 		return $this->_success;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate ID
+	 *
+	 * Checks whether a session ID record exists server-side,
+	 * to enforce session.use_strict_mode.
+	 *
+	 * @param	string	$id
+	 * @return	bool
+	 */
+	public function validateId($id)
+	{
+		$this->_memcached-get($this->_key_prefix.$id);
+		return ($this->_memcached->getResultCode() === Memcached::RES_SUCCESS);
+	}
+
 	// ------------------------------------------------------------------------
 
 	/**
diff --git a/system/libraries/Session/drivers/Session_redis_driver.php b/system/libraries/Session/drivers/Session_redis_driver.php
index 413c30d67..d7a57550a 100644
--- a/system/libraries/Session/drivers/Session_redis_driver.php
+++ b/system/libraries/Session/drivers/Session_redis_driver.php
@@ -153,6 +153,8 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 			return $this->_success;
 		}
 
+		$this->php5_validate_id();
+
 		return $this->_fail();
 	}
 
@@ -310,6 +312,22 @@ class CI_Session_redis_driver extends CI_Session_driver implements SessionHandle
 		return $this->_success;
 	}
 
+	// --------------------------------------------------------------------
+
+	/**
+	 * Validate ID
+	 *
+	 * Checks whether a session ID record exists server-side,
+	 * to enforce session.use_strict_mode.
+	 *
+	 * @param	string	$id
+	 * @return	bool
+	 */
+	public function validateId($id)
+	{
+		return (bool) $this->_redis->exists($this->_key_prefix.$id);
+	}
+
 	// ------------------------------------------------------------------------
 
 	/**