--- /dev/null
+<?php
+namespace Shaarli\Security;
+
+use Shaarli\Config\ConfigManager;
+
+/**
+ * Manages the server-side session
+ */
+class SessionManager
+{
+ /** @var int Session expiration timeout, in seconds */
+ public static $SHORT_TIMEOUT = 3600; // 1 hour
+
+ /** @var int Session expiration timeout, in seconds */
+ public static $LONG_TIMEOUT = 31536000; // 1 year
+
+ /** @var array Local reference to the global $_SESSION array */
+ protected $session = [];
+
+ /** @var ConfigManager Configuration Manager instance **/
+ protected $conf = null;
+
+ /** @var bool Whether the user should stay signed in (LONG_TIMEOUT) */
+ protected $staySignedIn = false;
+
+ /**
+ * Constructor
+ *
+ * @param array $session The $_SESSION array (reference)
+ * @param ConfigManager $conf ConfigManager instance
+ */
+ public function __construct(& $session, $conf)
+ {
+ $this->session = &$session;
+ $this->conf = $conf;
+ }
+
+ /**
+ * Define whether the user should stay signed in across browser sessions
+ *
+ * @param bool $staySignedIn Keep the user signed in
+ */
+ public function setStaySignedIn($staySignedIn)
+ {
+ $this->staySignedIn = $staySignedIn;
+ }
+
+ /**
+ * Generates a session token
+ *
+ * @return string token
+ */
+ public function generateToken()
+ {
+ $token = sha1(uniqid('', true) .'_'. mt_rand() . $this->conf->get('credentials.salt'));
+ $this->session['tokens'][$token] = 1;
+ return $token;
+ }
+
+ /**
+ * Checks the validity of a session token, and destroys it afterwards
+ *
+ * @param string $token The token to check
+ *
+ * @return bool true if the token is valid, else false
+ */
+ public function checkToken($token)
+ {
+ if (! isset($this->session['tokens'][$token])) {
+ // the token is wrong, or has already been used
+ return false;
+ }
+
+ // destroy the token to prevent future use
+ unset($this->session['tokens'][$token]);
+ return true;
+ }
+
+ /**
+ * Validate session ID to prevent Full Path Disclosure.
+ *
+ * See #298.
+ * The session ID's format depends on the hash algorithm set in PHP settings
+ *
+ * @param string $sessionId Session ID
+ *
+ * @return true if valid, false otherwise.
+ *
+ * @see http://php.net/manual/en/function.hash-algos.php
+ * @see http://php.net/manual/en/session.configuration.php
+ */
+ public static function checkId($sessionId)
+ {
+ if (empty($sessionId)) {
+ return false;
+ }
+
+ if (!$sessionId) {
+ return false;
+ }
+
+ if (!preg_match('/^[a-zA-Z0-9,-]{2,128}$/', $sessionId)) {
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Store user login information after a successful login
+ *
+ * @param string $clientIpId Client IP address identifier
+ */
+ public function storeLoginInfo($clientIpId)
+ {
+ $this->session['ip'] = $clientIpId;
+ $this->session['username'] = $this->conf->get('credentials.login');
+ $this->extendTimeValidityBy(self::$SHORT_TIMEOUT);
+ }
+
+ /**
+ * Extend session validity
+ */
+ public function extendSession()
+ {
+ if ($this->staySignedIn) {
+ return $this->extendTimeValidityBy(self::$LONG_TIMEOUT);
+ }
+ return $this->extendTimeValidityBy(self::$SHORT_TIMEOUT);
+ }
+
+ /**
+ * Extend expiration time
+ *
+ * @param int $duration Expiration time extension (seconds)
+ *
+ * @return int New session expiration time
+ */
+ protected function extendTimeValidityBy($duration)
+ {
+ $expirationTime = time() + $duration;
+ $this->session['expires_on'] = $expirationTime;
+ return $expirationTime;
+ }
+
+ /**
+ * Logout a user by unsetting all login information
+ *
+ * See:
+ * - https://secure.php.net/manual/en/function.setcookie.php
+ */
+ public function logout()
+ {
+ if (isset($this->session)) {
+ unset($this->session['ip']);
+ unset($this->session['expires_on']);
+ unset($this->session['username']);
+ unset($this->session['visibility']);
+ unset($this->session['untaggedonly']);
+ }
+ }
+
+ /**
+ * Check whether the session has expired
+ *
+ * @param string $clientIpId Client IP address identifier
+ *
+ * @return bool true if the session has expired, false otherwise
+ */
+ public function hasSessionExpired()
+ {
+ if (empty($this->session['expires_on'])) {
+ return true;
+ }
+ if (time() >= $this->session['expires_on']) {
+ return true;
+ }
+ return false;
+ }
+
+ /**
+ * Check whether the client IP address has changed
+ *
+ * @param string $clientIpId Client IP address identifier
+ *
+ * @return bool true if the IP has changed, false if it has not, or
+ * if session protection has been disabled
+ */
+ public function hasClientIpChanged($clientIpId)
+ {
+ if ($this->conf->get('security.session_protection_disabled') === true) {
+ return false;
+ }
+ if (isset($this->session['ip']) && $this->session['ip'] === $clientIpId) {
+ return false;
+ }
+ return true;
+ }
+}