* Implemented ITimeProviders

lib/TwoFactorAuth.php

@@ -3,6 +3,7 @@ namespace RobThree\Auth;
 
 use RobThree\Auth\Providers\Qr\IQRCodeProvider;
 use RobThree\Auth\Providers\Rng\IRNGProvider;
+use RobThree\Auth\Providers\Time\ITimeProvider;
 
 // Based on / inspired by: https://github.com/PHPGangsta/GoogleAuthenticator
 // Algorithms, digits, period etc. explained: https://github.com/google/google-authenticator/wiki/Key-Uri-Format
@@ -14,12 +15,13 @@ class TwoFactorAuth
     private $issuer;
     private $qrcodeprovider = null;
     private $rngprovider = null;
+    private $timeprovider = null;
     private static $_base32dict = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ234567=';
     private static $_base32;
     private static $_base32lookup = array();
     private static $_supportedalgos = array('sha1', 'sha256', 'sha512', 'md5');
 
-    function __construct($issuer = null, $digits = 6, $period = 30, $algorithm = 'sha1', IQRCodeProvider $qrcodeprovider = null, IRNGProvider $rngprovider = null)
+    function __construct($issuer = null, $digits = 6, $period = 30, $algorithm = 'sha1', IQRCodeProvider $qrcodeprovider = null, IRNGProvider $rngprovider = null, ITimeProvider $timeprovider = null)
     {
         $this->issuer = $issuer;
         if (!is_int($digits) || $digits <= 0)
@@ -36,6 +38,7 @@ class TwoFactorAuth
         $this->algorithm = $algorithm;
         $this->qrcodeprovider = $qrcodeprovider;
         $this->rngprovider = $rngprovider;
+        $this->timeprovider = $timeprovider;
 
         self::$_base32 = str_split(self::$_base32dict);
         self::$_base32lookup = array_flip(self::$_base32);
@@ -121,9 +124,37 @@ class TwoFactorAuth
             . base64_encode($qrcodeprovider->getQRCodeImage($this->getQRText($label, $secret), $size));
     }
 
+    /**
+     * Compare default timeprovider with specified timeproviders and ensure the time is within the specified number of seconds (leniency)
+     */
+    public function ensureCorrectTime(array $timeproviders = null, $leniency = 5)
+    {
+        if ($timeproviders != null && !is_array($timeproviders))
+            throw new TwoFactorAuthException('No timeproviders specified');
+
+        if ($timeproviders == null)
+            $timeproviders = array(
+                new Providers\Time\ConvertUnixTimeDotComTimeProvider(),
+                new Providers\Time\HttpTimeProvider()
+            );
+
+        // Get default time provider
+        $timeprovider = $this->getTimeProvider();
+
+        // Iterate specified time providers
+        foreach ($timeproviders as $t) {
+            if (!($t instanceof ITimeProvider))
+                throw new TwoFactorAuthException('Object does not implement ITimeProvider');
+
+            // Get time from default time provider and compare to specific time provider and throw if time difference is more than specified number of seconds leniency
+            if (abs($timeprovider->getTime() - $t->getTime()) > $leniency)
+                throw new TwoFactorAuthException(sprintf('Time for timeprovider is off by more than %d seconds when compared to %s', $leniency, get_class($t)));
+        }
+    }
+
     private function getTime($time)
     {
-        return ($time === null) ? time() : $time;
+        return ($time === null) ? $this->timeprovider->getTime() : $time;
     }
 
     private function getTimeSlice($time = null, $offset = 0)
@@ -165,6 +196,7 @@ class TwoFactorAuth
             $output .= chr(bindec(str_pad($block, 8, 0, STR_PAD_RIGHT)));
         return $output;
     }
+
     /**
      * @return IQRCodeProvider
      * @throws TwoFactorAuthException
@@ -177,6 +209,7 @@ class TwoFactorAuth
         }
         return $this->qrcodeprovider;
     }
+
     /**
      * @return IRNGProvider
      * @throws TwoFactorAuthException
@@ -200,4 +233,17 @@ class TwoFactorAuth
         }
         throw new TwoFactorAuthException('Unable to find a suited RNGProvider');
     }
+
+    /**
+     * @return ITimeProvider
+     * @throws TwoFactorAuthException
+     */
+    public function getTimeProvider()
+    {
+        // Set default time provider if none was specified
+        if (null === $this->timeprovider) {
+            return $this->timeprovider = new Providers\Time\LocalMachineTimeProvider();
+        }
+        return $this->timeprovider;
+    }
 }