diff --git a/GoogleAuthenticator.php b/GoogleAuthenticator.php new file mode 100644 index 0000000..64c5873 --- /dev/null +++ b/GoogleAuthenticator.php @@ -0,0 +1,208 @@ +_getBase32LookupTable(); + unset($validChars[32]); + + $secret = ''; + for ($i = 0; $i < $secretLength; $i++) { + $secret .= $validChars[array_rand($validChars)]; + } + return $secret; + } + + /** + * Calculate the code, with given secret and point in time + * + * @param string $secret + * @param int|null $timeSlice + * @return string + */ + public function getCode($secret, $timeSlice = null) + { + if ($timeSlice === null) { + $timeSlice = floor(time() / 30); + } + + $secretkey = $this->_base32Decode($secret); + + // Pack time into binary string + $time = chr(0).chr(0).chr(0).chr(0).pack('N*', $timeSlice); + // Hash it with users secret key + $hm = hash_hmac('SHA1', $time, $secretkey, true); + // Use last nipple of result as index/offset + $offset = ord(substr($hm, -1)) & 0x0F; + // grab 4 bytes of the result + $hashpart = substr($hm, $offset, 4); + + // Unpak binary value + $value = unpack('N', $hashpart); + $value = $value[1]; + // Only 32 bits + $value = $value & 0x7FFFFFFF; + + $modulo = pow(10, $this->_codeLength); + return str_pad($value % $modulo, $this->_codeLength, '0', STR_PAD_LEFT); + } + + /** + * Get QR-Code URL for image, from google charts + * + * @param string $name + * @param string $secret + * @param string $title + * @return string + */ + public function getQRCodeGoogleUrl($name, $secret, $title = null) { + $urlencoded = urlencode('otpauth://totp/'.$name.'?secret='.$secret.''); + if(isset($title)) { + $urlencoded .= urlencode('&issuer='.urlencode($title)); + } + return 'https://chart.googleapis.com/chart?chs=200x200&chld=M|0&cht=qr&chl='.$urlencoded.''; + } + + /** + * Check if the code is correct. This will accept codes starting from $discrepancy*30sec ago to $discrepancy*30sec from now + * + * @param string $secret + * @param string $code + * @param int $discrepancy This is the allowed time drift in 30 second units (8 means 4 minutes before or after) + * @param int|null $currentTimeSlice time slice if we want use other that time() + * @return bool + */ + public function verifyCode($secret, $code, $discrepancy = 1, $currentTimeSlice = null) + { + if ($currentTimeSlice === null) { + $currentTimeSlice = floor(time() / 30); + } + + for ($i = -$discrepancy; $i <= $discrepancy; $i++) { + $calculatedCode = $this->getCode($secret, $currentTimeSlice + $i); + if ($calculatedCode == $code ) { + return true; + } + } + + return false; + } + + /** + * Set the code length, should be >=6 + * + * @param int $length + * @return GoogleAuthenticator + */ + public function setCodeLength($length) + { + $this->_codeLength = $length; + return $this; + } + + /** + * Helper class to decode base32 + * + * @param $secret + * @return bool|string + */ + protected function _base32Decode($secret) + { + if (empty($secret)) return ''; + + $base32chars = $this->_getBase32LookupTable(); + $base32charsFlipped = array_flip($base32chars); + + $paddingCharCount = substr_count($secret, $base32chars[32]); + $allowedValues = array(6, 4, 3, 1, 0); + if (!in_array($paddingCharCount, $allowedValues)) return false; + for ($i = 0; $i < 4; $i++){ + if ($paddingCharCount == $allowedValues[$i] && + substr($secret, -($allowedValues[$i])) != str_repeat($base32chars[32], $allowedValues[$i])) return false; + } + $secret = str_replace('=','', $secret); + $secret = str_split($secret); + $binaryString = ""; + for ($i = 0; $i < count($secret); $i = $i+8) { + $x = ""; + if (!in_array($secret[$i], $base32chars)) return false; + for ($j = 0; $j < 8; $j++) { + $x .= str_pad(base_convert(@$base32charsFlipped[@$secret[$i + $j]], 10, 2), 5, '0', STR_PAD_LEFT); + } + $eightBits = str_split($x, 8); + for ($z = 0; $z < count($eightBits); $z++) { + $binaryString .= ( ($y = chr(base_convert($eightBits[$z], 2, 10))) || ord($y) == 48 ) ? $y:""; + } + } + return $binaryString; + } + + /** + * Helper class to encode base32 + * + * @param string $secret + * @param bool $padding + * @return string + */ + protected function _base32Encode($secret, $padding = true) + { + if (empty($secret)) return ''; + + $base32chars = $this->_getBase32LookupTable(); + + $secret = str_split($secret); + $binaryString = ""; + for ($i = 0; $i < count($secret); $i++) { + $binaryString .= str_pad(base_convert(ord($secret[$i]), 10, 2), 8, '0', STR_PAD_LEFT); + } + $fiveBitBinaryArray = str_split($binaryString, 5); + $base32 = ""; + $i = 0; + while ($i < count($fiveBitBinaryArray)) { + $base32 .= $base32chars[base_convert(str_pad($fiveBitBinaryArray[$i], 5, '0'), 2, 10)]; + $i++; + } + if ($padding && ($x = strlen($binaryString) % 40) != 0) { + if ($x == 8) $base32 .= str_repeat($base32chars[32], 6); + elseif ($x == 16) $base32 .= str_repeat($base32chars[32], 4); + elseif ($x == 24) $base32 .= str_repeat($base32chars[32], 3); + elseif ($x == 32) $base32 .= $base32chars[32]; + } + return $base32; + } + + /** + * Get array with all 32 characters for decoding from/encoding to base32 + * + * @return array + */ + protected function _getBase32LookupTable() + { + return array( + 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', // 7 + 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', // 15 + 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', // 23 + 'Y', 'Z', '2', '3', '4', '5', '6', '7', // 31 + '=' // padding char + ); + } +} diff --git a/README.md b/README.md index 7631ba2..246df2d 100644 --- a/README.md +++ b/README.md @@ -1 +1,14 @@ -# phpmfa \ No newline at end of file +# MFA / 2FA for PHP (Using GoogleAuthenticator) + +Add the GoogleAuthenticator.php file in your application. + +Generate a secret and store this in a database with the user. This secret should be unknown to anybody and is needed for the MFA confirmation. + +Scan the QR code generated + +Confirm the MFA code using your MFA application on your phone. + +## Note +For this test you have to put the code you generated into the check_mfa.php file and use a $_GET['code'] to check if the code is working or not. + +You should build this using a proper POST! \ No newline at end of file diff --git a/check_mfa.php b/check_mfa.php new file mode 100644 index 0000000..3525c74 --- /dev/null +++ b/check_mfa.php @@ -0,0 +1,23 @@ +Confirm code:

"; +$code = $_GET['code']; +echo "

Code: $code

"; + +$ga = new GoogleAuthenticator(); +// Code verify with your secret and the supplied code. +// Discrepancy is set to '2' which is 60 seconds. Default is 1 (30 seconds) but you might be too late to input the code. +$login = $ga->verifyCode($secret, $code, $discrepancy = 2); + +// If login returns TRUE +if ($login) { + echo "OK"; +} else { + echo "FAILED"; +} +?> diff --git a/generate.php b/generate.php new file mode 100644 index 0000000..150e036 --- /dev/null +++ b/generate.php @@ -0,0 +1,17 @@ +Create token:

"; +$user = 'MyLoginUsername'; + +// Generate a new secret for the user, this secret should be stored with the user in a database or make a static setting +$ga = new GoogleAuthenticator(); +$secret = $ga->createSecret(); +echo "

This personal secret should be stored in a database/user table and should never be known to anybody: $secret

"; +echo "
" + +// Generate QR by using Google Charts. +$qrCodeUrl = $ga->getQRCodeGoogleUrl($user, $secret, 'My Environment'); +echo "

Scan in Google Authenticator or Microsoft Authenticator" +echo ""; +?> \ No newline at end of file