From 847e509a1fd78cbf3cfcb5eb9fe14d5db7b56ff3 Mon Sep 17 00:00:00 2001
From: Frank Bischof
Date: Fri, 20 Jan 2023 14:21:17 +0100
Subject: [PATCH] Commit version 1.0
---
GoogleAuthenticator.php | 208 ++++++++++++++++++++++++++++++++++++++++
README.md | 15 ++-
check_mfa.php | 23 +++++
generate.php | 17 ++++
4 files changed, 262 insertions(+), 1 deletion(-)
create mode 100644 GoogleAuthenticator.php
create mode 100644 check_mfa.php
create mode 100644 generate.php
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