Completed
Push — development ( e14785...c4d33f )
by Nils
07:09
created

Duo::signVals()   A

Complexity

Conditions 2
Paths 2

Size

Total Lines 10
Code Lines 7

Duplication

Lines 0
Ratio 0 %

Importance

Changes 0
Metric Value
cc 2
eloc 7
nc 2
nop 5
dl 0
loc 10
rs 9.4285
c 0
b 0
f 0
1
<?php
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//namespace Duo;
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/*
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 * https://duo.com/docs/duoweb
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 */
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class Duo
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{
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    const DUO_PREFIX = "TX";
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    const APP_PREFIX = "APP";
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    const AUTH_PREFIX = "AUTH";
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    const DUO_EXPIRE = 300;
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    const APP_EXPIRE = 3600;
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    const IKEY_LEN = 20;
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    const SKEY_LEN = 40;
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    const AKEY_LEN = 40; // if this changes you have to change ERR_AKEY
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    const ERR_USER = 'ERR|The username passed to sign_request() is invalid.';
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    const ERR_IKEY = 'ERR|The Duo integration key passed to sign_request() is invalid.';
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    const ERR_SKEY = 'ERR|The Duo secret key passed to sign_request() is invalid.';
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    const ERR_AKEY = 'ERR|The application secret key passed to sign_request() must be at least 40 characters.';
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    private static function signVals($key, $vals, $prefix, $expire, $time = null)
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    {
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        $exp = ($time ? $time : time()) + $expire;
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        $val = $vals . '|' . $exp;
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        $b64 = base64_encode($val);
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        $cookie = $prefix . '|' . $b64;
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        $sig = hash_hmac("sha1", $cookie, $key);
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        return $cookie . '|' . $sig;
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    }
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    private static function parseVals($key, $val, $prefix, $ikey, $time = null)
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    {
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        $ts = ($time ? $time : time());
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        $parts = explode('|', $val);
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        if (count($parts) !== 3) {
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            return null;
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        }
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        list($u_prefix, $u_b64, $u_sig) = $parts;
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        $sig = hash_hmac("sha1", $u_prefix . '|' . $u_b64, $key);
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        if (hash_hmac("sha1", $sig, $key) !== hash_hmac("sha1", $u_sig, $key)) {
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            return null;
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        }
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        if ($u_prefix !== $prefix) {
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            return null;
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        }
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        $cookie_parts = explode('|', base64_decode($u_b64));
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        if (count($cookie_parts) !== 3) {
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            return null;
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        }
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        list($user, $u_ikey, $exp) = $cookie_parts;
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        if ($u_ikey !== $ikey) {
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            return null;
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        }
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        if ($ts >= intval($exp)) {
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            return null;
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        }
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        return $user;
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    }
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    public static function signRequest($ikey, $skey, $akey, $username, $time = null)
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    {
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        if (!isset($username) || strlen($username) === 0) {
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            return self::ERR_USER;
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        }
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        if (strpos($username, '|') !== false) {
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            return self::ERR_USER;
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        }
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        if (!isset($ikey) || strlen($ikey) !== self::IKEY_LEN) {
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            return self::ERR_IKEY;
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        }
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        if (!isset($skey) || strlen($skey) !== self::SKEY_LEN) {
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            return self::ERR_SKEY;
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        }
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        if (!isset($akey) || strlen($akey) < self::AKEY_LEN) {
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            return self::ERR_AKEY;
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        }
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        $vals = $username . '|' . $ikey;
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        $duo_sig = self::signVals($skey, $vals, self::DUO_PREFIX, self::DUO_EXPIRE, $time);
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        $app_sig = self::signVals($akey, $vals, self::APP_PREFIX, self::APP_EXPIRE, $time);
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        return $duo_sig . ':' . $app_sig;
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    }
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    public static function verifyResponse($ikey, $skey, $akey, $sig_response, $time = null)
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    {
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        list($auth_sig, $app_sig) = explode(':', $sig_response);
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        $auth_user = self::parseVals($skey, $auth_sig, self::AUTH_PREFIX, $ikey, $time);
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        $app_user = self::parseVals($akey, $app_sig, self::APP_PREFIX, $ikey, $time);
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        if ($auth_user !== $app_user) {
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            return null;
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        }
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        return $auth_user;
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    }
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}
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