File Source for auth.php

<?php
/**
* auth.php
*
* Contains functions used to do authentication.
*
* Dependencies:
* functions/global.php
* functions/strings.php.
*
* @copyright © 1999-2006 The SquirrelMail Project Team
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
* @version $Id: auth.php,v 1.59 2006/08/05 08:22:45 tokul Exp $
* @package squirrelmail
*/
/**
* Detect whether user is logged in
*
* Function is similar to is_logged_in() function. If user is logged in, function
* returns true. If user is not logged in or session is expired, function saves $_POST
* and $PHP_SELF in session and returns false. POST information is saved in
* 'session_expired_post' variable, PHP_SELF is saved in 'session_expired_location'.
*
* Script that uses this function instead of is_logged_in() function, must handle user
* level messages.
* @return boolean
* @since 1.5.1
*/
function sqauth_is_logged_in() {
if ( sqsession_is_registered('user_is_logged_in') ) {
return true;
}
// First we store some information in the new session to prevent
// information-loss.
sqGetGlobalVar('PHP_SELF', $PHP_SELF, SQ_SERVER);
$session_expired_post = $_POST;
$session_expired_location = $PHP_SELF;
if (!sqsession_is_registered('session_expired_post')) {
sqsession_register($session_expired_post,'session_expired_post');
}
if (!sqsession_is_registered('session_expired_location')) {
sqsession_register($session_expired_location,'session_expired_location');
}
session_write_close();
return false;
}
/**
* Reads and decodes stored user password information
*
* Direct access to password information is deprecated.
* @return string password in plain text
* @since 1.5.1
*/
function sqauth_read_password() {
sqgetGlobalVar('key', $key, SQ_COOKIE);
sqgetGlobalVar('onetimepad', $onetimepad,SQ_SESSION);
return OneTimePadDecrypt($key, $onetimepad);
}
/**
* Saves or updates user password information
*
* This function is used to update password information that SquirrelMail
* stores during existing web session. It does not modify password stored
* in authentication system used by IMAP server.
*
* Function must be called before any html output started. Direct access
* to password information is deprecated. Saved password information is
* available only to next executed SquirrelMail script. If your script needs
* access to saved password after sqauth_save_password() call, use returned
* OTP encrypted key.
* @param string $pass password
* @return string password encrypted with OTP. In case script wants to access
* password information before reloading page.
* @since 1.5.1
*/
function sqauth_save_password($pass) {
sqgetGlobalVar('base_uri', $base_uri, SQ_SESSION);
$onetimepad = OneTimePadCreate(strlen($pass));
sqsession_register($onetimepad,'onetimepad');
$key = OneTimePadEncrypt($pass, $onetimepad);
sqsetcookie('key', $key, false, $base_uri);
return $key;
}
/**
* Given the challenge from the server, supply the response using cram-md5 (See
* RFC 2195 for details)
*
* @param string $username User ID
* @param string $password User password supplied by User
* @param string $challenge The challenge supplied by the server
* @return string The response to be sent to the IMAP server
* @since 1.4.0
*/
function cram_md5_response ($username,$password,$challenge) {
$challenge=base64_decode($challenge);
$hash=bin2hex(hmac_md5($challenge,$password));
$response=base64_encode($username . " " . $hash) . "\r\n";
return $response;
}
/**
* Return Digest-MD5 response.
* Given the challenge from the server, calculate and return the
* response-string for digest-md5 authentication. (See RFC 2831 for more
* details)
*
* @param string $username User ID
* @param string $password User password supplied by User
* @param string $challenge The challenge supplied by the server
* @param string $service The service name, usually 'imap'; it is used to
* define the digest-uri.
* @param string $host The host name, usually the server's FQDN; it is used to
* define the digest-uri.
* @return string The response to be sent to the IMAP server
* @since 1.4.0
*/
function digest_md5_response ($username,$password,$challenge,$service,$host) {
$result=digest_md5_parse_challenge($challenge);
// verify server supports qop=auth
// $qop = explode(",",$result['qop']);
//if (!in_array("auth",$qop)) {
// rfc2831: client MUST fail if no qop methods supported
// return false;
//}
$cnonce = base64_encode(bin2hex(hmac_md5(microtime())));
$ncount = "00000001";
/* This can be auth (authentication only), auth-int (integrity protection), or
auth-conf (confidentiality protection). Right now only auth is supported.
DO NOT CHANGE THIS VALUE */
$qop_value = "auth";
$digest_uri_value = $service . '/' . $host;
// build the $response_value
//FIXME This will probably break badly if a server sends more than one realm
$string_a1 = utf8_encode($username).":";
$string_a1 .= utf8_encode($result['realm']).":";
$string_a1 .= utf8_encode($password);
$string_a1 = hmac_md5($string_a1);
$A1 = $string_a1 . ":" . $result['nonce'] . ":" . $cnonce;
$A1 = bin2hex(hmac_md5($A1));
$A2 = "AUTHENTICATE:$digest_uri_value";
// If qop is auth-int or auth-conf, A2 gets a little extra
if ($qop_value != 'auth') {
$A2 .= ':00000000000000000000000000000000';
}
$A2 = bin2hex(hmac_md5($A2));
$string_response = $result['nonce'] . ':' . $ncount . ':' . $cnonce . ':' . $qop_value;
$response_value = bin2hex(hmac_md5($A1.":".$string_response.":".$A2));
$reply = 'charset=utf-8,username="' . $username . '",realm="' . $result["realm"] . '",';
$reply .= 'nonce="' . $result['nonce'] . '",nc=' . $ncount . ',cnonce="' . $cnonce . '",';
$reply .= "digest-uri=\"$digest_uri_value\",response=$response_value";
$reply .= ',qop=' . $qop_value;
$reply = base64_encode($reply);
return $reply . "\r\n";
}
/**
* Parse Digest-MD5 challenge.
* This function parses the challenge sent during DIGEST-MD5 authentication and
* returns an array. See the RFC for details on what's in the challenge string.
*
* @param string $challenge Digest-MD5 Challenge
* @return array Digest-MD5 challenge decoded data
* @since 1.4.0
*/
function digest_md5_parse_challenge($challenge) {
$challenge=base64_decode($challenge);
while (isset($challenge)) {
if ($challenge{0} == ',') { // First char is a comma, must not be 1st time through loop
$challenge=substr($challenge,1);
}
$key=explode('=',$challenge,2);
$challenge=$key[1];
$key=$key[0];
if ($challenge{0} == '"') {
// We're in a quoted value
// Drop the first quote, since we don't care about it
$challenge=substr($challenge,1);
// Now explode() to the next quote, which is the end of our value
$val=explode('"',$challenge,2);
$challenge=$val[1]; // The rest of the challenge, work on it in next iteration of loop
$value=explode(',',$val[0]);
// Now, for those quoted values that are only 1 piece..
if (sizeof($value) == 1) {
$value=$value[0]; // Convert to non-array
}
} else {
// We're in a "simple" value - explode to next comma
$val=explode(',',$challenge,2);
if (isset($val[1])) {
$challenge=$val[1];
} else {
unset($challenge);
}
$value=$val[0];
}
$parsed["$key"]=$value;
} // End of while loop
return $parsed;
}
/**
* Creates a HMAC digest that can be used for auth purposes
* See RFCs 2104, 2617, 2831
* Uses mhash() extension if available
*
* @param string $data Data to apply hash function to.
* @param string $key Optional key, which, if supplied, will be used to
* calculate data's HMAC.
* @return string HMAC Digest string
* @since 1.4.0
*/
function hmac_md5($data, $key='') {
if (extension_loaded('mhash')) {
if ($key== '') {
$mhash=mhash(MHASH_MD5,$data);
} else {
$mhash=mhash(MHASH_MD5,$data,$key);
}
return $mhash;
}
if (!$key) {
return pack('H*',md5($data));
}
$key = str_pad($key,64,chr(0x00));
if (strlen($key) > 64) {
$key = pack("H*",md5($key));
}
$k_ipad = $key ^ str_repeat(chr(0x36), 64) ;
$k_opad = $key ^ str_repeat(chr(0x5c), 64) ;
/* Heh, let's get recursive. */
$hmac=hmac_md5($k_opad . pack("H*",md5($k_ipad . $data)) );
return $hmac;
}
/**
* Fillin user and password based on SMTP auth settings.
*
* @param string $user Reference to SMTP username
* @param string $pass Reference to SMTP password (unencrypted)
* @since 1.5.0
*/
function get_smtp_user(&$user, &$pass) {
global $username, $smtp_auth_mech,
$smtp_sitewide_user, $smtp_sitewide_pass;
if ($smtp_auth_mech == 'none') {
$user = '';
$pass = '';
} elseif ( isset($smtp_sitewide_user) && isset($smtp_sitewide_pass) &&
!empty($smtp_sitewide_user)) {
$user = $smtp_sitewide_user;
$pass = $smtp_sitewide_pass;
} else {
$user = $username;
$pass = sqauth_read_password();
}
}

Source for file auth.php