egroupware/phpgwapi/inc/class.egw_digest_auth.inc.php
2014-11-18 12:55:32 +00:00

254 lines
10 KiB
PHP

<?php
/**
* eGroupWare API: Basic and Digest Auth
*
* For Apache FCGI you need the following rewrite rule:
*
* RewriteEngine on
* RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization},L]
*
* Otherwise authentication request will be send over and over again, as password is NOT available to PHP!
* (This makes authentication details available in PHP as $_SERVER['REDIRECT_HTTP_AUTHORIZATION']
*
* @link http://www.egroupware.org
* @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
* @package api
* @subpackage auth
* @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @copyright (c) 2010 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @version $Id$
*/
/**
* Class to authenticate via basic or digest auth
*
* The more secure digest auth requires:
* a) cleartext passwords in SQL table
* b) md5 hashes of username, realm, password stored somewhere (NOT yet implemented)
* Otherwise digest auth is not possible and therefore not offered to the client.
*
* Usage example:
*
* $GLOBALS['egw_info']['flags'] = array(
* 'noheader' => True,
* 'currentapp' => 'someapp',
* 'no_exception_handler' => 'basic_auth', // we use a basic auth exception handler (sends exception message as basic auth realm)
* 'autocreate_session_callback' => array('egw_digest_auth','autocreate_session_callback'),
* 'auth_realm' => 'EGroupware',
* );
* include(dirname(__FILE__).'/header.inc.php');
*
* @link http://www.php.net/manual/en/features.http-auth.php
* @ToDo check if we have to check if returned nonce matches our challange (not done in above link, but why would it be there)
* @link http://en.wikipedia.org/wiki/Digest_access_authentication
* @link http://tools.ietf.org/html/rfc2617
*
* Commented out is accept-charset parameter from (seems not supported by any client I tested with)
* @link https://tools.ietf.org/id/draft-reschke-basicauth-enc-06.html
*
* Implemented support for clients sending credentials in in iso-8859-1 instead of our utf-8:
* - Firefox 19.0
* - Thunderbird 17.0.3 with Lightning 1.8
* - IE 8
* - Netdrive
* (Chrome 24 or Safari 6 sends credentials in charset of webpage.)
*/
class egw_digest_auth
{
/**
* Log to error_log:
* 0 = dont
* 1 = no cleartext passwords
* 2 = all
*/
const ERROR_LOG = 0;
/**
* Callback to be used to create session via header include authenticated via basic or digest auth
*
* @param array $account NOT used!
* @return string valid session-id or does NOT return at all!
*/
static public function autocreate_session_callback(&$account)
{
unset($account); // not used, but required by function signature
if (self::ERROR_LOG)
{
$pw = self::ERROR_LOG > 1 ? $_SERVER['PHP_AUTH_PW'] : '**********';
error_log(__METHOD__.'() PHP_AUTH_USER='.array2string($_SERVER['PHP_AUTH_USER']).', PHP_AUTH_PW='.array2string($pw).', PHP_AUTH_DIGEST='.array2string($_SERVER['PHP_AUTH_DIGEST']));
}
$realm = $GLOBALS['egw_info']['flags']['auth_realm'];
if (empty($realm)) $realm = 'EGroupware';
$username = $_SERVER['PHP_AUTH_USER']; $password = $_SERVER['PHP_AUTH_PW'];
// Support for basic auth when using PHP CGI (what about digest auth?)
if (!isset($username) && !empty($_SERVER['REDIRECT_HTTP_AUTHORIZATION']) && strpos($_SERVER['REDIRECT_HTTP_AUTHORIZATION'],'Basic ') === 0)
{
$hash = base64_decode(substr($_SERVER['REDIRECT_HTTP_AUTHORIZATION'],6));
if (strpos($hash, ':') !== false)
{
list($username, $password) = explode(':', $hash, 2);
}
}
elseif (isset($_SERVER['PHP_AUTH_DIGEST']) && !self::is_valid($realm,$_SERVER['PHP_AUTH_DIGEST'],$username,$password))
{
unset($password);
}
// if given password contains non-ascii chars AND we can not authenticate with it
if (isset($username) && isset($password) &&
(preg_match('/[^\x20-\x7F]/', $password) || strpos($password, '\\x') !== false) &&
!$GLOBALS['egw']->auth->authenticate($username, $password, 'text'))
{
// replace \x encoded non-ascii chars in password, as they are used eg. by Thunderbird for German umlauts
if (strpos($password, '\\x') !== false)
{
$password = preg_replace_callback('/\\\\x([0-9A-F]{2})/i', function($matches){
return chr(hexdec($matches[1]));
}, $password);
}
// try translating the password from iso-8859-1 to utf-8
$password = translation::convert($password, 'iso-8859-1');
//error_log(__METHOD__."() Fixed non-ascii password of user '$username' from '$_SERVER[PHP_AUTH_PW]' to '$password'");
}
// create session without session cookie (session->create(..., true), as we use pseudo sessionid from credentials
if (!isset($username) || !($sessionid = $GLOBALS['egw']->session->create($username, $password, 'text', true)))
{
// if the session class gives a reason why the login failed --> append it to the REALM
if ($GLOBALS['egw']->session->reason) $realm .= ': '.$GLOBALS['egw']->session->reason;
header('WWW-Authenticate: Basic realm="'.$realm.'"');// draft-reschke-basicauth-enc-06 adds, accept-charset="'.translation::charset().'"');
self::digest_header($realm);
header('HTTP/1.1 401 Unauthorized');
header('X-WebDAV-Status: 401 Unauthorized', true);
echo "<html>\n<head>\n<title>401 Unauthorized</title>\n<body>\nAuthorization failed.\n</body>\n</html>\n";
exit;
}
return $sessionid;
}
/**
* Check if digest auth is available for a given realm (and user): do we use cleartext passwords
*
* If no user is given, check is NOT authoretive, as we can only check if cleartext passwords are generally used
*
* @param string $realm
* @param string $username =null username or null to only check if we auth agains sql and use plaintext passwords
* @param string &$user_pw =null stored cleartext password, if $username given AND function returns true
* @return boolean true if digest auth is available, false otherwise
*/
static public function digest_auth_available($realm,$username=null,&$user_pw=null)
{
// we currently require plaintext passwords!
if (!($GLOBALS['egw_info']['server']['auth_type'] == 'sql' && $GLOBALS['egw_info']['server']['sql_encryption_type'] == 'plain') ||
$GLOBALS['egw_info']['server']['auth_type'] == 'ldap' && $GLOBALS['egw_info']['server']['ldap_encryption_type'] == 'plain')
{
if (self::ERROR_LOG) error_log(__METHOD__."('$username') return false (no plaintext passwords used)");
return false; // no plain-text passwords used
}
// check for specific user, if given
if (!is_null($username) && !(($user_pw = $GLOBALS['egw']->accounts->id2name($username,'account_pwd','u')) ||
$GLOBALS['egw_info']['server']['auth_type'] == 'sql' && substr($user_pw,0,7) != '{PLAIN}'))
{
unset($user_pw);
if (self::ERROR_LOG) error_log(__METHOD__."('$realm','$username') return false (unknown user or NO plaintext password for user)");
return false; // user does NOT exist, or has no plaintext passwords (ldap server requires real root_dn or special ACL!)
}
if (substr($user_pw,0,7) == '{PLAIN}') $user_pw = substr($user_pw,7);
if (self::ERROR_LOG)
{
$pw = self::ERROR_LOG > 1 ? $user_pw : '**********';
error_log(__METHOD__."('$realm','$username','$pw') return true");
}
return true;
}
/**
* Send header offering digest auth, if it's generally available
*
* @param string $realm
* @param string &$nonce=null on return
*/
static public function digest_header($realm,&$nonce=null)
{
if (self::digest_auth_available($realm))
{
$nonce = uniqid();
header('WWW-Authenticate: Digest realm="'.$realm.'",qop="auth",nonce="'.$nonce.'",opaque="'.md5($realm).'"');
if (self::ERROR_LOG) error_log(__METHOD__."() offering digest auth for realm '$realm' using nonce='$nonce'");
}
}
/**
* Check digest
*
* @param string $realm
* @param string $auth_digest =null default to $_SERVER['PHP_AUTH_DIGEST']
* @param string &$username on return username
* @param string &$password on return cleartext password
* @return boolean true if digest is correct, false otherwise
*/
static public function is_valid($realm,$auth_digest=null,&$username=null,&$password=null)
{
if (is_null($auth_digest)) $auth_digest = $_SERVER['PHP_AUTH_DIGEST'];
$data = self::parse_digest($auth_digest);
if (!$data || !($A1 = self::get_digest_A1($realm,$username=$data['username'],$password=null)))
{
error_log(__METHOD__."('$realm','$auth_digest','$username') returning FALSE");
return false;
}
$A2 = md5($_SERVER['REQUEST_METHOD'].':'.$data['uri']);
$valid_response = md5($A1.':'.$data['nonce'].':'.$data['nc'].':'.$data['cnonce'].':'.$data['qop'].':'.$A2);
if (self::ERROR_LOG) error_log(__METHOD__."('$realm','$auth_digest','$username') response='$data[response]', valid_response='$valid_response' returning ".array2string($data['response'] === $valid_response));
return $data['response'] === $valid_response;
}
/**
* Calculate the A1 digest hash
*
* @param string $realm
* @param string $username
* @param string &$password=null password to use or if null, on return stored password
* @return string|boolean false if $password not given and can NOT be read
*/
static private function get_digest_A1($realm,$username,&$password=null)
{
$user_pw = null;
if (empty($username) || empty($realm) || !self::digest_auth_available($realm,$username,$user_pw))
{
return false;
}
if (is_null($password)) $password = $user_pw;
$A1 = md5($username . ':' . $realm . ':' . $password);
if (self::ERROR_LOG > 1) error_log(__METHOD__."('$realm','$username','$password') returning ".array2string($A1));
return $A1;
}
/**
* Parse the http auth header
*/
static public function parse_digest($txt)
{
// protect against missing data
$needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1);
$data = array();
$keys = implode('|', array_keys($needed_parts));
$matches = null;
preg_match_all('@(' . $keys . ')=(?:([\'"])([^\2]+?)\2|([^\s,]+))@', $txt, $matches, PREG_SET_ORDER);
foreach ($matches as $m)
{
$data[$m[1]] = $m[3] ? $m[3] : $m[4];
unset($needed_parts[$m[1]]);
}
//error_log(__METHOD__."('$txt') returning ".array2string($needed_parts ? false : $data));
return $needed_parts ? false : $data;
}
}