HTTPAuthSession.php

<?php

class HTTPAuthSession {

  public $username;

  public $user_no;

  public $principal_id;

  public $email;

  public $fullname;

  public $groups;
 
  /* These fields were being added dynmically. Set to private mostly, I had to
   * set these as public for tests to pass: principal
   */
  private $dav_name;
  private $logged_in;
  public $principal;
  private $roles;

  function __construct() {
    global $c;
 
    if ( ! empty($_SERVER['PHP_AUTH_DIGEST'])) {
      $this->DigestAuthSession();
    }
    else if ( isset($_SERVER['PHP_AUTH_USER']) || isset($_SERVER["AUTHORIZATION"]) ) {
      $this->BasicAuthSession();
    }
    else if ( isset($c->http_auth_mode) && $c->http_auth_mode == "Digest" ) {
      $this->DigestAuthSession();
    }
    else {
      $this->BasicAuthSession();
    }
  }

  function AuthFailedResponse( $auth_header = "" ) {
    global $c;
    if ( $auth_header == "" ) {
      $auth_realm = $c->system_name;
      if ( isset($c->per_principal_realm) && $c->per_principal_realm && !empty($_SERVER['PATH_INFO']) ) {
        $principal_name = preg_replace( '{^/(.*?)/.*$}', '$1', $_SERVER['PATH_INFO']);
        if ( $principal_name != $_SERVER['PATH_INFO'] ) {
          $auth_realm .= ' - ' . $principal_name;
        }
      }
      dbg_error_log( "HTTPAuth", ":AuthFailedResponse Requesting authentication in the '%s' realm", $auth_realm );
      $auth_header = sprintf( 'WWW-Authenticate: Basic realm="%s"', $auth_realm );
    }
 
    header('HTTP/1.1 401 Unauthorized', true, 401 );
    header('Content-type: text/plain; ; charset="utf-8"' );
    if ( $c->test_mode ) header( "Request-ID: " . request_id() );
 
    header( $auth_header );
    echo 'Please log in for access to this system.';
    if ( isset($_SERVER['PHP_AUTH_USER']) ) {
      dbg_error_log( "ERROR", "authentication failure for user '%s' from host [%s]", $_SERVER['PHP_AUTH_USER'], $_SERVER['REMOTE_ADDR'] );
    } else {
      dbg_error_log( "HTTPAuth", ":Session: User is not authorised: %s ", $_SERVER['REMOTE_ADDR'] );
    }
    @ob_flush();   exit(0);
  }
 

  function BasicAuthSession() {
    global $c;

    if ( !isset($_SERVER['AUTHORIZATION']) && isset($_SERVER['HTTP_AUTHORIZATION']) && !empty($_SERVER['HTTP_AUTHORIZATION']))
      $_SERVER['AUTHORIZATION'] = $_SERVER['HTTP_AUTHORIZATION'];
    if (isset($_SERVER['AUTHORIZATION']) && !empty($_SERVER['AUTHORIZATION'])) {
      list ($type, $cred) = explode(" ", $_SERVER['AUTHORIZATION']);
      if ($type == 'Basic') {
        list ($user, $pass) = explode(":", base64_decode($cred), 2);
        $_SERVER['PHP_AUTH_USER'] = $user;
        $_SERVER['PHP_AUTH_PW'] = $pass;
      }
    }
    else if ( isset($c->authenticate_hook['server_auth_type'])
              && (  ( isset($_SERVER["REMOTE_USER"]) && !empty($_SERVER["REMOTE_USER"]) )  ||
                    ( isset($_SERVER["REDIRECT_REMOTE_USER"]) && !empty($_SERVER["REDIRECT_REMOTE_USER"]) )  )   ) {
      if ( ( is_array($c->authenticate_hook['server_auth_type'])
                    && in_array( strtolower($_SERVER['AUTH_TYPE']), array_map('strtolower', $c->authenticate_hook['server_auth_type'])) )
         ||
           ( !is_array($c->authenticate_hook['server_auth_type'])
                    && strtolower($c->authenticate_hook['server_auth_type']) == strtolower($_SERVER['AUTH_TYPE']) )
         ) {
        if (isset($_SERVER["REMOTE_USER"]))
          $_SERVER['PHP_AUTH_USER'] = $_SERVER['REMOTE_USER'];
        else
          $_SERVER['PHP_AUTH_USER'] = $_SERVER['REDIRECT_REMOTE_USER'];
        $_SERVER['PHP_AUTH_PW'] = 'Externally Authenticated';
        if ( ! isset($c->authenticate_hook['call']) ) {
          $c->authenticate_hook['call'] = 'auth_external';
        }
      }
    }
 

    if ( isset($_SERVER['PHP_AUTH_USER']) ) {
      if ( $p = $this->CheckPassword( $_SERVER['PHP_AUTH_USER'], $_SERVER['PHP_AUTH_PW'] ) ) {
        if ( isset($p->active) && !isset($p->user_active) ) {
          trace_bug('Some authentication failed to return a dav_principal record and needs fixing.');
          $p->user_active = $p->active;
        }

        if ( $p->user_active ) {
          $this->AssignSessionDetails($p);
          return;
        }
      }
    }
 
    if ( isset($c->allow_unauthenticated) && $c->allow_unauthenticated ) {
      $this->AssignSessionDetails('unauthenticated');
      $this->logged_in = false;
      return;
    }
 
    $this->AuthFailedResponse();
    // Does not return
  }
 

  function DigestAuthSession() {
    global $c;
 
    $realm = $c->system_name;
    $opaque = $realm;
    if ( isset($_SERVER['HTTP_USER_AGENT']) ) $opaque .= $_SERVER['HTTP_USER_AGENT'];
    if ( isset($_SERVER['REMOTE_ADDR']) )     $opaque .= $_SERVER['REMOTE_ADDR'];
    $opaque = sha1($opaque);
 
    if ( ! empty($_SERVER['PHP_AUTH_DIGEST'])) {
      // analyze the PHP_AUTH_DIGEST variable
      if ( $data = $this->ParseDigestHeader($_SERVER['PHP_AUTH_DIGEST']) ) {
 
        if ( $data['uri'] != $_SERVER['REQUEST_URI'] ) {
          dbg_error_log( "ERROR", " DigestAuth: WTF! URI is '%s' and request URI is '%s'!?!" );
          $this->AuthFailedResponse();
          // Does not return
        }
 
        // generate the valid response
        $test_user = new Principal('username', $data['username']);
 
        if ( preg_match( '{\*(Digest)?\*(.*)}', $test_user->password, $matches ) ) {
          if ( $matches[1] == 'Digest' )
            $A1 = $matches[2];
          else {
//            dbg_error_log( "HTTPAuth", "Constructing A1 from md5(%s:%s:%s)", $data['username'], $realm, $matches[2] );
            $A1 = md5($data['username'] . ':' . $realm . ':' . $matches[2]);
          }
          $A2 = md5($_SERVER['REQUEST_METHOD'].':'.$data['uri']);
          $auth_string = $A1.':'.$data['nonce'].':'.$data['nc'].':'.$data['cnonce'].':'.$data['qop'].':'.$A2;
//          dbg_error_log( "HTTPAuth", "DigestAuthString: %s", $auth_string);
          $valid_response = md5($auth_string);
//          dbg_error_log( "HTTPAuth", "DigestResponse: %s", $valid_response);
 
          if ( $data['response'] == $valid_response ) {
            $this->AssignSessionDetails($test_user);
//            dbg_error_log( "HTTPAuth", "Success!!!" );
            return;
          }
        }
        else {
          // Their account is not configured for Digest auth so we need to use Basic.
          $this->AuthFailedResponse();
          // Does not return
        }
      }
    }
 
    $nonce = sha1(uniqid('',true));
    $authheader = sprintf('WWW-Authenticate: Digest realm="%s", qop="auth", nonce="%s", opaque="%s", algorithm="MD5"',
                                     $realm, $nonce, $opaque );
    dbg_error_log( "HTTPAuth", $authheader );
    $this->AuthFailedResponse( $authheader );
    // Does not return
  }
 

  function ParseDigestHeader($auth_header) {
    // protect against missing data
    $needed_parts = array('nonce'=>1, 'nc'=>1, 'cnonce'=>1, 'qop'=>1, 'username'=>1, 'uri'=>1, 'response'=>1);
    $data = array();
 
    preg_match_all('{(\w+)="([^"]+)"}', $auth_header, $matches, PREG_SET_ORDER);
    foreach ($matches as $m) {
//      dbg_error_log( "HTTPAuth", 'Match: "%s"', $m[0] );
      $data[$m[1]] = $m[2];
      unset($needed_parts[$m[1]]);
      dbg_error_log( "HTTPAuth", 'Received: %s: %s', $m[1], $m[2] );
    }
 
    preg_match_all('{(\w+)=([^" ,]+)}', $auth_header, $matches, PREG_SET_ORDER);
    foreach ($matches as $m) {
//      dbg_error_log( "HTTPAuth", 'Match: "%s"', $m[0] );
      $data[$m[1]] = $m[2];
      unset($needed_parts[$m[1]]);
      dbg_error_log( "HTTPAuth", 'Received: %s: %s', $m[1], $m[2] );
    }
 
 
    @dbg_error_log( "HTTPAuth", 'Received: nonce: %s, nc: %s, cnonce: %s, qop: %s, username: %s, uri: %s, response: %s',
        $data['nonce'], $data['nc'], $data['cnonce'], $data['qop'], $data['username'], $data['uri'], $data['response']
      );
    return $needed_parts ? false : $data;
  }
 

  function CheckPassword( $username, $password ) {
    global $c;
 
    if(isset($c->login_append_domain_if_missing) && $c->login_append_domain_if_missing && !preg_match('/@/',$username))
      $username.='@'.$c->domain_name;
 
    $cache_result = $this->_CheckCache($username, $password);
 
    if ($cache_result == 0) {
      # noop as _CheckCache has nothing for this username/password combo
      # and we need to perform full authentication check.
 
    } else if ($cache_result == 1) {
      # cached credentials match and are valid
 
      if ( $principal = new Principal('username', $username) ) {
        if ( isset($c->dbg['password']) ) dbg_error_log( "password", ":CheckPassword (cached): Name:%s, Pass:%s, File:%s, Active:%s", $username, $password, $principal->password, ($principal->user_active?'Yes':'No') );
        if ( $principal->user_active ) {
          return $principal;
        } else {
          return false;
        }
      } else {
 
        # If we fail to find the Principal, then fall through to full authentication below.
        dbg_error_log('password', 'Cache check: Failed to find principal after valid cache result, falling through to full authentication check.');
      }
 
    } else if ($cache_result == 2) {
      # cached credentials match and are invalid
 
      return false;
    }
 
    if ( !isset($c->authenticate_hook) || !isset($c->authenticate_hook['call'])
                      || !function_exists($c->authenticate_hook['call'])
                      || (isset($c->authenticate_hook['optional']) && $c->authenticate_hook['optional']) )
    {
      if ( $principal = new Principal('username', $username) ) {
        if ( isset($c->dbg['password']) ) dbg_error_log( "password", ":CheckPassword: Name:%s, Pass:%s, File:%s, Active:%s", $username, $password, $principal->password, ($principal->user_active?'Yes':'No') );
        if ( $principal->user_active && session_validate_password( $password, $principal->password ) ) {
          $this->_SetCache($username, $password, 'pass');
          return $principal;
        }
      }
    }
 
    if ( isset($c->authenticate_hook) && isset($c->authenticate_hook['call']) && function_exists($c->authenticate_hook['call']) ) {
      $principal = call_user_func( $c->authenticate_hook['call'], $username, $password );
      if ( $principal !== false && !($principal instanceof Principal) ) {
        $principal = new Principal('username', $username);
      }
 
      if ( $principal === false ) {
        $this->_SetCache($username, $password, 'fail');
      } else {
        $this->_SetCache($username, $password, 'pass');
      }
 
      return $principal;
    }
 
    $this->_SetCache($username, $password, 'fail');
    return false;
  }
 

  function AllowedTo ( $whatever ) {
    return ( isset($this->logged_in) && $this->logged_in && isset($this->roles[$whatever]) && $this->roles[$whatever] );
  }
 

  function GetRoles () {
    $this->roles = array();
    $qry = new AwlQuery( 'SELECT role_name FROM role_member m join roles r ON r.role_no = m.role_no WHERE user_no = :user_no ',
                                array( ':user_no' => $this->user_no) );
    if ( $qry->Exec('BasicAuth') && $qry->rows() > 0 ) {
      while( $role = $qry->Fetch() ) {
        $this->roles[$role->role_name] = true;
      }
    }
  }
 

  function AssignSessionDetails( $principal ) {
    if ( is_string($principal) ) $principal = new Principal('username',$principal);
    if ( get_class($principal) != 'Principal' ) {
      $principal = new Principal('username',$principal->username);
    }
 
    if ( !get_class($principal) == 'Principal' ) {
      throw new Exception('HTTPAuthSession::AssignSessionDetails could not find a Principal object');
    }
    $this->username = $principal->username();
    $this->user_no  = $principal->user_no();
    $this->principal_id = $principal->principal_id();
    $this->email = $principal->email();
    $this->fullname = $principal->fullname;
    $this->dav_name = $principal->dav_name();
    $this->principal = $principal;
 
    $this->GetRoles();
    $this->logged_in = true;
    if ( function_exists("awl_set_locale") && isset($this->locale) && $this->locale != "" ) {
      awl_set_locale($this->locale);
    }
  }

  function _CheckCache( $username, $password ) {
    global $c;
 
    if (! $c->auth_cache) return 0;
    if (! isset($c->auth_cache_secret) || $c->auth_cache_secret == '') {
      dbg_error_log('LOG', "HTTPAuth:CheckCache: caching of credentials is enabled, but \$c->auth_cache_secret isn't set, using auth source");
      return 0;
    }
 
    $cache = getCacheInstance();
    if ($cache->isActive() === false) return 0;
 
    $cache_ns = 'auth-' . $username;
 
    $salt = $cache->get($cache_ns, 'salt');
 
    if (!isset($salt) || (is_bool($salt) && $salt == false) || $salt == '') {
      dbg_error_log('HTTPAuth', 'CheckCache: No stored salt for %s, need to use auth source', $username);
      return 0;
    }
 
    # The hashed password to fetch
    $hash = $this->_MakeHash($password, $salt);
    if (! isset($hash)) {
      dbg_error_log('LOG', 'HTTPAuth:CheckCache: failed to generate hash of credential, using auth source');
      return 0;
    }
 
    $cached_credentials = $cache->get($cache_ns, $hash);
 
    if (isset($cached_credentials)) {
      if ($cached_credentials === 'pass') {
        dbg_error_log('HTTPAuth', 'CheckCache: Cached credentials for %s are good and valid', $username);
        return 1;
 
      } else if ($cached_credentials === 'fail') {
        dbg_error_log('HTTPAuth', 'CheckCache: Cached credentials for %s are good and invalid', $username);
        return 2;
      }
 
      dbg_error_log('HTTPAuth', 'CheckCache: No stored salted password for %s, need to use auth source', $username);
    }
 
    # All hope is lost, we must have failed to find anything decent.
    return 0;
  }

  function _SetCache( $username, $password, $state ) {
    global $c;
 
    if (! $c->auth_cache) return 0;
    if (! isset($c->auth_cache_secret) || $c->auth_cache_secret === '') {
      dbg_error_log('LOG', "HTTPAuth:CheckCache: caching of credentials is enabled, \$c->auth_cache_secret isn't set, not caching credential");
      return 0;
    }
 
    # Work out the expiry to use, some sites might prefer different TTLs for
    # pass/fail results.
    if ($state === 'pass') {
      $expiry = $c->auth_cache_pass;
    } else if ($state === 'fail') {
      $expiry = $c->auth_cache_fail;
    } else {
      dbg_error_log('ERROR', 'HTTPAuth:CheckCache: SetCache: Unexpected state %s, bailing out from caching credential.', $state);
      return 0;
    }
 
    # Only cache if the expiry is set to non-zero. This allows disabling
    # caching on a pass or fail basis.
    if ($expiry == 0) {
      dbg_error_log('ERROR', 'HTTPAuth:CheckCache: SetCache: Expiry set to 0, not caching credential.', $state);
      return 0;
    }
 
 
    $cache = getCacheInstance();
    if ($cache->isActive() === false) return 0;
 
    $cache_ns = 'auth-' . $username;
 
    $salt = $cache->get($cache_ns, 'salt');
 
    if (!isset($salt) || (is_bool($salt) && $salt == false) || $salt == '') {
      # bcrypt requires the salt is 22 bytes.
      $salt = $this->_GenerateSalt(22);
 
      # We use the default expiry setting for the salt, because the worst
      # case scenario is that we won't access the cached credentials and
      # need to fail back to the full authentication source.
      if (! $cache->set($cache_ns, 'salt', $salt) ) {
        dbg_error_log('ERROR', 'HTTPAuth:CheckCache: SetCache: Failed to store salt, bailing out from caching credential.');
        return 0;
      }
    }
 
    # The hashed password to store
    $hash = $this->_MakeHash($password, $salt);
    if (! isset($hash)) {
      dbg_error_log('ERROR', 'HTTPAuth:CheckCache: SetCache: Failed to generate hash, bailing out from caching credential.');
      return 0;
    }
 
    if (! $cache->set($cache_ns, $hash, $state, $expiry) ) {
      dbg_error_log('ERROR', 'HTTPAuth:CheckCache: SetCache: Failed to store credential.');
      return 0;
    }
 
    return 1;
  }

  function _MakeHash( $password, $salt ) {
    global $c;
 
    $password_salt = '$2y$07$' . $salt . '$';
    $password_peppered = hash_hmac('sha256', $password, $c->auth_cache_secret);
    $password_hashed   = crypt($password_peppered, $password_salt);
 
    if ($password_hashed == $password_salt || $password_hashed == '*0')  {
        return NULL;
    } else {
        return $password_hashed;
    }
  }
 
  /*
   * Internal function to generate a salt.
   *
   * Uses random_bytes if available, falls back to mcrypt_create_iv if it
   * isn't.
   */
  function _GenerateSalt( $length ) {
    # We fetch a bit more incase we need to strip out unacceptable characters.
    if (function_exists('random_bytes')) {
        $salt = random_bytes($length + 20);
    } else {
        $salt = mcrypt_create_iv($length + 20, MCRYPT_DEV_URANDOM);
    }
 
    # We use this salt with CRYPT_BLOWFISH which only accepts the characters
    #./0-9a-zA-Z as per https://www.php.net/manual/en/function.crypt.php
    $salt = base64_encode($salt);
    $salt = preg_replace('/[^0-9\.\/a-zA-Z]/', '', $salt);
 
    $salt = substr($salt, 1, $length);
    return $salt;
  }
}