libraries/session.inc.php

   1 <?php
   2 /* vim: set expandtab sw=4 ts=4 sts=4: */
   3 /**
   4  * session handling
   5  *
   6  * @todo    add an option to use mm-module for session handler
   7  *
   8  * @package PhpMyAdmin
   9  * @see     https://secure.php.net/session
  10  */
  11 if (! defined('PHPMYADMIN')) {
  12     exit;
  13 }
  14
  15 require_once 'libraries/session.lib.php';
  16
  17 // verify if PHP supports session, die if it does not
  18
  19 if (!@function_exists('session_name')) {
  20     PMA_warnMissingExtension('session', true);
  21 } elseif (! empty(ini_get('session.auto_start')) && session_name() != 'phpMyAdmin' && !empty(session_id())) {
  22     // Do not delete the existing non empty session, it might be used by other
  23     // applications; instead just close it.
  24     if (empty($_SESSION)) {
  25         /* Ignore errors as this might have been destroyed in other request meanwhile */
  26         @session_destroy();
  27     } elseif (function_exists('session_abort')) {
  28         /* PHP 5.6 and newer */
  29         session_abort();
  30     } else {
  31         session_write_close();
  32     }
  33 }
  34
  35 // disable starting of sessions before all settings are done
  36 // does not work, besides how it is written in php manual
  37 //ini_set('session.auto_start', '0');
  38
  39 // session cookie settings
  40 session_set_cookie_params(
  41     0, $GLOBALS['PMA_Config']->getRootPath(),
  42     '', $GLOBALS['PMA_Config']->isHttps(), true
  43 );
  44
  45 // cookies are safer (use @ini_set() in case this function is disabled)
  46 @ini_set('session.use_cookies', 'true');
  47
  48 // optionally set session_save_path
  49 $path = $GLOBALS['PMA_Config']->get('SessionSavePath');
  50 if (!empty($path)) {
  51     session_save_path($path);
  52 }
  53
  54 // use cookies only
  55 @ini_set('session.use_only_cookies', '1');
  56 // strict session mode (do not accept random string as session ID)
  57 @ini_set('session.use_strict_mode', '1');
  58 // make the session cookie HttpOnly
  59 @ini_set('session.cookie_httponly', '1');
  60 // do not force transparent session ids
  61 @ini_set('session.use_trans_sid', '0');
  62
  63 // delete session/cookies when browser is closed
  64 @ini_set('session.cookie_lifetime', '0');
  65
  66 // warn but don't work with bug
  67 @ini_set('session.bug_compat_42', 'false');
  68 @ini_set('session.bug_compat_warn', 'true');
  69
  70 // use more secure session ids
  71 @ini_set('session.hash_function', '1');
  72
  73 // some pages (e.g. stylesheet) may be cached on clients, but not in shared
  74 // proxy servers
  75 session_cache_limiter('private');
  76
  77 // start the session
  78 // on some servers (for example, sourceforge.net), we get a permission error
  79 // on the session data directory, so I add some "@"
  80
  81
  82 function PMA_sessionFailed($errors)
  83 {
  84     $messages = array();
  85     foreach ($errors as $error) {
  86         /*
  87          * Remove path from open() in error message to avoid path disclossure
  88          *
  89          * This can happen with PHP 5 when nonexisting session ID is provided,
  90          * since PHP 7, session existence is checked first.
  91          *
  92          * This error can also happen in case of session backed error (eg.
  93          * read only filesystem) on any PHP version.
  94          *
  95          * The message string is currently hardcoded in PHP, so hopefully it
  96          * will not change in future.
  97          */
  98         $messages[] = preg_replace(
  99             '/open\(.*, O_RDWR\)/',
 100             'open(SESSION_FILE, O_RDWR)',
 101             htmlspecialchars($error->getMessage())
 102         );
 103     }
 104
 105     /*
 106      * Session initialization is done before selecting language, so we
 107      * can not use translations here.
 108      */
 109     PMA_fatalError(
 110         'Error during session start; please check your PHP and/or '
 111         . 'webserver log file and configure your PHP '
 112         . 'installation properly. Also ensure that cookies are enabled '
 113         . 'in your browser.'
 114         . '<br /><br />'
 115         . implode('<br /><br />', $messages)
 116     );
 117 }
 118
 119 // See bug #1538132. This would block normal behavior on a cluster
 120 //ini_set('session.save_handler', 'files');
 121
 122 $session_name = 'phpMyAdmin';
 123 @session_name($session_name);
 124
 125 // Restore correct sesion ID (it might have been reset by auto started session
 126 if (isset($_COOKIE['phpMyAdmin'])) {
 127     session_id($_COOKIE['phpMyAdmin']);
 128 }
 129
 130 // on first start of session we check for errors
 131 // f.e. session dir cannot be accessed - session file not created
 132 $orig_error_count = $GLOBALS['error_handler']->countErrors(false);
 133
 134 $session_result = session_start();
 135
 136 if ($session_result !== true
 137     || $orig_error_count != $GLOBALS['error_handler']->countErrors(false)
 138 ) {
 139     setcookie($session_name, '', 1);
 140     $errors = $GLOBALS['error_handler']->sliceErrors($orig_error_count);
 141     PMA_sessionFailed($errors);
 142 }
 143 unset($orig_error_count, $session_result);
 144
 145 /**
 146  * Disable setting of session cookies for further session_start() calls.
 147  */
 148 @ini_set('session.use_cookies', 'true');
 149
 150 /**
 151  * Token which is used for authenticating access queries.
 152  * (we use "space PMA_token space" to prevent overwriting)
 153  */
 154 if (empty($_SESSION[' PMA_token '])) {
 155     PMA_generateToken();
 156
 157     /**
 158      * Check for disk space on session storage by trying to write it.
 159      *
 160      * This seems to be most reliable approach to test if sessions are working,
 161      * otherwise the check would fail with custom session backends.
 162      */
 163     $orig_error_count = $GLOBALS['error_handler']->countErrors();
 164     session_write_close();
 165     if ($GLOBALS['error_handler']->countErrors() > $orig_error_count) {
 166         $errors = $GLOBALS['error_handler']->sliceErrors($orig_error_count);
 167         PMA_sessionFailed($errors);
 168     }
 169     session_start();
 170     if (empty($_SESSION[' PMA_token '])) {
 171         PMA_fatalError(
 172             'Failed to store CSRF token in session! ' .
 173             'Probably sessions are not working properly.'
 174         );
 175     }
 176 }