SunshinePHP Developer Conference 2015

Runkit_Sandbox

(PECL runkit >= 0.7.0)

Runkit_Sandbox Runkit Sandbox Class -- PHP Virtual Machine

Descrizione

Instantiating the Runkit_Sandbox class creates a new thread with its own scope and program stack. Using a set of options passed to the constructor, this environment may be restricted to a subset of what the primary interpreter can do and provide a safer environment for executing user supplied code.

Nota: Il support sandbox (richiesto per runkit_lint(), runkit_lint_file(), e per la classe Runkit_Sandbox) è disponibile solo con PHP 5.1.0 o versioni appositamente patchate di PHP 5.0 e richiede che sia abilitata la thread safety. Vedere il file README incluso nel package runkit per ulteriori informazioni.

Constructor

void Runkit_Sandbox::__construct ([ array $options ] )

options is an associative array containing any combination of the special ini options listed below.

safe_mode

If the outer script which is instantiating the Runkit_Sandbox class is configured with safe_mode = off, then safe_mode may be turned on for the sandbox environment. This setting can not be used to disable safe_mode when it's already enabled in the outer script.

safe_mode_gid

If the outer script which is instantiating the Runkit_Sandbox class is configured with safe_mode_gid = on, then safe_mode_gid may be turned off for the sandbox environment. This setting can not be used to enable safe_mode_gid when it's already disabled in the outer script.

safe_mode_include_dir

If the outer script which is instantiating the Runkit_Sandbox class is configured with a safe_mode_include_dir, then a new safe_mode_include_dir may be set for sandbox environments below the currently defined value. safe_mode_include_dir may also be cleared to indicate that the bypass feature is disabled. If safe_mode_include_dir was blank in the outer script, but safe_mode was not enabled, then any arbitrary safe_mode_include_dir may be set while turning safe_mode on.

open_basedir

open_basedir may be set to any path below the current setting of open_basedir. If open_basedir is not set within the global scope, then it is assumed to be the root directory and may be set to any location.

allow_url_fopen

Like safe_mode, this setting can only be made more restrictive, in this case by setting it to FALSE when it is previously set to TRUE

disable_functions

Comma separated list of functions to disable within the sandbox sub-interpreter. This list need not contain the names of the currently disabled functions, they will remain disabled whether listed here or not.

disable_classes

Comma separated list of classes to disable within the sandbox sub-interpreter. This list need not contain the names of the currently disabled classes, they will remain disabled whether listed here or not.

runkit.superglobal

Comma separated list of variables to be treated as superglobals within the sandbox sub-interpreter. These variables will be used in addition to any variables defined internally or through the global runkit.superglobal setting.

runkit.internal_override

Ini option runkit.internal_override may be disabled (but not re-enabled) within sandboxes.

Example #1 Instantiating a restricted sandbox

<?php
$options 
= array(
  
'safe_mode'=>true,
  
'open_basedir'=>'/var/www/users/jdoe/',
  
'allow_url_fopen'=>'false',
  
'disable_functions'=>'exec,shell_exec,passthru,system',
  
'disable_classes'=>'myAppClass');
$sandbox = new Runkit_Sandbox($options);
/* Non-protected ini settings may set normally */
$sandbox->ini_set('html_errors',true);
?>

Accessing Variables

All variables in the global scope of the sandbox environment are accessible as properties of the sandbox object. The first thing to note is that because of the way memory between these two threads is managed, object and resource variables can not currently be exchanged between interpreters. Additionally, all arrays are deep copied and any references will be lost. This also means that references between interpreters are not possible.

Example #2 Working with variables in a sandbox

<?php
$sandbox 
= new Runkit_Sandbox();

$sandbox->foo 'bar';
$sandbox->eval('echo "$foo\n"; $bar = $foo . "baz";');
echo 
"{$sandbox->bar}\n";
if (isset(
$sandbox->foo)) unset($sandbox->foo);
$sandbox->eval('var_dump(isset($foo));');
?>

Il precedente esempio visualizzerà:

bar
barbaz
bool(false)

Calling PHP Functions

Any function defined within the sandbox may be called as a method on the sandbox object. This also includes a few pseudo-function language constructs: eval(), include, include_once, require, require_once, echo, print, die(), and exit().

Example #3 Calling sandbox functions

<?php
$sandbox 
= new Runkit_Sandbox();

echo 
$sandbox->str_replace('a','f','abc');
?>

Il precedente esempio visualizzerà:

fbc

When passing arguments to a sandbox function, the arguments are taken from the outer instance of PHP. If you wish to pass arguments from the sandbox's scope, be sure to access them as properties of the sandbox object as illustrated above.

Example #4 Passing arguments to sandbox functions

<?php
$sandbox 
= new Runkit_Sandbox();

$foo 'bar';
$sandbox->foo 'baz';
echo 
$sandbox->str_replace('a',$foo,'a');
echo 
$sandbox->str_replace('a',$sandbox->foo,'a');
?>

Il precedente esempio visualizzerà:

bar
baz

Changing Sandbox Settings

As of runkit version 0.5, certain Sandbox settings may be modified on the fly using ArrayAccess syntax. Some settings, such as active are read-only and meant to provide status information. Other settings, such as output_handler may be set and read much like a normal array offset. Future settings may be write-only, however no such settings currently exist.

Sandbox Settings / Status Indicators
Setting Type Purpose Default
active Boolean (Read Only) TRUE if the Sandbox is still in a usable state, FALSE if the request is in bailout due to a call to die(), exit(), or because of a fatal error condition. TRUE (Initial)
output_handler Callback When set to a valid callback, all output generated by the Sandbox instance will be processed through the named function. Sandbox output handlers follow the same calling conventions as the system-wide output handler. None
parent_access Boolean May the sandbox use instances of the Runkit_Sandbox_Parent class? Must be enabled for other Runkit_Sandbox_Parent related settings to work. FALSE
parent_read Boolean May the sandbox read variables in its parent's context? FALSE
parent_write Boolean May the sandbox modify variables in its parent's context? FALSE
parent_eval Boolean May the sandbox evaluate arbitrary code in its parent's context? DANGEROUS FALSE
parent_include Boolean May the sandbox include php code files in its parent's context? DANGEROUS FALSE
parent_echo Boolean May the sandbox echo data in its parent's context effectively bypassing its own output_handler? FALSE
parent_call Boolean May the sandbox call functions in its parent's context? FALSE
parent_die Boolean May the sandbox kill its own parent? (And thus itself) FALSE
parent_scope Integer What scope will parental property access look at? 0 == Global scope, 1 == Calling scope, 2 == Scope preceding calling scope, 3 == The scope before that, etc..., etc... 0 (Global)
parent_scope String When parent_scope is set to a string value, it refers to a named array variable in the global scope. If the named variable does not exist at the time of access it will be created as an empty array. If the variable exists but it not an array, a dummy array will be created containing a reference to the named global variable.  

add a note add a note

User Contributed Notes

There are no user contributed notes for this page.
To Top