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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- EN-Revision: 1.16 Maintainer: perugini Status: working -->
<chapter id="features.safe-mode">
<title>Modalit sicura (Safe mode)</title>
<para>
La modalit Safe Mode un tentativo di risolvere il problema di sicurezza
derivante dalla condivisione del server. Dal punto di vista architetturale
non corretto cercare di risolvere questo problema al livello del PHP, ma
poich le alternative al livello del web server e del SO (Sistema Operativo)
non sono realistiche, in molti, specialmente ISP (Internet Service Provider),
utilizzano la modalit sicura.
</para>
<para>
Le direttive di configurazione che controllano la modalit sicura sono:
<programlisting role="ini">
<![CDATA[
safe_mode = Off
open_basedir =
safe_mode_exec_dir =
safe_mode_allowed_env_vars = PHP_
safe_mode_protected_env_vars = LD_LIBRARY_PATH
disable_functions =
]]>
</programlisting>
</para>
<para>
Quando <link linkend="ini.safe-mode">safe_mode</link> attiva (on), il PHP
verifica se il proprietario dello
script in esecuzione e il proprietario del file su cui si sta operando con
una funzione sui file, coincidono. Per esempio:
<programlisting role="ls">
<![CDATA[
-rw-rw-r-- 1 rasmus rasmus 33 Jul 1 19:20 script.php
-rw-r--r-- 1 root root 1116 May 26 18:01 /etc/passwd
]]>
</programlisting>
Eseguendo questo script.php
<programlisting role="php">
<![CDATA[
<?php
readfile('/etc/passwd');
?>
]]>
</programlisting>
results in this error when Safe Mode is enabled:
<screen>
<![CDATA[
Warning: SAFE MODE Restriction in effect. The script whose uid is 500 is not
allowed to access /etc/passwd owned by uid 0 in /docroot/script.php on line 2
]]>
</screen>
</para>
<para>
Se, invece di <link linkend="ini.safe-mode">safe_mode</link>, viene definita
una directory open_basedir allora tutte le operazioni sui file saranno limitate ai file
sottostanti la directory specificata. Per esempio (nel file httpd.conf di Apache):
<programlisting role="ini">
<![CDATA[
<Directory /docroot>
php_admin_value open_basedir /docroot
</Directory>
]]>
</programlisting>
If you run the same script.php with this open_basedir setting then this is
the result:
<screen>
<![CDATA[
Warning: open_basedir restriction in effect. File is in wrong directory in
/docroot/script.php on line 2
]]>
</screen>
</para>
<para>
È possibile inoltre disabilitare le singole funzioni. Se si aggiunge
la seguente riga al file php.ini:
<programlisting role="ini">
<![CDATA[
disable_functions readfile,system
]]>
</programlisting>
Then we get this output:
<screen>
<![CDATA[
Warning: readfile() has been disabled for security reasons in
/docroot/script.php on line 2
]]>
</screen>
</para>
<sect1 id="features.safe-mode.functions">
<title>Funzioni limitate/disabilitate dalla modalit sicura (safe-mode)</title>
<para>
Questo un elenco probabilmente ancora incompleto e forse non esatto delle
funzioni limitate da
<link linkend="features.safe-mode">Safe Mode</link>.
<!-- TODO: add ¬e.sm.*; to the functions mentioned here.
That entity should link to this section -->
<table>
<title>Funzioni limitate dalla modalit sicura</title>
<tgroup cols="2">
<thead>
<row>
<entry>Funzioni</entry>
<entry>Limitazioni</entry>
</row>
</thead>
<tbody>
<row>
<entry><function>dbmopen</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>dbase_open</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>filepro</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>filepro_rowcount</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>filepro_retrieve</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>ifx_*</function></entry>
<entry>sql_safe_mode restrictions, (!= Safe Mode)</entry>
<!-- TODO: more info on sql-safe-mode -->
</row>
<row>
<entry><function>ingres_*</function></entry>
<entry>sql_safe_mode restrictions, (!= Safe Mode)</entry>
<!-- TODO: more info on sql-safe-mode -->
</row>
<row>
<entry><function>mysql_*</function></entry>
<entry>sql_safe_mode restrictions, (!= Safe Mode)</entry>
<!-- TODO: more info on sql-safe-mode -->
</row>
<row>
<entry><function>pg_loimport</function></entry>
<entry>&sm.uidcheck;</entry>
<!-- source TODO: there is no PHP-warning for that safe-mode-restriction -->
</row>
<row>
<entry><function>posix_mkfifo</function></entry>
<entry>&sm.uidcheck.dir;</entry>
</row>
<row>
<entry><function>putenv</function></entry>
<entry>Obbedisce le direttive del file ini safe_mode_protected_env_vars e
safe_mode_allowed_env_vars. Vedere la documentazione relativa
on <function>putenv</function></entry>
<!-- TODO: document those directives in chapters/config.xml -->
</row>
<row>
<entry><function>move_uploaded_file</function></entry>
<entry>&sm.uidcheck; <!-- TODO: check this --></entry>
</row>
<!-- TODO: from here on, add warning to the function itself -->
<row>
<entry><function>chdir</function></entry>
<entry>&sm.uidcheck.dir;</entry>
</row>
<row>
<entry><function>dl</function></entry>
<entry>&sm.disabled;</entry>
</row>
<row>
<entry><link linkend="language.operators.execution">backtick operator</link></entry>
<entry>&sm.disabled;</entry>
</row>
<row>
<entry><function>shell_exec</function> (functional equivalent
of backticks)</entry>
<entry>&sm.disabled;</entry>
</row>
<row>
<entry><function>exec</function></entry>
<entry>You can only execute executables within the <link
linkend="ini.safe-mode-exec-dir">safe_mode_exec_dir</link>.
For practical reasons it's currently not allowed to have
<literal>..</literal> components in the path to the executable.</entry>
</row>
<row>
<entry><function>system</function></entry>
<entry>You can only execute executables within the <link
linkend="ini.safe-mode-exec-dir">safe_mode_exec_dir</link>.
For practical reasons it's currently not allowed to have
<literal>..</literal> components in the path to the executable.</entry>
</row>
<row>
<entry><function>passthru</function></entry>
<entry>You can only execute executables within the <link
linkend="ini.safe-mode-exec-dir">safe_mode_exec_dir</link>.
For practical reasons it's currently not allowed to have
<literal>..</literal> components in the path to the executable.</entry>
</row>
<row>
<entry><function>popen</function></entry>
<entry>You can only execute executables within the <link
linkend="ini.safe-mode-exec-dir">safe_mode_exec_dir</link>.
For practical reasons it's currently not allowed to have
<literal>..</literal> components in the path to the executable.</entry>
<!-- TODO: not sure. popen uses a completely different implementation
Don't know why, don't know whether it's behaving the same -->
</row>
<row>
<entry><function>mkdir</function></entry>
<entry>&sm.uidcheck.dir;</entry>
</row>
<row>
<entry><function>rmdir</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>rename</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir;<!-- on the old name only, it seems. Is rename preventing moving files? --></entry>
</row>
<row>
<entry><function>unlink</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir;</entry>
</row>
<row>
<entry><function>copy</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir; (on
<parameter>source</parameter> and
<parameter>target</parameter>) </entry>
</row>
<row>
<entry><function>chgrp</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>chown</function></entry>
<entry>&sm.uidcheck;</entry>
</row>
<row>
<entry><function>chmod</function></entry>
<entry>&sm.uidcheck; In addition, you cannot
set the SUID, SGID and sticky bits</entry>
</row>
<row>
<entry><function>touch</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir;</entry>
</row>
<row>
<entry><function>symlink</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir; (note: only the target is
checked)</entry>
</row>
<row>
<entry><function>link</function></entry>
<entry>&sm.uidcheck; &sm.uidcheck.dir; (note: only the target is
checked)</entry>
</row>
<row>
<entry><function>getallheaders</function></entry>
<entry>In Safe Mode, headers beginning with 'authorization'
(case-insensitive)
will not be returned. Warning: this is broken with the aol-server
implementation of <function>getallheaders</function>!</entry>
</row>
<row>
<entry>Qualsiasi funzione che utilizza
<filename>php4/main/fopen_wrappers.c</filename>
</entry>
<entry>??</entry>
</row>
</tbody>
</tgroup>
</table>
</para>
</sect1>
</chapter>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"../../manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
|
