Quick and dirty xml-ation of the safe-mode sheet by Rasmus.

Doesn't build because of FAQ :(


git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@51111 c90b9560-bf6c-de11-be94-00142212c4b1

features/safe-mode.xml

@@ -0,0 +1,85 @@
+ <chapter id="features.safe-mode">
+  <title>Safe mode</title>
+
+  <para>
+   Safe Mode is an attempt to solve the shared-server security problem. It is
+   architecturally incorrect to try to solve this problem at the PHP level, 
+   but since the alternatives at the web server and OS levels aren't very 
+   realistic, many people, especially ISP's, use safe mode for now. 
+  </para>
+  <para>
+   The configuration directives that control safe mode are: 
+   <programlisting role="ini">
+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>
+   When safe_mode is on, PHP checks to see if the owner of the current script 
+   matches the owner of the file to be operated on by a file function. For 
+   example: 
+   <computeroutput>
+-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 
+   </computeroutput>
+   Running this script.php 
+   <programlisting role="php">
+<?php
+ readfile('/etc/passwd'); 
+?>  
+   </programlisting>
+   results in this error when safe mode is enabled: 
+   <computeroutput>
+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
+   </computeroutput>
+  </para>
+  <para>
+   If instead of safe_mode, you set an open_basedir directory then all file 
+   operations will be limited to files under the specified directory. For 
+   example (Apache httpd.ini example): 
+   <programlisting role="ini">
+&lt;Directory /docroot&gt; 
+php_admin_value open_basedir /docroot 
+&lt;/Directory&gt;  
+   </programlisting>
+   If you run the same script.php with this open_basedir setting then this is 
+   the result: 
+   <computeroutput>
+Warning: open_basedir restriction in effect. File is in wrong directory in 
+/docroot/script.php on line 2 
+   </computeroutput>
+  </para>
+  <para>
+   You can also disable individual functions. If we add this to our php.ini 
+   file: 
+   <programlisting role="ini">
+disable_functions readfile,system  
+   </programlisting>
+   Then we get this output: 
+   <computeroutput>
+Warning: readfile() has been disabled for security reasons in /docroot/script.php on line 2 
+   </computeroutput>
+  </para>
+ </chapter>
+
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