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It is a known issue that spaces are not escaped in shell commands, which can be especially problematic on Windows. This adds a warning about this behaviour to the function, including a way to solve this in userland code. Ref: https://bugs.php.net/bug.php?id=43261 (last two comments) Also see: https://github.com/squizlabs/PHP_CodeSniffer/pull/3214 Co-authored-by: jrfnl <jrfnl@users.noreply.github.com>
138 lines
4 KiB
XML
138 lines
4 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<!-- splitted from ./en/functions/exec.xml, last change in rev 1.2 -->
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<refentry xml:id="function.escapeshellcmd" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>escapeshellcmd</refname>
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<refpurpose>Escape shell metacharacters</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>string</type><methodname>escapeshellcmd</methodname>
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<methodparam><type>string</type><parameter>command</parameter></methodparam>
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</methodsynopsis>
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<para>
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<function>escapeshellcmd</function> escapes any characters in a
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string that might be used to trick a shell command into executing
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arbitrary commands. This function should be used to make sure
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that any data coming from user input is escaped before this data
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is passed to the <function>exec</function> or
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<function>system</function> functions, or to the <link
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linkend="language.operators.execution">backtick
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operator</link>.
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</para>
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<para>
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Following characters are preceded by a backslash:
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<literal>&#;`|*?~<>^()[]{}$\</literal>, <literal>\x0A</literal>
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and <literal>\xFF</literal>. <literal>'</literal> and <literal>"</literal>
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are escaped only if they are not paired. On Windows, all these characters
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plus <literal>%</literal> and <literal>!</literal> are preceded by a caret
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(<literal>^</literal>).
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>command</parameter></term>
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<listitem>
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<para>
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The command that will be escaped.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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The escaped string.
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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<example>
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<title><function>escapeshellcmd</function> example</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// We allow arbitrary number of arguments intentionally here.
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$command = './configure '.$_POST['configure_options'];
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$escaped_command = escapeshellcmd($command);
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system($escaped_command);
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?>
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]]>
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</programlisting>
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</example>
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</para>
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</refsect1>
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<refsect1 role="notes">
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<warning xmlns="http://docbook.org/ns/docbook">
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<para>
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<function>escapeshellcmd</function> should be used on the whole
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command string, and it still allows the attacker to pass
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arbitrary number of arguments. For escaping a single argument
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<function>escapeshellarg</function> should be used instead.
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</para>
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</warning>
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<warning xmlns="http://docbook.org/ns/docbook">
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<para>
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Spaces will not be escaped by <function>escapeshellcmd</function>
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which can be problematic on Windows with paths like:
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<literal>C:\Program Files\ProgramName\program.exe</literal>.
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This can be mitigated using the following code snippet:
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<programlisting role="php">
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<![CDATA[
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<?php
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$cmd = preg_replace('`(?<!^) `', '^ ', escapeshellcmd($cmd));
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]]>
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</programlisting>
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</para>
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</warning>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>escapeshellarg</function></member>
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<member><function>exec</function></member>
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<member><function>popen</function></member>
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<member><function>system</function></member>
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<member><link linkend="language.operators.execution">backtick operator</link></member>
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</simplelist>
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"~/.phpdoc/manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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