escapeshellcmd
(PHP 4, PHP 5)
escapeshellcmd — Escape shell metacharacters
说明
string escapeshellcmd ( string $command )escapeshellcmd() escapes any characters in a string that might be used to trick a shell command into executing arbitrary commands. This function should be used to make sure that any data coming from user input is escaped before this data is passed to the exec() or system() functions, or to the backtick operator.
Following characters are preceded by a backslash: #&;`|*?~<>^()[]{}$, x0A and xFF. ' and " are escaped only if they are not paired. In Windows, all these characters plus % are replaced by a space instead.
参数
- command
-
The command that will be escaped.
返回值
The escaped string.
范例
Example #1 escapeshellcmd() example
<?php
// We allow arbitrary number of arguments intentionaly here.
$command = './configure '.$_POST['configure_options'];
$escaped_command = escapeshellcmd($command);
system($escaped_command);
?>
escapeshellcmd() should be used on the whole command string, and it still allows the attacker to pass arbitrary number of arguments. For escaping a single argument escapeshellarg() should be used instead.
参见
- escapeshellarg() - Escape a string to be used as a shell argument
- exec() - Execute an external program
- popen() - 打开进程文件指针
- system() - Execute an external program and display the output
- backtick operator
