I would like to create a php script to execute a shell command and return its output. The server requires a private key. When I first decided to test this out I created this:
<?php
$command = "ls";
$output = shell_exec($command);
echo "<pre>$output</pre>";
?>
That worked just fine. But when I changed $command to the command I really wanted to run:
$command = "/etc/init.d/mycontrollerd status /etc/mycontrollerconfig";
it gave me this output:
You need root privileges to run this script
My guess is I need to use sudo. Of course that will require putting the pem file somewhere on the server. Assuming I do that, what exactly should $command be? Should I use shell_exec(), exec(), system() or something else?
It does not matter which php function you use to start the script - what lacks is the authorization of your user account.
Either use sudo (preconfigure the web server user to run the exact command without password via visudo, and prefix the command with sudo) or set up a setuid script that executes the command on itself.
What you really need to do is set your web server to run as a specific user (other than 'nobody' for example), or give that user permissions to what you want to execute.
See also: PHP shell_exec() and sudo: must be setuid root
Related
Good day all, I m trying to implement a web interface that will operate my wireless network.
One of the operations is to configure my card into monitor mode. pretty simple, if you run this command:
bash prepareCard.sh wlan0
and the script prepareCard.sh is as follows:
#! /bin/bash
IFACE=$1
ifconfig $IFACE down
iwconfig $IFACE mode monitor
ifconfig $IFACE up
Now I want to execute this script via a php script:
$cmd = shell_exec("bash prepareCard.sh wlan0");
when I check if the card has been set to monitor mode, nothing! it's still in management mode!!
Can you please tell me where did I go wrong?
Assuming the webserver user that is running the script does not have sufficient permissions, you can try this way to fix it:
Use command visudo to edit /etc/sudoers and add this line:
ALL ALL=(root) NOPASSWD: /absolute/path/prepareCard.sh
Make sure to set permissions 700 to the script, so no one else can edit it. Then execute your script with sudo like this:
$cmd = shell_exec("sudo /absolute/path/prepareCard.sh wlan0");
That should execute the script as root without a need to enter a password.
One good way to debug BASH scripts is to set debug mode on (either by passing an -x flag to bash in your shell_exec call, by running set -x, or in the shebang line #!/bin/bash -x). This shows you what's going on during execution of the bash script. In your case, I suggest the first case, since you don't know if the script is even being loaded in the first place.
$cmd = shell_exec("bash -x prepareCard.sh wlan0");
After that, you should have more in your $cmd variable.
I'm trying to run a Python script from PHP using the following command:
exec('/usr/bin/python2.7 /srv/http/assets/py/switch.py arg1 arg2');
However, PHP simply doesn't produce any output. Error reporting is set to E_ALL and display_errors is on.
Here's what I've tried:
I used python2, /usr/bin/python2 and python2.7 instead of /usr/bin/python2.7
I also used a relative path instead of an absolute path which didn't change anything either.
I tried using the commands exec, shell_exec, system.
However, if I run
if (exec('echo TEST') == 'TEST')
{
echo 'exec works!';
}
it works perfectly fine while shutdown now doesn't do anything.
PHP has the permissions to access and execute the file.
EDIT: Thanks to Alejandro, I was able to fix the problem. If you have the same problem, don't forget that your webserver probably/hopefully doesn't run as root. Try logging in as your webserver's user or a user with similar permissions and try to run the commands yourself.
Tested on Ubuntu Server 10.04. I hope it helps you also on Arch Linux.
In PHP use shell_exec function:
Execute command via shell and return the complete output as a string.
It returns the output from the executed command or NULL if an error
occurred or the command produces no output.
<?php
$command = escapeshellcmd('/usr/custom/test.py');
$output = shell_exec($command);
echo $output;
?>
Into Python file test.py, verify this text in first line: (see shebang explain):
#!/usr/bin/env python
If you have several versions of Python installed, /usr/bin/env will
ensure the interpreter used is the first one on your environment's
$PATH. The alternative would be to hardcode something like
#!/usr/bin/python; that's ok, but less flexible.
In Unix, an executable file that's meant to be interpreted can indicate
what interpreter to use by having a #! at the start of the first line,
followed by the interpreter (and any flags it may need).
If you're talking about other platforms, of course, this rule does not
apply (but that "shebang line" does no harm, and will help if you ever
copy that script to a platform with a Unix base, such as Linux,
Mac, etc).
This applies when you run it in Unix by making it executable
(chmod +x myscript.py) and then running it directly: ./myscript.py,
rather than just python myscript.py
To make executable a file on unix-type platforms:
chmod +x myscript.py
Also Python file must have correct privileges (execution for user www-data / apache if PHP script runs in browser or curl)
and/or must be "executable". Also all commands into .py file must have correct privileges.
Taken from php manual:
Just a quick reminder for those trying to use shell_exec on a
unix-type platform and can't seem to get it to work. PHP executes as
the web user on the system (generally www for Apache), so you need to
make sure that the web user has rights to whatever files or
directories that you are trying to use in the shell_exec command.
Other wise, it won't appear to be doing anything.
I recommend using passthru and handling the output buffer directly:
ob_start();
passthru('/usr/bin/python2.7 /srv/http/assets/py/switch.py arg1 arg2');
$output = ob_get_clean();
If you want to know the return status of the command and get the entire stdout output you can actually use exec:
$command = 'ls';
exec($command, $out, $status);
$out is an array of all lines. $status is the return status. Very useful for debugging.
If you also want to see the stderr output you can either play with proc_open or simply add 2>&1 to your $command. The latter is often sufficient to get things working and way faster to "implement".
To clarify which command to use based on the situation
exec() - Execute an external program
system() - Execute an external program and display the output
passthru() - Execute an external program and display raw output
Source: http://php.net/manual/en/function.exec.php
Alejandro nailed it, adding clarification to the exception (Ubuntu or Debian) - I don't have the rep to add to the answer itself:
sudoers file:
sudo visudo
exception added:
www-data ALL=(ALL) NOPASSWD: ALL
In my case I needed to create a new folder in the www directory called scripts. Within scripts I added a new file called test.py.
I then used sudo chown www-data:root scripts and sudo chown www-data:root test.py.
Then I went to the new scripts directory and used sudo chmod +x test.py.
My test.py file it looks like this. Note the different Python version:
#!/usr/bin/env python3.5
print("Hello World!")
From php I now do this:
$message = exec("/var/www/scripts/test.py 2>&1");
print_r($message);
And you should see: Hello World!
The above methods seem to be complex. Use my method as a reference.
I have these two files:
run.php
mkdir.py
Here, I've created an HTML page which contains a GO button. Whenever you press this button a new folder will be created in directory whose path you have mentioned.
run.php
<html>
<body>
<head>
<title>
run
</title>
</head>
<form method="post">
<input type="submit" value="GO" name="GO">
</form>
</body>
</html>
<?php
if(isset($_POST['GO']))
{
shell_exec("python /var/www/html/lab/mkdir.py");
echo"success";
}
?>
mkdir.py
#!/usr/bin/env python
import os
os.makedirs("thisfolder");
This is so trivial, but just wanted to help anyone who already followed along Alejandro's suggestion but encountered this error:
sh: blabla.py: command not found
If anyone encountered that error, then a little change needs to be made to the php file by Alejandro:
$command = escapeshellcmd('python blabla.py');
All the options above create new system process. Which is a performance nightmare.
For this purpose I stitched together PHP module with "transparent" calls to Python.
https://github.com/kirmorozov/runpy
It may be tricky to compile, but will save system processes and will let you keep Python runtime between PHP calls.
Inspired by Alejandro Quiroz:
<?php
$command = escapeshellcmd('python test.py');
$output = shell_exec($command);
echo $output;
?>
Need to add Python, and don't need the path.
purpose: use php to input commands directly into the minecraft server console
Im trying to use a php script (run from browser) to exec() a shell script. when i run the php from a terminal it works! But in the browser, nothing happens.
exec('sudo -u root sh /home/minecraft/whitelist-reload.sh', $out, $ret_val);
When running from terminal, i get a "array 0" but the browser gives me a "array 1"
what is the issue?
and once i run the shell, shouldn't everything after that work as if you were on a terminal?(does it matter what is inside of shell script?)
the shell has all rx permissions and is in the sudoers file as
www-data ALL = NOPASSWD: /home/minecraft/whitelist-reload.sh
The problem is, that you run the script on a terminal as a user that probably has the sudo rights, whereas the apache/webserver user doesn't, so the $ret_val (which is actually just a status code) is set to 1 (means error).
try var_dump($out); in both cases to see the results of your exec call. To do this kind of thing from the browser, you might want to look into proc_open and family, or have a script that is chmod'ed to 777, so the apache user can run it, too. Let that script then call the actual shell script and return it's output back. This is, however very dangerous, and should only be used for testing environments on your own machine. Never do this in production environments!
I have posted a couple of questions here, too that might prove informative:
interaction over ssh
opening a second shell, and load profile variables AND call another script
Turns out... after inputting www-data into the sudoers file, all i needed to do was take of the "-u root" after it
I'm trying to execute a command as su from php.
When I put the command in terminal or with php /var/www/script.php it works perfect, but when I open script.php through browser it returns - sudo: no tty present and no askpass program specified
Thanks.
According to this:
ssh does not allocate a tty by default when running a remote command.
Without a tty, sudo cannot disable echo when prompting for a password.
You can use ssh's "-t" option to force it to allocate a tty.
Alternately, if you do not mind your password being echoed to the
screen, you can use the "visiblepw" sudoers option to allow this.
I recently published a project that allows PHP to obtain and interact with a real Bash shell. Get it here: https://github.com/merlinthemagic/MTS
You can get a real bash shell as root. You can then either trigger your php script or execute the commands directly in bash.
After downloading you would simply use the following code:
$shell = \MTS\Factories::getDevices()->getLocalHost()->getShell('bash', true);
$return1 = $shell->exeCmd('yourFirstCommand');
$return2 = $shell->exeCmd('yourSecondCommand');
//the return will be a string containing the return of the script
echo $return1;
echo $return2;
//or if you want to trigger your script as root
$return3 = $shell->exeCmd('php /my/script.php');
echo $return3;
//If your script contains code to make an SSH connection to another server
//there is a much easier way to do that using the project:
$shell = \MTS\Factories::getDevices()->getRemoteHost('ip_address')->getShellBySsh('username', 'secretPassword');
I can run an svn command from the command line but not from within a PHP script. Significantly, I can run the PHP script on my Mac and it returns the expected data just fine but when I upload it to my Linux server it won't work (from within PHP... I can run the svn command from the terminal). I'm pretty sure this is a user or permission issue of some sort.
I can run (from command line):
svn log http://whatever.com/svn/foo
but none of the following work (run separately... not all together like this):
exec('svn log http://whatever.com/svn/foo');
exec('svn log http://whatever.com/svn/foo',$out);
exec('/usr/bin/svn log http://whatever.com/svn/foo');
However this works:
exec('ls');
I assume the problem is that when I run from the command line I am running as root whereas when I run from PHP I am running as the apache user (www-data)? Perhaps? Any suggestions on how to be able to run exec('svn log http://whatever.com/svn/foo');?
Changing permissions to 777 (just trying to get it working!) does not help.
Here are a couple of threads that I think might help:
Thread 1 (read as there is more):
$cmd = '/usr/bin/svn list --config-dir /some/place file:///var/subversion/devfoundry/ 2>&1';
exec($cmd, $output);
$output = implode("\n", $output) . "\n";
echo $output;
Thread 2:
The Subversion error "svn: Can't
recode string" can be caused by the
locale being wrong. Try
<?php
putenv('LANG=en_US.UTF-8');
?>
(or whatever your preferred locale is)
before you call shell_exec()
Thread 3: PHP Interactive Shell
May be you can use a svn client for php. Here is a good one
http://code.google.com/p/phpsvnclient/
When you run Subversion from the command line, you are running it as yourself. That is, you are the user logged in and running the command.
If you are running Php from a webpage, it is the user who is running the Apache httpd daemon (which could be "apache", "www", "runwww", etc. depending upon the platform). The user running the PHP script may not have read/write permissions to the Subversion repository.
You have two ways of solving this:
Provide your program with user credentials via the --username and --password command line parameters.
Setup the user running httpd with Subversion credentials. Once it is done, it'll never have to be done again. This way, your PHP code doesn't contain login credentials.