PHP shell_exec does not work for some commands?

Question

If I do the following command, I get an 'hey' output:

echo shell_exec("echo 'hey'");

But If I do the following command, it will not kill any screen:

echo shell_exec("killall screen");

Or if I do

echo shell_exec("sh /var/www/html/run.sh");

It will not run that file at all (that file does the screen killing aswell)

And If I even get that file with get contents, it successfully reads the content in it.

If it can execute echo so whats wrong?

It's probably permissions. killall usually needs su/sudo permission, if it's not your own process. — aynber
– aynber, Commented Oct 19, 2017 at 13:42
Most likely the user your website runs as does not have permission to execute kill and similar commands. — Mikk3lRo
– Mikk3lRo, Commented Oct 19, 2017 at 13:42
There's a good reason for this type of protection...try to imagine how catastrophic it would be to let any user run any command in a shared hosting environment: "Today i feel like taking a break..." shell_exec("poweroff") ;) — Mikk3lRo
– Mikk3lRo, Commented Oct 19, 2017 at 13:45
@Mikk3lRo I know it's risky, but I am wondering how can I whitelist some commands — Ben Beri
– Ben Beri, Commented Oct 19, 2017 at 13:46

Ben Beri · Accepted Answer · 2017-10-19 19:09:50Z

0

To run such powerful commands, I had to use this library as stated in this question. This allows me to login into the SSH with root access and execute any command!

function ssh_script($script, $ip, $user, $pass) {
            $ssh = new Net_SSH2($ip);
    if (!$ssh->login($user, $pass)) {
        exit('Login Failed');
    }

    if ($ssh !== false) {
        echo $ssh->exec("sh " . $script);
    }
    else {
        echo "fail";
    }
}

answered Oct 19, 2017 at 19:09

Ben Beri

1,2215 gold badges26 silver badges66 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

PHP shell_exec does not work for some commands?

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related