How to call shell script from php that requires SUDO?

There are various solutions for this problem.

• First of all, consider changing the script permissions, if reason why you want sudo is simply a permission issue (see the comment I added to the question above).

• Another approach would be using the setuid bit. [Edit: Looks like setuid does not work well with scripts. For explananations, see this link.]

• A third, but very insecure method is to read the password from a password file. Warning: This is very insecure, if there's any other possibility, don't do it. And if you do it, try hiding the password file somewhere in your folder hierarchy.

  <?php
  shell_exec('sudo -u root -S bash script.sh < /home/[user]/passwordfile');
  ?>
  

• And a fourth possibility is to use the NOPASSWD tag in the sudoers file. You should limit this power to the specific commands you need.

You can add something like this to your sudoers file:

username ALL=NOPASSWD: /path/to/script

This will allow that particular user to call sudo on that particular script without being prompted for a password.

Edit the sudoers file (with visudo) and add a rule that allows the web server user to run the command without a password. For example:

www-data ALL=NOPASSWD: /path/to/script