Executing a shell script from a PHP script

Question

I want to execute a Bash script present on the system from a PHP script  I have two scripts present on the system  One of them is a PHP script called client php present at  var www html and the other is a Bash script called testscript present at  home testuser    My client php script looks like     lt  php    message shell exec   home testuser testscript 2 gt  amp 1      print r  message     gt      My testscript looks like     bin bash echo  Testscript run succesful    When i do the following on terminal  php client php   I get the following output on terminal  Testscript run successful   But when i open the page at   http   serverdomain client php   I get the following output  sh   home testuser testscript  Permission denied    I get this error even after I did chmod  x testscript  How do I get it to work from the browser  Please help

User · Answer

Without really knowing the complexity of the setup, I like the sudo route. First, you must configure sudo to permit your webserver to sudo run the given command as root. Then, you need to have the script that the webserver shell_exec's(testscript) run the command with sudo.

For A Debian box with Apache and sudo:

Configure sudo:
- As root, run the following to edit a new/dedicated configuration file for sudo:
```
visudo -f /etc/sudoers.d/Webserver
```
  (or whatever you want to call your file in /etc/sudoers.d/)
- Add the following to the file:
```
www-data ALL = (root) NOPASSWD: <executable_file_path>
```
  where <executable_file_path> is the command that you need to be able to run as root with the full path in its name(say /bin/chown for the chown executable). If the executable will be run with the same arguments every time, you can add its arguments right after the executable file's name to further restrict its use.
  
  For example, say we always want to copy the same file in the /root/ directory, we would write the following:
```
www-data ALL = (root) NOPASSWD: /bin/cp /root/test1 /root/test2
```
Modify the script(testscript):

Edit your script such that sudo appears before the command that requires root privileges(say sudo /bin/chown ... or sudo /bin/cp /root/test1 /root/test2). Make sure that the arguments specified in the sudo configuration file exactly match the arguments used with the executable in this file. So, for our example above, we would have the following in the script:
```
sudo /bin/cp /root/test1 /root/test2
```

If you are still getting permission denied, the script file and it's parent directories' permissions may not allow the webserver to execute the script itself. Thus, you need to move the script to a more appropriate directory and/or change the script and parent directory's permissions to allow execution by www-data(user or group), which is beyond the scope of this tutorial.

Keep in mind:

When configuring sudo, the objective is to permit the command in it's most restricted form. For example, instead of permitting the general use of the cp command, you only allow the cp command if the arguments are, say, /root/test1 /root/test2. This means that cp's arguments(and cp's functionality cannot be altered).

User · Answer

I would have a directory somewhere called scripts under the WWW folder so that it s not reachable from the web but is reachable by PHP    e g   var www scripts testscript  Make sure the user group for your testscript is the same as your webfiles  For instance if your client php is owned by apache apache  change the bash script to the same user group using chown  You can find out what your client php and web files are owned by doing ls -al    Then run   lt  php        message shell exec   var www scripts testscript 2 gt  amp 1          print r  message         gt      EDIT   If you really want to run a file as root from a webserver you can try this binary wrapper below  Check out this solution for the same thing you want to do    Execute root commands via PHP

User · Answer

It s a simple problem  When you are running from terminal  you are running the php file from terminal as a privileged user  When you go to the php from your web browser  the php script is being run as the web server user which does not have permissions to execute files in your home directory  In Ubuntu  the www-data user is the apache web server user  If you re on ubuntu you would have to do the following  chown yourusername www-data  home testuser testscript chmod g x  home testuser testscript  what the above does is transfers user ownership of the file to you  and gives the webserver group ownership of it  the next command gives the group executable permission to the file  Now the next time you go ahead and do it from the browser  it should work

User · Answer

I was struggling with this exact issue for three days  I had set permissions on  the script to 755  I had been calling my script as follows     lt  php     outcome   shell exec   tmp clearUp sh       echo  outcome    gt    My script was as follows     bin bash find   -maxdepth 1 -name  search  csv  -mmin  0 -exec rm         I was getting no output or feedback  The change I made to get the script to run was to add a cd to tmp inside the script     bin bash cd  tmp  find   -maxdepth 1 -name  search  csv  -mmin  0 -exec rm         This was more by luck than judgement but it is now working perfectly  I hope this helps

[php] Executing a shell script from a PHP script

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