Php Exec external python script - Permission Denied

Question

I can't run command line script from Exec

$exec = exec($command, $output, $return );

I have tried passthru,shell_exec,system but obviously this is not the problem.

sudo chown -R www-data:www-data /root/path/nonce.py
sudo chmo 775 /path/nonce.py
sudo chmo 777 /path/nonce.py
sudo chmo 755 /path/nonce.py

didn't helped

exec("python -V 2>&1");

works

But

/usr/bin/python /root/path/nonce.py 
 Array ( [0] => /usr/bin/python: can't open file '/root/path/nonce.py': [Errno 13] Permission denied ) 

dosent

running on nginx and php5-fpm

Answer 1

You need to consider the permissions for each directory on the path to the Python script. This means:

/root
/root/path
/root/path/nonce.py

The permissions for the root account are naturally restricted. If you look a root's home directory:

$ ls -ld /root
dr-xr-x---. 9 root root 4096 Aug 20 23:50 root

You will see that only the root user, and users within group root, can read or list the contents of /root.

It's a bad idea to place your script in root's home. There are more appropriate places such as /var/www/cgi-bin assuming that your script is a CGI script. On my system:

$ ls -ld /var/www
drwxr-xr-x. 4 root root 4096 Jul 17 17:22 /var/www
$ ls -ld /var/www/cgi-bin
drwxr-xr-x. 2 root root 4096 Jul 17 17:22 /var/www/cgi-bin/

which can be read and listed by any user. You should install the script in a directory appropriate for nginx.

Answer 2

one of the directories on the path probably lacks r permisison for the relevant user - most likely /root

can you move the python script to a dir that is world readable?