shell_exec on php

[iamresearcher]

I have this code below:

 

shell_exec("/usr/bin/sudo /usr/sbin/usermod -p $userpwd $username");

 

 

Its purpose is to modify the password of the username using php.

Please dont criticize why I do what I do.

 

I would like to ask your assistance if that script is correct on its syntax like

if I use " or should I use '.

 

I have tried every combination to make it work, but it is not working till now.

 

I also tried:

 

shell_exec("/usr/bin/sudo /usr/sbin/usermod -p". $userpwd . " " . $username);

 

Still not working to update the password of the user.

[trq]

the syntax is fine.

 

does apache have permission to use sudo?

[iamresearcher]

What syntax is fine?

 

I dont know if apache allows sudo? can you help me find out if apache allows sudo.

[trq]

The first syntax is fine.

 

You will need to take a look at your /etc/sudoers file. Use sudoedit to open it though.

[iamresearcher]

really my first sytax is fine?  was it right to use " instead of ' ? and the position of my quotes?

 

on my sudoers file, is

 

root ALL=<ALL>    ALL

[trq]

Both of the syntaxes you posted are fine.

 

That entry within your sudoers file simply means that root can execute all commands. You need to make sure your Apache user (whatever that is) is allowed to execute sudo. This also assumes you are trying to execute this line of php from a page requested via Apache?

[iamresearcher]

I only have one user and that is root. do I have to place NOPASSWD:ALL LIKE

 

root ALL=<ALL>    NOPASSWD:ALL

 

Yes I am using php with apache.

 

but I dont get it why I dont have any result from my script.

[trq]

I only have one user and that is root

 

No you don't. Linux systems have multiple users even if you haven't setup any. There are system users which various pieces of software run as. Apache runs as one of these users.

 

You can find out which user apache is running as by looking for the User and Group directives within your configuration. Assuming your main configuration file is /etc/apache/httpd.conf, this command should show you which user Apache is running as.

 

grep User /etc/apache/httpd.conf

 

I say should because not all configs are setup the same. You will need to investigate this further yourself, or let us know which distribution you are using.

[iamresearcher]

using grep User /etc/httpd/conf/httpd.conf, the result is below:

 

[root@s1 ~]# grep User /etc/httpd/conf/httpd.conf

# AssignUserID: Takes two parameters, uid and gid (or really, user name and

# User/Group: The name (or #number) of the user/group to run httpd as.

#  . On SCO (ODT 3) use "User nouser" and "Group nogroup".

User apache

# UserDir: The name of the directory that is appended onto a user's home

    # UserDir is disabled by default since it can confirm the presence

    UserDir disabled

    # directory, remove the "UserDir disabled" line above, and uncomment

    #UserDir public_html

# Control access to UserDir directories.  The following is an example

LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined

LogFormat "%{User-agent}i" agent

#LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O"

combinedio

[root@s1 ~]#

 

I am using centos 5

 

 

[trq]

As you can tell by the output of that command Apache runs as a user called apache. this user will need to be granted permission to use sudo without password.

 

Be aware that this also opens massive security holes. You should lockdown the sudo access to only the specific commands you wish to execute.

[iamresearcher]

what I have now on my sudoers which I only modified was:

 

root ALL=(ALL) ALL

apache ALL=NOPASSWD: /usr/bin/sudo, /usr/sbin/useradd, /usr/sbin/usermod, /usr/sbin/userdel

 

that is all.

 

 

I restart httpd but still shell_exec does not perform.

 

Is the syntax below correct?

 

shell_exec('/usr/bin/sudo /usr/sbin/userdel -r ' . $username);