CODEWITHSUNDEEP
phplinuxfilepermissionscentos
Ahmad Ameri
Ahmad Ameri

Reputation: 400

How to prevent a file in linux from being changed

I've installed a CMS on my CentOS which changes a file constantly. And I want to prevent it from being changed. I tried:

chattr +i file.php

Or:

chmod 444 file.php

Even I've tried copying file(as file.php2) and then mounting it:

mount --bind file.php2 file.php -o ro

Then how can I prevent my file from being changed by that CMS?

Upvotes: 0

Views: 961

Answers (2)

PayPal_Kartik
PayPal_Kartik

Reputation: 226

Try sudo chmod 400 file.php This will make the file non editable to other users.

Upvotes: 1

nipil
nipil

Reputation: 88

You must

  • prevent others than owner to write the file :

chmod 644 file.php

  • you must set the ownership of the file to a different user and group than the user running the CMS

chown root:root file.php

  • Additionnaly, prevent others than owner to write to directory :

chmod 755 /path/to/dir/containing/

  • Additionnaly, change owner of folder to another user/group

chown root:root /path/to/dir/containing/

Why work on the folder too ?

Because a user having write rights on a folder can delete any other user's files, even if he couldn't write to it or read it. As a consequence, if you do not change the folder's permission too, the CMS user could delete your 'protected' file and write another one in its place.

Edit: and of course, your CMS shouldn't run as root, or all the above would be ignored

Upvotes: 1

Related Questions