Why doesn't chown -R root:www-data work on my Wordpress installation?

July 29, 2015 72.2k views
WordPress Security Nginx Ubuntu
nyubbie
By:
nyubbie

Quite some time ago, I was following this tutorial which showed me how to install Wordpress on an NGINX + Ubuntu (LEMP) setup:

https://www.digitalocean.com/community/tutorials/how-to-install-wordpress-with-nginx-on-ubuntu-14-04

I got stuck on this portion for quite some time back then as I used root as the user for this instruction snippet below:

The group that nginx operates under is www-data. For the user portion, enter your user account name. We will demonstrate with an account called demo here:

sudo chown -R demo:www-data /var/www/html/*

To clarify, it didn't give me any errors or anything, but what I found out was that if I used root:www-data for my file ownership settings, I wouldn't be able to add / update plugins / edit code on the site. It would always prompt me for FTP / SFTP details, in which it would fail even if i entered the correct credentials due to the permissions being drwxr-xr-x (Owner has write permission).

So i tried this:

sudo chown -R www-data:www-data /var/www/html/*

and it worked -- I was able to write / update plugins freely as the Wordpress site admin.

However, I now have a roughly better understanding of how ownership and groups work, and I'm concerned that by doing chown -R www-data:www-data, I opened a security flaw on my own.

Am I doing it right? Why didn't root:www-data work for being able to update the site in the first place?

Log In to Comment
6 Answers
sugarhill July 29, 2015

I researched the same problem and I found the solution.
The trick is to add your user "demo" to the group www-data (since www-data is a group)

add user "demo" to group "www-data" (below replace demo with your username)

sudo usermod -a -G www-data demo

set permissions for user group www-data

sudo chgrp -R www-data /var/www/html

followed by

sudo chmod -R g+w /var/www/html

Now you can modify files as "demo" via SFTP and your wordpress installation can modify files without requesting credentials

Reply
ryanpq MOD July 29, 2015

Since the nginx process is running as www-data the root:www-data ownership would only work with group write permissions set. There is no major issue with running with your web files owned by www-data:www-data but if you are concerned you could give ownership of wp-content to www-data and leave the rest of the install as root:www-data.

Reply
sergiozac05 October 25, 2016

this solved my issue, worked perfect!

Reply
joefoe December 29, 2017

Thank you sugarhill! Such an important thing ... surprised we had to dig for it

Reply
trinad536 April 12, 2018

Thank you so much, Worked like a charm.

Reply
skaryan February 27, 2019

This solution worked indeed - Thanks a lot sugarhill
BUT unfortunately, the file permissions changed from 755 to 775... and a warning message is appearing now in the wp-admin interface, stating -
---------->>
var/www/html/wp-content is write-able. When finished installing the plugin, change the permissions back to the default: chmod 755 /var/www/html/wp-content. Permissions are currently 775.
---------->>
If I change the file permission, then it again shows the same issue. Any suggestion? Thanks for your support.

Reply
Have another answer? Share your knowledge.

Related Questions