Question
Owner of NGINX process
- Posted on November 7, 2017
- NginxSecurityUbuntuUbuntu 16.04
Asked by mhampel
Hi there!
I’ve just installed nginx and wondering why there are two processes.
One process is owned by root, the other one is owned by www-data.
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7017 root 20 0 124972 1432 80 S 0.0 0.3 0:00.00 nginx
7018 www-data 20 0 125332 3168 1588 S 0.0 0.6 0:00.00 nginx
I didn’t changed the nginx.conf yet, so the configured user is still www-data.
Is it correct that one process is owned by root? Is that a security risk I need to worry about?
Thank you very much!
- Matthias
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A bit of clarification - only the root user can listen on ports less than 1024. This is for security reasons, otherwise system users could eavesdrop on each other.
Since web traffic is typically hosted on ports 80 and 443, a web server actually needs to run as root in order to listen on and server traffic over those ports.
To reduce the attack surface, increase stability (and probably other reasons) NGINX runs one parent process as root. The parent process manages spawning child processes as well as passing requests off to them. This means that the actual process that handles each request is non-root and less privileged.
The nginx process is running as www-data, so, 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.
The process owned by
rootis the nginx parent process. This process forks worker processes which are run by the user defined innginx.conf.