Bind Linux Process to Well Known Web Ports When Not Root

scottalanmiller

If you have ever tried to run a user space program on Linux with a port below 1024 you know that this is a security problem and you are not allowed to do so. There is a simple fix for this, but it is not well known.

Once you know the binary that you will be using to open the low number (well known) port you can use this command to grant it permission to use these ports without otherwise compromising security.

setcap cap_net_bind_service+ep /my/binary/file

Now you can run your application. This is most commonly used for user space web applications that want to use port 80 or 443 without requiring that you run a reverse proxy in front of them.

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@scottalanmiller said in Bind Linux Process to Well Known Web Ports When Not Root:

If you have ever tried to run a user space program on Linux with a port below 1024 you know that this is a security problem and you are not allowed to do so. There is a simple fix for this, but it is not well known.

Once you know the binary that you will be using to open the low number (well known) port you can use this command to grant it permission to use these ports without otherwise compromising security.
setcap cap_net_bind_service+ep /my/binary/file
Now you can run your application. This is most commonly used for user space web applications that want to use port 80 or 443 without requiring that you run a reverse proxy in front of them.

Good to know!

I found this as an example of how to use it and also commands to remove the permission:
https://cwiki.apache.org/confluence/display/HTTPD/NonRootPortBinding

The setcap utility seems to be available in the libcap2-bin package on debian distros.

I haven't checked if it's installed by default.