Drop privileges if started as root

[glaslos]

If Glutton is started as root, we should drop privileges to the nobody user.

[HashCode55]

Hi Lukas, I wrote this small snippet to drop the privileges -

    uid := syscall.Getuid()
	if uid == 0 {
		// process is running as root
		logger.Info("[glutton ] The server is running as root. Dropping privilages to nobody...")
		// drop the group privilages to nobody user
		if err := syscall.Setgid(65534); err != nil {
			logger.Fatal("Could not set group privilages. ", err)
		} else {
			logger.Info("[glutton ] Group privilages dropped.")
		}
		// drop the user privilages
		if err := syscall.Setuid(65534); err != nil {
			logger.Fatal("Could not set user privilages. ", err)
		} else {
			logger.Info("[glutton ] User privilages dropped.")
		}
	}

But unfortunately, the implementation of Getuid is not at all reliable for a multithreaded code. I compiled the code and tested it in my environment with it always failing with operation not supported.

Refs -
http://stackoverflow.com/questions/41248866/golang-dropping-privileges-v1-7
There is a ticket in the golang codebase too -
golang/go#1435

[glaslos]

Well, tell me, why do we have to run Glutton as root?

[HashCode55]

@glaslos I don't know if I'm right or not but what I thought was we don't have to run glutton server as root. I'm sorry if I'm wrong about it.

[glaslos]

Try to figure out why we need to run as root...

[HashCode55]

I need root privileges to bind to port numbers under 1024.

[glaslos]

Where do we need root privileges?

[HashCode55]

When we are initializing the ssh proxy, specifically, when we are trying to bind the docker proxy to the ssh port. And that means I cannot drop the privileges in the beginning. I'll have to drop it after binding the port. Also that log.Fatal call was catastrophic in that case. Am I right?

[glaslos]

Forget about docker. Think about how we get the packages in the first place.

[glaslos]

@HashCode55 are you still looking into this?

[t3chn0m4g3]

Have you figured how to run w/o root privileges?

Even when manually adding capabilities to server via setcap I am not able to run server w/o root privileges.