Run process as nobody from Go

main.go

// Author Christoph Hartmann
// This is a simple test that tries to execute a simple binary that prints its uid:

// package main
//
// import (
// 	"fmt"
// 	"os/user"
// )
//
// func main() {
// 	current, _ := user.Current()
// 	fmt.Printf("my uid is %s (%s)\n", current.Name, current.Uid)
// }

// Build the binary and make nobody owner of that file
// $ go build -o no main.go
// $ chown nobody:nobody no
// Now, you're able to execute the program

package main

import (
	"fmt"
	"log"
	"os/exec"
	"os/user"
	"strconv"
	"syscall"
)

func main() {
	// no
	command := "./no"
	args := []string{}

	cmd := exec.Command(command, args...)

	// find nobody
	nobody, _ := user.Lookup("nobody")
	var uid, gid uint32

	if s, err := strconv.ParseUint(nobody.Uid, 10, 32); err == nil {
		uid = uint32(s)
	}

	if s, err := strconv.ParseUint(nobody.Gid, 10, 32); err == nil {
		gid = uint32(s)
	}

	fmt.Printf("Run as user: %d gid: %d\n", uid, gid)

	cmd.SysProcAttr = &syscall.SysProcAttr{}
	cmd.SysProcAttr.Credential = &syscall.Credential{Uid: uid, Gid: gid}

	out, err := cmd.CombinedOutput()
	if err != nil {
		log.Println(err)
	}

	fmt.Printf("%s\n", out)
}

// $ sudo go run main.go                                                              x130 
// Run as user: 4294967294 gid: 4294967294
// my uid is Unprivileged User (4294967294)