Golang : Force your program to run with root permissions

Problem:

Because of security requirements, you need to create programs that can only be executed with the proper root permissions. For example, if a non-root user tries to execute the executable, instead of running as usual......the program will not prompt for the root password and will also display a warning message that it is only meant for those with root privilege before exiting.

How do to that?

Solution:

On Mac/Unix/Linux operating systems, there is a program call id that is used to return the user identity. For example, if you have the root privilege, executing the command sudo id -u will return 0 instead of 501

$id -u

501

$sudo id -u

0

We will incorporate this id -u command into our simple Golang program to check for the root privilege. Try executing the following program with and without sudo to see the differences.

Here you go!

 package main

 import (
 "log"
 "os/exec"
 "strconv"
 )

 func main() {
 cmd := exec.Command("id", "-u")
 output, err := cmd.Output()

 if err != nil {
 log.Fatal(err)
 }

 // output has trailing \n
 // need to remove the \n
 // otherwise it will cause error for strconv.Atoi
 // log.Println(output[:len(output)-1])

 // 0 = root, 501 = non-root user
 i, err := strconv.Atoi(string(output[:len(output)-1]))

 if err != nil {
 log.Fatal(err)
 }

 if i == 0 {
 log.Println("Awesome! You are now running this program with root permissions!")
 } else {
 log.Fatal("This program must be run as root! (sudo)")
 }

 }

Output:

$ ./checksudo

2017/04/22 16:23:10 This program must be run as root! (sudo)

$ sudo ./checksudo

Password:

2017/04/22 16:23:16 Awesome! You are now running this program with root permissions!

References:

https://www.socketloop.com/tutorials/execute-shell-command-golang

https://adamscheller.com/systems-administration/check-if-bash-script-is-run-with-root-permissions/