NetUserGetInfo tester tool for Windows

netusergetinfo.go

package main

import (
	"flag"
	"log"
	"os/user"
	"syscall"
	"unsafe"

	"golang.org/x/sys/windows"
)

func main() {
	var serverName = flag.String("server-name", "", "server name")
	var userName = flag.String("username", "", "user name")
	var currentUser = flag.Bool("current", false, "Print value from Go's user.Current().")

	flag.Parse()

	if *currentUser {
		log.Println("Calling user.Current()")
		u, err := user.Current()
		if err != nil {
			log.Fatal("Error:", err)
		}
		log.Printf("Current user: %#v", u)
		return
	} else if *serverName != "" || *userName != "" {
		log.Printf("Calling NetUserGetInfo(%q, %q, 10, <buf>)", *serverName, *userName)
		fullName, err := NetUserGetInfo(*serverName, *userName)
		log.Print("Exited NetUserGetInfo")
		if err != nil {
			log.Fatal("Error:", err)
		}
		log.Println("User Full Name:", fullName)
	} else {
		flag.Usage()
	}
}

func NetUserGetInfo(servername, username string) (string, error) {
	var s *uint16
	if servername != "" {
		var e error
		s, e = syscall.UTF16PtrFromString(servername)
		if e != nil {
			return "", e
		}
	}
	u, e := syscall.UTF16PtrFromString(username)
	if e != nil {
		return "", e
	}
	var p *byte
	e = syscall.NetUserGetInfo(s, u, 10, &p)
	if e != nil {
		return "", e
	}
	defer syscall.NetApiBufferFree(p)
	i := (*syscall.UserInfo10)(unsafe.Pointer(p))
	return windows.UTF16PtrToString(i.FullName), nil
}

sample_output.md

Output when run as a SYSTEM user:

PS C:\> PsExec.exe -s C:\netusergetinfo.exe -current

PsExec v2.34 - Execute processes remotely
Copyright (C) 2001-2021 Mark Russinovich
Sysinternals - www.sysinternals.com


2022/06/03 02:00:22 Calling user.Current()
2022/06/03 02:00:22 Current user: &user.User{Uid:"S-1-5-18", Gid:"S-1-5-18", Username:"NT AUTHORITY\\SYSTEM", Name:"SYSTEM", HomeDir:"C:\\Windows\\system32\\config\\systemprofile"}
C:\netusergetinfo.exe exited on AKROH-WINDOWS20 with error code 0.

Output as a regular user:

PS C:\> .\netusergetinfo.exe -current
2022/06/03 02:00:39 Calling user.Current()
2022/06/03 02:00:39 Current user: &user.User{Uid:"S-1-5-21-1844000655-3260516853-2179737697-1000", Gid:"S-1-5-21-1844000655-3260516853-2179737697-513", Username:"AKROH-WINDOWS20\\andrew_kroh", Name:"andrew_kroh", HomeDir:"C:\\Users\\andrew_kroh"}

Fast failure when attempting to get full name of NT AUTHORITY\SYSTEM.

PS C:\> .\netusergetinfo.exe -username SYSTEM -server-name "NT AUTHORITY"
2022/06/03 02:00:46 Calling NetUserGetInfo("NT AUTHORITY", "SYSTEM", 10, <buf>)
2022/06/03 02:00:46 Exited NetUserGetInfo
2022/06/03 02:00:46 Error:The RPC server is unavailable.