/
setuser.go
76 lines (72 loc) · 1.4 KB
/
setuser.go
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package main
import (
"fmt"
"os"
"os/exec"
"os/user"
"strconv"
"syscall"
)
func abort(err error) {
fmt.Fprintf(os.Stderr, "setuser: %s\n", err.Error())
os.Exit(1)
}
func setupEnv(u *user.User) (err error) {
var (
uid int
gid int
)
if uid, err = strconv.Atoi(u.Uid); err != nil {
return
}
if gid, err = strconv.Atoi(u.Gid); err != nil {
return
}
//if err = syscall.Setgroups([]int{gid}); err != nil {
// return
//}
_, _, e1 := syscall.RawSyscall(syscall.SYS_SETGID, uintptr(gid), 0, 0)
if e1 != 0 {
err = e1
return
}
_, _, e1 = syscall.RawSyscall(syscall.SYS_SETUID, uintptr(uid), 0, 0)
if e1 != 0 {
err = e1
return
}
os.Setenv("USER", u.Username)
os.Setenv("HOME", u.HomeDir)
os.Setenv("UID", u.Uid)
return nil
}
func main() {
var (
u *user.User
err error
username string
program string
command []string
)
if len(os.Args[1:]) < 2 {
fmt.Fprintf(os.Stderr, "Usage: %s USERNAME COMMAND [args...]\n", os.Args[0])
os.Exit(1)
}
username = os.Args[1]
program = os.Args[2]
command = append(command, os.Args[3:]...)
if u, err = user.Lookup(username); err != nil {
abort(err)
}
if program, err = exec.LookPath(program); err != nil {
abort(err)
}
if err = setupEnv(u); err != nil {
abort(err)
}
fmt.Println("Found binary at", program)
fmt.Println("Args: ", command)
if err = syscall.Exec(program, command, os.Environ()); err != nil {
abort(err)
}
}