.gitignore

@@ -1,3 +1,2 @@
 port80
-port80fg
 port80and443

LICENSE

@@ -1,4 +1,4 @@
-Copyright (C) 2022 Marius Schellenberger
+Copyright (C) 2017 Marius Schellenberger
 All rights reserved.
 
 Redistribution and use in source and binary forms, with or without

README.md

@@ -1,5 +1,5 @@
 # godrop - drop privileges
 
-Godrop is a simple library to drop privileges on Linux and OpenBSD.
+Godrop is a simple library to drop privileges on linux maschines.
 
 See the examples directory on how to use the `Drop` and `MultiDrop` functions.

example/port80.go

@@ -2,27 +2,28 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"net"
 	"net/http"
 	"os"
 
-	"git.giftfish.de/ston1th/godrop/v2"
+	"git.giftfish.de/ston1th/godrop"
 )
 
 func main() {
 	cfg := godrop.Config{
-		User:  "nobody",
+		User:       "nobody",
-		Group: "nobody",
+		Group:      "nobody",
+		Foreground: true,
 	}
 	err := godrop.Drop(cfg, func() (net.Listener, error) { return net.Listen("tcp", ":80") })
 	if err != nil {
-		log.Fatal(err)
+		fmt.Println(err)
 	}
 
 	l, err := godrop.GetListener()
 	if err != nil {
-		log.Fatal("Failed to listen on FD 3:", err)
+		fmt.Println("Failed to listen on FD 3:", err)
+		os.Exit(1)
 	}
 	_, port, _ := net.SplitHostPort(l.Addr().String())
 

example/port80and443.go

@@ -2,12 +2,11 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"net"
 	"net/http"
 	"os"
 
-	"git.giftfish.de/ston1th/godrop/v2"
+	"git.giftfish.de/ston1th/godrop"
 )
 
 func main() {
@@ -25,23 +24,23 @@ func main() {
 		return []net.Listener{l1, l2}, err
 	})
 	if err != nil {
-		log.Fatal(err)
+		fmt.Println(err)
 	}
 
 	l1, err := godrop.GetListener()
 	if err != nil {
-		log.Fatal("Failed to listen on FD 3:", err)
+		fmt.Println("Failed to listen on FD 3:", err)
+		os.Exit(1)
 	}
 	_, port1, _ := net.SplitHostPort(l1.Addr().String())
 
 	l2, err := godrop.GetListenerFd(4)
 	if err != nil {
-		log.Fatal("Failed to listen on FD 4:", err)
+		fmt.Println("Failed to listen on FD 4:", err)
+		os.Exit(1)
 	}
 	_, port2, _ := net.SplitHostPort(l2.Addr().String())
 
-	fmt.Printf("port1 %s\nport2 %s\npid %d\nuid %d\ngid %d\n", port1, port2, os.Getpid(), os.Getuid(), os.Getgid())
-
 	go func() {
 		http.Serve(l1, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			fmt.Fprintf(w, "port %s\npid %d\nuid %d\ngid %d", port1, os.Getpid(), os.Getuid(), os.Getgid())

example/port80fg.go

@@ -1,35 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"log"
-	"net"
-	"net/http"
-	"os"
-
-	"git.giftfish.de/ston1th/godrop/v2"
-)
-
-func main() {
-	cfg := godrop.Config{
-		User:       "nobody",
-		Group:      "nobody",
-		Foreground: true,
-	}
-	err := godrop.Drop(cfg, func() (net.Listener, error) { return net.Listen("tcp", ":80") })
-	if err != nil {
-		log.Fatal(err)
-	}
-
-	l, err := godrop.GetListener()
-	if err != nil {
-		log.Fatal("Failed to listen on FD 3:", err)
-	}
-	_, port, _ := net.SplitHostPort(l.Addr().String())
-
-	fmt.Printf("port %s\npid %d\nuid %d\ngid %d\n", port, os.Getpid(), os.Getuid(), os.Getgid())
-
-	http.Serve(l, http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		fmt.Fprintf(w, "port %s\npid %d\nuid %d\ngid %d", port, os.Getpid(), os.Getuid(), os.Getgid())
-	}))
-}

go.mod

@@ -1,5 +0,0 @@
-module git.giftfish.de/ston1th/godrop/v2
-
-go 1.19
-
-require golang.org/x/sys v0.24.0

go.sum

@@ -1,2 +0,0 @@
-golang.org/x/sys v0.24.0 h1:Twjiwq9dn6R1fQcyiK+wQyHWfaz/BJB+YIpzU/Cv3Xg=
-golang.org/x/sys v0.24.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=

godrop.go

@@ -1,9 +1,6 @@
-// Copyright (C) 2022 Marius Schellenberger
+// Copyright (C) 2017 Marius Schellenberger
 
-//go:build go1.11
+// Package godrop provides a simple privileges dropping library
-// +build go1.11
-
-// Package godrop provides a simple library to drop privileges on Linux and OpenBSD.
 package godrop
 
 import (
@@ -16,6 +13,10 @@ import (
 	"syscall"
 )
 
+func errf(err error) error {
+	return fmt.Errorf("godrop: %s", err)
+}
+
 // Config represents the drop config
 type Config struct {
 	// User is the user to drop privileges to.
@@ -41,21 +42,21 @@ func Drop(c Config, f func() (net.Listener, error)) error {
 func MultiDrop(c Config, f func() ([]net.Listener, error)) error {
 	uid, err := userID(c.User)
 	if err != nil {
-		return errors.New("godrop: " + err.Error())
+		return errf(err)
 	}
 	if uid == 0 {
-		return fmt.Errorf("godrop: you can't drop privileges to uid 0 (%s)", c.User)
+		return errf(errors.New("unable to drop privileges to uid 0 (root)"))
 	}
 	gid, err := groupID(c.Group)
 	if err != nil {
-		return errors.New("godrop: " + err.Error())
+		return errf(err)
 	}
 	switch os.Getuid() {
 	case 0:
 		cmd := exec.Command(os.Args[0], os.Args[1:]...)
 		ln, err := f()
 		if err != nil {
-			return errors.New("godrop: " + err.Error())
+			return errf(err)
 		}
 		for i, v := range ln {
 			var f *os.File
@@ -67,14 +68,20 @@ func MultiDrop(c Config, f func() ([]net.Listener, error)) error {
 				f, err = l.File()
 				l.Close()
 			default:
-				return fmt.Errorf("godrop: index %d listener is not type of either *net.TCPListener or *net.UnixListener", i)
+				return errf(fmt.Errorf("index: %d listener is not type of either *net.TCPListener or *net.UnixListener", i))
 			}
 			if err != nil {
-				return fmt.Errorf("godrop: index %d %s", i, err)
+				return errf(fmt.Errorf("index: %d %s", i, err))
 			}
 			cmd.ExtraFiles = append(cmd.ExtraFiles, f)
 		}
 
+		if c.Foreground {
+			cmd.Stdin = os.Stdin
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+		}
+
 		cmd.SysProcAttr = &syscall.SysProcAttr{
 			Chroot: c.Chroot,
 			Credential: &syscall.Credential{
@@ -84,31 +91,16 @@ func MultiDrop(c Config, f func() ([]net.Listener, error)) error {
 			Setsid: true,
 		}
 
-		if c.Foreground {
-			cmd.Stdin = os.Stdin
-			cmd.Stdout = os.Stdout
-			cmd.Stderr = os.Stderr
-		}
-
 		if err := cmd.Start(); err != nil {
-			return errors.New("godrop: " + err.Error())
+			return errf(err)
 		}
 
 		if c.Foreground {
 			go func() {
-				term := make(chan os.Signal)
-				signal.Notify(term, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
 				sigs := make(chan os.Signal)
-				signal.Notify(sigs, syscall.SIGSTOP, syscall.SIGCONT, syscall.SIGUSR1, syscall.SIGUSR2)
+				signal.Notify(sigs, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
-				for {
+				sig := <-sigs
-					select {
+				cmd.Process.Signal(sig)
-					case sig := <-term:
-						cmd.Process.Signal(sig)
-						return
-					case sig := <-sigs:
-						cmd.Process.Signal(sig)
-					}
-				}
 			}()
 			_ = cmd.Wait()
 			os.Exit(int(cmd.ProcessState.Sys().(syscall.WaitStatus)))
@@ -118,7 +110,7 @@ func MultiDrop(c Config, f func() ([]net.Listener, error)) error {
 	case uid:
 		return nil
 	}
-	return errors.New("godrop: dropping priviledges failed")
+	return errf(errors.New("dropping priviledges failed"))
 }
 
 // GetListener returns the listener socket of file descriptor 3
@@ -128,9 +120,6 @@ func GetListener() (net.Listener, error) {
 
 // GetListenerFd returns the listener socket of the given file descriptor
 func GetListenerFd(fd int) (net.Listener, error) {
-	if fd < 3 {
-		return nil, errors.New("godrop: fd is less than 3")
-	}
 	f := os.NewFile(uintptr(fd), "")
 	defer f.Close()
 	return net.FileListener(f)

lookup.go

@@ -1,14 +1,8 @@
-// Copyright (C) 2022 Marius Schellenberger
+// Copyright (C) 2017 Marius Schellenberger
-
-//go:build go1.11
-// +build go1.11
 
 package godrop
 
-import (
+import "strconv"
-	"os/user"
-	"strconv"
-)
 
 func atoi(a string) (int, error) {
 	i, err := strconv.Atoi(a)
@@ -18,18 +12,18 @@ func atoi(a string) (int, error) {
 	return i, nil
 }
 
-func userID(username string) (int, error) {
+func userID(username string) (uid int, err error) {
-	u, err := user.Lookup(username)
+	id, err := lookupUID(username)
 	if err != nil {
 		return -1, err
 	}
-	return atoi(u.Uid)
+	return atoi(id)
 }
 
 func groupID(name string) (int, error) {
-	g, err := user.LookupGroup(name)
+	id, err := lookupGID(name)
 	if err != nil {
 		return -1, err
 	}
-	return atoi(g.Gid)
+	return atoi(id)
 }

lookup_cgo.go

@@ -0,0 +1,23 @@
+// Copyright (C) 2017 Marius Schellenberger
+
+// +build cgo
+
+package godrop
+
+import "os/user"
+
+func lookupUID(username string) (string, error) {
+	u, err := user.Lookup(username)
+	if err != nil {
+		return "", err
+	}
+	return u.Uid, err
+}
+
+func lookupGID(name string) (string, error) {
+	g, err := user.LookupGroup(name)
+	if err != nil {
+		return "", err
+	}
+	return g.Gid, err
+}

lookup_nocgo.go

@@ -0,0 +1,43 @@
+// Copyright (C) 2017 Marius Schellenberger
+
+// +build darwin dragonfly freebsd android linux netbsd openbsd solaris
+// +build !cgo
+
+package godrop
+
+import (
+	"io/ioutil"
+	"os"
+	"regexp"
+)
+
+func readFile(name, file string) (id string, err error) {
+	id = "-1"
+	if name == "" {
+		return
+	}
+	f, err := os.Open(file)
+	if err != nil {
+		return
+	}
+	b, err := ioutil.ReadAll(f)
+	if err != nil {
+		return
+	}
+	r := regexp.MustCompile(name + `:.*?:(\d+):`)
+	m := r.FindAllStringSubmatch(string(b), 1)
+	if len(m) == 1 {
+		if len(m[0]) == 2 {
+			return m[0][1], nil
+		}
+	}
+	return
+}
+
+func lookupUID(username string) (string, error) {
+	return readFile(username, "/etc/passwd")
+}
+
+func lookupGID(name string) (string, error) {
+	return readFile(name, "/etc/group")
+}

lookup_test.go

@@ -1,4 +1,4 @@
-// Copyright (C) 2022 Marius Schellenberger
+// Copyright (C) 2017 Marius Schellenberger
 
 package godrop
 

pledge.go

@@ -1,15 +0,0 @@
-// Copyright (C) 2022 Marius Schellenberger
-
-//go:build !openbsd
-// +build !openbsd
-
-package godrop
-
-// Pledge is currently only supported on OpenBSD.
-func Pledge(promises, execpromises string) error { return nil }
-
-// PledgePromises is currently only supported on OpenBSD.
-func PledgePromises(promises string) error { return nil }
-
-// PledgeExecPromises is currently only supported on OpenBSD.
-func PledgeExecpromises(execpromises string) error { return nil }

pledge_openbsd.go

@@ -1,44 +0,0 @@
-// Copyright (C) 2022 Marius Schellenberger
-
-//go:build openbsd
-// +build openbsd
-
-package godrop
-
-import (
-	"errors"
-	"golang.org/x/sys/unix"
-)
-
-// Pledge is a wrapper for x/sys/unix Pledge.
-//
-// See https://go.googlesource.com/sys/+/master/unix/openbsd_pledge.go for usage.
-func Pledge(promises, execpromises string) (err error) {
-	err = unix.Pledge(promises, execpromises)
-	if err != nil {
-		err = errors.New("pledge: " + err.Error())
-	}
-	return
-}
-
-// PledgePromises is a wrapper for x/sys/unix PledgePromises.
-//
-// See https://go.googlesource.com/sys/+/master/unix/openbsd_pledge.go for usage.
-func PledgePromises(promises string) (err error) {
-	err = unix.PledgePromises(promises)
-	if err != nil {
-		err = errors.New("pledge: " + err.Error())
-	}
-	return
-}
-
-// PledgeExecpromises is a wrapper for x/sys/unix PledgeExecpromises.
-//
-// See https://go.googlesource.com/sys/+/master/unix/openbsd_pledge.go for usage.
-func PledgeExecpromises(execpromises string) (err error) {
-	err = unix.PledgeExecpromises(execpromises)
-	if err != nil {
-		err = errors.New("pledge: " + err.Error())
-	}
-	return
-}

unveil.go

@@ -1,12 +0,0 @@
-// Copyright (C) 2022 Marius Schellenberger
-
-//go:build !openbsd
-// +build !openbsd
-
-package godrop
-
-// Unveil is currently only supported on OpenBSD.
-func Unveil(path, flags string) error { return nil }
-
-// UnveilBlock is currently only supported on OpenBSD.
-func UnveilBlock() error { return nil }

unveil_openbsd.go

@@ -1,33 +0,0 @@
-// Copyright (C) 2022 Marius Schellenberger
-
-//go:build openbsd
-// +build openbsd
-
-package godrop
-
-import (
-	"errors"
-	"golang.org/x/sys/unix"
-)
-
-// Unveil is a wrapper for x/sys/unix Unveil.
-//
-// See https://go.googlesource.com/sys/+/master/unix/openbsd_unveil.go for usage.
-func Unveil(path, flags string) (err error) {
-	err = unix.Unveil(path, flags)
-	if err != nil {
-		err = errors.New("unveil: " + err.Error())
-	}
-	return
-}
-
-// UnveilBlock is a wrapper for x/sys/unix UnveilBlock.
-//
-// See https://go.googlesource.com/sys/+/master/unix/openbsd_unveil.go for usage.
-func UnveilBlock() (err error) {
-	err = unix.UnveilBlock()
-	if err != nil {
-		err = errors.New("unveil: " + err.Error())
-	}
-	return
-}