Golang syscall.Setgid函数代码示例

func chuser(username string) (uid, gid int) {
	usr, err := user.Lookup(username)

	if err != nil {
		fmt.Printf("failed to find user %q: %s", username, err)
	}

	uid, err = strconv.Atoi(usr.Uid)

	if err != nil {
		fmt.Printf("bad user ID %q: %s", usr.Uid, err)
	}

	gid, err = strconv.Atoi(usr.Gid)

	if err != nil {
		fmt.Printf("bad group ID %q: %s", usr.Gid, err)
	}

	if err := syscall.Setgid(gid); err != nil {
		fmt.Printf("setgid(%d): %s", gid, err)
	}

	if err := syscall.Setuid(uid); err != nil {
		fmt.Printf("setuid(%d): %s", uid, err)
	}

	return uid, gid
}

// SetupUser changes the groups, gid, and uid for the user inside the container
func SetupUser(u string) error {
	uid, gid, suppGids, home, err := user.GetUserGroupSupplementaryHome(u, syscall.Getuid(), syscall.Getgid(), "/")
	if err != nil {
		return fmt.Errorf("get supplementary groups %s", err)
	}

	if err := syscall.Setgroups(suppGids); err != nil {
		return fmt.Errorf("setgroups %s", err)
	}

	if err := syscall.Setgid(gid); err != nil {
		return fmt.Errorf("setgid %s", err)
	}

	if err := syscall.Setuid(uid); err != nil {
		return fmt.Errorf("setuid %s", err)
	}

	// if we didn't get HOME already, set it based on the user's HOME
	if envHome := os.Getenv("HOME"); envHome == "" {
		if err := os.Setenv("HOME", home); err != nil {
			return fmt.Errorf("set HOME %s", err)
		}
	}

	return nil
}

// Takes care of dropping privileges to the desired user
func changeUser(args *DockerInitArgs) error {
	if args.user == "" {
		return nil
	}
	userent, err := utils.UserLookup(args.user)
	if err != nil {
		return fmt.Errorf("Unable to find user %v: %v", args.user, err)
	}

	uid, err := strconv.Atoi(userent.Uid)
	if err != nil {
		return fmt.Errorf("Invalid uid: %v", userent.Uid)
	}
	gid, err := strconv.Atoi(userent.Gid)
	if err != nil {
		return fmt.Errorf("Invalid gid: %v", userent.Gid)
	}

	if err := syscall.Setgid(gid); err != nil {
		return fmt.Errorf("setgid failed: %v", err)
	}
	if err := syscall.Setuid(uid); err != nil {
		return fmt.Errorf("setuid failed: %v", err)
	}

	return nil
}

// Takes care of dropping privileges to the desired user
func changeUser(u string) {
	if u == "" {
		return
	}
	userent, err := utils.UserLookup(u)
	if err != nil {
		log.Fatalf("Unable to find user %v: %v", u, err)
	}

	uid, err := strconv.Atoi(userent.Uid)
	if err != nil {
		log.Fatalf("Invalid uid: %v", userent.Uid)
	}
	gid, err := strconv.Atoi(userent.Gid)
	if err != nil {
		log.Fatalf("Invalid gid: %v", userent.Gid)
	}

	if err := syscall.Setgid(gid); err != nil {
		log.Fatalf("setgid failed: %v", err)
	}
	if err := syscall.Setuid(uid); err != nil {
		log.Fatalf("setuid failed: %v", err)
	}
}

func DropPrivileges(username string) error {
	userInfo, err := user.Lookup(username)
	if err != nil {
		return err
	}

	uid, err := strconv.Atoi(userInfo.Uid)
	if err != nil {
		return err
	}

	gid, err := strconv.Atoi(userInfo.Gid)
	if err != nil {
		return err
	}

	// TODO: should set secondary groups too
	err = syscall.Setgroups([]int{gid})
	if err != nil {
		return err
	}

	err = syscall.Setgid(gid)
	if err != nil {
		return err
	}

	err = syscall.Setuid(uid)
	if err != nil {
		return err
	}

	return nil
}

// SetupEnv will create pidfile and possibly change the workdir.
func SetupEnv(cfg *config.Config) error {

	if cfg.System.User != "" {
		// Get the current user
		currentUser, err := user.Current()
		if err != nil {
			return fmt.Errorf("Could not get the current user: %s", err)
		}

		// If the current user is different than the wanted user, try to change it
		if currentUser.Username != cfg.System.User {

			wantedUser, err := user.Lookup(cfg.System.User)
			if err != nil {
				return err
			}

			uid, err := strconv.Atoi(wantedUser.Uid)
			if err != nil {
				return fmt.Errorf("Error converting UID [%s] to int: %s", wantedUser.Uid, err)
			}

			gid, err := strconv.Atoi(wantedUser.Gid)
			if err != nil {
				return fmt.Errorf("Error converting GID [%s] to int: %s", wantedUser.Gid, err)
			}

			if err = syscall.Setgid(gid); err != nil {
				return fmt.Errorf("Setting group id: %s", err)
			}

			if err = syscall.Setuid(uid); err != nil {
				return fmt.Errorf("Setting user id: %s", err)
			}
		}
	}

	if cfg.System.Workdir != "" {
		if err := os.Chdir(cfg.System.Workdir); err != nil {
			return fmt.Errorf("Could not chdir to '%s': %s", cfg.System.Workdir, err)
		}
	}

	pFile, err := os.Create(cfg.System.Pidfile)

	if err != nil {
		return err
	}
	defer pFile.Close()

	_, err = pFile.WriteString(fmt.Sprintf("%d", os.Getpid()))

	if err != nil {
		return err
	}

	return nil
}

func DropPrivileges(uid int, gid int) (error, bool) {
	if err := syscall.Setuid(uid); err != nil {
		return err, false
	}
	if err := syscall.Setgid(gid); err != nil {
		return err, false
	}
	return nil, true
}

// SetRuntimeGroup sets group on what to run as
func SetRuntimeGroup(groupname string) (err error) {
	log.Printf("Setting gid to %s", groupname)
	gstruct, err := user.LookupGroupId(groupname)
	if err != nil {
		return
	}
	egid, _ := strconv.Atoi(gstruct.Gid)
	syscall.Setgid(egid)
	return
}

func setuid(u string, g string) (err error) {

	if len(u) <= 0 {
		return
	}

	uid := -1
	gid := -1

	for {
		userent, err := user.Lookup(u)
		if err != nil {
			if userent, err = user.LookupId(u); err != nil {
				log.Println("Unable to find user", u, err)
				break
			}
		}

		uid, err = strconv.Atoi(userent.Uid)
		if err != nil {
			log.Println("Invalid uid:", userent.Uid)
		}
		gid, err = strconv.Atoi(userent.Gid)
		if err != nil {
			log.Println("Invalid gid:", userent.Gid)
		}
		break
	}

	if uid < 0 {
		uid, err = strconv.Atoi(u)
		if err != nil {
			log.Println("Invalid uid:", u, err)
			return
		}
	}

	if gid < 0 {
		gid, err = strconv.Atoi(g)
		if err != nil {
			log.Println("Invalid gid:", g, err)
			return
		}
	}

	if err = syscall.Setgid(gid); err != nil {
		log.Println("setgid failed: ", err)
	}
	if err = syscall.Setuid(uid); err != nil {
		log.Println("setuid failed: ", err)
	}
	return
}

func (s *internalService) DropPrivileges(arg *struct{ R internalDropArg }, result *struct{ R internalDropResult }) error {
	if rv := syscall.Setgid(arg.R.Gid); rv != nil {
		result.R.SetgidErrno = uintptr(rv.(syscall.Errno))
	} else {
		result.R.GidDropped = true
	}
	if rv := syscall.Setuid(arg.R.Uid); rv != nil {
		result.R.SetuidErrno = uintptr(rv.(syscall.Errno))
	} else {
		result.R.UidDropped = true
	}
	return nil
}

func AttachFiles(containerId, fromFile, toDir, rootDir, perm, uid, gid string) error {
	if containerId == "" {
		return fmt.Errorf("Please make sure the arguments are not NULL!\n")
	}
	permInt, err := strconv.Atoi(perm)
	if err != nil {
		return err
	}
	// It just need the block device without copying any files
	// FIXME whether we need to return an error if the target directory is null
	if toDir == "" {
		return nil
	}
	// Make a new file with the given premission and wirte the source file content in it
	if _, err := os.Stat(fromFile); err != nil && os.IsNotExist(err) {
		return err
	}
	buf, err := ioutil.ReadFile(fromFile)
	if err != nil {
		return err
	}
	targetDir := path.Join(rootDir, containerId, "rootfs", toDir)
	_, err = os.Stat(targetDir)
	targetFile := targetDir
	if err != nil && os.IsNotExist(err) {
		// we need to create a target directory with given premission
		if err := os.MkdirAll(targetDir, os.FileMode(permInt)); err != nil {
			return err
		}
		targetFile = targetDir + "/" + filepath.Base(fromFile)
	} else {
		targetFile = targetDir + "/" + filepath.Base(fromFile)
	}
	err = ioutil.WriteFile(targetFile, buf, os.FileMode(permInt))
	if err != nil {
		return err
	}
	user_id, _ := strconv.Atoi(uid)
	err = syscall.Setuid(user_id)
	if err != nil {
		return err
	}
	group_id, _ := strconv.Atoi(gid)
	err = syscall.Setgid(group_id)
	if err != nil {
		return err
	}

	return nil
}

func chrootuid(dir, user string) {
	pw_filename := "/etc/passwd"
	pwf, err := os.Open(pw_filename)
	if err != nil {
		log.Fatalf("%%Can't open %s: %s", pw_filename, err)
	}
	pwr := bufio.NewReader(pwf)
	for {
		line, err := pwr.ReadString('\n')
		if err != nil {
			log.Fatalf("%%Can't find UID for %s: %s", user, err)
		}
		pw_row := strings.SplitN(line, ":", 5)
		if len(pw_row) != 5 {
			continue
		}
		if pw_row[0] == user {
			uid, err = strconv.Atoi(pw_row[2])
			if err != nil {
				log.Fatalln("%Wrong UID:", err)
			}
			gid, err = strconv.Atoi(pw_row[3])
			if err != nil {
				log.Fatalln("%Wrong GID:", err)
			}
			break
		}
	}

	err = syscall.Chroot(dir)
	if err != nil {
		log.Fatalln("%Chroot error:", err)
	}

	err = syscall.Setgid(gid)
	if err != nil {
		log.Fatalln("%Setgid error:", err)
	}

	err = syscall.Setuid(uid)
	if err != nil {
		log.Fatalln("%Setuid error:", err)
	}

	err = os.Chdir("/")
	if err != nil {
		log.Fatalln("%Can't cd to '/':", err)
	}
}

func MaybeBecomeChildProcess() {
	lrs := os.Getenv("_RUNSIT_LAUNCH_INFO")
	if lrs == "" {
		return
	}
	defer os.Exit(2) // should never make it this far, though

	lr := new(LaunchRequest)
	d := gob.NewDecoder(base64.NewDecoder(base64.StdEncoding, strings.NewReader(lrs)))
	err := d.Decode(lr)
	if err != nil {
		log.Fatalf("Failed to decode LaunchRequest in child: %v", err)
	}
	if lr.NumFiles != 0 {
		var lim syscall.Rlimit
		if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
			log.Fatalf("failed to get NOFILE rlimit: %v", err)
		}
		noFile := rlim_t(lr.NumFiles)
		lim.Cur = noFile
		lim.Max = noFile
		if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &lim); err != nil {
			log.Fatalf("failed to set NOFILE rlimit: %v", err)
		}
	}
	if lr.Gid != 0 {
		if err := syscall.Setgid(lr.Gid); err != nil {
			log.Fatalf("failed to Setgid(%d): %v", lr.Gid, err)
		}
	}
	if len(lr.Gids) != 0 {
		if err := syscall.Setgroups(lr.Gids); err != nil {
			log.Printf("setgroups: %v", err)
		}
	}
	if lr.Uid != 0 {
		if err := syscall.Setuid(lr.Uid); err != nil {
			log.Fatalf("failed to Setuid(%d): %v", lr.Uid, err)
		}
	}
	if lr.Path != "" {
		err = os.Chdir(lr.Dir)
		if err != nil {
			log.Fatalf("failed to chdir to %q: %v", lr.Dir, err)
		}
	}
	err = syscall.Exec(lr.Path, lr.Argv, lr.Env)
	log.Fatalf("failed to exec %q: %v", lr.Path, err)
}

func setgid() error {
	exe, err := exec.LookPath(os.Args[0])
	if err != nil {
		return err
	}

	st, err := os.Stat(exe)
	if err != nil {
		return err
	}

	gid := int(st.Sys().(*syscall.Stat_t).Gid)

	return syscall.Setgid(gid)
}

// Init create pid file, set working dir, setgid and setuid.
func Init(userGroup, dir, pidFile string) error {
	// change working dir
	if err := os.Chdir(dir); err != nil {
		return err
	}
	// create pid file
	if err := ioutil.WriteFile(pidFile, []byte(fmt.Sprintf("%d\n", os.Getpid())), 0644); err != nil {
		return err
	}
	// setuid and setgid
	ug := strings.SplitN(userGroup, " ", 2)
	usr := defaultUser
	grp := defaultGroup
	if len(ug) == 0 {
		// default user and group (nobody)
	} else if len(ug) == 1 {
		usr = ug[0]
		grp = ""
	} else if len(ug) == 2 {
		usr = ug[0]
		grp = ug[1]
	}
	uid := 0
	gid := 0
	ui, err := user.Lookup(usr)
	if err != nil {
		return err
	}
	uid, _ = strconv.Atoi(ui.Uid)
	// group no set
	if grp == "" {
		gid, _ = strconv.Atoi(ui.Gid)
	} else {
		// use user's group instread
		// TODO LookupGroup
		gid, _ = strconv.Atoi(ui.Gid)
	}
	if err := syscall.Setgid(gid); err != nil {
		return err
	}
	if err := syscall.Setuid(uid); err != nil {
		return err
	}
	return nil
}