WIP test

client/cmd/root.go

@@ -77,6 +77,8 @@ var (
 	updateSettingsDisabled  bool
 	captureEnabled          bool
 	networksDisabled        bool
+	socketOwner             string
+	strictSocketDisabled    bool
 
 	rootCmd = &cobra.Command{
 		Use:          "netbird",

client/cmd/service.go

@@ -57,6 +57,9 @@ func init() {
 	installCmd.Flags().StringSliceVar(&serviceEnvVars, "service-env", nil, serviceEnvDesc)
 	reconfigureCmd.Flags().StringSliceVar(&serviceEnvVars, "service-env", nil, serviceEnvDesc)
 
+	serviceCmd.PersistentFlags().StringVar(&socketOwner, "socket-owner", "", "Socket owner TODO")
+	serviceCmd.PersistentFlags().BoolVar(&strictSocketDisabled, "disable-strict-socket", false, "Restrict socket permissions TODO")
+
 	rootCmd.AddCommand(serviceCmd)
 }
 

client/cmd/service_controller.go

@@ -4,9 +4,13 @@ package cmd
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"net"
 	"os"
+	"os/exec"
+	"os/user"
+	"strconv"
 	"strings"
 	"time"
 
@@ -55,7 +59,32 @@ func (p *program) Start(svc service.Service) error {
 		defer listen.Close()
 
 		if split[0] == "unix" {
-			if err := os.Chmod(split[1], 0666); err != nil {
+			socketPerm := os.FileMode(0666)
+			if socketOwner != "" && !strictSocketDisabled {
+				socketPerm = 0660
+				gid, err := addGroup("netbird")
+				if err != nil {
+					log.Errorf("failed setting up group (%d): %v", gid, err)
+				}
+				user, err := user.Lookup(socketOwner)
+				if err != nil {
+					log.Errorf("lookup user %q: %v", socketOwner, err)
+					return
+				}
+				uid, err := strconv.ParseInt(user.Uid, 10, 64)
+				if err != nil {
+					log.Errorf("falied to convert uid (%d) to int: %v", uid, err)
+					return
+				}
+				if err = os.Chown(split[1], int(uid), int(gid)); err != nil {
+					log.Errorf("failed setting daemon group (%d) on socket: %v", gid, split[1])
+					return
+				}
+			}
+			if socketOwner == "" && !strictSocketDisabled {
+				// TODO: handle TOFU
+			}
+			if err := os.Chmod(split[1], socketPerm); err != nil {
 				log.Errorf("failed setting daemon permissions: %v", split[1])
 				return
 			}
@@ -79,6 +108,36 @@ func (p *program) Start(svc service.Service) error {
 	return nil
 }
 
+// addGroup creates a system group if it doesn't already exist and returns the gid.
+// Must run as root.
+func addGroup(name string) (int, error) {
+	if group, err := user.LookupGroup(name); err == nil {
+		gid, err := strconv.ParseInt(group.Gid, 10, 64)
+		return int(gid), err
+	} else if _, ok := err.(user.UnknownGroupError); !ok {
+		return -1, fmt.Errorf("lookup group %q: %w", name, err)
+	}
+
+	groupadd, err := exec.LookPath("groupadd")
+	if err != nil {
+		// Fallback for Alpine/BusyBox systems.
+		if groupadd, err = exec.LookPath("addgroup"); err != nil {
+			return -1, errors.New("neither groupadd nor addgroup found")
+		}
+	}
+
+	// Use --system for a service/daemon group (no login, low GID).
+	out, err := exec.Command(groupadd, "--system", name).CombinedOutput()
+	if err != nil {
+		return -1, fmt.Errorf("create group %q: %w: %s", name, err, out)
+	}
+	if group, err := user.LookupGroup(name); err == nil {
+		gid, err := strconv.ParseInt(group.Gid, 10, 64)
+		return int(gid), err
+	}
+	return -1, fmt.Errorf("lookup group %q: %w", name, err)
+}
+
 func (p *program) Stop(srv service.Service) error {
 	p.serverInstanceMu.Lock()
 	if p.serverInstance != nil {

client/cmd/service_installer.go

@@ -67,6 +67,10 @@ func buildServiceArguments() []string {
 		args = append(args, "--disable-networks")
 	}
 
+	if socketOwner != "" {
+		args = append(args, "--socket-owner", socketOwner)
+	}
+
 	return args
 }
 
@@ -127,6 +131,8 @@ var installCmd = &cobra.Command{
 			return err
 		}
 
+		cmd.Printf("SUDO_UID: %s\n", os.Getenv("SUDO_UID"))
+
 		if err := loadAndApplyServiceParams(cmd); err != nil {
 			cmd.PrintErrf("Warning: failed to load saved service params: %v\n", err)
 		}