Golang capabilities.DropBoundingSet函数代码示例

// FinalizeNamespace drops the caps, sets the correct user
// and working dir, and closes any leaky file descriptors
// before execing the command inside the namespace
func FinalizeNamespace(container *libcontainer.Container) error {
	if err := system.CloseFdsFrom(3); err != nil {
		return fmt.Errorf("close open file descriptors %s", err)
	}

	// drop capabilities in bounding set before changing user
	if err := capabilities.DropBoundingSet(container); err != nil {
		return fmt.Errorf("drop bounding set %s", err)
	}

	// preserve existing capabilities while we change users
	if err := system.SetKeepCaps(); err != nil {
		return fmt.Errorf("set keep caps %s", err)
	}

	if err := SetupUser(container.User); err != nil {
		return fmt.Errorf("setup user %s", err)
	}

	if err := system.ClearKeepCaps(); err != nil {
		return fmt.Errorf("clear keep caps %s", err)
	}

	// drop all other capabilities
	if err := capabilities.DropCapabilities(container); err != nil {
		return fmt.Errorf("drop capabilities %s", err)
	}

	if container.WorkingDir != "" {
		if err := system.Chdir(container.WorkingDir); err != nil {
			return fmt.Errorf("chdir to %s %s", container.WorkingDir, err)
		}
	}
	return nil
}

func finalizeNamespace(args *InitArgs) error {
	if err := utils.CloseExecFrom(3); err != nil {
		return err
	}

	// We use the native drivers default template so that things like caps are consistent
	// across both drivers
	container := template.New()

	if !args.Privileged {
		// drop capabilities in bounding set before changing user
		if err := capabilities.DropBoundingSet(container.Capabilities); err != nil {
			return fmt.Errorf("drop bounding set %s", err)
		}

		// preserve existing capabilities while we change users
		if err := system.SetKeepCaps(); err != nil {
			return fmt.Errorf("set keep caps %s", err)
		}
	}

	if err := namespaces.SetupUser(args.User); err != nil {
		return fmt.Errorf("setup user %s", err)
	}

	if !args.Privileged {
		if err := system.ClearKeepCaps(); err != nil {
			return fmt.Errorf("clear keep caps %s", err)
		}

		var (
			adds  []string
			drops []string
		)

		if args.CapAdd != "" {
			adds = strings.Split(args.CapAdd, ":")
		}
		if args.CapDrop != "" {
			drops = strings.Split(args.CapDrop, ":")
		}

		caps, err := execdriver.TweakCapabilities(container.Capabilities, adds, drops)
		if err != nil {
			return err
		}

		// drop all other capabilities
		if err := capabilities.DropCapabilities(caps); err != nil {
			return fmt.Errorf("drop capabilities %s", err)
		}
	}

	if err := setupWorkingDirectory(args); err != nil {
		return err
	}

	return nil
}

// FinalizeNamespace drops the caps, sets the correct user
// and working dir, and closes any leaky file descriptors
// before execing the command inside the namespace
func FinalizeNamespace(container *libcontainer.Config) error {
	// Ensure that all non-standard fds we may have accidentally
	// inherited are marked close-on-exec so they stay out of the
	// container
	if err := utils.CloseExecFrom(3); err != nil {
		return fmt.Errorf("close open file descriptors %s", err)
	}

	// drop capabilities in bounding set before changing user
	if err := capabilities.DropBoundingSet(container.Capabilities); err != nil {
		return fmt.Errorf("drop bounding set %s", err)
	}

	// preserve existing capabilities while we change users
	if err := system.SetKeepCaps(); err != nil {
		return fmt.Errorf("set keep caps %s", err)
	}

	if err := SetupUser(container.User); err != nil {
		return fmt.Errorf("setup user %s", err)
	}

	if err := system.ClearKeepCaps(); err != nil {
		return fmt.Errorf("clear keep caps %s", err)
	}

	// drop all other capabilities
	if err := capabilities.DropCapabilities(container.Capabilities); err != nil {
		return fmt.Errorf("drop capabilities %s", err)
	}

	if container.WorkingDir != "" {
		if err := system.Chdir(container.WorkingDir); err != nil {
			return fmt.Errorf("chdir to %s %s", container.WorkingDir, err)
		}
	}

	return nil
}

func dropCaps() (err error) {
	// Drop capabilities except those in the whitelist, from https://github.com/docker/docker/blob/master/daemon/execdriver/native/template/default_template.go
	cape := capabilities.DropBoundingSet([]string{
		"CHOWN",
		"DAC_OVERRIDE",
		"FSETID",
		"FOWNER",
		//"MKNOD",
		//"NET_RAW",
		//"SETGID",
		//"SETUID",
		"SETFCAP",
		"SETPCAP",
		"NET_BIND_SERVICE",
		"SYS_CHROOT",
		"KILL",
		"AUDIT_WRITE",
	})
	if cape != nil {
		panic(cape)
	}
	return nil
}

func DropBoundingSet(container *libcontainer.Config) error {
	return capabilities.DropBoundingSet(container.Capabilities)
}