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