diff --git a/libcontainer/nsinit/init.go b/libcontainer/nsinit/init.go index af60d73..25b5fc4 100644 --- a/libcontainer/nsinit/init.go +++ b/libcontainer/nsinit/init.go @@ -81,7 +81,7 @@ func Init(container *libcontainer.Container, uncleanRootfs, consolePath string, return fmt.Errorf("set process label %s", err) } if container.Context["restrictions"] != "" { - if err := restrict.Restrict("proc", "sys"); err != nil { + if err := restrict.Restrict("proc/sys", "proc/sysrq-trigger", "proc/irq", "proc/bus", "sys"); err != nil { return err } } diff --git a/libcontainer/security/restrict/restrict.go b/libcontainer/security/restrict/restrict.go index 361d076..a22a1aa 100644 --- a/libcontainer/security/restrict/restrict.go +++ b/libcontainer/security/restrict/restrict.go @@ -10,12 +10,31 @@ import ( "github.com/dotcloud/docker/pkg/system" ) +const defaultMountFlags = syscall.MS_NOEXEC | syscall.MS_NOSUID | syscall.MS_NODEV + +func mountReadonly(path string) error { + if err := system.Mount("", path, "", syscall.MS_REMOUNT|syscall.MS_RDONLY, ""); err != nil { + if err == syscall.EINVAL { + // Probably not a mountpoint, use bind-mount + if err := system.Mount(path, path, "", syscall.MS_BIND, ""); err != nil { + return err + } + if err := system.Mount(path, path, "", syscall.MS_BIND|syscall.MS_REMOUNT|syscall.MS_RDONLY|syscall.MS_REC|defaultMountFlags, ""); err != nil { + return err + } + } else { + return err + } + } + return nil +} + // This has to be called while the container still has CAP_SYS_ADMIN (to be able to perform mounts). // However, afterwards, CAP_SYS_ADMIN should be dropped (otherwise the user will be able to revert those changes). func Restrict(mounts ...string) error { // remount proc and sys as readonly for _, dest := range mounts { - if err := system.Mount("", dest, "", syscall.MS_REMOUNT|syscall.MS_RDONLY, ""); err != nil { + if err := mountReadonly(dest); err != nil { return fmt.Errorf("unable to remount %s readonly: %s", dest, err) } }