package generate import ( "fmt" "io/ioutil" "os" "path/filepath" "strings" "github.com/containers/libpod/pkg/rootless" "github.com/opencontainers/runc/libcontainer/configs" "github.com/opencontainers/runc/libcontainer/devices" spec "github.com/opencontainers/runtime-spec/specs-go" "github.com/opencontainers/runtime-tools/generate" "github.com/pkg/errors" "golang.org/x/sys/unix" ) func u32Ptr(i int64) *uint32 { u := uint32(i); return &u } func fmPtr(i int64) *os.FileMode { fm := os.FileMode(i); return &fm } // Device transforms a libcontainer configs.Device to a specs.LinuxDevice object. func Device(d *configs.Device) spec.LinuxDevice { return spec.LinuxDevice{ Type: string(d.Type), Path: d.Path, Major: d.Major, Minor: d.Minor, FileMode: fmPtr(int64(d.FileMode)), UID: u32Ptr(int64(d.Uid)), GID: u32Ptr(int64(d.Gid)), } } func addPrivilegedDevices(g *generate.Generator) error { hostDevices, err := getDevices("/dev") if err != nil { return err } g.ClearLinuxDevices() if rootless.IsRootless() { mounts := make(map[string]interface{}) for _, m := range g.Mounts() { mounts[m.Destination] = true } newMounts := []spec.Mount{} for _, d := range hostDevices { devMnt := spec.Mount{ Destination: d.Path, Type: TypeBind, Source: d.Path, Options: []string{"slave", "nosuid", "noexec", "rw", "rbind"}, } if d.Path == "/dev/ptmx" || strings.HasPrefix(d.Path, "/dev/tty") { continue } if _, found := mounts[d.Path]; found { continue } st, err := os.Stat(d.Path) if err != nil { if err == unix.EPERM { continue } return errors.Wrapf(err, "stat %s", d.Path) } // Skip devices that the user has not access to. if st.Mode()&0007 == 0 { continue } newMounts = append(newMounts, devMnt) } g.Config.Mounts = append(newMounts, g.Config.Mounts...) g.Config.Linux.Resources.Devices = nil } else { for _, d := range hostDevices { g.AddDevice(Device(d)) } // Add resources device - need to clear the existing one first. g.Config.Linux.Resources.Devices = nil g.AddLinuxResourcesDevice(true, "", nil, nil, "rwm") } return nil } // DevicesFromPath computes a list of devices func DevicesFromPath(g *generate.Generator, devicePath string) error { devs := strings.Split(devicePath, ":") resolvedDevicePath := devs[0] // check if it is a symbolic link if src, err := os.Lstat(resolvedDevicePath); err == nil && src.Mode()&os.ModeSymlink == os.ModeSymlink { if linkedPathOnHost, err := filepath.EvalSymlinks(resolvedDevicePath); err == nil { resolvedDevicePath = linkedPathOnHost } } st, err := os.Stat(resolvedDevicePath) if err != nil { return errors.Wrapf(err, "cannot stat %s", devicePath) } if st.IsDir() { found := false src := resolvedDevicePath dest := src var devmode string if len(devs) > 1 { if len(devs[1]) > 0 && devs[1][0] == '/' { dest = devs[1] } else { devmode = devs[1] } } if len(devs) > 2 { if devmode != "" { return errors.Wrapf(unix.EINVAL, "invalid device specification %s", devicePath) } devmode = devs[2] } // mount the internal devices recursively if err := filepath.Walk(resolvedDevicePath, func(dpath string, f os.FileInfo, e error) error { if f.Mode()&os.ModeDevice == os.ModeDevice { found = true device := fmt.Sprintf("%s:%s", dpath, filepath.Join(dest, strings.TrimPrefix(dpath, src))) if devmode != "" { device = fmt.Sprintf("%s:%s", device, devmode) } if err := addDevice(g, device); err != nil { return errors.Wrapf(err, "failed to add %s device", dpath) } } return nil }); err != nil { return err } if !found { return errors.Wrapf(unix.EINVAL, "no devices found in %s", devicePath) } return nil } return addDevice(g, strings.Join(append([]string{resolvedDevicePath}, devs[1:]...), ":")) } func BlockAccessToKernelFilesystems(privileged, pidModeIsHost bool, g *generate.Generator) { if !privileged { for _, mp := range []string{ "/proc/acpi", "/proc/kcore", "/proc/keys", "/proc/latency_stats", "/proc/timer_list", "/proc/timer_stats", "/proc/sched_debug", "/proc/scsi", "/sys/firmware", "/sys/fs/selinux", } { g.AddLinuxMaskedPaths(mp) } if pidModeIsHost && rootless.IsRootless() { return } for _, rp := range []string{ "/proc/asound", "/proc/bus", "/proc/fs", "/proc/irq", "/proc/sys", "/proc/sysrq-trigger", } { g.AddLinuxReadonlyPaths(rp) } } } // based on getDevices from runc (libcontainer/devices/devices.go) func getDevices(path string) ([]*configs.Device, error) { files, err := ioutil.ReadDir(path) if err != nil { if rootless.IsRootless() && os.IsPermission(err) { return nil, nil } return nil, err } out := []*configs.Device{} for _, f := range files { switch { case f.IsDir(): switch f.Name() { // ".lxc" & ".lxd-mounts" added to address https://github.com/lxc/lxd/issues/2825 case "pts", "shm", "fd", "mqueue", ".lxc", ".lxd-mounts": continue default: sub, err := getDevices(filepath.Join(path, f.Name())) if err != nil { return nil, err } if sub != nil { out = append(out, sub...) } continue } case f.Name() == "console": continue } device, err := devices.DeviceFromPath(filepath.Join(path, f.Name()), "rwm") if err != nil { if err == devices.ErrNotADevice { continue } if os.IsNotExist(err) { continue } return nil, err } out = append(out, device) } return out, nil } func addDevice(g *generate.Generator, device string) error { src, dst, permissions, err := ParseDevice(device) if err != nil { return err } dev, err := devices.DeviceFromPath(src, permissions) if err != nil { return errors.Wrapf(err, "%s is not a valid device", src) } if rootless.IsRootless() { if _, err := os.Stat(src); err != nil { if os.IsNotExist(err) { return errors.Wrapf(err, "the specified device %s doesn't exist", src) } return errors.Wrapf(err, "stat device %s exist", src) } perm := "ro" if strings.Contains(permissions, "w") { perm = "rw" } devMnt := spec.Mount{ Destination: dst, Type: TypeBind, Source: src, Options: []string{"slave", "nosuid", "noexec", perm, "rbind"}, } g.Config.Mounts = append(g.Config.Mounts, devMnt) return nil } dev.Path = dst linuxdev := spec.LinuxDevice{ Path: dev.Path, Type: string(dev.Type), Major: dev.Major, Minor: dev.Minor, FileMode: &dev.FileMode, UID: &dev.Uid, GID: &dev.Gid, } g.AddDevice(linuxdev) g.AddLinuxResourcesDevice(true, string(dev.Type), &dev.Major, &dev.Minor, dev.Permissions) return nil } // ParseDevice parses device mapping string to a src, dest & permissions string func ParseDevice(device string) (string, string, string, error) { //nolint src := "" dst := "" permissions := "rwm" arr := strings.Split(device, ":") switch len(arr) { case 3: if !IsValidDeviceMode(arr[2]) { return "", "", "", fmt.Errorf("invalid device mode: %s", arr[2]) } permissions = arr[2] fallthrough case 2: if IsValidDeviceMode(arr[1]) { permissions = arr[1] } else { if arr[1][0] != '/' { return "", "", "", fmt.Errorf("invalid device mode: %s", arr[1]) } dst = arr[1] } fallthrough case 1: src = arr[0] default: return "", "", "", fmt.Errorf("invalid device specification: %s", device) } if dst == "" { dst = src } return src, dst, permissions, nil } // IsValidDeviceMode checks if the mode for device is valid or not. // IsValid mode is a composition of r (read), w (write), and m (mknod). func IsValidDeviceMode(mode string) bool { var legalDeviceMode = map[rune]bool{ 'r': true, 'w': true, 'm': true, } if mode == "" { return false } for _, c := range mode { if !legalDeviceMode[c] { return false } legalDeviceMode[c] = false } return true }