package generate import ( "fmt" "io/fs" "os" "path" "path/filepath" "strings" "github.com/containers/podman/v4/libpod/define" "github.com/containers/podman/v4/pkg/rootless" "github.com/containers/podman/v4/pkg/util" spec "github.com/opencontainers/runtime-spec/specs-go" "github.com/opencontainers/runtime-tools/generate" "github.com/pkg/errors" "github.com/sirupsen/logrus" "golang.org/x/sys/unix" ) // 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 err } 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.WalkDir(resolvedDevicePath, func(dpath string, d fs.DirEntry, e error) error { if d.Type()&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, mask, unmask []string, g *generate.Generator) { defaultMaskPaths := []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", "/sys/dev/block", } if !privileged { for _, mp := range defaultMaskPaths { // check that the path to mask is not in the list of paths to unmask if shouldMask(mp, unmask) { g.AddLinuxMaskedPaths(mp) } } for _, rp := range []string{ "/proc/asound", "/proc/bus", "/proc/fs", "/proc/irq", "/proc/sys", "/proc/sysrq-trigger", } { if shouldMask(rp, unmask) { g.AddLinuxReadonlyPaths(rp) } } if pidModeIsHost && rootless.IsRootless() { return } } // mask the paths provided by the user for _, mp := range mask { if !path.IsAbs(mp) && mp != "" { logrus.Errorf("Path %q is not an absolute path, skipping...", mp) continue } g.AddLinuxMaskedPaths(mp) } } func addDevice(g *generate.Generator, device string) error { src, dst, permissions, err := ParseDevice(device) if err != nil { return err } dev, err := util.DeviceFromPath(src) if err != nil { return errors.Wrapf(err, "%s is not a valid device", src) } if rootless.IsRootless() { if _, err := os.Stat(src); err != nil { return err } perm := "ro" if strings.Contains(permissions, "w") { perm = "rw" } devMnt := spec.Mount{ Destination: dst, Type: define.TypeBind, Source: src, Options: []string{"slave", "nosuid", "noexec", perm, "rbind"}, } g.Config.Mounts = append(g.Config.Mounts, devMnt) return nil } else if src == "/dev/fuse" { // if the user is asking for fuse inside the container // make sure the module is loaded. f, err := unix.Open(src, unix.O_RDONLY|unix.O_NONBLOCK, 0) if err == nil { unix.Close(f) } } dev.Path = dst g.AddDevice(*dev) g.AddLinuxResourcesDevice(true, dev.Type, &dev.Major, &dev.Minor, permissions) return nil } // ParseDevice parses device mapping string to a src, dest & permissions string func ParseDevice(device string) (string, string, string, error) { var src string var dst string 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 } func supportAmbientCapabilities() bool { err := unix.Prctl(unix.PR_CAP_AMBIENT, unix.PR_CAP_AMBIENT_IS_SET, 0, 0, 0) return err == nil } func shouldMask(mask string, unmask []string) bool { for _, m := range unmask { if strings.ToLower(m) == "all" { return false } for _, m1 := range strings.Split(m, ":") { match, err := filepath.Match(m1, mask) if err != nil { logrus.Errorf(err.Error()) } if match { return false } } } return true }