feat: restrict directories for included files in the cluster templates

client/pkg/omnictl/cluster/template/delete.go

@@ -39,7 +39,7 @@ func deleteImpl(ctx context.Context, client *client.Client, _ access.ServerInfo)
 
 	defer f.Close() //nolint:errcheck
 
-	return operations.DeleteTemplate(ctx, f, os.Stdout, client.Omni().State(), deleteCmdFlags.options)
+	return operations.DeleteTemplate(ctx, f, os.Stdout, client.Omni().State(), deleteCmdFlags.options, resolvedRoot)
 }
 
 func init() {

client/pkg/omnictl/cluster/template/diff.go

@@ -35,7 +35,7 @@ func diff(ctx context.Context, client *client.Client, _ access.ServerInfo) error
 
 	defer f.Close() //nolint:errcheck
 
-	return operations.DiffTemplate(ctx, f, os.Stdout, client.Omni().State())
+	return operations.DiffTemplate(ctx, f, os.Stdout, client.Omni().State(), resolvedRoot)
 }
 
 func init() {

client/pkg/omnictl/cluster/template/render.go

@@ -32,7 +32,7 @@ func render() error {
 
 	defer f.Close() //nolint:errcheck
 
-	return operations.RenderTemplate(f, os.Stdout)
+	return operations.RenderTemplate(f, os.Stdout, resolvedRoot)
 }
 
 func init() {

client/pkg/omnictl/cluster/template/status.go

@@ -52,7 +52,7 @@ func status(ctx context.Context, client *client.Client, _ access.ServerInfo) err
 		statusCmdFlags.options.Wait = false
 	}
 
-	return operations.StatusTemplate(ctx, f, os.Stdout, client.Omni().State(), statusCmdFlags.options)
+	return operations.StatusTemplate(ctx, f, os.Stdout, client.Omni().State(), statusCmdFlags.options, resolvedRoot)
 }
 
 func init() {

client/pkg/omnictl/cluster/template/sync.go

@@ -100,7 +100,7 @@ func syncTemplateFiles(ctx context.Context, client *client.Client, _ access.Serv
 			return fmt.Errorf("failed to open template file %q: %w", file, err)
 		}
 
-		err = operations.SyncTemplate(ctx, f, os.Stdout, client.Omni().State(), syncCmdFlags.options)
+		err = operations.SyncTemplate(ctx, f, os.Stdout, client.Omni().State(), syncCmdFlags.options, resolvedRoot)
 		f.Close() //nolint:errcheck
 
 		if err != nil {

client/pkg/omnictl/cluster/template/template.go

@@ -6,6 +6,9 @@
 package template
 
 import (
+	"os"
+	"path/filepath"
+
 	"github.com/siderolabs/gen/ensure"
 	"github.com/spf13/cobra"
 )
@@ -14,23 +17,50 @@ import (
 var cmdFlags struct {
 	// Path to the cluster template file.
 	TemplatePath string
+	// AllowedDir is the directory that restricts file access in the template.
+	AllowedDir string
 }
 
+// resolvedRoot is an *os.Root opened at the root dir, resolved relative to the template file's directory.
+// It is populated by PersistentPreRunE on templateCmd before any subcommand runs.
+var resolvedRoot *os.Root
+
 // templateCmd represents the template sub-command.
 var templateCmd = &cobra.Command{
 	Use:     "template",
 	Aliases: []string{"t"},
 	Short:   "Cluster template management subcommands.",
 	Long:    `Commands to render, validate, manage cluster templates.`,
 	Example: "",
+	PersistentPreRunE: func(*cobra.Command, []string) error {
+		templateDir := filepath.Dir(cmdFlags.TemplatePath)
+
+		p := cmdFlags.AllowedDir
+		if !filepath.IsAbs(p) {
+			p = filepath.Join(templateDir, p)
+		}
+
+		var err error
+
+		resolvedRoot, err = os.OpenRoot(p)
+		if err != nil {
+			return err
+		}
+
+		return nil
+	},
 }
 
 // RootCmd exports templateCmd.
 func RootCmd() *cobra.Command {
+	templateCmd.PersistentFlags().StringVar(&cmdFlags.AllowedDir, "allowed-dir", "./", "allowed directory for file access in the template;"+
+		" relative paths are resolved against the template file's directory.")
+
 	return templateCmd
 }
 
 func addRequiredFileFlag(cmd *cobra.Command) {
 	cmd.PersistentFlags().StringVarP(&cmdFlags.TemplatePath, "file", "f", "", "path to the cluster template file or directory.")
+
 	ensure.NoError(cmd.MarkPersistentFlagRequired("file"))
 }

client/pkg/omnictl/cluster/template/validate.go

@@ -32,7 +32,7 @@ func validate() error {
 
 	defer f.Close() //nolint:errcheck
 
-	return operations.ValidateTemplate(f)
+	return operations.ValidateTemplate(f, resolvedRoot)
 }
 
 func init() {

client/pkg/template/internal/models/cluster.go

@@ -82,7 +82,7 @@ type TalosCluster struct {
 }
 
 // Validate the model.
-func (cluster *Cluster) Validate() error {
+func (cluster *Cluster) Validate(opts ValidateOptions) error {
 	var multiErr error
 
 	validator := omni.ClusterValidator{
@@ -101,11 +101,11 @@ func (cluster *Cluster) Validate() error {
 		multiErr = multierror.Append(multiErr, err)
 	}
 
-	if err := cluster.Patches.Validate(); err != nil {
+	if err := cluster.Patches.Validate(opts); err != nil {
 		multiErr = multierror.Append(multiErr, err)
 	}
 
-	if err := cluster.Kubernetes.Manifests.Validate(); err != nil {
+	if err := cluster.Kubernetes.Manifests.Validate(opts); err != nil {
 		multiErr = multierror.Append(multiErr, err)
 	}
 
@@ -132,12 +132,12 @@ func (cluster *Cluster) Translate(ctx TranslateContext) ([]resource.Resource, er
 	clusterResource.TypedSpec().Value.KubernetesVersion = strings.TrimLeft(cluster.Kubernetes.Version, "v")
 	clusterResource.TypedSpec().Value.TalosVersion = strings.TrimLeft(cluster.Talos.Version, "v")
 
-	patches, err := cluster.Patches.Translate(fmt.Sprintf("cluster-%s", cluster.Name), constants.PatchBaseWeightCluster, pair.MakePair(omni.LabelCluster, cluster.Name))
+	patches, err := cluster.Patches.Translate(ctx, fmt.Sprintf("cluster-%s", cluster.Name), constants.PatchBaseWeightCluster, pair.MakePair(omni.LabelCluster, cluster.Name))
 	if err != nil {
 		return nil, err
 	}
 
-	manifests, err := cluster.Kubernetes.Manifests.Translate(fmt.Sprintf("cluster-%s", cluster.Name), constants.PatchBaseWeightCluster,
+	manifests, err := cluster.Kubernetes.Manifests.Translate(ctx, fmt.Sprintf("cluster-%s", cluster.Name), constants.PatchBaseWeightCluster,
 		pair.MakePair(omni.LabelCluster, cluster.Name),
 	)
 	if err != nil {

client/pkg/template/internal/models/controlplane.go

@@ -22,7 +22,7 @@ type ControlPlane struct {
 }
 
 // Validate the model.
-func (controlplane *ControlPlane) Validate() error {
+func (controlplane *ControlPlane) Validate(opts ValidateOptions) error {
 	var multiErr error
 
 	if controlplane.Name != "" {
@@ -47,7 +47,7 @@ func (controlplane *ControlPlane) Validate() error {
 		multiErr = multierror.Append(multiErr, fmt.Errorf("deleteStrategy is not allowed in the controlplane"))
 	}
 
-	multiErr = joinErrors(multiErr, controlplane.MachineSet.Validate(), controlplane.Machines.Validate(), controlplane.Patches.Validate())
+	multiErr = joinErrors(multiErr, controlplane.MachineSet.Validate(), controlplane.Machines.Validate(), controlplane.Patches.Validate(opts))
 	if multiErr != nil {
 		return fmt.Errorf("controlplane is invalid: %w", multiErr)
 	}

client/pkg/template/internal/models/kubernetes_manifest.go

@@ -8,7 +8,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"os"
 
 	"github.com/cosi-project/runtime/pkg/resource"
 	"github.com/cosi-project/runtime/pkg/resource/kvutils"
@@ -65,7 +64,7 @@ type KubernetesManifest struct {
 }
 
 // Validate a kubernetes manifest.
-func (km *KubernetesManifest) Validate() error {
+func (km *KubernetesManifest) Validate(opts ValidateOptions) error {
 	var errs error
 
 	name := km.Name
@@ -95,7 +94,7 @@ func (km *KubernetesManifest) Validate() error {
 
 	switch {
 	case km.File != "":
-		_, err := os.Stat(km.File)
+		_, err := StatFile(opts.Root, km.File)
 		if err != nil {
 			errs = errors.Join(errs, fmt.Errorf("failed to access %q: %w", km.File, err))
 		}
@@ -110,7 +109,7 @@ func (km *KubernetesManifest) Validate() error {
 }
 
 // Translate the model into a resource.
-func (km *KubernetesManifest) Translate(prefix string, weight int, labels ...pair.Pair[string, string]) (*omni.KubernetesManifestGroup, error) {
+func (km *KubernetesManifest) Translate(ctx TranslateContext, prefix string, weight int, labels ...pair.Pair[string, string]) (*omni.KubernetesManifestGroup, error) {
 	name := km.Name
 	if name == "" {
 		name = km.File
@@ -125,7 +124,7 @@ func (km *KubernetesManifest) Translate(prefix string, weight int, labels ...pai
 
 	switch {
 	case km.File != "":
-		raw, err = os.ReadFile(km.File)
+		raw, err = ReadFile(ctx.Root, km.File)
 	case km.Inline != nil:
 		var buf bytes.Buffer
 
@@ -172,11 +171,11 @@ func (km *KubernetesManifest) Translate(prefix string, weight int, labels ...pai
 type KubernetesManifestsList []KubernetesManifest
 
 // Validate the manifests in the list.
-func (k KubernetesManifestsList) Validate() error {
+func (k KubernetesManifestsList) Validate(opts ValidateOptions) error {
 	names := make(map[string]struct{}, len(k))
 
 	return errors.Join(xslices.Map(k, func(m KubernetesManifest) error {
-		if err := m.Validate(); err != nil {
+		if err := m.Validate(opts); err != nil {
 			return err
 		}
 
@@ -196,11 +195,11 @@ func (k KubernetesManifestsList) Validate() error {
 }
 
 // Translate the list of KubernetesManifests into a list of resources.
-func (l KubernetesManifestsList) Translate(prefix string, baseWeight int, labels ...pair.Pair[string, string]) ([]resource.Resource, error) {
+func (l KubernetesManifestsList) Translate(ctx TranslateContext, prefix string, baseWeight int, labels ...pair.Pair[string, string]) ([]resource.Resource, error) {
 	resources := make([]resource.Resource, 0, len(l))
 
 	for i, manifest := range l {
-		r, err := manifest.Translate(prefix, baseWeight+i, labels...)
+		r, err := manifest.Translate(ctx, prefix, baseWeight+i, labels...)
 		if err != nil {
 			return nil, err
 		}

client/pkg/template/internal/models/list.go

@@ -6,6 +6,7 @@ package models
 
 import (
 	"fmt"
+	"os"
 	"slices"
 
 	"github.com/cosi-project/runtime/pkg/resource"
@@ -24,11 +25,11 @@ type List []Model
 // Each model should be valid, but also the set of models should be complete.
 //
 //nolint:gocyclo,cyclop
-func (l List) Validate() error {
+func (l List) Validate(opts ValidateOptions) error {
 	var multiErr error
 
 	for _, model := range l {
-		multiErr = joinErrors(multiErr, model.Validate())
+		multiErr = joinErrors(multiErr, model.Validate(opts))
 	}
 
 	// complete template should contain 1 cluster, 1 controlplane, 0-N workers
@@ -121,11 +122,12 @@ func (l List) Validate() error {
 // Translate a set of models (template) to a set of Omni resources.
 //
 // Translate assumes that the template is valid.
-func (l List) Translate() ([]resource.Resource, error) {
+func (l List) Translate(root *os.Root) ([]resource.Resource, error) {
 	context := TranslateContext{
 		LockedMachines:            map[MachineID]struct{}{},
 		MachineDescriptors:        map[MachineID]Descriptors{},
 		MachineSetLevelKernelArgs: map[MachineID]KernelArgs{},
+		Root:                      root,
 	}
 
 	for _, model := range l {

client/pkg/template/internal/models/machine.go

@@ -81,7 +81,7 @@ func (install *MachineInstall) Validate() error {
 }
 
 // Validate the model.
-func (machine *Machine) Validate() error {
+func (machine *Machine) Validate(opts ValidateOptions) error {
 	var multiErr error
 
 	if machine.Name == "" {
@@ -92,7 +92,7 @@ func (machine *Machine) Validate() error {
 		multiErr = multierror.Append(multiErr, err)
 	}
 
-	multiErr = joinErrors(multiErr, machine.Name.Validate(), machine.Install.Validate(), machine.Patches.Validate())
+	multiErr = joinErrors(multiErr, machine.Name.Validate(), machine.Install.Validate(), machine.Patches.Validate(opts))
 	if multiErr != nil {
 		return fmt.Errorf("machine %q is invalid: %w", machine.Name, multiErr)
 	}
@@ -117,6 +117,7 @@ func (machine *Machine) Translate(ctx TranslateContext) ([]resource.Resource, er
 		}
 
 		patchResource, err := patch.Translate(
+			ctx,
 			fmt.Sprintf("cm-%s", machine.Name),
 			constants.PatchWeightInstallDisk,
 			pair.MakePair(omni.LabelCluster, ctx.ClusterName),
@@ -131,6 +132,7 @@ func (machine *Machine) Translate(ctx TranslateContext) ([]resource.Resource, er
 	}
 
 	patches, err := machine.Patches.Translate(
+		ctx,
 		fmt.Sprintf("cm-%s", machine.Name),
 		constants.PatchBaseWeightClusterMachine,
 		pair.MakePair(omni.LabelCluster, ctx.ClusterName),

client/pkg/template/internal/models/machineset.go

@@ -273,6 +273,7 @@ func (machineset *MachineSet) translate(ctx TranslateContext, nameSuffix, roleLa
 	}
 
 	patches, err := machineset.Patches.Translate(
+		ctx,
 		id,
 		constants.PatchBaseWeightMachineSet,
 		pair.MakePair(omni.LabelCluster, ctx.ClusterName),

client/pkg/template/internal/models/models.go

@@ -7,6 +7,8 @@ package models
 
 import (
 	"fmt"
+	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/cosi-project/runtime/pkg/resource"
@@ -24,6 +26,8 @@ type Meta struct {
 
 // TranslateContext is a context for translation.
 type TranslateContext struct {
+	// Root restricts file access to a single directory tree. When nil, no restriction is applied.
+	Root                      *os.Root
 	LockedMachines            map[MachineID]struct{}
 	MachineDescriptors        map[MachineID]Descriptors
 	MachineSetLevelKernelArgs map[MachineID]KernelArgs
@@ -97,9 +101,58 @@ func (d *Descriptors) Apply(res resource.Resource) {
 	}
 }
 
+// ValidateOptions contains options for model validation.
+type ValidateOptions struct {
+	// Root restricts file access to a single directory tree. When nil, no restriction is applied.
+	Root *os.Root
+}
+
+// resolveForRoot translates a CWD-relative path into a path relative to the root directory.
+func resolveForRoot(root *os.Root, path string) (string, error) {
+	absPath, err := filepath.Abs(path)
+	if err != nil {
+		return "", err
+	}
+
+	rootAbs, err := filepath.Abs(root.Name())
+	if err != nil {
+		return "", err
+	}
+
+	return filepath.Rel(rootAbs, absPath)
+}
+
+// ReadFile reads a file, using root to restrict access when non-nil.
+func ReadFile(root *os.Root, path string) ([]byte, error) {
+	if root == nil {
+		return os.ReadFile(path)
+	}
+
+	rel, err := resolveForRoot(root, path)
+	if err != nil {
+		return nil, err
+	}
+
+	return root.ReadFile(rel)
+}
+
+// StatFile stats a file, using root to restrict access when non-nil.
+func StatFile(root *os.Root, path string) (os.FileInfo, error) {
+	if root == nil {
+		return os.Stat(path)
+	}
+
+	rel, err := resolveForRoot(root, path)
+	if err != nil {
+		return nil, err
+	}
+
+	return root.Stat(rel)
+}
+
 // Model is a base interface for cluster templates.
 type Model interface {
-	Validate() error
+	Validate(ValidateOptions) error
 	Translate(TranslateContext) ([]resource.Resource, error)
 }