Add preflight checks to Boxcutter applier

Signed-off-by: Per Goncalves da Silva <pegoncal@redhat.com>

Author: Per Goncalves da Silva

cmd/operator-controller/main.go

@@ -598,7 +598,12 @@ func (c *boxcutterReconcilerConfigurator) Configure(ceReconciler *controllers.Cl
 		return err
 	}
 
-	// TODO: add support for preflight checks
+	// determine if PreAuthorizer should be enabled based on feature gate
+	var preAuth authorization.PreAuthorizer
+	if features.OperatorControllerFeatureGate.Enabled(features.PreflightPermissions) {
+		preAuth = authorization.NewRBACPreAuthorizer(c.mgr.GetClient())
+	}
+
 	// TODO: better scheme handling - which types do we want to support?
 	_ = apiextensionsv1.AddToScheme(c.mgr.GetScheme())
 	rg := &applier.SimpleRevisionGenerator{
@@ -610,6 +615,7 @@ func (c *boxcutterReconcilerConfigurator) Configure(ceReconciler *controllers.Cl
 		Scheme:            c.mgr.GetScheme(),
 		RevisionGenerator: rg,
 		Preflights:        c.preflights,
+		PreAuthorizer:     preAuth,
 		FieldOwner:        fmt.Sprintf("%s/clusterextension-controller", fieldOwnerPrefix),
 	}
 	revisionStatesGetter := &controllers.BoxcutterRevisionStatesGetter{Reader: c.mgr.GetClient()}

internal/operator-controller/applier/boxcutter.go

@@ -5,6 +5,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io"
 	"io/fs"
 	"maps"
 	"slices"
@@ -16,6 +17,8 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/authorization/authorizer"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
 	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
@@ -25,6 +28,7 @@ import (
 	helmclient "github.com/operator-framework/helm-operator-plugins/pkg/client"
 
 	ocv1 "github.com/operator-framework/operator-controller/api/v1"
+	"github.com/operator-framework/operator-controller/internal/operator-controller/authorization"
 	"github.com/operator-framework/operator-controller/internal/operator-controller/labels"
 	"github.com/operator-framework/operator-controller/internal/shared/util/cache"
 )
@@ -279,28 +283,27 @@ type Boxcutter struct {
 	Scheme            *runtime.Scheme
 	RevisionGenerator ClusterExtensionRevisionGenerator
 	Preflights        []Preflight
+	PreAuthorizer     authorization.PreAuthorizer
 	FieldOwner        string
 }
 
-func (bc *Boxcutter) getObjects(rev *ocv1.ClusterExtensionRevision) []client.Object {
-	var objs []client.Object
-	for _, phase := range rev.Spec.Phases {
-		for _, phaseObject := range phase.Objects {
-			objs = append(objs, &phaseObject.Object)
-		}
-	}
-	return objs
-}
-
-func (bc *Boxcutter) createOrUpdate(ctx context.Context, obj client.Object) error {
-	if obj.GetObjectKind().GroupVersionKind().Empty() {
-		gvk, err := apiutil.GVKForObject(obj, bc.Scheme)
+// createOrUpdate creates or updates the revision object. PreAuthorization checks are performed to ensure the
+// manifestManager has sufficient permissions to manage the revision and its resources
+func (bc *Boxcutter) createOrUpdate(ctx context.Context, manifestManager user.Info, rev *ocv1.ClusterExtensionRevision) error {
+	if rev.GetObjectKind().GroupVersionKind().Empty() {
+		gvk, err := apiutil.GVKForObject(rev, bc.Scheme)
 		if err != nil {
 			return err
 		}
-		obj.GetObjectKind().SetGroupVersionKind(gvk)
+		rev.GetObjectKind().SetGroupVersionKind(gvk)
 	}
-	return bc.Client.Patch(ctx, obj, client.Apply, client.FieldOwner(bc.FieldOwner), client.ForceOwnership)
+
+	// Run auth preflight checks
+	if err := bc.runPreAuthorizationChecks(ctx, manifestManager, rev); err != nil {
+		return err
+	}
+
+	return bc.Client.Patch(ctx, rev, client.Apply, client.FieldOwner(bc.FieldOwner), client.ForceOwnership)
 }
 
 func (bc *Boxcutter) Apply(ctx context.Context, contentFS fs.FS, ext *ocv1.ClusterExtension, objectLabels, revisionAnnotations map[string]string) error {
@@ -329,7 +332,7 @@ func (bc *Boxcutter) Apply(ctx context.Context, contentFS fs.FS, ext *ocv1.Clust
 		desiredRevision.Spec.Revision = currentRevision.Spec.Revision
 		desiredRevision.Name = currentRevision.Name
 
-		err := bc.createOrUpdate(ctx, desiredRevision)
+		err := bc.createOrUpdate(ctx, getUserInfo(ext), desiredRevision)
 		switch {
 		case apierrors.IsInvalid(err):
 			// We could not update the current revision due to trying to update an immutable field.
@@ -344,7 +347,7 @@ func (bc *Boxcutter) Apply(ctx context.Context, contentFS fs.FS, ext *ocv1.Clust
 	}
 
 	// Preflights
-	plainObjs := bc.getObjects(desiredRevision)
+	plainObjs := getObjects(desiredRevision)
 	for _, preflight := range bc.Preflights {
 		if shouldSkipPreflight(ctx, preflight, ext, state) {
 			continue
@@ -379,14 +382,31 @@ func (bc *Boxcutter) Apply(ctx context.Context, contentFS fs.FS, ext *ocv1.Clust
 			return fmt.Errorf("garbage collecting old revisions: %w", err)
 		}
 
-		if err := bc.createOrUpdate(ctx, desiredRevision); err != nil {
+		if err := bc.createOrUpdate(ctx, getUserInfo(ext), desiredRevision); err != nil {
 			return fmt.Errorf("creating new Revision: %w", err)
 		}
 	}
 
 	return nil
 }
 
+// runPreAuthorizationChecks runs PreAuthorization checks if the PreAuthorizer is set. An error will be returned if
+// the ClusterExtension service account does not have the necessary permissions to manage the revision's resources
+func (bc *Boxcutter) runPreAuthorizationChecks(ctx context.Context, manifestManager user.Info, rev *ocv1.ClusterExtensionRevision) error {
+	if bc.PreAuthorizer == nil {
+		return nil
+	}
+
+	// collect the revision manifests
+	manifestReader, err := revisionManifestReader(rev)
+	if err != nil {
+		return err
+	}
+
+	// run preauthorization check
+	return formatPreAuthorizerOutput(bc.PreAuthorizer.PreAuthorize(ctx, manifestManager, manifestReader, revisionManagementPerms(rev)))
+}
+
 // garbageCollectOldRevisions deletes archived revisions beyond ClusterExtensionRevisionRetentionLimit.
 // Active revisions are never deleted. revisionList must be sorted oldest to newest.
 func (bc *Boxcutter) garbageCollectOldRevisions(ctx context.Context, revisionList []ocv1.ClusterExtensionRevision) error {
@@ -445,3 +465,45 @@ func splitManifestDocuments(file string) []string {
 	}
 	return docs
 }
+
+// getObjects returns a slice of all objects in the revision
+func getObjects(rev *ocv1.ClusterExtensionRevision) []client.Object {
+	var objs []client.Object
+	for _, phase := range rev.Spec.Phases {
+		for _, phaseObject := range phase.Objects {
+			objs = append(objs, &phaseObject.Object)
+		}
+	}
+	return objs
+}
+
+// revisionManifestReader returns an io.Reader containing all manifests in the revision
+func revisionManifestReader(rev *ocv1.ClusterExtensionRevision) (io.Reader, error) {
+	var manifestBuilder strings.Builder
+	for _, obj := range getObjects(rev) {
+		objBytes, err := yaml.Marshal(obj)
+		if err != nil {
+			return nil, fmt.Errorf("error generating revision manifest: %w", err)
+		}
+		manifestBuilder.WriteString("---\n")
+		manifestBuilder.WriteString(string(objBytes))
+		manifestBuilder.WriteString("\n")
+	}
+	return strings.NewReader(manifestBuilder.String()), nil
+}
+
+func revisionManagementPerms(rev *ocv1.ClusterExtensionRevision) func(user.Info) []authorizer.AttributesRecord {
+	return func(user user.Info) []authorizer.AttributesRecord {
+		return []authorizer.AttributesRecord{
+			{
+				User:            user,
+				Name:            rev.Name,
+				APIGroup:        ocv1.GroupVersion.Group,
+				APIVersion:      ocv1.GroupVersion.Version,
+				Resource:        "clusterextensionrevisions/finalizers",
+				ResourceRequest: true,
+				Verb:            "update",
+			},
+		}
+	}
+}