/
validator.go
272 lines (238 loc) · 10.6 KB
/
validator.go
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// Package roletemplate is used for validating roletemplate objects.
package roletemplate
import (
"fmt"
"strings"
v3 "github.com/rancher/rancher/pkg/apis/management.cattle.io/v3"
"github.com/rancher/webhook/pkg/admission"
"github.com/rancher/webhook/pkg/auth"
controllerv3 "github.com/rancher/webhook/pkg/generated/controllers/management.cattle.io/v3"
objectsv3 "github.com/rancher/webhook/pkg/generated/objects/management.cattle.io/v3"
"github.com/rancher/webhook/pkg/resources/common"
"github.com/sirupsen/logrus"
admissionv1 "k8s.io/api/admission/v1"
admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
"k8s.io/apimachinery/pkg/api/equality"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apimachinery/pkg/util/validation/field"
authorizationv1 "k8s.io/client-go/kubernetes/typed/authorization/v1"
"k8s.io/kubernetes/pkg/registry/rbac/validation"
"k8s.io/utils/trace"
)
const (
clusterContext = "cluster"
projectContext = "project"
emptyContext = ""
rtRefIndex = "management.cattle.io/rt-by-reference"
rtGlobalRefIndex = "management.cattle.io/rt-by-ref-grb"
escalateVerb = "escalate"
)
var gvr = schema.GroupVersionResource{
Group: "management.cattle.io",
Version: "v3",
Resource: "roletemplates",
}
// NewValidator returns a new validator used for validating roleTemplates.
func NewValidator(resolver validation.AuthorizationRuleResolver, roleTemplateResolver *auth.RoleTemplateResolver,
sar authorizationv1.SubjectAccessReviewInterface, grCache controllerv3.GlobalRoleCache) *Validator {
roleTemplateResolver.RoleTemplateCache().AddIndexer(rtRefIndex, roleTemplatesByReference)
grCache.AddIndexer(rtGlobalRefIndex, roleTemplatesByGlobalReference)
return &Validator{
admitter: admitter{
grCache: grCache,
resolver: resolver,
roleTemplateResolver: roleTemplateResolver,
sar: sar,
},
}
}
// Validator for validating roleTemplates.
type Validator struct {
admitter admitter
}
// GVR returns the GroupVersionKind for this CRD.
func (v *Validator) GVR() schema.GroupVersionResource {
return gvr
}
// Operations returns list of operations handled by this validator.
func (v *Validator) Operations() []admissionregistrationv1.OperationType {
return []admissionregistrationv1.OperationType{admissionregistrationv1.Update, admissionregistrationv1.Create, admissionregistrationv1.Delete}
}
// ValidatingWebhook returns the ValidatingWebhook used for this CRD.
func (v *Validator) ValidatingWebhook(clientConfig admissionregistrationv1.WebhookClientConfig) []admissionregistrationv1.ValidatingWebhook {
return []admissionregistrationv1.ValidatingWebhook{*admission.NewDefaultValidatingWebhook(v, clientConfig, admissionregistrationv1.ClusterScope, v.Operations())}
}
// Admitters returns the admitter objects used to validate RoleTemplates.
func (v *Validator) Admitters() []admission.Admitter {
return []admission.Admitter{&v.admitter}
}
type admitter struct {
grCache controllerv3.GlobalRoleCache
resolver validation.AuthorizationRuleResolver
roleTemplateResolver *auth.RoleTemplateResolver
sar authorizationv1.SubjectAccessReviewInterface
}
// Admit handles the webhook admission request sent to this webhook.
func (a *admitter) Admit(request *admission.Request) (*admissionv1.AdmissionResponse, error) {
listTrace := trace.New("Validator Admit", trace.Field{Key: "user", Value: request.UserInfo.Username})
defer listTrace.LogIfLong(admission.SlowTraceDuration)
oldRT, newRT, err := objectsv3.RoleTemplateOldAndNewFromRequest(&request.AdmissionRequest)
if err != nil {
return nil, fmt.Errorf("failed to get RoleTemplate from request: %w", err)
}
fldPath := field.NewPath("roletemplate")
var fieldErr *field.Error
switch request.Operation {
case admissionv1.Update:
if newRT.DeletionTimestamp != nil {
// Object is in the process of being deleted, so admit it.
// This admits update operations that happen to remove finalizers.
// This is needed to supported the deletion of old RoleTemplates that would not pass the update check that verifies all rules have verbs.
return admission.ResponseAllowed(), nil
}
fieldErr = a.validateUpdateFields(oldRT, newRT, fldPath)
case admissionv1.Create:
fieldErr = validateCreateFields(newRT, fldPath)
case admissionv1.Delete:
return a.validateDelete(oldRT)
default:
return nil, fmt.Errorf("roleTemplate operation %v: %w", request.Operation, admission.ErrUnsupportedOperation)
}
if fieldErr != nil {
return admission.ResponseBadRequest(fieldErr.Error()), nil
}
// check for circular references produced by this role.
circularTemplate, err := a.checkCircularRef(newRT)
if err != nil {
logrus.Errorf("Error when trying to check for a circular ref: %s", err)
return nil, err
}
if circularTemplate != nil {
return admission.ResponseBadRequest(fmt.Sprintf("Circular Reference: RoleTemplate %s already inherits RoleTemplate %s", circularTemplate.Name, newRT.Name)), nil
}
rules, err := a.roleTemplateResolver.RulesFromTemplate(newRT)
if err != nil {
return nil, fmt.Errorf("failed to get all rules for '%s': %w", newRT.Name, err)
}
// verify inherited rules have verbs
if err := common.CheckForVerbs(rules); err != nil {
return admission.ResponseBadRequest(err.Error()), nil
}
allowed, err := auth.RequestUserHasVerb(request, gvr, a.sar, escalateVerb, "", "")
if err != nil {
logrus.Warnf("Failed to check for the 'escalate' verb on RoleTemplates: %v", err)
} else if allowed {
return admission.ResponseAllowed(), nil
}
err = auth.ConfirmNoEscalation(request, rules, "", a.resolver)
if err != nil {
return admission.ResponseFailedEscalation(err.Error()), nil
}
return admission.ResponseAllowed(), nil
}
// validateUpdateFields checks if the fields being changed are valid update fields.
func (a *admitter) validateUpdateFields(oldRole, newRole *v3.RoleTemplate, fldPath *field.Path) *field.Error {
if err := validateContextValue(newRole, fldPath); err != nil {
return err
}
// if this is not a built in role, prevent it from becoming one. Otherwise, no further validation is needed
if !oldRole.Builtin {
if newRole.Builtin {
return field.Forbidden(fldPath, fmt.Sprintf("cannot update non-builtIn RoleTemplate %s to be builtIn", oldRole.Name))
}
return nil
}
// allow changes to meta data and defaults
oldRole.ClusterCreatorDefault = newRole.ClusterCreatorDefault
oldRole.ProjectCreatorDefault = newRole.ProjectCreatorDefault
oldRole.Locked = newRole.Locked
// we do not want to block K8s controllers from adding metadata or typemeta to the object.
oldRole.ObjectMeta = newRole.ObjectMeta
oldRole.TypeMeta = newRole.TypeMeta
if !equality.Semantic.DeepEqual(oldRole, newRole) {
return field.Forbidden(fldPath, "updates to builtIn RoleTemplates for fields other than CreatorDefault are forbidden")
}
return nil
}
// validateCreateFields checks if all required fields are present and valid.
func validateCreateFields(newRole *v3.RoleTemplate, fldPath *field.Path) *field.Error {
if newRole.Builtin {
return field.Forbidden(fldPath, "creating new builtIn RoleTemplates is forbidden")
}
return validateContextValue(newRole, fldPath)
}
func validateContextValue(newRole *v3.RoleTemplate, fldPath *field.Path) *field.Error {
if newRole.Administrative && newRole.Context != clusterContext {
return field.Forbidden(fldPath.Child("administrative"), "only cluster roles can be administrative")
}
if newRole.Context != clusterContext && newRole.Context != projectContext && newRole.Context != emptyContext {
return field.NotSupported(fldPath.Child("context"), newRole.Context, []string{clusterContext, projectContext})
}
return nil
}
func (a *admitter) validateDelete(oldRT *v3.RoleTemplate) (*admissionv1.AdmissionResponse, error) {
refRT, err := a.roleTemplateResolver.RoleTemplateCache().GetByIndex(rtRefIndex, oldRT.Name)
if err != nil {
return nil, fmt.Errorf("failed to list RoleTemplates that reference '%s': %w", oldRT.Name, err)
}
// verify that the role is not currently inherited
if len(refRT) != 0 {
var names []string
for _, rt := range refRT {
names = append(names, rt.Name)
}
joinedNames := strings.Join(names, ", ")
return admission.ResponseBadRequest(fmt.Sprintf("roletemplate %q cannot be deleted because it is inherited by roletemplate(s) %q", oldRT.Name, joinedNames)), nil
}
globalRefs, err := a.grCache.GetByIndex(rtGlobalRefIndex, oldRT.Name)
if err != nil {
return nil, fmt.Errorf("failed to list GlobalRoles that reference %q: %w", oldRT.Name, err)
}
if len(globalRefs) != 0 {
var names []string
for _, globalRef := range globalRefs {
names = append(names, globalRef.Name)
}
joinedNames := strings.Join(names, ", ")
return admission.ResponseBadRequest(fmt.Sprintf("roletemplate %q cannot be deleted because it is inherited by globalRole(s) %q", oldRT.Name, joinedNames)), nil
}
return admission.ResponseAllowed(), nil
}
// roleTemplatesByReference returns a list of keys that can be used to retrieve the provided RT.
// each key represents the name of a RoleTemplate that the provided object references.
func roleTemplatesByReference(rt *v3.RoleTemplate) ([]string, error) {
return rt.RoleTemplateNames, nil
}
func roleTemplatesByGlobalReference(gr *v3.GlobalRole) ([]string, error) {
return gr.InheritedClusterRoles, nil
}
// checkCircularRef looks for a circular ref between this role template and any role template that it inherits
// for example - template 1 inherits template 2 which inherits template 1. These setups can cause high cpu usage/crashes
// If a circular ref was found, returns the first template which inherits this role template. Returns nil otherwise.
// Can return an error if any role template was not found.
func (a *admitter) checkCircularRef(template *v3.RoleTemplate) (*v3.RoleTemplate, error) {
seen := make(map[string]struct{})
queue := []*v3.RoleTemplate{template}
for len(queue) > 0 {
current := queue[0]
queue = queue[1:]
for _, inherited := range current.RoleTemplateNames {
// if we found a circular reference, exit here and go no further
if inherited == template.Name {
// note: we only look for circular references to this role. We don't check for circular dependencies which
// don't have this role as one of the targets. Those should have been taken care of when they were originally made
return current, nil
}
// if we haven't seen this yet, we add to the queue to process
if _, ok := seen[inherited]; !ok {
newTemplate, err := a.roleTemplateResolver.RoleTemplateCache().Get(inherited)
if err != nil {
return nil, fmt.Errorf("unable to get roletemplate %s with error %w", inherited, err)
}
seen[inherited] = struct{}{}
queue = append(queue, newTemplate)
}
}
}
return nil, nil
}