Esempio n. 1
0
// Authorize makes a REST request to the remote service describing the attempted action as a JSON
// serialized api.authorization.v1beta1.SubjectAccessReview object. An example request body is
// provided bellow.
//
//     {
//       "apiVersion": "authorization.k8s.io/v1beta1",
//       "kind": "SubjectAccessReview",
//       "spec": {
//         "resourceAttributes": {
//           "namespace": "kittensandponies",
//           "verb": "GET",
//           "group": "group3",
//           "resource": "pods"
//         },
//         "user": "******",
//         "group": [
//           "group1",
//           "group2"
//         ]
//       }
//     }
//
// The remote service is expected to fill the SubjectAccessReviewStatus field to either allow or
// disallow access. A permissive response would return:
//
//     {
//       "apiVersion": "authorization.k8s.io/v1beta1",
//       "kind": "SubjectAccessReview",
//       "status": {
//         "allowed": true
//       }
//     }
//
// To disallow access, the remote service would return:
//
//     {
//       "apiVersion": "authorization.k8s.io/v1beta1",
//       "kind": "SubjectAccessReview",
//       "status": {
//         "allowed": false,
//         "reason": "user does not have read access to the namespace"
//       }
//     }
//
func (w *WebhookAuthorizer) Authorize(attr authorizer.Attributes) (authorized bool, reason string, err error) {
	r := &authorization.SubjectAccessReview{}
	if user := attr.GetUser(); user != nil {
		r.Spec = authorization.SubjectAccessReviewSpec{
			User:   user.GetName(),
			Groups: user.GetGroups(),
			Extra:  convertToSARExtra(user.GetExtra()),
		}
	}

	if attr.IsResourceRequest() {
		r.Spec.ResourceAttributes = &authorization.ResourceAttributes{
			Namespace:   attr.GetNamespace(),
			Verb:        attr.GetVerb(),
			Group:       attr.GetAPIGroup(),
			Version:     attr.GetAPIVersion(),
			Resource:    attr.GetResource(),
			Subresource: attr.GetSubresource(),
			Name:        attr.GetName(),
		}
	} else {
		r.Spec.NonResourceAttributes = &authorization.NonResourceAttributes{
			Path: attr.GetPath(),
			Verb: attr.GetVerb(),
		}
	}
	key, err := json.Marshal(r.Spec)
	if err != nil {
		return false, "", err
	}
	if entry, ok := w.responseCache.Get(string(key)); ok {
		r.Status = entry.(authorization.SubjectAccessReviewStatus)
	} else {
		var (
			result *authorization.SubjectAccessReview
			err    error
		)
		webhook.WithExponentialBackoff(w.initialBackoff, func() error {
			result, err = w.subjectAccessReview.Create(r)
			return err
		})
		if err != nil {
			// An error here indicates bad configuration or an outage. Log for debugging.
			glog.Errorf("Failed to make webhook authorizer request: %v", err)
			return false, "", err
		}
		r.Status = result.Status
		if r.Status.Allowed {
			w.responseCache.Add(string(key), r.Status, w.authorizedTTL)
		} else {
			w.responseCache.Add(string(key), r.Status, w.unauthorizedTTL)
		}
	}
	return r.Status.Allowed, r.Status.Reason, nil
}
Esempio n. 2
0
func resourceMatches(p api.Policy, a authorizer.Attributes) bool {
	// A resource policy cannot match a non-resource request
	if a.IsResourceRequest() {
		if p.Spec.Namespace == "*" || p.Spec.Namespace == a.GetNamespace() {
			if p.Spec.Resource == "*" || p.Spec.Resource == a.GetResource() {
				if p.Spec.APIGroup == "*" || p.Spec.APIGroup == a.GetAPIGroup() {
					return true
				}
			}
		}
	}
	return false
}
Esempio n. 3
0
func forbiddenMessage(attributes authorizer.Attributes) string {
	username := ""
	if user := attributes.GetUser(); user != nil {
		username = user.GetName()
	}

	resource := attributes.GetResource()
	if group := attributes.GetAPIGroup(); len(group) > 0 {
		resource = resource + "." + group
	}
	if subresource := attributes.GetSubresource(); len(subresource) > 0 {
		resource = resource + "/" + subresource
	}

	if ns := attributes.GetNamespace(); len(ns) > 0 {
		return fmt.Sprintf("User %q cannot %s %s in the namespace %q.", username, attributes.GetVerb(), resource, ns)
	}

	return fmt.Sprintf("User %q cannot %s %s at the cluster scope.", username, attributes.GetVerb(), resource)
}
Esempio n. 4
0
func (r *RBACAuthorizer) Authorize(requestAttributes authorizer.Attributes) (bool, string, error) {
	rules, ruleResolutionError := r.authorizationRuleResolver.RulesFor(requestAttributes.GetUser(), requestAttributes.GetNamespace())
	if RulesAllow(requestAttributes, rules...) {
		return true, "", nil
	}

	// Build a detailed log of the denial.
	// Make the whole block conditional so we don't do a lot of string-building we won't use.
	if glog.V(2) {
		var operation string
		if requestAttributes.IsResourceRequest() {
			operation = fmt.Sprintf(
				"%q on \"%v.%v/%v\"",
				requestAttributes.GetVerb(),
				requestAttributes.GetResource(), requestAttributes.GetAPIGroup(), requestAttributes.GetSubresource(),
			)
		} else {
			operation = fmt.Sprintf("%q nonResourceURL %q", requestAttributes.GetVerb(), requestAttributes.GetPath())
		}

		var scope string
		if ns := requestAttributes.GetNamespace(); len(ns) > 0 {
			scope = fmt.Sprintf("in namespace %q", ns)
		} else {
			scope = "cluster-wide"
		}

		glog.Infof("RBAC DENY: user %q groups %v cannot %s %s", requestAttributes.GetUser().GetName(), requestAttributes.GetUser().GetGroups(), operation, scope)
	}

	reason := ""
	if ruleResolutionError != nil {
		reason = fmt.Sprintf("%v", ruleResolutionError)
	}
	return false, reason, nil
}
Esempio n. 5
0
// AllowedSubjects returns the subjects that can perform an action and any errors encountered while computing the list.
// It is possible to have both subjects and errors returned if some rolebindings couldn't be resolved, but others could be.
func (r *SubjectAccessEvaluator) AllowedSubjects(requestAttributes authorizer.Attributes) ([]rbac.Subject, error) {
	subjects := []rbac.Subject{{Kind: rbac.GroupKind, Name: user.SystemPrivilegedGroup}}
	if len(r.superUser) > 0 {
		subjects = append(subjects, rbac.Subject{Kind: rbac.UserKind, APIVersion: "v1alpha1", Name: r.superUser})
	}
	errorlist := []error{}

	if clusterRoleBindings, err := r.clusterRoleBindingLister.ListClusterRoleBindings(); err != nil {
		errorlist = append(errorlist, err)

	} else {
		for _, clusterRoleBinding := range clusterRoleBindings {
			rules, err := r.roleToRuleMapper.GetRoleReferenceRules(clusterRoleBinding.RoleRef, "")
			if err != nil {
				// if we have an error, just keep track of it and keep processing.  Since rules are additive,
				// missing a reference is bad, but we can continue with other rolebindings and still have a list
				// that does not contain any invalid values
				errorlist = append(errorlist, err)
			}
			if RulesAllow(requestAttributes, rules...) {
				subjects = append(subjects, clusterRoleBinding.Subjects...)
			}
		}
	}

	if namespace := requestAttributes.GetNamespace(); len(namespace) > 0 {
		if roleBindings, err := r.roleBindingLister.ListRoleBindings(namespace); err != nil {
			errorlist = append(errorlist, err)

		} else {
			for _, roleBinding := range roleBindings {
				rules, err := r.roleToRuleMapper.GetRoleReferenceRules(roleBinding.RoleRef, namespace)
				if err != nil {
					// if we have an error, just keep track of it and keep processing.  Since rules are additive,
					// missing a reference is bad, but we can continue with other rolebindings and still have a list
					// that does not contain any invalid values
					errorlist = append(errorlist, err)
				}
				if RulesAllow(requestAttributes, rules...) {
					subjects = append(subjects, roleBinding.Subjects...)
				}
			}
		}
	}

	dedupedSubjects := []rbac.Subject{}
	for _, subject := range subjects {
		found := false
		for _, curr := range dedupedSubjects {
			if curr == subject {
				found = true
				break
			}
		}

		if !found {
			dedupedSubjects = append(dedupedSubjects, subject)
		}
	}

	return subjects, utilerrors.NewAggregate(errorlist)
}