Beispiel #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": "jane",
//         "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
}
Beispiel #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
}
Beispiel #3
0
func RuleAllows(requestAttributes authorizer.Attributes, rule rbac.PolicyRule) bool {
	if requestAttributes.IsResourceRequest() {
		resource := requestAttributes.GetResource()
		if len(requestAttributes.GetSubresource()) > 0 {
			resource = requestAttributes.GetResource() + "/" + requestAttributes.GetSubresource()
		}

		return rbac.VerbMatches(rule, requestAttributes.GetVerb()) &&
			rbac.APIGroupMatches(rule, requestAttributes.GetAPIGroup()) &&
			rbac.ResourceMatches(rule, resource) &&
			rbac.ResourceNameMatches(rule, requestAttributes.GetName())
	}

	return rbac.VerbMatches(rule, requestAttributes.GetVerb()) &&
		rbac.NonResourceURLMatches(rule, requestAttributes.GetPath())
}
Beispiel #4
0
func nonResourceMatches(p api.Policy, a authorizer.Attributes) bool {
	// A non-resource policy cannot match a resource request
	if !a.IsResourceRequest() {
		// Allow wildcard match
		if p.Spec.NonResourcePath == "*" {
			return true
		}
		// Allow exact match
		if p.Spec.NonResourcePath == a.GetPath() {
			return true
		}
		// Allow a trailing * subpath match
		if strings.HasSuffix(p.Spec.NonResourcePath, "*") && strings.HasPrefix(a.GetPath(), strings.TrimRight(p.Spec.NonResourcePath, "*")) {
			return true
		}
	}
	return false
}
Beispiel #5
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
}