// 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
}
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
}
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())
}
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
}
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
}