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kyverno/pkg/auth/auth.go

108 lines
3.4 KiB
Go

package auth
import (
"fmt"
"reflect"
"github.com/golang/glog"
client "github.com/nirmata/kyverno/pkg/dclient"
authorizationv1 "k8s.io/api/authorization/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime/schema"
)
//CanIOptions provides utility ti check if user has authorization for the given operation
type CanIOptions struct {
namespace string
verb string
kind string
client *client.Client
}
//NewCanI returns a new instance of operation access controler evaluator
func NewCanI(client *client.Client, kind, namespace, verb string) *CanIOptions {
o := CanIOptions{
client: client,
}
o.namespace = namespace
o.kind = kind
o.verb = verb
return &o
}
//RunAccessCheck checks if the caller can perform the operation
// - operation is a combination of namespace, kind, verb
// - can only evaluate a single verb
// - group version resource is determined from the kind using the discovery client REST mapper
// - If disallowed, the reason and evaluationError is avialable in the logs
// - each can generates a SelfSubjectAccessReview resource and response is evaluated for permissions
func (o *CanIOptions) RunAccessCheck() (bool, error) {
// get GroupVersionResource from RESTMapper
// get GVR from kind
gvr := o.client.DiscoveryClient.GetGVRFromKind(o.kind)
if reflect.DeepEqual(gvr, schema.GroupVersionResource{}) {
// cannot find GVR
return false, fmt.Errorf("failed to get the Group Version Resource for kind %s", o.kind)
}
var sar *authorizationv1.SelfSubjectAccessReview
sar = &authorizationv1.SelfSubjectAccessReview{
Spec: authorizationv1.SelfSubjectAccessReviewSpec{
ResourceAttributes: &authorizationv1.ResourceAttributes{
Namespace: o.namespace,
Verb: o.verb,
Group: gvr.Group,
Resource: gvr.Resource,
},
},
}
// Set self subject access review
// - namespace
// - verb
// - resource
// - subresource
// Create the Resource
resp, err := o.client.CreateResource("SelfSubjectAccessReview", "", sar, false)
if err != nil {
glog.Errorf("failed to create resource %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
return false, err
}
// status.allowed
allowed, ok, err := unstructured.NestedBool(resp.Object, "status", "allowed")
if !ok {
if err != nil {
glog.Errorf("unexpected error when getting status.allowed for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
glog.Errorf("status.allowed not found for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
if !allowed {
// status.reason
reason, ok, err := unstructured.NestedString(resp.Object, "status", "reason")
if !ok {
if err != nil {
glog.Errorf("unexpected error when getting status.reason for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
glog.Errorf("status.reason not found for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
// status.evaluationError
evaluationError, ok, err := unstructured.NestedString(resp.Object, "status", "evaludationError")
if !ok {
if err != nil {
glog.Errorf("unexpected error when getting status.evaluationError for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
glog.Errorf("status.evaluationError not found for %s/%s/%s", sar.Kind, sar.Namespace, sar.Name)
}
// Reporting ? (just logs)
glog.Errorf("reason to disallow operation: %s", reason)
glog.Errorf("evaluationError to disallow operation: %s", evaluationError)
}
return allowed, nil
}