webhook/pkg/auth/escalation.go

90 lines
3.0 KiB
Go

// Package auth is holds common webhook code used during authentication
package auth
import (
"context"
"fmt"
"net/http"
"github.com/rancher/webhook/pkg/admission"
admissionv1 "k8s.io/api/admission/v1"
authenticationv1 "k8s.io/api/authentication/v1"
v1 "k8s.io/api/authorization/v1"
rbacv1 "k8s.io/api/rbac/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
"k8s.io/apiserver/pkg/authentication/user"
k8srequest "k8s.io/apiserver/pkg/endpoints/request"
authorizationv1 "k8s.io/client-go/kubernetes/typed/authorization/v1"
"k8s.io/kubernetes/pkg/registry/rbac/validation"
)
// RequestUserHasVerb checks if the user associated with the context has a given verb on a given gvr for a specified name/namespace
func RequestUserHasVerb(request *admission.Request, gvr schema.GroupVersionResource, sar authorizationv1.SubjectAccessReviewInterface, verb, name, namespace string) (bool, error) {
extras := map[string]v1.ExtraValue{}
for k, v := range request.UserInfo.Extra {
extras[k] = v1.ExtraValue(v)
}
resp, err := sar.Create(request.Context, &v1.SubjectAccessReview{
Spec: v1.SubjectAccessReviewSpec{
ResourceAttributes: &v1.ResourceAttributes{
Verb: verb,
Namespace: namespace,
Version: gvr.Version,
Resource: gvr.Resource,
Group: gvr.Group,
Name: name,
},
User: request.UserInfo.Username,
Groups: request.UserInfo.Groups,
Extra: extras,
UID: request.UserInfo.UID,
},
}, metav1.CreateOptions{})
if err != nil {
return false, fmt.Errorf("failed to checkout create sar request: %w", err)
}
return resp.Status.Allowed, nil
}
// ConfirmNoEscalation checks that the user attempting to create a binding/role has all the permissions they are attempting
// to grant.
func ConfirmNoEscalation(request *admission.Request, rules []rbacv1.PolicyRule, namespace string, ruleResolver validation.AuthorizationRuleResolver) error {
userInfo := &user.DefaultInfo{
Name: request.UserInfo.Username,
UID: request.UserInfo.UID,
Groups: request.UserInfo.Groups,
Extra: ToExtraString(request.UserInfo.Extra),
}
globalCtx := k8srequest.WithNamespace(k8srequest.WithUser(context.Background(), userInfo), namespace)
return validation.ConfirmNoEscalation(globalCtx, ruleResolver, rules)
}
// ToExtraString will convert a map of map[string]authenticationv1.ExtraValue to map[string]string.
func ToExtraString(extra map[string]authenticationv1.ExtraValue) map[string][]string {
result := make(map[string][]string)
for k, v := range extra {
result[k] = v
}
return result
}
// SetEscalationResponse will update the given webhook response based on the provided error from an escalation request.
// Deprecated: use admission.ResponseFailedEscalation() instead.
func SetEscalationResponse(response *admissionv1.AdmissionResponse, err error) {
if err == nil {
response.Allowed = true
return
}
response.Result = &metav1.Status{
Status: "Failure",
Message: err.Error(),
Reason: metav1.StatusReasonInvalid,
Code: http.StatusUnprocessableEntity,
}
}