/
server.go
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/
server.go
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package admission
import (
"context"
"crypto/tls"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
configuration "github.com/kong/kubernetes-ingress-controller/railgun/apis/configuration/v1"
"github.com/sirupsen/logrus"
admission "k8s.io/api/admission/v1"
corev1 "k8s.io/api/core/v1"
meta "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/serializer"
)
var (
scheme = runtime.NewScheme()
codecs = serializer.NewCodecFactory(scheme)
)
const DefaultAdmissionWebhookCertPath = "/admission-webhook/tls.crt"
const DefaultAdmissionWebhookKeyPath = "/admission-webhook/tls.key"
type ServerConfig struct {
ListenAddr string
CertPath string
Cert string
KeyPath string
Key string
}
func readKeyPairFiles(certPath, keyPath string) ([]byte, []byte, error) {
cert, err := ioutil.ReadFile(certPath)
if err != nil {
return nil, nil, fmt.Errorf("read cert from file %q: %w", certPath, err)
}
key, err := ioutil.ReadFile(keyPath)
if err != nil {
return nil, nil, fmt.Errorf("read key from file %q: %w", keyPath, err)
}
return cert, key, nil
}
func (sc *ServerConfig) toTLSConfig() (*tls.Config, error) {
var cert, key []byte
switch {
case sc.CertPath == "" && sc.KeyPath == "" && sc.Cert != "" && sc.Key != "":
cert, key = []byte(sc.Cert), []byte(sc.Key)
case sc.CertPath != "" && sc.KeyPath != "" && sc.Cert == "" && sc.Key == "":
var err error
cert, key, err = readKeyPairFiles(sc.CertPath, sc.KeyPath)
if err != nil {
return nil, err
}
case sc.CertPath == "" && sc.KeyPath == "" && sc.Cert == "" && sc.Key == "":
var err error
cert, key, err = readKeyPairFiles(DefaultAdmissionWebhookCertPath, DefaultAdmissionWebhookKeyPath)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("either cert/key files OR cert/key values must be provided, or none")
}
keyPair, err := tls.X509KeyPair(cert, key)
if err != nil {
return nil, fmt.Errorf("X509KeyPair error: %w", err)
}
return &tls.Config{ //nolint:gosec
Certificates: []tls.Certificate{keyPair},
}, nil
}
func MakeTLSServer(config *ServerConfig, handler http.Handler) (*http.Server, error) {
tlsConfig, err := config.toTLSConfig()
if err != nil {
return nil, err
}
return &http.Server{
Addr: config.ListenAddr,
TLSConfig: tlsConfig,
Handler: handler,
}, nil
}
// RequestHandler is an HTTP server that can validate Kong Ingress Controllers'
// Custom Resources using Kubernetes Admission Webhooks.
type RequestHandler struct {
// Validator validates the entities that the k8s API-server asks
// it the server to validate.
Validator KongValidator
Logger logrus.FieldLogger
}
// ServeHTTP parses AdmissionReview requests and responds back
// with the validation result of the entity.
func (a RequestHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
if r.Body == nil {
a.Logger.Error("received request with empty body")
http.Error(w, "admission review object is missing",
http.StatusBadRequest)
return
}
data, err := ioutil.ReadAll(r.Body)
if err != nil {
a.Logger.Errorf("failed to read request from client: %v", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
review := admission.AdmissionReview{}
if err := json.Unmarshal(data, &review); err != nil {
a.Logger.Errorf("failed to parse AdmissionReview object: %v", err)
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
response, err := a.handleValidation(r.Context(), *review.Request)
if err != nil {
a.Logger.Errorf("failed to run validation: %v", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
review.Response = response
data, err = json.Marshal(review)
if err != nil {
a.Logger.Errorf("failed to marshal response: %v", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
_, err = w.Write(data)
if err != nil {
a.Logger.Errorf("failed to write response: %v", err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
var (
consumerGVResource = meta.GroupVersionResource{
Group: configuration.SchemeGroupVersion.Group,
Version: configuration.SchemeGroupVersion.Version,
Resource: "kongconsumers"}
pluginGVResource = meta.GroupVersionResource{
Group: configuration.SchemeGroupVersion.Group,
Version: configuration.SchemeGroupVersion.Version,
Resource: "kongplugins"}
secretGVResource = meta.GroupVersionResource{
Group: corev1.SchemeGroupVersion.Group,
Version: corev1.SchemeGroupVersion.Version,
Resource: "secrets"}
)
func (a RequestHandler) handleValidation(ctx context.Context, request admission.AdmissionRequest) (
*admission.AdmissionResponse, error) {
var response admission.AdmissionResponse
var ok bool
var message string
var err error
switch request.Resource {
case consumerGVResource:
consumer := configuration.KongConsumer{}
deserializer := codecs.UniversalDeserializer()
_, _, err = deserializer.Decode(request.Object.Raw,
nil, &consumer)
if err != nil {
return nil, err
}
switch request.Operation {
case admission.Create:
ok, message, err = a.Validator.ValidateConsumer(ctx, consumer)
if err != nil {
return nil, err
}
case admission.Update:
var oldConsumer configuration.KongConsumer
_, _, err = deserializer.Decode(request.OldObject.Raw,
nil, &oldConsumer)
if err != nil {
return nil, err
}
// validate only if the username is being changed
if consumer.Username != oldConsumer.Username {
ok, message, err = a.Validator.ValidateConsumer(ctx, consumer)
if err != nil {
return nil, err
}
} else {
ok = true
}
default:
return nil, fmt.Errorf("unknown operation '%v'", string(request.Operation))
}
case pluginGVResource:
plugin := configuration.KongPlugin{}
deserializer := codecs.UniversalDeserializer()
_, _, err = deserializer.Decode(request.Object.Raw,
nil, &plugin)
if err != nil {
return nil, err
}
ok, message, err = a.Validator.ValidatePlugin(ctx, plugin)
if err != nil {
return nil, err
}
case secretGVResource:
secret := corev1.Secret{}
deserializer := codecs.UniversalDeserializer()
_, _, err = deserializer.Decode(request.Object.Raw,
nil, &secret)
if err != nil {
return nil, err
}
if _, ok = secret.Data["kongCredType"]; !ok {
// secret does not look like a credential resource in Kong
ok = true
break
}
ok, message, err = a.Validator.ValidateCredential(secret)
if err != nil {
return nil, err
}
default:
return nil, fmt.Errorf("unknown resource type to validate: %s/%s %s",
request.Resource.Group, request.Resource.Version,
request.Resource.Resource)
}
if err != nil {
return nil, err
}
response.UID = request.UID
response.Allowed = ok
response.Result = &meta.Status{
Message: message,
}
if !ok {
response.Result.Code = 400
}
return &response, nil
}