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Merge pull request #626 from ericchiang/storage-kubernetes-guess-namespace-from-service-account-token

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storage/kubernetes: guess namespace from the service account token
This commit is contained in:
Eric Chiang 2016-10-25 16:54:58 -07:00 committed by GitHub
commit d350938fb0
2 changed files with 95 additions and 6 deletions
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41
storage/kubernetes/client.go
View file

@ -320,6 +320,32 @@ func loadKubeConfig(kubeConfigPath string) (cluster k8sapi.Cluster, user k8sapi.
return
}
func namespaceFromServiceAccountJWT(s string) (string, error) {
// The service account token is just a JWT. Parse it as such.
parts := strings.Split(s, ".")
if len(parts) < 2 {
// It's extremely important we don't log the actual service account token.
return "", fmt.Errorf("malformed service account token: expected 3 parts got %d", len(parts))
}
payload, err := base64.RawURLEncoding.DecodeString(parts[1])
if err != nil {
return "", fmt.Errorf("malformed service account token: %v", err)
}
var data struct {
// The claim Kubernetes uses to identify which namespace a service account belongs to.
//
// See: https://github.com/kubernetes/kubernetes/blob/v1.4.3/pkg/serviceaccount/jwt.go#L42
Namespace string `json:"kubernetes.io/serviceaccount/namespace"`
}
if err := json.Unmarshal(payload, &data); err != nil {
return "", fmt.Errorf("malformed service account token: %v", err)
}
if data.Namespace == "" {
return "", errors.New(`jwt claim "kubernetes.io/serviceaccount/namespace" not found`)
}
return data.Namespace, nil
}
func inClusterConfig() (cluster k8sapi.Cluster, user k8sapi.AuthInfo, namespace string, err error) {
host, port := os.Getenv("KUBERNETES_SERVICE_HOST"), os.Getenv("KUBERNETES_SERVICE_PORT")
if len(host) == 0 || len(port) == 0 {
@ -330,17 +356,20 @@ func inClusterConfig() (cluster k8sapi.Cluster, user k8sapi.AuthInfo, namespace
Server: "https://" + host + ":" + port,
CertificateAuthority: "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt",
}
if namespace = os.Getenv("KUBERNETES_POD_NAMESPACE"); namespace == "" {
err = fmt.Errorf("unable to load in-cluster configuration, KUBERNETES_POD_NAMESPACE must be defined")
return
}
token, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/token")
if err != nil {
return
}
user = k8sapi.AuthInfo{Token: string(token)}
if namespace = os.Getenv("KUBERNETES_POD_NAMESPACE"); namespace == "" {
namespace, err = namespaceFromServiceAccountJWT(user.Token)
if err != nil {
err = fmt.Errorf("failed to inspect service account token: %v", err)
return
}
}
return
}

60
storage/kubernetes/client_test.go Normal file
View file

@ -0,0 +1,60 @@
package kubernetes
import "testing"
func TestNamespaceFromServiceAccountJWT(t *testing.T) {
namespace, err := namespaceFromServiceAccountJWT(serviceAccountToken)
if err != nil {
t.Fatal(err)
}
wantNamespace := "dex-test-namespace"
if namespace != wantNamespace {
t.Errorf("expected namespace %q got %q", wantNamespace, namespace)
}
}
var serviceAccountToken = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.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.KViBpPwCiBwxDvAjYUUXoVvLVwqV011aLlYQpNtX12Bh8M-QAFch-3RWlo_SR00bcdFg_nZo9JKACYlF_jHMEsf__PaYms9r7vEaSg0jPfkqnL2WXZktzQRyLBr0n-bxeUrbwIWsKOAC0DfFB5nM8XoXljRmq8yAx8BAdmQp7MIFb4EOV9nYthhua6pjzYyaFSiDiYTjw7HtXOvoL8oepodJ3-37pUKS8vdBvnvUoqC4M1YAhkO5L36JF6KV_RfmG8GPEdNQfXotHcsR-3jKi1n8S5l7Xd-rhrGOhSGQizH3dORzo9GvBAhYeqbq1O-NLzm2EQUiMQayIUx7o4g3Kw"
// The following program was used to generate the example token. Since we don't want to
// import Kubernetes, just leave it as a comment.
/*
package main
import (
"crypto/rand"
"crypto/rsa"
"fmt"
"log"
"k8s.io/kubernetes/pkg/api"
"k8s.io/kubernetes/pkg/serviceaccount"
"k8s.io/kubernetes/pkg/util/uuid"
)
func main() {
key, err := rsa.GenerateKey(rand.Reader, 2048)
if err != nil {
log.Fatal(err)
}
sa := api.ServiceAccount{
ObjectMeta: api.ObjectMeta{
Namespace: "dex-test-namespace",
Name: "dotherobot",
UID: uuid.NewUUID(),
},
}
secret := api.Secret{
ObjectMeta: api.ObjectMeta{
Namespace: "dex-test-namespace",
Name: "dotherobot-secret",
UID: uuid.NewUUID(),
},
}
token, err := serviceaccount.JWTTokenGenerator(key).GenerateToken(sa, secret)
if err != nil {
log.Fatal(err)
}
fmt.Println(token)
}
*/