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tailscale/cmd/containerboot/kube.go

147 lines
4.7 KiB
Go

// Copyright (c) Tailscale Inc & AUTHORS
// SPDX-License-Identifier: BSD-3-Clause
//go:build linux
package main
import (
"context"
"encoding/json"
"errors"
"fmt"
"log"
"net/http"
"net/netip"
"os"
"tailscale.com/kube"
"tailscale.com/tailcfg"
)
// storeDeviceInfo writes deviceID into the "device_id" data field of the kube
// secret secretName.
func storeDeviceInfo(ctx context.Context, secretName string, deviceID tailcfg.StableNodeID, fqdn string, addresses []netip.Prefix) error {
// First check if the secret exists at all. Even if running on
// kubernetes, we do not necessarily store state in a k8s secret.
if _, err := kc.GetSecret(ctx, secretName); err != nil {
if s, ok := err.(*kube.Status); ok {
if s.Code >= 400 && s.Code <= 499 {
// Assume the secret doesn't exist, or we don't have
// permission to access it.
return nil
}
}
return err
}
var ips []string
for _, addr := range addresses {
ips = append(ips, addr.Addr().String())
}
deviceIPs, err := json.Marshal(ips)
if err != nil {
return err
}
m := &kube.Secret{
Data: map[string][]byte{
"device_id": []byte(deviceID),
"device_fqdn": []byte(fqdn),
"device_ips": deviceIPs,
},
}
return kc.StrategicMergePatchSecret(ctx, secretName, m, "tailscale-container")
}
// deleteAuthKey deletes the 'authkey' field of the given kube
// secret. No-op if there is no authkey in the secret.
func deleteAuthKey(ctx context.Context, secretName string) error {
// m is a JSON Patch data structure, see https://jsonpatch.com/ or RFC 6902.
m := []kube.JSONPatch{
{
Op: "remove",
Path: "/data/authkey",
},
}
if err := kc.JSONPatchSecret(ctx, secretName, m); err != nil {
if s, ok := err.(*kube.Status); ok && s.Code == http.StatusUnprocessableEntity {
// This is kubernetes-ese for "the field you asked to
// delete already doesn't exist", aka no-op.
return nil
}
return err
}
return nil
}
var kc kube.Client
// setupKube is responsible for doing any necessary configuration and checks to
// ensure that tailscale state storage and authentication mechanism will work on
// Kubernetes.
func (cfg *settings) setupKube(ctx context.Context) error {
if cfg.KubeSecret == "" {
return nil
}
canPatch, canCreate, err := kc.CheckSecretPermissions(ctx, cfg.KubeSecret)
if err != nil {
return fmt.Errorf("Some Kubernetes permissions are missing, please check your RBAC configuration: %v", err)
}
cfg.KubernetesCanPatch = canPatch
s, err := kc.GetSecret(ctx, cfg.KubeSecret)
if err != nil && kube.IsNotFoundErr(err) && !canCreate {
return fmt.Errorf("Tailscale state Secret %s does not exist and we don't have permissions to create it. "+
"If you intend to store tailscale state elsewhere than a Kubernetes Secret, "+
"you can explicitly set TS_KUBE_SECRET env var to an empty string. "+
"Else ensure that RBAC is set up that allows the service account associated with this installation to create Secrets.", cfg.KubeSecret)
} else if err != nil && !kube.IsNotFoundErr(err) {
return fmt.Errorf("Getting Tailscale state Secret %s: %v", cfg.KubeSecret, err)
}
if cfg.AuthKey == "" && !isOneStepConfig(cfg) {
if s == nil {
log.Print("TS_AUTHKEY not provided and kube secret does not exist, login will be interactive if needed.")
return nil
}
keyBytes, _ := s.Data["authkey"]
key := string(keyBytes)
if key != "" {
// This behavior of pulling authkeys from kube secrets was added
// at the same time as the patch permission, so we can enforce
// that we must be able to patch out the authkey after
// authenticating if you want to use this feature. This avoids
// us having to deal with the case where we might leave behind
// an unnecessary reusable authkey in a secret, like a rake in
// the grass.
if !cfg.KubernetesCanPatch {
return errors.New("authkey found in TS_KUBE_SECRET, but the pod doesn't have patch permissions on the secret to manage the authkey.")
}
cfg.AuthKey = key
} else {
log.Print("No authkey found in kube secret and TS_AUTHKEY not provided, login will be interactive if needed.")
}
}
return nil
}
func initKubeClient(root string) {
if root != "/" {
// If we are running in a test, we need to set the root path to the fake
// service account directory.
kube.SetRootPathForTesting(root)
}
var err error
kc, err = kube.New()
if err != nil {
log.Fatalf("Error creating kube client: %v", err)
}
if (root != "/") || os.Getenv("TS_KUBERNETES_READ_API_SERVER_ADDRESS_FROM_ENV") == "true" {
// Derive the API server address from the environment variables
// Used to set http server in tests, or optionally enabled by flag
kc.SetURL(fmt.Sprintf("https://%s:%s", os.Getenv("KUBERNETES_SERVICE_HOST"), os.Getenv("KUBERNETES_SERVICE_PORT_HTTPS")))
}
}