k3s/pkg/secretsencrypt/config.go

287 lines
8.9 KiB
Go

package secretsencrypt
import (
"bytes"
"context"
"crypto/sha256"
"encoding/hex"
"encoding/json"
"fmt"
"os"
"time"
"github.com/k3s-io/k3s/pkg/daemons/config"
"github.com/k3s-io/k3s/pkg/util"
"github.com/k3s-io/k3s/pkg/version"
"github.com/prometheus/common/expfmt"
corev1 "k8s.io/api/core/v1"
"k8s.io/client-go/tools/clientcmd"
"github.com/k3s-io/k3s/pkg/generated/clientset/versioned/scheme"
"github.com/sirupsen/logrus"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/util/wait"
apiserverconfigv1 "k8s.io/apiserver/pkg/apis/config/v1"
"k8s.io/client-go/rest"
)
const (
EncryptionStart string = "start"
EncryptionPrepare string = "prepare"
EncryptionRotate string = "rotate"
EncryptionRotateKeys string = "rotate_keys"
EncryptionReencryptRequest string = "reencrypt_request"
EncryptionReencryptActive string = "reencrypt_active"
EncryptionReencryptFinished string = "reencrypt_finished"
)
var EncryptionHashAnnotation = version.Program + ".io/encryption-config-hash"
func GetEncryptionProviders(runtime *config.ControlRuntime) ([]apiserverconfigv1.ProviderConfiguration, error) {
curEncryptionByte, err := os.ReadFile(runtime.EncryptionConfig)
if err != nil {
return nil, err
}
curEncryption := apiserverconfigv1.EncryptionConfiguration{}
if err = json.Unmarshal(curEncryptionByte, &curEncryption); err != nil {
return nil, err
}
return curEncryption.Resources[0].Providers, nil
}
// GetEncryptionKeys returns a list of encryption keys from the current encryption configuration.
// If includeIdentity is true, it will also include a fake key representing the identity provider, which
// is used to determine if encryption is enabled/disabled.
func GetEncryptionKeys(runtime *config.ControlRuntime, includeIdentity bool) ([]apiserverconfigv1.Key, error) {
providers, err := GetEncryptionProviders(runtime)
if err != nil {
return nil, err
}
if len(providers) > 2 {
return nil, fmt.Errorf("more than 2 providers (%d) found in secrets encryption", len(providers))
}
var curKeys []apiserverconfigv1.Key
for _, p := range providers {
// Since identity doesn't have keys, we make up a fake key to represent it, so we can
// know that encryption is enabled/disabled in the request.
if p.Identity != nil && includeIdentity {
curKeys = append(curKeys, apiserverconfigv1.Key{
Name: "identity",
Secret: "identity",
})
}
if p.AESCBC != nil {
curKeys = append(curKeys, p.AESCBC.Keys...)
}
if p.AESGCM != nil || p.KMS != nil || p.Secretbox != nil {
return nil, fmt.Errorf("non-standard encryption keys found")
}
}
return curKeys, nil
}
func WriteEncryptionConfig(runtime *config.ControlRuntime, keys []apiserverconfigv1.Key, enable bool) error {
// Placing the identity provider first disables encryption
var providers []apiserverconfigv1.ProviderConfiguration
if enable {
providers = []apiserverconfigv1.ProviderConfiguration{
{
AESCBC: &apiserverconfigv1.AESConfiguration{
Keys: keys,
},
},
{
Identity: &apiserverconfigv1.IdentityConfiguration{},
},
}
} else {
providers = []apiserverconfigv1.ProviderConfiguration{
{
Identity: &apiserverconfigv1.IdentityConfiguration{},
},
{
AESCBC: &apiserverconfigv1.AESConfiguration{
Keys: keys,
},
},
}
}
encConfig := apiserverconfigv1.EncryptionConfiguration{
TypeMeta: metav1.TypeMeta{
Kind: "EncryptionConfiguration",
APIVersion: "apiserver.config.k8s.io/v1",
},
Resources: []apiserverconfigv1.ResourceConfiguration{
{
Resources: []string{"secrets"},
Providers: providers,
},
},
}
jsonfile, err := json.Marshal(encConfig)
if err != nil {
return err
}
return util.AtomicWrite(runtime.EncryptionConfig, jsonfile, 0600)
}
func GenEncryptionConfigHash(runtime *config.ControlRuntime) (string, error) {
curEncryptionByte, err := os.ReadFile(runtime.EncryptionConfig)
if err != nil {
return "", err
}
encryptionConfigHash := sha256.Sum256(curEncryptionByte)
return hex.EncodeToString(encryptionConfigHash[:]), nil
}
// GenReencryptHash generates a sha256 hash from the existing secrets keys and
// any identity providers plus a new key based on the input arguments.
func GenReencryptHash(runtime *config.ControlRuntime, keyName string) (string, error) {
keys, err := GetEncryptionKeys(runtime, true)
if err != nil {
return "", err
}
newKey := apiserverconfigv1.Key{
Name: keyName,
Secret: "12345",
}
keys = append(keys, newKey)
b, err := json.Marshal(keys)
if err != nil {
return "", err
}
hash := sha256.Sum256(b)
return hex.EncodeToString(hash[:]), nil
}
func getEncryptionHashFile(runtime *config.ControlRuntime) (string, error) {
curEncryptionByte, err := os.ReadFile(runtime.EncryptionHash)
if err != nil {
return "", err
}
return string(curEncryptionByte), nil
}
func BootstrapEncryptionHashAnnotation(node *corev1.Node, runtime *config.ControlRuntime) error {
existingAnn, err := getEncryptionHashFile(runtime)
if err != nil {
return err
}
node.Annotations[EncryptionHashAnnotation] = existingAnn
return nil
}
func WriteEncryptionHashAnnotation(runtime *config.ControlRuntime, node *corev1.Node, stage string) error {
encryptionConfigHash, err := GenEncryptionConfigHash(runtime)
if err != nil {
return err
}
if node.Annotations == nil {
return fmt.Errorf("node annotations do not exist for %s", node.ObjectMeta.Name)
}
ann := stage + "-" + encryptionConfigHash
node.Annotations[EncryptionHashAnnotation] = ann
if _, err = runtime.Core.Core().V1().Node().Update(node); err != nil {
return err
}
logrus.Debugf("encryption hash annotation set successfully on node: %s\n", node.ObjectMeta.Name)
return os.WriteFile(runtime.EncryptionHash, []byte(ann), 0600)
}
// WaitForEncryptionConfigReload watches the metrics API, polling the latest time the encryption config was reloaded.
func WaitForEncryptionConfigReload(runtime *config.ControlRuntime, reloadSuccesses, reloadTime int64) error {
var lastFailure string
err := wait.PollImmediate(5*time.Second, 60*time.Second, func() (bool, error) {
newReloadTime, newReloadSuccess, err := GetEncryptionConfigMetrics(runtime, false)
if err != nil {
return true, err
}
if newReloadSuccess <= reloadSuccesses || newReloadTime <= reloadTime {
lastFailure = fmt.Sprintf("apiserver has not reloaded encryption configuration (reload success: %d/%d, reload timestamp %d/%d)", newReloadSuccess, reloadSuccesses, newReloadTime, reloadTime)
return false, nil
}
logrus.Infof("encryption config reloaded successfully %d times", newReloadSuccess)
logrus.Debugf("encryption config reloaded at %s", time.Unix(newReloadTime, 0))
return true, nil
})
if err != nil {
err = fmt.Errorf("%w: %s", err, lastFailure)
}
return err
}
// GetEncryptionConfigMetrics fetches the metrics API and returns the last time the encryption config was reloaded
// and the number of times it has been reloaded.
func GetEncryptionConfigMetrics(runtime *config.ControlRuntime, initialMetrics bool) (int64, int64, error) {
var unixUpdateTime int64
var reloadSuccessCounter int64
var lastFailure string
restConfig, err := clientcmd.BuildConfigFromFlags("", runtime.KubeConfigSupervisor)
if err != nil {
return 0, 0, err
}
restConfig.GroupVersion = &apiserverconfigv1.SchemeGroupVersion
restConfig.NegotiatedSerializer = scheme.Codecs.WithoutConversion()
restClient, err := rest.RESTClientFor(restConfig)
if err != nil {
return 0, 0, err
}
// This is wrapped in a poller because on startup no metrics exist. Its only after the encryption config
// is modified and the first reload occurs that the metrics are available.
err = wait.PollImmediate(5*time.Second, 60*time.Second, func() (bool, error) {
data, err := restClient.Get().AbsPath("/metrics").DoRaw(context.TODO())
if err != nil {
return true, err
}
reader := bytes.NewReader(data)
var parser expfmt.TextParser
mf, err := parser.TextToMetricFamilies(reader)
if err != nil {
return true, err
}
tsMetric := mf["apiserver_encryption_config_controller_automatic_reload_last_timestamp_seconds"]
successMetric := mf["apiserver_encryption_config_controller_automatic_reload_success_total"]
// First time, no metrics exist, so return zeros
if tsMetric == nil && successMetric == nil && initialMetrics {
return true, nil
}
if tsMetric == nil {
lastFailure = "encryption config time metric not found"
return false, nil
}
if successMetric == nil {
lastFailure = "encryption config success metric not found"
return false, nil
}
unixUpdateTime = int64(tsMetric.GetMetric()[0].GetGauge().GetValue())
if time.Now().Unix() < unixUpdateTime {
return true, fmt.Errorf("encryption reload time is incorrectly ahead of current time")
}
reloadSuccessCounter = int64(successMetric.GetMetric()[0].GetCounter().GetValue())
return true, nil
})
if err != nil {
err = fmt.Errorf("%w: %s", err, lastFailure)
}
return unixUpdateTime, reloadSuccessCounter, err
}