mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-09 16:00:22 +00:00
299 lines
8.8 KiB
Go
299 lines
8.8 KiB
Go
/*
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Copyright 2019 The Ceph-CSI Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package kms
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import (
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"context"
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"github.com/ceph/ceph-csi/internal/util/k8s"
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"golang.org/x/crypto/scrypt"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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)
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const (
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// Encryption passphrase location in K8s secrets.
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encryptionPassphraseKey = "encryptionPassphrase"
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// kmsTypeSecretsMetadata is the secretKMS with per-volume encryption,
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// where the DEK is stored in the metadata of the volume itself.
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kmsTypeSecretsMetadata = "metadata"
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// metadataSecretNameKey contains the key which corresponds to the
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// kubernetes secret name from where encryptionPassphrase is feteched.
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metadataSecretNameKey = "secretName"
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// metadataSecretNamespaceKey contains the key which corresponds to the
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// kubernetes secret namespace from where encryptionPassphrase is feteched.
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metadataSecretNamespaceKey = "secretNamespace"
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)
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// secretsKMS is default KMS implementation that means no KMS is in use.
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type secretsKMS struct {
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integratedDEK
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passphrase string
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}
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var _ = RegisterProvider(Provider{
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UniqueID: DefaultKMSType,
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Initializer: newSecretsKMS,
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})
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// newSecretsKMS initializes a secretsKMS that uses the passphrase from the
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// secret that is configured for the StorageClass. This KMS provider uses a
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// single (LUKS) passhprase for all volumes.
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func newSecretsKMS(args ProviderInitArgs) (EncryptionKMS, error) {
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passphraseValue, ok := args.Secrets[encryptionPassphraseKey]
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if !ok {
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return nil, errors.New("missing encryption passphrase in secrets")
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}
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return secretsKMS{passphrase: passphraseValue}, nil
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}
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// Destroy frees all used resources.
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func (kms secretsKMS) Destroy() {
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// nothing to do
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}
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// FetchDEK returns passphrase from Kubernetes secrets.
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func (kms secretsKMS) FetchDEK(ctx context.Context, key string) (string, error) {
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return kms.passphrase, nil
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}
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// StoreDEK does nothing, as there is no passphrase per key (volume), so
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// no need to store is anywhere.
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func (kms secretsKMS) StoreDEK(ctx context.Context, key, value string) error {
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return nil
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}
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// RemoveDEK is doing nothing as no new passphrases are saved with
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// secretsKMS.
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func (kms secretsKMS) RemoveDEK(ctx context.Context, key string) error {
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return nil
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}
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// secretsMetadataKMS is a KMS based on the secretKMS, but stores the
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// Data-Encryption-Key (DEK) in the metadata of the volume.
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type secretsMetadataKMS struct {
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secretsKMS
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}
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var _ = RegisterProvider(Provider{
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UniqueID: kmsTypeSecretsMetadata,
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Initializer: initSecretsMetadataKMS,
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})
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// initSecretsMetadataKMS initializes a secretsMetadataKMS that wraps a secretKMS,
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// so that the passphrase from the user provided or StorageClass secrets can be used
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// for encrypting/decrypting DEKs that are stored in a detached DEKStore.
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func initSecretsMetadataKMS(args ProviderInitArgs) (EncryptionKMS, error) {
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var (
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smKMS secretsMetadataKMS
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encryptionPassphrase string
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ok bool
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err error
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)
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encryptionPassphrase, err = smKMS.fetchEncryptionPassphrase(
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args.Config, args.Tenant)
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if err != nil {
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if !errors.Is(err, errConfigOptionMissing) {
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return nil, err
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}
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// if 'userSecret' option is not specified, fetch encryptionPassphrase
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// from storageclass secrets.
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encryptionPassphrase, ok = args.Secrets[encryptionPassphraseKey]
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if !ok {
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return nil, fmt.Errorf(
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"missing %q in storageclass secret", encryptionPassphraseKey)
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}
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}
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smKMS.secretsKMS = secretsKMS{passphrase: encryptionPassphrase}
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return smKMS, nil
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}
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// fetchEncryptionPassphrase fetches encryptionPassphrase from user provided secret.
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func (kms secretsMetadataKMS) fetchEncryptionPassphrase(
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config map[string]interface{},
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defaultNamespace string,
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) (string, error) {
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var (
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secretName string
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secretNamespace string
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)
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err := setConfigString(&secretName, config, metadataSecretNameKey)
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if err != nil {
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return "", err
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}
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err = setConfigString(&secretNamespace, config, metadataSecretNamespaceKey)
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if err != nil {
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if !errors.Is(err, errConfigOptionMissing) {
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return "", err
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}
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// if 'secretNamespace' option is not specified, defaults to namespace in
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// which PVC was created
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secretNamespace = defaultNamespace
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}
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c, err := k8s.NewK8sClient()
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if err != nil {
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return "", fmt.Errorf("can not get Secret %s/%s, failed to "+
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"connect to Kubernetes: %w", secretNamespace, secretName, err)
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}
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secret, err := c.CoreV1().Secrets(secretNamespace).Get(context.TODO(),
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secretName, metav1.GetOptions{})
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if err != nil {
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return "", fmt.Errorf("failed to get Secret %s/%s: %w",
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secretNamespace, secretName, err)
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}
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passphraseValue, ok := secret.Data[encryptionPassphraseKey]
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if !ok {
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return "", fmt.Errorf("missing %q in Secret %s/%s",
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encryptionPassphraseKey, secretNamespace, secretName)
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}
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return string(passphraseValue), nil
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}
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// Destroy frees all used resources.
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func (kms secretsMetadataKMS) Destroy() {
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kms.secretsKMS.Destroy()
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}
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func (kms secretsMetadataKMS) RequiresDEKStore() DEKStoreType {
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return DEKStoreMetadata
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}
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// encryptedMetedataDEK contains the encrypted DEK and the Nonce that was used
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// during encryption. This structure is stored (in JSON format) in the DEKStore
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// that is linked to this KMS provider.
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type encryptedMetedataDEK struct {
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// DEK is the encrypted data-encryption-key for the volume.
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DEK []byte `json:"dek"`
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// Nonce is a random byte slice to guarantee the uniqueness of the
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// encrypted DEK.
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Nonce []byte `json:"nonce"`
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}
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// EncryptDEK encrypts the plainDEK with a key derived from the passphrase from
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// the secretsKMS and the volumeID.
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// The resulting encryptedDEK contains a JSON with the encrypted DEK and the
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// nonce that was used for encrypting.
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func (kms secretsMetadataKMS) EncryptDEK(ctx context.Context, volumeID, plainDEK string) (string, error) {
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// use the passphrase from the secretKMS
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passphrase, err := kms.secretsKMS.FetchDEK(ctx, volumeID)
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if err != nil {
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return "", fmt.Errorf("failed to get passphrase: %w", err)
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}
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aead, err := generateCipher(passphrase, volumeID)
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if err != nil {
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return "", fmt.Errorf("failed to generate cipher: %w", err)
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}
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emd := encryptedMetedataDEK{}
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emd.Nonce, err = generateNonce(aead.NonceSize())
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if err != nil {
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return "", fmt.Errorf("failed to generated nonce: %w", err)
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}
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emd.DEK = aead.Seal(nil, emd.Nonce, []byte(plainDEK), nil)
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emdData, err := json.Marshal(&emd)
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if err != nil {
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return "", fmt.Errorf("failed to convert "+
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"encryptedMetedataDEK to JSON: %w", err)
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}
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return string(emdData), nil
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}
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// DecryptDEK takes the JSON formatted `encryptedMetadataDEK` contents, and it
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// fetches secretKMS passphrase to decrypt the DEK.
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func (kms secretsMetadataKMS) DecryptDEK(ctx context.Context, volumeID, encryptedDEK string) (string, error) {
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// use the passphrase from the secretKMS
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passphrase, err := kms.secretsKMS.FetchDEK(ctx, volumeID)
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if err != nil {
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return "", fmt.Errorf("failed to get passphrase: %w", err)
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}
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aead, err := generateCipher(passphrase, volumeID)
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if err != nil {
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return "", fmt.Errorf("failed to generate cipher: %w", err)
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}
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emd := encryptedMetedataDEK{}
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err = json.Unmarshal([]byte(encryptedDEK), &emd)
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if err != nil {
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return "", fmt.Errorf("failed to convert data to "+
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"encryptedMetedataDEK: %w", err)
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}
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dek, err := aead.Open(nil, emd.Nonce, emd.DEK, nil)
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if err != nil {
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return "", fmt.Errorf("failed to decrypt DEK: %w", err)
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}
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return string(dek), nil
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}
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func (kms secretsMetadataKMS) GetSecret(ctx context.Context, volumeID string) (string, error) {
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// use the passphrase from the secretKMS
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return kms.secretsKMS.FetchDEK(ctx, volumeID)
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}
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// generateCipher returns a AEAD cipher based on a passphrase and salt
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// (volumeID). The cipher can then be used to encrypt/decrypt the DEK.
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func generateCipher(passphrase, salt string) (cipher.AEAD, error) {
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key, err := scrypt.Key([]byte(passphrase), []byte(salt), 32768, 8, 1, 32)
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if err != nil {
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return nil, err
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}
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blockCipher, err := aes.NewCipher(key)
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if err != nil {
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return nil, err
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}
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aead, err := cipher.NewGCM(blockCipher)
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if err != nil {
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return nil, err
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}
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return aead, nil
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}
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// generateNonce returns a byte slice with random contents.
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func generateNonce(size int) ([]byte, error) {
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nonce := make([]byte, size)
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if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
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return nil, err
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}
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return nonce, nil
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}
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