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feat:(kms) encrypt data with DEK using AES-GCM instead of AES-CBC

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Signed-off-by: Anish Ramasekar <anish.ramasekar@gmail.com>
This commit is contained in:
Anish Ramasekar 2022-07-13 17:14:50 +00:00
parent 12004ea53d
commit d54631a41a
No known key found for this signature in database
GPG Key ID: F1F7F3518F1ECB0C
3 changed files with 57 additions and 57 deletions
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6
staging/src/k8s.io/apiserver/pkg/server/options/encryptionconfig/config.go
View File

@ -369,8 +369,10 @@ func secretboxPrefixTransformer(config *apiserverconfig.SecretboxConfiguration)
func envelopePrefixTransformer(config *apiserverconfig.KMSConfiguration, envelopeService envelope.Service, prefix string) (value.PrefixTransformer, error) {
baseTransformerFunc := func(block cipher.Block) value.Transformer {
// v1.24: write using AES-CBC only but support reads via AES-CBC and AES-GCM (so we can move to AES-GCM)
// TODO(aramase): swap this ordering in v1.25
return unionTransformers{aestransformer.NewCBCTransformer(block), aestransformer.NewGCMTransformer(block)}
// v1.25: write using AES-GCM only but support reads via AES-GCM and fallback to AES-CBC for backwards compatibility
// TODO(aramase): Post v1.25: We cannot drop CBC read support until we automate storage migration.
// We could have a release note that hard requires users to perform storage migration.
return unionTransformers{aestransformer.NewGCMTransformer(block), aestransformer.NewCBCTransformer(block)}
}
envelopeTransformer, err := envelope.NewEnvelopeTransformer(envelopeService, int(*config.CacheSize), baseTransformerFunc)

98
test/integration/controlplane/transformation/kms_transformation_test.go
View File

@ -25,7 +25,6 @@ import (
"crypto/aes"
"encoding/base64"
"encoding/binary"
"errors"
"fmt"
"net/http"
"strings"
@ -87,10 +86,10 @@ func (r envelope) plainTextPayload(secretETCDPath string) ([]byte, error) {
// etcd path of the key is used as the authenticated context - need to pass it to decrypt
ctx := context.Background()
dataCtx := value.DefaultContext([]byte(secretETCDPath))
aescbcTransformer := aestransformer.NewCBCTransformer(block)
plainSecret, _, err := aescbcTransformer.TransformFromStorage(ctx, r.cipherTextPayload(), dataCtx)
aesgcmTransformer := aestransformer.NewGCMTransformer(block)
plainSecret, _, err := aesgcmTransformer.TransformFromStorage(ctx, r.cipherTextPayload(), dataCtx)
if err != nil {
return nil, fmt.Errorf("failed to transform from storage via AESCBC, err: %w", err)
return nil, fmt.Errorf("failed to transform from storage via AESGCM, err: %w", err)
}
return plainSecret, nil
@ -103,10 +102,10 @@ func (r envelope) plainTextPayload(secretETCDPath string) ([]byte, error) {
// 3. KMS gRPC Plugin should encrypt the DEK with a Key Encryption Key (KEK) and pass it back to envelopeTransformer
// 4. The cipherTextPayload (ex. Secret) should be encrypted via AES CBC transform
// 5. Prefix-EncryptedDEK-EncryptedPayload structure should be deposited to ETCD
// 6. Direct AES CBC decryption of the cipherTextPayload written with AES GCM transform does not work
// 7. AES GCM secrets should be un-enveloped on direct reads from Kube API Server
// 8. No-op updates to the secret should cause new AES CBC key to be used
// 9. Direct AES CBC decryption works after the new AES CBC key is used
// 6. Direct AES GCM decryption of the cipherTextPayload written with AES CBC transform does not work
// 7. Existing AES CBC secrets should be un-enveloped on direct reads from Kube API Server
// 8. No-op updates to the secret should cause new AES GCM key to be used
// 9. Direct AES GCM decryption works after the new AES GCM key is used
func TestKMSProvider(t *testing.T) {
encryptionConfig := `
kind: EncryptionConfiguration
@ -194,90 +193,89 @@ resources:
t.Fatalf("expected %s from KubeAPI, but got %s", secretVal, string(s.Data[secretKey]))
}
// write data using AES GCM to simulate a downgrade
futureSecretBytes, err := base64.StdEncoding.DecodeString(futureSecret)
// write data using AES CBC to simulate a downgrade
oldSecretBytes, err := base64.StdEncoding.DecodeString(oldSecret)
if err != nil {
t.Fatalf("failed to base64 decode future secret, err: %v", err)
t.Fatalf("failed to base64 decode old secret, err: %v", err)
}
futureKeyBytes, err := base64.StdEncoding.DecodeString(futureAESGCMKey)
oldKeyBytes, err := base64.StdEncoding.DecodeString(oldAESCBCKey)
if err != nil {
t.Fatalf("failed to base64 decode future key, err: %v", err)
t.Fatalf("failed to base64 decode old key, err: %v", err)
}
block, err := aes.NewCipher(futureKeyBytes)
block, err := aes.NewCipher(oldKeyBytes)
if err != nil {
t.Fatalf("invalid key, err: %v", err)
}
// we cannot precompute this because the authenticated data changes per run
futureEncryptedSecretBytes, err := aestransformer.NewGCMTransformer(block).TransformToStorage(ctx, futureSecretBytes, value.DefaultContext(secretETCDPath))
oldEncryptedSecretBytes, err := aestransformer.NewCBCTransformer(block).TransformToStorage(ctx, oldSecretBytes, value.DefaultContext(secretETCDPath))
if err != nil {
t.Fatalf("failed to encrypt future secret, err: %v", err)
t.Fatalf("failed to encrypt old secret, err: %v", err)
}
futureEncryptedSecretBuf := cryptobyte.NewBuilder(nil)
futureEncryptedSecretBuf.AddBytes([]byte(wantPrefix))
futureEncryptedSecretBuf.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes([]byte(futureAESGCMKey))
oldEncryptedSecretBuf := cryptobyte.NewBuilder(nil)
oldEncryptedSecretBuf.AddBytes([]byte(wantPrefix))
oldEncryptedSecretBuf.AddUint16LengthPrefixed(func(b *cryptobyte.Builder) {
b.AddBytes([]byte(oldAESCBCKey))
})
futureEncryptedSecretBuf.AddBytes(futureEncryptedSecretBytes)
oldEncryptedSecretBuf.AddBytes(oldEncryptedSecretBytes)
_, err = test.writeRawRecordToETCD(secretETCDPath, futureEncryptedSecretBuf.BytesOrPanic())
_, err = test.writeRawRecordToETCD(secretETCDPath, oldEncryptedSecretBuf.BytesOrPanic())
if err != nil {
t.Fatalf("failed to write future encrypted secret, err: %v", err)
t.Fatalf("failed to write old encrypted secret, err: %v", err)
}
// confirm that direct AES CBC decryption does not work
// confirm that direct AES GCM decryption does not work
failingRawEnvelope, err := test.getRawSecretFromETCD()
if err != nil {
t.Fatalf("failed to read %s from etcd: %v", secretETCDPath, err)
}
failingFutureEnvelope := envelope{
failingOldEnvelope := envelope{
providerName: providerName,
rawEnvelope: failingRawEnvelope,
plainTextDEK: futureKeyBytes,
plainTextDEK: oldKeyBytes,
}
failingFuturePlainSecret, err := failingFutureEnvelope.plainTextPayload(secretETCDPath)
if err == nil || !errors.Is(err, aestransformer.ErrInvalidBlockSize) {
t.Fatalf("AESCBC decryption failure not seen, err: %v, data: %s", err, string(failingFuturePlainSecret))
failingOldPlainSecret, err := failingOldEnvelope.plainTextPayload(secretETCDPath)
if err == nil {
t.Fatalf("AESGCM decryption failure not seen, data: %s", string(failingOldPlainSecret))
}
// AES GCM secrets should be un-enveloped on direct reads from Kube API Server.
futureSecretObj, err := secretClient.Get(ctx, testSecret, metav1.GetOptions{})
// Existing AES CBC secrets should be un-enveloped on direct reads from Kube API Server.
oldSecretObj, err := secretClient.Get(ctx, testSecret, metav1.GetOptions{})
if err != nil {
t.Fatalf("failed to read future secret via Kube API, err: %v", err)
t.Fatalf("failed to read old secret via Kube API, err: %v", err)
}
if futureSecretVal != string(futureSecretObj.Data[secretKey]) {
t.Fatalf("expected %s from KubeAPI, but got %s", futureSecretVal, string(futureSecretObj.Data[secretKey]))
if oldSecretVal != string(oldSecretObj.Data[secretKey]) {
t.Fatalf("expected %s from KubeAPI, but got %s", oldSecretVal, string(oldSecretObj.Data[secretKey]))
}
// no-op update should cause new AES CBC key to be used
futureSecretUpdated, err := secretClient.Update(ctx, futureSecretObj, metav1.UpdateOptions{})
// no-op update should cause new AES GCM key to be used
oldSecretUpdated, err := secretClient.Update(ctx, oldSecretObj, metav1.UpdateOptions{})
if err != nil {
t.Fatalf("failed to update future secret via Kube API, err: %v", err)
t.Fatalf("failed to update old secret via Kube API, err: %v", err)
}
if futureSecretObj.ResourceVersion == futureSecretUpdated.ResourceVersion {
t.Fatalf("future secret not updated on no-op write: %s", futureSecretObj.ResourceVersion)
if oldSecretObj.ResourceVersion == oldSecretUpdated.ResourceVersion {
t.Fatalf("old secret not updated on no-op write: %s", oldSecretObj.ResourceVersion)
}
// confirm that direct AES CBC decryption works
futureRawEnvelope, err := test.getRawSecretFromETCD()
// confirm that direct AES GCM decryption works
oldRawEnvelope, err := test.getRawSecretFromETCD()
if err != nil {
t.Fatalf("failed to read %s from etcd: %v", secretETCDPath, err)
}
futureEnvelope := envelope{
oldEnvelope := envelope{
providerName: providerName,
rawEnvelope: futureRawEnvelope,
rawEnvelope: oldRawEnvelope,
plainTextDEK: pluginMock.LastEncryptRequest(),
}
if !bytes.HasPrefix(futureRawEnvelope, []byte(wantPrefix)) {
t.Fatalf("expected secret to be prefixed with %s, but got %s", wantPrefix, futureRawEnvelope)
if !bytes.HasPrefix(oldRawEnvelope, []byte(wantPrefix)) {
t.Fatalf("expected secret to be prefixed with %s, but got %s", wantPrefix, oldRawEnvelope)
}
futurePlainSecret, err := futureEnvelope.plainTextPayload(secretETCDPath)
oldPlainSecret, err := oldEnvelope.plainTextPayload(secretETCDPath)
if err != nil {
t.Fatalf("failed to transform from storage via AESCBC, err: %v", err)
t.Fatalf("failed to transform from storage via AESGCM, err: %v", err)
}
if !strings.Contains(string(futurePlainSecret), futureSecretVal) {
t.Fatalf("expected %q after decryption, but got %q", futureSecretVal, string(futurePlainSecret))
if !strings.Contains(string(oldPlainSecret), oldSecretVal) {
t.Fatalf("expected %q after decryption, but got %q", oldSecretVal, string(oldPlainSecret))
}
}

10
test/integration/controlplane/transformation/transformation_testcase.go
View File

@ -51,11 +51,11 @@ const (
testSecret = "test-secret"
metricsPrefix = "apiserver_storage_"
// precomputed key and secret for use with AES GCM
// this looks exactly the same as the AES CBC secret but with a different value
futureAESGCMKey = "e0/+tts8FS254BZimFZWtUsOCOUDSkvzB72PyimMlkY="
futureSecret = "azhzAAoMCgJ2MRIGU2VjcmV0En4KXwoLdGVzdC1zZWNyZXQSABoWc2VjcmV0LWVuY3J5cHRpb24tdGVzdCIAKiQ3MmRmZTVjNC0xNDU2LTQyMzktYjFlZC1hZGZmYTJmMWY3YmEyADgAQggI5Jy/7wUQAHoAEhMKB2FwaV9rZXkSCPCfpJfwn5C8GgZPcGFxdWUaACIA"
futureSecretVal = "\xf0\x9f\xa4\x97\xf0\x9f\x90\xbc"
// precomputed key and secret for use with AES CBC
// this looks exactly the same as the AES GCM secret but with a different value
oldAESCBCKey = "e0/+tts8FS254BZimFZWtUsOCOUDSkvzB72PyimMlkY="
oldSecret = "azhzAAoMCgJ2MRIGU2VjcmV0En4KXwoLdGVzdC1zZWNyZXQSABoWc2VjcmV0LWVuY3J5cHRpb24tdGVzdCIAKiQ3MmRmZTVjNC0xNDU2LTQyMzktYjFlZC1hZGZmYTJmMWY3YmEyADgAQggI5Jy/7wUQAHoAEhMKB2FwaV9rZXkSCPCfpJfwn5C8GgZPcGFxdWUaACIA"
oldSecretVal = "\xf0\x9f\xa4\x97\xf0\x9f\x90\xbc"
)
type unSealSecret func(ctx context.Context, cipherText []byte, dataCtx value.Context, config apiserverconfigv1.ProviderConfiguration) ([]byte, error)