-
Notifications
You must be signed in to change notification settings - Fork 15
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Add support for using GCP KMS in example-gcp (#153)
- Loading branch information
Showing
4 changed files
with
204 additions
and
11 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,167 @@ | ||
| // Copyright 2024 The Tessera authors. All Rights Reserved. | ||
| // | ||
| // Licensed under the Apache License, Version 2.0 (the "License"); | ||
| // you may not use this file except in compliance with the License. | ||
| // You may obtain a copy of the License at | ||
| // | ||
| // http://www.apache.org/licenses/LICENSE-2.0 | ||
| // | ||
| // Unless required by applicable law or agreed to in writing, software | ||
| // distributed under the License is distributed on an "AS IS" BASIS, | ||
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| // See the License for the specific language governing permissions and | ||
| // limitations under the License. | ||
|
|
||
| package main | ||
|
|
||
| import ( | ||
| "context" | ||
| "crypto/ed25519" | ||
| "crypto/sha256" | ||
| "crypto/x509" | ||
| "encoding/binary" | ||
| "encoding/pem" | ||
| "errors" | ||
|
|
||
| kms "cloud.google.com/go/kms/apiv1" | ||
| "golang.org/x/mod/sumdb/note" | ||
|
|
||
| "cloud.google.com/go/kms/apiv1/kmspb" | ||
| ) | ||
|
|
||
| const ( | ||
| // KeyVersionNameFormat is the GCP resource identifier for a key version. | ||
| // google.cloud.kms.v1.CryptoKeyVersion.name | ||
| // https://cloud.google.com/php/docs/reference/cloud-kms/latest/V1.CryptoKeyVersion | ||
| KeyVersionNameFormat = "projects/%s/locations/%s/keyRings/%s/cryptoKeys/%s/cryptoKeyVersions/%d" | ||
| // From | ||
| // https://cs.opensource.google/go/x/mod/+/refs/tags/v0.12.0:sumdb/note/note.go;l=232;drc=baa5c2d058db25484c20d76985ba394e73176132 | ||
| algEd25519 = 1 | ||
| ) | ||
|
|
||
| func publicKeyFromPEM(pemKey []byte) ([]byte, error) { | ||
| block, _ := pem.Decode(pemKey) | ||
| if block == nil { | ||
| return nil, errors.New("failed to decode pemKey") | ||
| } | ||
|
|
||
| k, err := x509.ParsePKIXPublicKey(block.Bytes) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| publicKey, ok := k.(ed25519.PublicKey) | ||
| if !ok { | ||
| return nil, errors.New("failed to assert ed25519.PublicKey type") | ||
| } | ||
|
|
||
| return publicKey, nil | ||
| } | ||
|
|
||
| // keyHash calculates the ed25519 key hash from the key name and public key. | ||
| func keyHash(keyName string, publicKey []byte) (uint32, error) { | ||
| h := sha256.New() | ||
| h.Write([]byte(keyName)) | ||
| h.Write([]byte("\n")) | ||
| prefixedPublicKey := append([]byte{algEd25519}, publicKey...) | ||
| h.Write(prefixedPublicKey) | ||
| sum := h.Sum(nil) | ||
|
|
||
| return binary.BigEndian.Uint32(sum), nil | ||
| } | ||
|
|
||
| // Signer is an implementation of a | ||
| // [note signer](https://pkg.go.dev/golang.org/x/mod/sumdb/note#Signer) which | ||
| // interfaces with GCP KMS. | ||
| type Signer struct { | ||
| // ctx must be stored because Signer is used as an implementation of the | ||
| // note.Signer interface, which does not allow for a context in the Sign | ||
| // method. However, the KMS AsymmetricSign API requires a context. | ||
| ctx context.Context | ||
| client *kms.KeyManagementClient | ||
| keyHash uint32 | ||
| keyName string | ||
| kmsKeyName string | ||
| } | ||
|
|
||
| // NewKMSSigner creates a signer which uses an Ed25519 key in GCP KMS. | ||
| // See https://cloud.google.com/kms/docs/algorithms#elliptic_curve_signing_algorithms | ||
| // | ||
| // kmsKeyName is the GCP KMS name of the key to be used. | ||
| // noteKeyName is the value used as the signer name in the note signature. | ||
| func NewKMSSigner(ctx context.Context, c *kms.KeyManagementClient, kmsKeyName, noteKeyName string) (*Signer, error) { | ||
| s := &Signer{} | ||
|
|
||
| s.client = c | ||
| s.ctx = ctx | ||
| s.keyName = noteKeyName | ||
| s.kmsKeyName = kmsKeyName | ||
|
|
||
| // Set keyHash. | ||
| req := &kmspb.GetPublicKeyRequest{ | ||
| Name: kmsKeyName, | ||
| } | ||
| resp, err := c.GetPublicKey(ctx, req) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| publicKey, err := publicKeyFromPEM([]byte(resp.Pem)) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| kh, err := keyHash(s.keyName, publicKey) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| s.keyHash = kh | ||
|
|
||
| return s, nil | ||
| } | ||
|
|
||
| // Name identifies the key that this Signer uses. | ||
| func (s *Signer) Name() string { | ||
| return s.keyName | ||
| } | ||
|
|
||
| // KeyHash returns the computed key hash of the signer's public key and name. | ||
| // It is used as a hint in identifying the correct key to verify with. | ||
| func (s *Signer) KeyHash() uint32 { | ||
| return s.keyHash | ||
| } | ||
|
|
||
| // Sign returns a signature for the given message. | ||
| func (s *Signer) Sign(msg []byte) ([]byte, error) { | ||
| req := &kmspb.AsymmetricSignRequest{ | ||
| Name: s.kmsKeyName, | ||
| Data: msg, | ||
| } | ||
| resp, err := s.client.AsymmetricSign(s.ctx, req) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
|
||
| return resp.GetSignature(), nil | ||
| } | ||
|
|
||
| // VerifierKeyString returns a string which can be used to create a note | ||
| // verifier based on a GCP KMS | ||
| // [Ed25519](https://pkg.go.dev/golang.org/x/mod/sumdb/note#hdr-Generating_Keys) | ||
| // key. | ||
| func VerifierKeyString(ctx context.Context, c *kms.KeyManagementClient, kmsKeyName, noteKeyName string) (string, error) { | ||
| req := &kmspb.GetPublicKeyRequest{ | ||
| Name: kmsKeyName, | ||
| } | ||
| resp, err := c.GetPublicKey(ctx, req) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
|
|
||
| publicKey, err := publicKeyFromPEM([]byte(resp.Pem)) | ||
| if err != nil { | ||
| return "", err | ||
| } | ||
|
|
||
| return note.NewEd25519VerifierKey(noteKeyName, publicKey) | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters