| // Copyright 2022 Google LLC |
| // |
| // 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 jwt |
| |
| import ( |
| "crypto/ecdsa" |
| "crypto/rand" |
| "errors" |
| "fmt" |
| |
| "google.golang.org/protobuf/proto" |
| "github.com/google/tink/go/core/registry" |
| "github.com/google/tink/go/keyset" |
| subtlesign "github.com/google/tink/go/signature/subtle" |
| "github.com/google/tink/go/subtle" |
| jepb "github.com/google/tink/go/proto/jwt_ecdsa_go_proto" |
| tinkpb "github.com/google/tink/go/proto/tink_go_proto" |
| ) |
| |
| const ( |
| jwtECDSASignerKeyVersion = 0 |
| jwtECDSASignerTypeURL = "type.googleapis.com/google.crypto.tink.JwtEcdsaPrivateKey" |
| ) |
| |
| var ( |
| errECDSAInvalidKey = errors.New("invalid JwtEcdsaPrivateKey key") |
| errECDSAInvalidKeyFormat = errors.New("invalid key format") |
| ) |
| |
| // jwtECDSASignerKeyManager implements the KeyManager interface |
| // for JWT Signing using the 'ES256', 'ES384', and 'ES512' JWA algorithm. |
| type jwtECDSASignerKeyManager struct{} |
| |
| var _ registry.PrivateKeyManager = (*jwtECDSASignerKeyManager)(nil) |
| |
| func (km *jwtECDSASignerKeyManager) Primitive(serializedKey []byte) (interface{}, error) { |
| if serializedKey == nil { |
| return nil, errECDSAInvalidKey |
| } |
| privKey := &jepb.JwtEcdsaPrivateKey{} |
| if err := proto.Unmarshal(serializedKey, privKey); err != nil { |
| return nil, fmt.Errorf("failed to unmarshal JwtEcdsaPrivateKey: %v", err) |
| } |
| params, err := km.validateKey(privKey) |
| if err != nil { |
| return nil, err |
| } |
| ts, err := subtlesign.NewECDSASigner(params.Hash, params.Curve, jwtECDSAEncoding, privKey.GetKeyValue()) |
| if err != nil { |
| return nil, fmt.Errorf("failed to create ECDSASigner: %v", err) |
| } |
| pubKey := privKey.GetPublicKey() |
| var kid *string = nil |
| if pubKey.GetCustomKid() != nil { |
| k := pubKey.GetCustomKid().GetValue() |
| kid = &k |
| } |
| return newSignerWithKID(ts, pubKey.GetAlgorithm().String(), kid) |
| } |
| |
| func (km *jwtECDSASignerKeyManager) NewKey(serializedKeyFormat []byte) (proto.Message, error) { |
| if serializedKeyFormat == nil { |
| return nil, errECDSAInvalidKeyFormat |
| } |
| keyFormat := &jepb.JwtEcdsaKeyFormat{} |
| if err := proto.Unmarshal(serializedKeyFormat, keyFormat); err != nil { |
| return nil, fmt.Errorf("failed to unmarshal JwtEcdsaKeyFormat: %v", err) |
| } |
| params, ok := esAlgToParams[keyFormat.GetAlgorithm()] |
| if !ok { |
| return nil, errECDSAInvalidAlgorithm |
| } |
| k, err := ecdsa.GenerateKey(subtle.GetCurve(params.Curve), rand.Reader) |
| if err != nil { |
| return nil, fmt.Errorf("failed to generate key: %v", err) |
| } |
| return &jepb.JwtEcdsaPrivateKey{ |
| Version: jwtECDSASignerKeyVersion, |
| PublicKey: &jepb.JwtEcdsaPublicKey{ |
| Version: jwtECDSASignerKeyVersion, |
| Algorithm: keyFormat.GetAlgorithm(), |
| X: k.X.Bytes(), |
| Y: k.Y.Bytes(), |
| }, |
| KeyValue: k.D.Bytes(), |
| }, nil |
| } |
| |
| func (km *jwtECDSASignerKeyManager) NewKeyData(serializedKeyFormat []byte) (*tinkpb.KeyData, error) { |
| if serializedKeyFormat == nil { |
| return nil, errECDSAInvalidKeyFormat |
| } |
| key, err := km.NewKey(serializedKeyFormat) |
| if err != nil { |
| return nil, err |
| } |
| serializedKey, err := proto.Marshal(key) |
| if err != nil { |
| return nil, fmt.Errorf("failed to marshal JwtEcdsaPrivateKey: %v", err) |
| } |
| return &tinkpb.KeyData{ |
| TypeUrl: jwtECDSASignerTypeURL, |
| Value: serializedKey, |
| KeyMaterialType: tinkpb.KeyData_ASYMMETRIC_PRIVATE, |
| }, nil |
| } |
| |
| func (km *jwtECDSASignerKeyManager) PublicKeyData(serializedPrivKey []byte) (*tinkpb.KeyData, error) { |
| if serializedPrivKey == nil { |
| return nil, errECDSAInvalidKey |
| } |
| privKey := &jepb.JwtEcdsaPrivateKey{} |
| if err := proto.Unmarshal(serializedPrivKey, privKey); err != nil { |
| return nil, fmt.Errorf("failed to unmarshal JwtEcdsaPrivateKey: %v", err) |
| } |
| serializedPubKey, err := proto.Marshal(privKey.GetPublicKey()) |
| if err != nil { |
| return nil, err |
| } |
| return &tinkpb.KeyData{ |
| TypeUrl: jwtECDSAVerifierTypeURL, |
| Value: serializedPubKey, |
| KeyMaterialType: tinkpb.KeyData_ASYMMETRIC_PUBLIC, |
| }, nil |
| } |
| |
| func (km *jwtECDSASignerKeyManager) DoesSupport(typeURL string) bool { |
| return jwtECDSASignerTypeURL == typeURL |
| } |
| |
| func (km *jwtECDSASignerKeyManager) TypeURL() string { |
| return jwtECDSASignerTypeURL |
| } |
| |
| func (km *jwtECDSASignerKeyManager) validateKey(key *jepb.JwtEcdsaPrivateKey) (ecdsaParams, error) { |
| if err := keyset.ValidateKeyVersion(key.Version, jwtECDSASignerKeyVersion); err != nil { |
| return ecdsaParams{}, fmt.Errorf("invalid key version: %v", err) |
| } |
| if key.GetPublicKey() == nil { |
| return ecdsaParams{}, fmt.Errorf("no public key in JwtEcdsaPrivateKey") |
| } |
| params, ok := esAlgToParams[key.GetPublicKey().GetAlgorithm()] |
| if !ok { |
| return ecdsaParams{}, errECDSAInvalidAlgorithm |
| } |
| return params, nil |
| } |