| // Copyright 2017 Google Inc. |
| // |
| // 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 gcpkms provides integration with the GCP Cloud KMS. |
| // Tink APIs work with GCP and AWS KMS. |
| // GCP Example below: |
| // |
| // package main |
| // |
| // import ( |
| // "github.com/google/tink/go/aead" |
| // "github.com/google/tink/go/core/registry" |
| // "github.com/google/tink/go/integration/gcpkms" |
| // "github.com/google/tink/go/keyset" |
| // ) |
| // |
| // const ( |
| // keyURI = "gcp-kms://......" |
| // ) |
| // |
| // func main() { |
| // gcpclient, err := gcpkms.NewClientWithCredentials(keyURI, "/mysecurestorage/credentials.json") |
| // if err != nil { |
| // //handle error |
| // } |
| // registry.RegisterKMSClient(gcpclient) |
| // |
| // dek := aead.AES128CTRHMACSHA256KeyTemplate() |
| // kh, err := keyset.NewHandle(aead.KMSEnvelopeAEADKeyTemplate(keyURI, dek)) |
| // if err != nil { |
| // // handle error |
| // } |
| // a, err := aead.New(kh) |
| // if err != nil { |
| // // handle error |
| // } |
| // |
| // ct, err = a.Encrypt([]byte("secret message"), []byte("associated data")) |
| // if err != nil { |
| // // handle error |
| // } |
| // |
| // pt, err = a.Decrypt(ct, []byte("associated data")) |
| // if err != nil { |
| // // handle error |
| // } |
| // } |
| |
| package gcpkms |
| |
| import ( |
| "context" |
| "errors" |
| "fmt" |
| "io/ioutil" |
| "strings" |
| |
| "google.golang.org/api/cloudkms/v1" |
| "golang.org/x/oauth2/google" |
| "golang.org/x/oauth2" |
| "github.com/google/tink/go/core/registry" |
| "github.com/google/tink/go/tink" |
| ) |
| |
| const ( |
| gcpPrefix = "gcp-kms://" |
| ) |
| |
| var ( |
| errCred = errors.New("invalid credential path") |
| ) |
| |
| // gcpClient represents a client that connects to the GCP KMS backend. |
| type gcpClient struct { |
| keyURIPrefix string |
| kms *cloudkms.Service |
| } |
| |
| var _ registry.KMSClient = (*gcpClient)(nil) |
| |
| // NewClient returns a new GCP KMS client which will use default |
| // credentials to handle keys with uriPrefix prefix. |
| // uriPrefix must have the following format: 'gcp-kms://[:path]'. |
| func NewClient(uriPrefix string) (registry.KMSClient, error) { |
| if !strings.HasPrefix(strings.ToLower(uriPrefix), gcpPrefix) { |
| return nil, fmt.Errorf("uriPrefix must start with %s", gcpPrefix) |
| } |
| |
| ctx := context.Background() |
| client, err := google.DefaultClient(ctx, cloudkms.CloudPlatformScope) |
| if err != nil { |
| return nil, err |
| } |
| |
| kmsService, err := cloudkms.New(client) |
| if err != nil { |
| return nil, err |
| } |
| |
| return &gcpClient{ |
| keyURIPrefix: uriPrefix, |
| kms: kmsService, |
| }, nil |
| } |
| |
| // NewClientWithCredentials returns a new GCP KMS client which will use given |
| // credentials to handle keys with uriPrefix prefix. |
| // uriPrefix must have the following format: 'gcp-kms://[:path]'. |
| func NewClientWithCredentials(uriPrefix string, credentialPath string) (registry.KMSClient, error) { |
| if !strings.HasPrefix(strings.ToLower(uriPrefix), gcpPrefix) { |
| return nil, fmt.Errorf("uriPrefix must start with %s", gcpPrefix) |
| } |
| |
| ctx := context.Background() |
| if len(credentialPath) <= 0 { |
| return nil, errCred |
| } |
| data, err := ioutil.ReadFile(credentialPath) |
| if err != nil { |
| return nil, errCred |
| } |
| creds, err := google.CredentialsFromJSON(ctx, data, "https://www.googleapis.com/auth/cloudkms") |
| if err != nil { |
| return nil, errCred |
| } |
| client := oauth2.NewClient(ctx, creds.TokenSource) |
| kmsService, err := cloudkms.New(client) |
| if err != nil { |
| return nil, err |
| } |
| |
| return &gcpClient{ |
| keyURIPrefix: uriPrefix, |
| kms: kmsService, |
| }, nil |
| } |
| |
| // Supported true if this client does support keyURI |
| func (c *gcpClient) Supported(keyURI string) bool { |
| return strings.HasPrefix(keyURI, c.keyURIPrefix) |
| } |
| |
| // GetAEAD gets an AEAD backend by keyURI. |
| func (c *gcpClient) GetAEAD(keyURI string) (tink.AEAD, error) { |
| if !c.Supported(keyURI) { |
| return nil, errors.New("unsupported keyURI") |
| } |
| |
| uri := strings.TrimPrefix(keyURI, gcpPrefix) |
| return newGCPAEAD(uri, c.kms), nil |
| } |