| // 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. |
| package gcpkms |
| |
| import ( |
| "context" |
| "errors" |
| "fmt" |
| "io/ioutil" |
| "net/http" |
| "runtime" |
| "strings" |
| |
| "google.golang.org/api/cloudkms/v1" |
| "google.golang.org/api/option" |
| "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") |
| tinkUserAgent = "Tink/" + tink.Version + " Golang/" + runtime.Version() |
| ) |
| |
| // gcpClient represents a client that connects to the GCP KMS backend. |
| type gcpClient struct { |
| keyURIPrefix string |
| kms *cloudkms.Service |
| } |
| |
| var _ registry.KMSClient = (*gcpClient)(nil) |
| |
| // NewClientWithOptions returns a new GCP KMS client with provided Google API |
| // options to handle keys with uriPrefix prefix. |
| // uriPrefix must have the following format: 'gcp-kms://[:path]'. |
| func NewClientWithOptions(ctx context.Context, uriPrefix string, opts ...option.ClientOption) (registry.KMSClient, error) { |
| if !strings.HasPrefix(strings.ToLower(uriPrefix), gcpPrefix) { |
| return nil, fmt.Errorf("uriPrefix must start with %s", gcpPrefix) |
| } |
| |
| opts = append(opts, option.WithUserAgent(tinkUserAgent)) |
| kmsService, err := cloudkms.NewService(ctx, opts...) |
| if err != nil { |
| return nil, err |
| } |
| |
| return &gcpClient{ |
| keyURIPrefix: uriPrefix, |
| kms: kmsService, |
| }, nil |
| } |
| |
| // ClientConfig defines the configuration that can be provided to configure |
| // a GCP KMS client. |
| // |
| // Deprecated: Use NewClientWithOptions instead to provide client options. |
| type ClientConfig struct { |
| // HTTP transport for use with the GCP KMS client. |
| // If it is nil, default config will be used. |
| HTTPTransport *http.Transport |
| } |
| |
| // NewClientWithConfig returns a new GCP KMS client |
| // using the provided ClientConfig. |
| // It will use default credentials to handle keys with uriPrefix prefix. |
| // uriPrefix must have the following format: 'gcp-kms://[:path]'. |
| // |
| // Deprecated: Use NewClientWithOptions instead. |
| // To provide a custom HTTP client, use option.WithHTTPClient. |
| func NewClientWithConfig(uriPrefix string, config *ClientConfig) (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 |
| } |
| if config != nil && config.HTTPTransport != nil { |
| t, ok := client.Transport.(*oauth2.Transport) |
| if !ok { |
| return nil, fmt.Errorf("unable to type assert HTTP client.Transport to *oauth2.Transport, got %T", client.Transport) |
| } |
| t.Base = config.HTTPTransport |
| } |
| |
| kmsService, err := cloudkms.New(client) |
| if err != nil { |
| return nil, err |
| } |
| |
| return &gcpClient{ |
| keyURIPrefix: uriPrefix, |
| kms: kmsService, |
| }, 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]'. |
| // |
| // Deprecated: Use NewClientWithOptions instead. |
| func NewClient(uriPrefix string) (registry.KMSClient, error) { |
| return NewClientWithConfig(uriPrefix, 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]'. |
| // |
| // Deprecated: Use NewClientWithOptions instead. |
| // To provide a credential file, use option.WithCredentialsFile. |
| 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) |
| kmsService.UserAgent = tinkUserAgent |
| 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 |
| } |