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https://github.com/edgelesssys/constellation.git
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0e71322e2e
Recovery (disk-mapper) and init (bootstrapper) will have to work with multiple external KMSes in the future.
106 lines
3.6 KiB
Go
106 lines
3.6 KiB
Go
/*
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Copyright (c) Edgeless Systems GmbH
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SPDX-License-Identifier: AGPL-3.0-only
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*/
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package storage
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import (
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"bytes"
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"context"
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"fmt"
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"io"
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"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob"
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"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/blob"
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"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/bloberror"
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"github.com/Azure/azure-sdk-for-go/sdk/storage/azblob/container"
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"github.com/edgelesssys/constellation/v2/internal/kms/config"
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)
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type azureBlobAPI interface {
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CreateContainer(context.Context, string, *container.CreateOptions) (azblob.CreateContainerResponse, error)
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DownloadStream(context.Context, string, string, *blob.DownloadStreamOptions) (azblob.DownloadStreamResponse, error)
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UploadStream(context.Context, string, string, io.Reader, *azblob.UploadStreamOptions) (azblob.UploadStreamResponse, error)
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}
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// AzureStorage is an implementation of the Storage interface, storing keys in the Azure Blob Store.
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type AzureStorage struct {
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client azureBlobAPI
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connectionString string
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containerName string
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opts *AzureOpts
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}
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// AzureOpts are additional options to be used when interacting with the Azure API.
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type AzureOpts struct {
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service *azblob.ClientOptions
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download *azblob.DownloadStreamOptions
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upload *azblob.UploadStreamOptions
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}
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// NewAzureStorage initializes a storage client using Azure's Blob Storage: https://azure.microsoft.com/en-us/services/storage/blobs/
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//
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// A connections string is required to connect to the Storage Account, see https://docs.microsoft.com/en-us/azure/storage/common/storage-configure-connection-string
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// If the container does not exists, a new one is created automatically.
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// Connect options for the Client, Downloader and Uploader can be configured using opts.
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func NewAzureStorage(ctx context.Context, connectionString, containerName string, opts *AzureOpts) (*AzureStorage, error) {
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if opts == nil {
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opts = &AzureOpts{}
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}
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client, err := azblob.NewClientFromConnectionString(connectionString, opts.service)
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if err != nil {
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return nil, fmt.Errorf("creating storage client from connection string: %w", err)
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}
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s := &AzureStorage{
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client: client,
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connectionString: connectionString,
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containerName: containerName,
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opts: opts,
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}
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// Try to create a new storage container, continue if it already exists
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if err := s.createContainerOrContinue(ctx); err != nil {
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return nil, err
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}
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return s, nil
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}
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// Get returns a DEK from from Azure Blob Storage by key ID.
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func (s *AzureStorage) Get(ctx context.Context, keyID string) ([]byte, error) {
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res, err := s.client.DownloadStream(ctx, s.containerName, keyID, s.opts.download)
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if err != nil {
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if bloberror.HasCode(err, bloberror.BlobNotFound) {
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return nil, ErrDEKUnset
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}
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return nil, fmt.Errorf("downloading DEK from storage: %w", err)
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}
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defer res.Body.Close()
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return io.ReadAll(res.Body)
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}
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// Put saves a DEK to Azure Blob Storage by key ID.
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func (s *AzureStorage) Put(ctx context.Context, keyID string, encDEK []byte) error {
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if _, err := s.client.UploadStream(ctx, s.containerName, keyID, bytes.NewReader(encDEK), s.opts.upload); err != nil {
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return fmt.Errorf("uploading DEK to storage: %w", err)
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}
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return nil
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}
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// createContainerOrContinue creates a new storage container if necessary, or continues if it already exists.
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func (s *AzureStorage) createContainerOrContinue(ctx context.Context) error {
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_, err := s.client.CreateContainer(ctx, s.containerName, &azblob.CreateContainerOptions{
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Metadata: config.StorageTags,
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})
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if (err == nil) || bloberror.HasCode(err, bloberror.ContainerAlreadyExists) {
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return nil
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}
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return fmt.Errorf("creating storage container: %w", err)
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}
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