internal async Task <(DataEncryptionKeyProperties, InMemoryRawDek)> FetchUnwrappedAsync(
string id,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
try
{
DataEncryptionKeyProperties dekProperties = await this.DekProvider.DekCache.GetOrAddDekPropertiesAsync(
id,
this.ReadResourceAsync,
diagnosticsContext,
cancellationToken);
InMemoryRawDek inMemoryRawDek = await this.DekProvider.DekCache.GetOrAddRawDekAsync(
dekProperties,
this.UnwrapAsync,
diagnosticsContext,
cancellationToken);
return(dekProperties, inMemoryRawDek);
}
catch (CosmosException exception)
{
throw EncryptionExceptionFactory.EncryptionKeyNotFoundException(
$"Failed to retrieve Data Encryption Key with id: '{id}'.",
exception);
}
}
internal async Task <(byte[], EncryptionKeyWrapMetadata, InMemoryRawDek)> WrapAsync(
string id,
byte[] key,
string encryptionAlgorithm,
EncryptionKeyWrapMetadata metadata,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
EncryptionKeyWrapResult keyWrapResponse;
using (diagnosticsContext.CreateScope("WrapDataEncryptionKey"))
{
keyWrapResponse = await this.DekProvider.EncryptionKeyWrapProvider.WrapKeyAsync(key, metadata, cancellationToken);
}
// Verify
DataEncryptionKeyProperties tempDekProperties = new DataEncryptionKeyProperties(id, encryptionAlgorithm, keyWrapResponse.WrappedDataEncryptionKey, keyWrapResponse.EncryptionKeyWrapMetadata, DateTime.UtcNow);
InMemoryRawDek roundTripResponse = await this.UnwrapAsync(tempDekProperties, diagnosticsContext, cancellationToken);
if (!roundTripResponse.DataEncryptionKey.RawKey.SequenceEqual(key))
{
throw new InvalidOperationException("The key wrapping provider configured was unable to unwrap the wrapped key correctly.");
}
return(keyWrapResponse.WrappedDataEncryptionKey, keyWrapResponse.EncryptionKeyWrapMetadata, roundTripResponse);
}
public CachedDekProperties(
DataEncryptionKeyProperties serverProperties,
DateTime serverPropertiesExpiryUtc)
{
Debug.Assert(serverProperties != null);
this.ServerProperties = serverProperties;
this.ServerPropertiesExpiryUtc = serverPropertiesExpiryUtc;
}
private async Task <CachedDekProperties> FetchAsync(
string dekId,
Func <string, CosmosDiagnosticsContext, CancellationToken, Task <DataEncryptionKeyProperties> > fetcher,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
DataEncryptionKeyProperties serverProperties = await fetcher(dekId, diagnosticsContext, cancellationToken);
return(new CachedDekProperties(serverProperties, DateTime.UtcNow + this.dekPropertiesTimeToLive));
}
/// <inheritdoc/>
public override async Task <ItemResponse <DataEncryptionKeyProperties> > RewrapDataEncryptionKeyAsync(
string id,
EncryptionKeyWrapMetadata newWrapMetadata,
ItemRequestOptions requestOptions = null,
CancellationToken cancellationToken = default)
{
if (newWrapMetadata == null)
{
throw new ArgumentNullException(nameof(newWrapMetadata));
}
CosmosDiagnosticsContext diagnosticsContext = CosmosDiagnosticsContext.Create(requestOptions);
(DataEncryptionKeyProperties dekProperties, InMemoryRawDek inMemoryRawDek) = await this.FetchUnwrappedAsync(
id,
diagnosticsContext,
cancellationToken);
(byte[] wrappedDek, EncryptionKeyWrapMetadata updatedMetadata, InMemoryRawDek updatedRawDek) = await this.WrapAsync(
id,
inMemoryRawDek.DataEncryptionKey.RawKey,
dekProperties.EncryptionAlgorithm,
newWrapMetadata,
diagnosticsContext,
cancellationToken);
if (requestOptions == null)
{
requestOptions = new ItemRequestOptions();
}
requestOptions.IfMatchEtag = dekProperties.ETag;
DataEncryptionKeyProperties newDekProperties = new DataEncryptionKeyProperties(dekProperties)
{
WrappedDataEncryptionKey = wrappedDek,
EncryptionKeyWrapMetadata = updatedMetadata,
};
ItemResponse <DataEncryptionKeyProperties> response = await this.DekProvider.Container.ReplaceItemAsync(
newDekProperties,
newDekProperties.Id,
new PartitionKey(newDekProperties.Id),
requestOptions,
cancellationToken);
Debug.Assert(response.Resource != null);
this.DekProvider.DekCache.SetDekProperties(id, response.Resource);
this.DekProvider.DekCache.SetRawDek(id, updatedRawDek);
return(response);
}
internal async Task <InMemoryRawDek> UnwrapAsync(
DataEncryptionKeyProperties dekProperties,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
EncryptionKeyUnwrapResult unwrapResult;
using (diagnosticsContext.CreateScope("UnwrapDataEncryptionKey"))
{
unwrapResult = await this.DekProvider.EncryptionKeyWrapProvider.UnwrapKeyAsync(
dekProperties.WrappedDataEncryptionKey,
dekProperties.EncryptionKeyWrapMetadata,
cancellationToken);
}
DataEncryptionKey dek = DataEncryptionKey.Create(unwrapResult.DataEncryptionKey, dekProperties.EncryptionAlgorithm);
return(new InMemoryRawDek(dek, unwrapResult.ClientCacheTimeToLive));
}
internal async Task <(DataEncryptionKeyProperties, InMemoryRawDek)> FetchUnwrappedAsync(
string id,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
DataEncryptionKeyProperties dekProperties = await this.DekProvider.DekCache.GetOrAddDekPropertiesAsync(
id,
this.ReadResourceAsync,
diagnosticsContext,
cancellationToken);
InMemoryRawDek inMemoryRawDek = await this.DekProvider.DekCache.GetOrAddRawDekAsync(
dekProperties,
this.UnwrapAsync,
diagnosticsContext,
cancellationToken);
return(dekProperties, inMemoryRawDek);
}
public override async Task <ItemResponse <DataEncryptionKeyProperties> > CreateDataEncryptionKeyAsync(
string id,
string encryptionAlgorithm,
EncryptionKeyWrapMetadata encryptionKeyWrapMetadata,
ItemRequestOptions requestOptions = null,
CancellationToken cancellationToken = default)
{
if (string.IsNullOrEmpty(id))
{
throw new ArgumentNullException(nameof(id));
}
if (encryptionAlgorithm != CosmosEncryptionAlgorithm.AEAes256CbcHmacSha256Randomized)
{
throw new ArgumentException(string.Format("Unsupported Encryption Algorithm {0}", encryptionAlgorithm), nameof(encryptionAlgorithm));
}
if (encryptionKeyWrapMetadata == null)
{
throw new ArgumentNullException(nameof(encryptionKeyWrapMetadata));
}
CosmosDiagnosticsContext diagnosticsContext = CosmosDiagnosticsContext.Create(requestOptions);
byte[] rawDek = DataEncryptionKey.Generate(encryptionAlgorithm);
(byte[] wrappedDek, EncryptionKeyWrapMetadata updatedMetadata, InMemoryRawDek inMemoryRawDek) = await this.WrapAsync(
id,
rawDek,
encryptionAlgorithm,
encryptionKeyWrapMetadata,
diagnosticsContext,
cancellationToken);
DataEncryptionKeyProperties dekProperties = new DataEncryptionKeyProperties(id, encryptionAlgorithm, wrappedDek, updatedMetadata, DateTime.UtcNow);
ItemResponse <DataEncryptionKeyProperties> dekResponse = await this.DekProvider.Container.CreateItemAsync(dekProperties, new PartitionKey(dekProperties.Id), cancellationToken : cancellationToken);
this.DekProvider.DekCache.SetDekProperties(id, dekResponse.Resource);
this.DekProvider.DekCache.SetRawDek(id, inMemoryRawDek);
return(dekResponse);
}
public async Task <InMemoryRawDek> GetOrAddRawDekAsync(
DataEncryptionKeyProperties dekProperties,
Func <DataEncryptionKeyProperties, CosmosDiagnosticsContext, CancellationToken, Task <InMemoryRawDek> > unwrapper,
CosmosDiagnosticsContext diagnosticsContext,
CancellationToken cancellationToken)
{
InMemoryRawDek inMemoryRawDek = await this.RawDekCache.GetAsync(
dekProperties.SelfLink,
null,
() => unwrapper(dekProperties, diagnosticsContext, cancellationToken),
cancellationToken);
if (inMemoryRawDek.RawDekExpiry <= DateTime.UtcNow)
{
inMemoryRawDek = await this.RawDekCache.GetAsync(
dekProperties.SelfLink,
null,
() => unwrapper(dekProperties, diagnosticsContext, cancellationToken),
cancellationToken,
forceRefresh : true);
}
return(inMemoryRawDek);
}
public void SetDekProperties(string dekId, DataEncryptionKeyProperties dekProperties)
{
CachedDekProperties cachedDekProperties = new CachedDekProperties(dekProperties, DateTime.UtcNow + this.dekPropertiesTimeToLive);
this.DekPropertiesCache.Set(dekId, cachedDekProperties);
}
/// <inheritdoc/>
public override async Task <ItemResponse <DataEncryptionKeyProperties> > RewrapDataEncryptionKeyAsync(
string id,
EncryptionKeyWrapMetadata newWrapMetadata,
ItemRequestOptions requestOptions = null,
CancellationToken cancellationToken = default)
{
if (newWrapMetadata == null)
{
throw new ArgumentNullException(nameof(newWrapMetadata));
}
CosmosDiagnosticsContext diagnosticsContext = CosmosDiagnosticsContext.Create(requestOptions);
(DataEncryptionKeyProperties dekProperties, InMemoryRawDek inMemoryRawDek) = await this.FetchUnwrappedAsync(
id,
diagnosticsContext,
cancellationToken);
(byte[] wrappedDek, EncryptionKeyWrapMetadata updatedMetadata, InMemoryRawDek updatedRawDek) = await this.WrapAsync(
id,
inMemoryRawDek.DataEncryptionKey.RawKey,
dekProperties.EncryptionAlgorithm,
newWrapMetadata,
diagnosticsContext,
cancellationToken);
if (requestOptions == null)
{
requestOptions = new ItemRequestOptions();
}
requestOptions.IfMatchEtag = dekProperties.ETag;
DataEncryptionKeyProperties newDekProperties = new DataEncryptionKeyProperties(dekProperties)
{
WrappedDataEncryptionKey = wrappedDek,
EncryptionKeyWrapMetadata = updatedMetadata,
};
ItemResponse <DataEncryptionKeyProperties> response;
try
{
response = await this.DekProvider.Container.ReplaceItemAsync(
newDekProperties,
newDekProperties.Id,
new PartitionKey(newDekProperties.Id),
requestOptions,
cancellationToken);
Debug.Assert(response.Resource != null);
}
catch (CosmosException ex)
{
if (!ex.StatusCode.Equals(HttpStatusCode.PreconditionFailed))
{
throw;
}
// Handle if exception is due to etag mismatch. The scenario is as follows - say there are 2 clients A and B that both have the DEK properties cached.
// From A, rewrap worked and the DEK is updated. Now from B, rewrap was attempted later based on the cached properties which will fail due to etag mismatch.
// To address this, we do an explicit read, which reads the key from storage and updates the cached properties; and then attempt rewrap again.
await this.ReadDataEncryptionKeyAsync(
newDekProperties.Id,
requestOptions,
cancellationToken);
return(await this.RewrapDataEncryptionKeyAsync(
id,
newWrapMetadata,
requestOptions,
cancellationToken));
}
this.DekProvider.DekCache.SetDekProperties(id, response.Resource);
this.DekProvider.DekCache.SetRawDek(id, updatedRawDek);
return(response);
}
