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/*
* Copyright 2014 The Android Open Source Project
*
* 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.
*/
#include <keymaster/android_keymaster.h>
#include <assert.h>
#include <string.h>
#include <cstddef>
#include <openssl/rand.h>
#include <openssl/x509.h>
#include <UniquePtr.h>
#include <keymaster/android_keymaster_utils.h>
#include <keymaster/key_factory.h>
#include <keymaster/keymaster_context.h>
#include "ae.h"
#include "key.h"
#include "openssl_err.h"
#include "operation.h"
#include "operation_table.h"
namespace keymaster {
const uint8_t MAJOR_VER = 1;
const uint8_t MINOR_VER = 1;
const uint8_t SUBMINOR_VER = 0;
AndroidKeymaster::AndroidKeymaster(KeymasterContext* context, size_t operation_table_size)
: context_(context), operation_table_(new OperationTable(operation_table_size)) {
}
AndroidKeymaster::~AndroidKeymaster() {
}
struct AE_CTX_Delete {
void operator()(ae_ctx* ctx) const { ae_free(ctx); }
};
typedef UniquePtr<ae_ctx, AE_CTX_Delete> Unique_ae_ctx;
// TODO(swillden): Unify support analysis. Right now, we have per-keytype methods that determine if
// specific modes, padding, etc. are supported for that key type, and AndroidKeymaster also has
// methods that return the same information. They'll get out of sync. Best to put the knowledge in
// the keytypes and provide some mechanism for AndroidKeymaster to query the keytypes for the
// information.
template <typename T>
bool check_supported(const KeymasterContext& context, keymaster_algorithm_t algorithm,
SupportedResponse<T>* response) {
if (context.GetKeyFactory(algorithm) == NULL) {
response->error = KM_ERROR_UNSUPPORTED_ALGORITHM;
return false;
}
return true;
}
void AndroidKeymaster::GetVersion(const GetVersionRequest&, GetVersionResponse* rsp) {
if (rsp == NULL)
return;
rsp->major_ver = MAJOR_VER;
rsp->minor_ver = MINOR_VER;
rsp->subminor_ver = SUBMINOR_VER;
rsp->error = KM_ERROR_OK;
}
void AndroidKeymaster::SupportedAlgorithms(const SupportedAlgorithmsRequest& /* request */,
SupportedAlgorithmsResponse* response) {
if (response == NULL)
return;
response->error = KM_ERROR_OK;
size_t algorithm_count = 0;
const keymaster_algorithm_t* algorithms = context_->GetSupportedAlgorithms(&algorithm_count);
if (algorithm_count == 0)
return;
response->results_length = algorithm_count;
response->results = dup_array(algorithms, algorithm_count);
if (!response->results)
response->error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
}
template <typename T>
void GetSupported(const KeymasterContext& context, keymaster_algorithm_t algorithm,
keymaster_purpose_t purpose,
const T* (OperationFactory::*get_supported_method)(size_t* count) const,
SupportedResponse<T>* response) {
if (response == NULL || !check_supported(context, algorithm, response))
return;
const OperationFactory* factory = context.GetOperationFactory(algorithm, purpose);
if (!factory) {
response->error = KM_ERROR_UNSUPPORTED_PURPOSE;
return;
}
size_t count;
const T* supported = (factory->*get_supported_method)(&count);
response->SetResults(supported, count);
}
void AndroidKeymaster::SupportedBlockModes(const SupportedBlockModesRequest& request,
SupportedBlockModesResponse* response) {
GetSupported(*context_, request.algorithm, request.purpose,
&OperationFactory::SupportedBlockModes, response);
}
void AndroidKeymaster::SupportedPaddingModes(const SupportedPaddingModesRequest& request,
SupportedPaddingModesResponse* response) {
GetSupported(*context_, request.algorithm, request.purpose,
&OperationFactory::SupportedPaddingModes, response);
}
void AndroidKeymaster::SupportedDigests(const SupportedDigestsRequest& request,
SupportedDigestsResponse* response) {
GetSupported(*context_, request.algorithm, request.purpose, &OperationFactory::SupportedDigests,
response);
}
void AndroidKeymaster::SupportedImportFormats(const SupportedImportFormatsRequest& request,
SupportedImportFormatsResponse* response) {
if (response == NULL || !check_supported(*context_, request.algorithm, response))
return;
size_t count;
const keymaster_key_format_t* formats =
context_->GetKeyFactory(request.algorithm)->SupportedImportFormats(&count);
response->SetResults(formats, count);
}
void AndroidKeymaster::SupportedExportFormats(const SupportedExportFormatsRequest& request,
SupportedExportFormatsResponse* response) {
if (response == NULL || !check_supported(*context_, request.algorithm, response))
return;
size_t count;
const keymaster_key_format_t* formats =
context_->GetKeyFactory(request.algorithm)->SupportedExportFormats(&count);
response->SetResults(formats, count);
}
void AndroidKeymaster::AddRngEntropy(const AddEntropyRequest& request,
AddEntropyResponse* response) {
response->error = context_->AddRngEntropy(request.random_data.peek_read(),
request.random_data.available_read());
}
void AndroidKeymaster::GenerateKey(const GenerateKeyRequest& request,
GenerateKeyResponse* response) {
if (response == NULL)
return;
keymaster_algorithm_t algorithm;
KeyFactory* factory = 0;
UniquePtr<Key> key;
if (!request.key_description.GetTagValue(TAG_ALGORITHM, &algorithm) ||
!(factory = context_->GetKeyFactory(algorithm)))
response->error = KM_ERROR_UNSUPPORTED_ALGORITHM;
else {
KeymasterKeyBlob key_blob;
response->enforced.Clear();
response->unenforced.Clear();
response->error = factory->GenerateKey(request.key_description, &key_blob,
&response->enforced, &response->unenforced);
if (response->error == KM_ERROR_OK)
response->key_blob = key_blob.release();
}
}
void AndroidKeymaster::GetKeyCharacteristics(const GetKeyCharacteristicsRequest& request,
GetKeyCharacteristicsResponse* response) {
if (response == NULL)
return;
KeymasterKeyBlob key_material;
response->error =
context_->ParseKeyBlob(KeymasterKeyBlob(request.key_blob), request.additional_params,
&key_material, &response->enforced, &response->unenforced);
if (response->error != KM_ERROR_OK)
return;
}
static KeyFactory* GetKeyFactory(const KeymasterContext& context,
const AuthorizationSet& hw_enforced,
const AuthorizationSet& sw_enforced,
keymaster_algorithm_t* algorithm, keymaster_error_t* error) {
*error = KM_ERROR_UNSUPPORTED_ALGORITHM;
if (!hw_enforced.GetTagValue(TAG_ALGORITHM, algorithm) &&
!sw_enforced.GetTagValue(TAG_ALGORITHM, algorithm))
return nullptr;
KeyFactory* factory = context.GetKeyFactory(*algorithm);
if (factory)
*error = KM_ERROR_OK;
return factory;
}
void AndroidKeymaster::BeginOperation(const BeginOperationRequest& request,
BeginOperationResponse* response) {
if (response == NULL)
return;
response->op_handle = 0;
AuthorizationSet hw_enforced;
AuthorizationSet sw_enforced;
const KeyFactory* key_factory;
UniquePtr<Key> key;
response->error = LoadKey(request.key_blob, request.additional_params, &hw_enforced,
&sw_enforced, &key_factory, &key);
if (response->error != KM_ERROR_OK)
return;
// TODO(swillden): Move this check to a general authorization checker.
// TODO(swillden): Consider introducing error codes for unauthorized usages.
response->error = KM_ERROR_INCOMPATIBLE_PURPOSE;
if (!hw_enforced.Contains(TAG_PURPOSE, request.purpose) &&
!sw_enforced.Contains(TAG_PURPOSE, request.purpose))
return;
response->error = KM_ERROR_UNSUPPORTED_PURPOSE;
OperationFactory* factory = key_factory->GetOperationFactory(request.purpose);
if (!factory)
return;
UniquePtr<Operation> operation(
factory->CreateOperation(*key, request.additional_params, &response->error));
if (operation.get() == NULL)
return;
response->output_params.Clear();
response->error = operation->Begin(request.additional_params, &response->output_params);
if (response->error != KM_ERROR_OK)
return;
response->error = operation_table_->Add(operation.release(), &response->op_handle);
}
void AndroidKeymaster::UpdateOperation(const UpdateOperationRequest& request,
UpdateOperationResponse* response) {
if (response == NULL)
return;
response->error = KM_ERROR_INVALID_OPERATION_HANDLE;
Operation* operation = operation_table_->Find(request.op_handle);
if (operation == NULL)
return;
response->error =
operation->Update(request.additional_params, request.input, &response->output_params,
&response->output, &response->input_consumed);
if (response->error != KM_ERROR_OK) {
// Any error invalidates the operation.
operation_table_->Delete(request.op_handle);
}
}
void AndroidKeymaster::FinishOperation(const FinishOperationRequest& request,
FinishOperationResponse* response) {
if (response == NULL)
return;
response->error = KM_ERROR_INVALID_OPERATION_HANDLE;
Operation* operation = operation_table_->Find(request.op_handle);
if (operation == NULL)
return;
response->error = operation->Finish(request.additional_params, request.signature,
&response->output_params, &response->output);
operation_table_->Delete(request.op_handle);
}
void AndroidKeymaster::AbortOperation(const AbortOperationRequest& request,
AbortOperationResponse* response) {
if (!response)
return;
Operation* operation = operation_table_->Find(request.op_handle);
if (!operation) {
response->error = KM_ERROR_INVALID_OPERATION_HANDLE;
return;
}
response->error = operation->Abort();
operation_table_->Delete(request.op_handle);
}
void AndroidKeymaster::ExportKey(const ExportKeyRequest& request, ExportKeyResponse* response) {
if (response == NULL)
return;
AuthorizationSet hw_enforced;
AuthorizationSet sw_enforced;
KeymasterKeyBlob key_material;
response->error =
context_->ParseKeyBlob(KeymasterKeyBlob(request.key_blob), request.additional_params,
&key_material, &hw_enforced, &sw_enforced);
if (response->error != KM_ERROR_OK)
return;
keymaster_algorithm_t algorithm;
KeyFactory* key_factory =
GetKeyFactory(*context_, hw_enforced, sw_enforced, &algorithm, &response->error);
if (!key_factory)
return;
UniquePtr<Key> key;
response->error = key_factory->LoadKey(key_material, hw_enforced, sw_enforced, &key);
if (response->error != KM_ERROR_OK)
return;
UniquePtr<uint8_t[]> out_key;
size_t size;
response->error = key->formatted_key_material(request.key_format, &out_key, &size);
if (response->error == KM_ERROR_OK) {
response->key_data = out_key.release();
response->key_data_length = size;
}
}
void AndroidKeymaster::ImportKey(const ImportKeyRequest& request, ImportKeyResponse* response) {
if (response == NULL)
return;
keymaster_algorithm_t algorithm;
KeyFactory* factory = 0;
UniquePtr<Key> key;
if (!request.key_description.GetTagValue(TAG_ALGORITHM, &algorithm) ||
!(factory = context_->GetKeyFactory(algorithm)))
response->error = KM_ERROR_UNSUPPORTED_ALGORITHM;
else {
keymaster_key_blob_t key_material = {request.key_data, request.key_data_length};
KeymasterKeyBlob key_blob;
response->error = factory->ImportKey(request.key_description, request.key_format,
KeymasterKeyBlob(key_material), &key_blob,
&response->enforced, &response->unenforced);
if (response->error == KM_ERROR_OK)
response->key_blob = key_blob.release();
}
}
void AndroidKeymaster::DeleteKey(const DeleteKeyRequest& request, DeleteKeyResponse* response) {
if (!response)
return;
response->error = context_->DeleteKey(KeymasterKeyBlob(request.key_blob));
}
void AndroidKeymaster::DeleteAllKeys(const DeleteAllKeysRequest&, DeleteAllKeysResponse* response) {
if (!response)
return;
response->error = context_->DeleteAllKeys();
}
keymaster_error_t AndroidKeymaster::LoadKey(const keymaster_key_blob_t& key_blob,
const AuthorizationSet& additional_params,
AuthorizationSet* hw_enforced,
AuthorizationSet* sw_enforced,
const KeyFactory** factory, UniquePtr<Key>* key) {
KeymasterKeyBlob key_material;
keymaster_error_t error = context_->ParseKeyBlob(KeymasterKeyBlob(key_blob), additional_params,
&key_material, hw_enforced, sw_enforced);
if (error != KM_ERROR_OK)
return error;
keymaster_algorithm_t algorithm;
*factory = GetKeyFactory(*context_, *hw_enforced, *sw_enforced, &algorithm, &error);
if (error != KM_ERROR_OK)
return error;
return (*factory)->LoadKey(key_material, *hw_enforced, *sw_enforced, key);
}
} // namespace keymaster