blob: 6ed52766aad968e08196b31440f0f952df677bae [file] [log] [blame]
* Copyright (C) 2016 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
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* See the License for the specific language governing permissions and
* limitations under the License.
#include "KeyBuffer.h"
#include <memory>
#include <string>
#include <utility>
#include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
#include <android-base/macros.h>
#include "authorization_set.h"
namespace android {
namespace vold {
using ::android::hardware::keymaster::V3_0::IKeymasterDevice;
using ::keystore::ErrorCode;
using ::keystore::KeyPurpose;
using ::keystore::AuthorizationSet;
// C++ wrappers to the Keymaster hidl interface.
// This is tailored to the needs of KeyStorage, but could be extended to be
// a more general interface.
// Wrapper for a Keymaster operation handle representing an
// ongoing Keymaster operation. Aborts the operation
// in the destructor if it is unfinished. Methods log failures
// to LOG(ERROR).
class KeymasterOperation {
// Is this instance valid? This is false if creation fails, and becomes
// false on finish or if an update fails.
explicit operator bool() { return mError == ErrorCode::OK; }
ErrorCode errorCode() { return mError; }
// Call "update" repeatedly until all of the input is consumed, and
// concatenate the output. Return true on success.
template <class TI, class TO>
bool updateCompletely(TI& input, TO* output) {
if (output) output->clear();
return updateCompletely(, input.size(), [&](const char* b, size_t n) {
if (output) std::copy(b, b+n, std::back_inserter(*output));
// Finish and write the output to this string, unless pointer is null.
bool finish(std::string* output);
// Move constructor
KeymasterOperation(KeymasterOperation&& rhs) {
mDevice = std::move(rhs.mDevice);
mOpHandle = std::move(rhs.mOpHandle);
mError = std::move(rhs.mError);
// Construct an object in an error state for error returns
: mDevice{nullptr}, mOpHandle{0},
mError {ErrorCode::UNKNOWN_ERROR} {}
// Move Assignment
KeymasterOperation& operator= (KeymasterOperation&& rhs) {
mDevice = std::move(rhs.mDevice);
mOpHandle = std::move(rhs.mOpHandle);
mError = std::move(rhs.mError);
rhs.mError = ErrorCode::UNKNOWN_ERROR;
rhs.mOpHandle = 0;
return *this;
KeymasterOperation(const sp<IKeymasterDevice>& d, uint64_t h)
: mDevice{d}, mOpHandle{h}, mError {ErrorCode::OK} {}
KeymasterOperation(ErrorCode error)
: mDevice{nullptr}, mOpHandle{0},
mError {error} {}
bool updateCompletely(const char* input, size_t inputLen,
const std::function<void(const char*, size_t)> consumer);
sp<IKeymasterDevice> mDevice;
uint64_t mOpHandle;
ErrorCode mError;
friend class Keymaster;
// Wrapper for a Keymaster device for methods that start a KeymasterOperation or are not
// part of one.
class Keymaster {
// false if we failed to open the keymaster device.
explicit operator bool() { return mDevice.get() != nullptr; }
// Generate a key in the keymaster from the given params.
bool generateKey(const AuthorizationSet& inParams, std::string* key);
// If the keymaster supports it, permanently delete a key.
bool deleteKey(const std::string& key);
// Replace stored key blob in response to KM_ERROR_KEY_REQUIRES_UPGRADE.
bool upgradeKey(const std::string& oldKey, const AuthorizationSet& inParams,
std::string* newKey);
// Begin a new cryptographic operation, collecting output parameters if pointer is non-null
KeymasterOperation begin(KeyPurpose purpose, const std::string& key,
const AuthorizationSet& inParams, AuthorizationSet* outParams);
bool isSecure();
sp<hardware::keymaster::V3_0::IKeymasterDevice> mDevice;
} // namespace vold
} // namespace android
// FIXME no longer needed now cryptfs is in C++.
* The following functions provide C bindings to keymaster services
* needed by cryptfs scrypt. The compatibility check checks whether
* the keymaster implementation is considered secure, i.e., TEE backed.
* The create_key function generates an RSA key for signing.
* The sign_object function signes an object with the given keymaster
* key.
/* Return values for keymaster_sign_object_for_cryptfs_scrypt */
enum class KeymasterSignResult {
ok = 0,
error = -1,
upgrade = -2,
int keymaster_compatibility_cryptfs_scrypt();
int keymaster_create_key_for_cryptfs_scrypt(uint32_t rsa_key_size,
uint64_t rsa_exponent,
uint32_t ratelimit,
uint8_t* key_buffer,
uint32_t key_buffer_size,
uint32_t* key_out_size);
int keymaster_upgrade_key_for_cryptfs_scrypt(uint32_t rsa_key_size, uint64_t rsa_exponent,
uint32_t ratelimit, const uint8_t* key_blob,
size_t key_blob_size, uint8_t* key_buffer,
uint32_t key_buffer_size, uint32_t* key_out_size);
KeymasterSignResult keymaster_sign_object_for_cryptfs_scrypt(
const uint8_t* key_blob, size_t key_blob_size, uint32_t ratelimit, const uint8_t* object,
const size_t object_size, uint8_t** signature_buffer, size_t* signature_buffer_size);