2 * Copyright (C) 2016 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #ifndef ANDROID_VOLD_KEYMASTER_H
18 #define ANDROID_VOLD_KEYMASTER_H
22 #include "KeyBuffer.h"
28 #include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
29 #include <android-base/macros.h>
30 #include <keystore/authorization_set.h>
34 using ::android::hardware::keymaster::V3_0::IKeymasterDevice;
35 using ::keystore::ErrorCode;
36 using ::keystore::KeyPurpose;
37 using ::keystore::AuthorizationSet;
39 // C++ wrappers to the Keymaster hidl interface.
40 // This is tailored to the needs of KeyStorage, but could be extended to be
41 // a more general interface.
43 // Wrapper for a Keymaster operation handle representing an
44 // ongoing Keymaster operation. Aborts the operation
45 // in the destructor if it is unfinished. Methods log failures
47 class KeymasterOperation {
49 ~KeymasterOperation();
50 // Is this instance valid? This is false if creation fails, and becomes
51 // false on finish or if an update fails.
52 explicit operator bool() { return mError == ErrorCode::OK; }
53 ErrorCode errorCode() { return mError; }
54 // Call "update" repeatedly until all of the input is consumed, and
55 // concatenate the output. Return true on success.
56 template <class TI, class TO>
57 bool updateCompletely(TI& input, TO* output) {
58 if (output) output->clear();
59 return updateCompletely(input.data(), input.size(), [&](const char* b, size_t n) {
60 if (output) std::copy(b, b+n, std::back_inserter(*output));
64 // Finish and write the output to this string, unless pointer is null.
65 bool finish(std::string* output);
67 KeymasterOperation(KeymasterOperation&& rhs) {
68 mDevice = std::move(rhs.mDevice);
69 mOpHandle = std::move(rhs.mOpHandle);
70 mError = std::move(rhs.mError);
72 // Construct an object in an error state for error returns
74 : mDevice{nullptr}, mOpHandle{0},
75 mError {ErrorCode::UNKNOWN_ERROR} {}
77 KeymasterOperation& operator= (KeymasterOperation&& rhs) {
78 mDevice = std::move(rhs.mDevice);
79 mOpHandle = std::move(rhs.mOpHandle);
80 mError = std::move(rhs.mError);
81 rhs.mError = ErrorCode::UNKNOWN_ERROR;
87 KeymasterOperation(const sp<IKeymasterDevice>& d, uint64_t h)
88 : mDevice{d}, mOpHandle{h}, mError {ErrorCode::OK} {}
89 KeymasterOperation(ErrorCode error)
90 : mDevice{nullptr}, mOpHandle{0},
93 bool updateCompletely(const char* input, size_t inputLen,
94 const std::function<void(const char*, size_t)> consumer);
96 sp<IKeymasterDevice> mDevice;
99 DISALLOW_COPY_AND_ASSIGN(KeymasterOperation);
100 friend class Keymaster;
103 // Wrapper for a Keymaster device for methods that start a KeymasterOperation or are not
108 // false if we failed to open the keymaster device.
109 explicit operator bool() { return mDevice.get() != nullptr; }
110 // Generate a key in the keymaster from the given params.
111 bool generateKey(const AuthorizationSet& inParams, std::string* key);
112 // If the keymaster supports it, permanently delete a key.
113 bool deleteKey(const std::string& key);
114 // Replace stored key blob in response to KM_ERROR_KEY_REQUIRES_UPGRADE.
115 bool upgradeKey(const std::string& oldKey, const AuthorizationSet& inParams,
116 std::string* newKey);
117 // Begin a new cryptographic operation, collecting output parameters if pointer is non-null
118 KeymasterOperation begin(KeyPurpose purpose, const std::string& key,
119 const AuthorizationSet& inParams, AuthorizationSet* outParams);
123 sp<hardware::keymaster::V3_0::IKeymasterDevice> mDevice;
124 DISALLOW_COPY_AND_ASSIGN(Keymaster);
128 } // namespace android
130 #endif // __cplusplus
134 * The following functions provide C bindings to keymaster services
135 * needed by cryptfs scrypt. The compatibility check checks whether
136 * the keymaster implementation is considered secure, i.e., TEE backed.
137 * The create_key function generates an RSA key for signing.
138 * The sign_object function signes an object with the given keymaster
143 int keymaster_compatibility_cryptfs_scrypt();
144 int keymaster_create_key_for_cryptfs_scrypt(uint32_t rsa_key_size,
145 uint64_t rsa_exponent,
148 uint32_t key_buffer_size,
149 uint32_t* key_out_size);
151 int keymaster_sign_object_for_cryptfs_scrypt(const uint8_t* key_blob,
152 size_t key_blob_size,
154 const uint8_t* object,
155 const size_t object_size,
156 uint8_t** signature_buffer,
157 size_t* signature_buffer_size);