rsa_keymaster0_key.cpp revision 34f09c52b08e654b8b76d9796240a5104c13a4a8 
1/*
2 * Copyright 2015 The Android Open Source Project
3 *
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
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
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.
15 */
16
17#include "rsa_keymaster0_key.h"
18
19#include <memory>
20
21#define LOG_TAG "RsaKeymaster0Key"
22#include <cutils/log.h>
23
24#include <keymaster/android_keymaster_utils.h>
25#include <keymaster/logger.h>
26#include <keymaster/soft_keymaster_context.h>
27
28#include "keymaster0_engine.h"
29#include "openssl_utils.h"
30
31using std::unique_ptr;
32
33namespace keymaster {
34
35RsaKeymaster0KeyFactory::RsaKeymaster0KeyFactory(const SoftKeymasterContext* context,
36                                                 const Keymaster0Engine* engine)
37    : RsaKeyFactory(context), engine_(engine), soft_context_(context) {}
38
39keymaster_error_t RsaKeymaster0KeyFactory::GenerateKey(const AuthorizationSet& key_description,
40                                                       KeymasterKeyBlob* key_blob,
41                                                       AuthorizationSet* hw_enforced,
42                                                       AuthorizationSet* sw_enforced) const {
43    if (!key_blob || !hw_enforced || !sw_enforced)
44        return KM_ERROR_OUTPUT_PARAMETER_NULL;
45
46    if (!engine_)
47        return super::GenerateKey(key_description, key_blob, hw_enforced, sw_enforced);
48
49    uint64_t public_exponent;
50    if (!key_description.GetTagValue(TAG_RSA_PUBLIC_EXPONENT, &public_exponent)) {
51        LOG_E("%s", "No public exponent specified for RSA key generation");
52        return KM_ERROR_INVALID_ARGUMENT;
53    }
54
55    uint32_t key_size;
56    if (!key_description.GetTagValue(TAG_KEY_SIZE, &key_size)) {
57        LOG_E("%s", "No key size specified for RSA key generation");
58        return KM_ERROR_UNSUPPORTED_KEY_SIZE;
59    }
60
61    KeymasterKeyBlob key_material;
62    if (!engine_->GenerateRsaKey(public_exponent, key_size, &key_material))
63        return KM_ERROR_UNKNOWN_ERROR;
64
65    // These tags are hardware-enforced.  Putting them in the hw_enforced set here will ensure that
66    // context_->CreateKeyBlob doesn't put them in sw_enforced.
67    hw_enforced->push_back(TAG_ALGORITHM, KM_ALGORITHM_RSA);
68    hw_enforced->push_back(TAG_RSA_PUBLIC_EXPONENT, public_exponent);
69    hw_enforced->push_back(TAG_KEY_SIZE, key_size);
70    hw_enforced->push_back(TAG_ORIGIN, KM_ORIGIN_UNKNOWN);
71
72    return context_->CreateKeyBlob(key_description, KM_ORIGIN_UNKNOWN, key_material, key_blob,
73                                   hw_enforced, sw_enforced);
74}
75
76keymaster_error_t RsaKeymaster0KeyFactory::ImportKey(
77    const AuthorizationSet& key_description, keymaster_key_format_t input_key_material_format,
78    const KeymasterKeyBlob& input_key_material, KeymasterKeyBlob* output_key_blob,
79    AuthorizationSet* hw_enforced, AuthorizationSet* sw_enforced) const {
80    if (!output_key_blob || !hw_enforced || !sw_enforced)
81        return KM_ERROR_OUTPUT_PARAMETER_NULL;
82
83    if (!engine_)
84        return super::ImportKey(key_description, input_key_material_format, input_key_material,
85                                output_key_blob, hw_enforced, sw_enforced);
86
87    AuthorizationSet authorizations;
88    uint64_t public_exponent;
89    uint32_t key_size;
90    keymaster_error_t error =
91        UpdateImportKeyDescription(key_description, input_key_material_format, input_key_material,
92                                   &authorizations, &public_exponent, &key_size);
93    if (error != KM_ERROR_OK)
94        return error;
95
96    KeymasterKeyBlob imported_hw_key;
97    if (!engine_->ImportKey(input_key_material_format, input_key_material, &imported_hw_key))
98        return KM_ERROR_UNKNOWN_ERROR;
99
100    // These tags are hardware-enforced.  Putting them in the hw_enforced set here will ensure that
101    // context_->CreateKeyBlob doesn't put them in sw_enforced.
102    hw_enforced->push_back(TAG_ALGORITHM, KM_ALGORITHM_RSA);
103    hw_enforced->push_back(TAG_RSA_PUBLIC_EXPONENT, public_exponent);
104    hw_enforced->push_back(TAG_KEY_SIZE, key_size);
105    hw_enforced->push_back(TAG_ORIGIN, KM_ORIGIN_UNKNOWN);
106
107    return context_->CreateKeyBlob(authorizations, KM_ORIGIN_UNKNOWN, imported_hw_key,
108                                   output_key_blob, hw_enforced, sw_enforced);
109}
110
111keymaster_error_t RsaKeymaster0KeyFactory::LoadKey(const KeymasterKeyBlob& key_material,
112                                                   const AuthorizationSet& hw_enforced,
113                                                   const AuthorizationSet& sw_enforced,
114                                                   UniquePtr<Key>* key) const {
115    if (!key)
116        return KM_ERROR_OUTPUT_PARAMETER_NULL;
117
118    if (sw_enforced.GetTagCount(TAG_ALGORITHM) == 1)
119        return super::LoadKey(key_material, hw_enforced, sw_enforced, key);
120
121    unique_ptr<RSA, RSA_Delete> rsa(engine_->BlobToRsaKey(key_material));
122    if (!rsa)
123        return KM_ERROR_UNKNOWN_ERROR;
124
125    keymaster_error_t error;
126    key->reset(new (std::nothrow)
127                   RsaKeymaster0Key(rsa.release(), hw_enforced, sw_enforced, engine_, &error));
128    if (!key->get())
129        error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
130
131    if (error != KM_ERROR_OK)
132        return error;
133
134    return KM_ERROR_OK;
135}
136
137RsaKeymaster0Key::RsaKeymaster0Key(RSA* rsa_key, const AuthorizationSet& hw_enforced,
138                                   const AuthorizationSet& sw_enforced,
139                                   const Keymaster0Engine* engine, keymaster_error_t* error)
140    : RsaKey(rsa_key, hw_enforced, sw_enforced, error), engine_(engine) {}
141
142keymaster_error_t RsaKeymaster0Key::key_material(UniquePtr<uint8_t[]>* material,
143                                                 size_t* size) const {
144    if (!engine_)
145        return super::key_material(material, size);
146
147    const keymaster_key_blob_t* blob = engine_->RsaKeyToBlob(key());
148    if (!blob)
149        return KM_ERROR_UNKNOWN_ERROR;
150
151    *size = blob->key_material_size;
152    material->reset(dup_buffer(blob->key_material, *size));
153    if (!material->get())
154        return KM_ERROR_MEMORY_ALLOCATION_FAILED;
155    return KM_ERROR_OK;
156}
157
158}  // namespace keymaster
159