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_keymaster1_operation.h"
18
19 #include <memory>
20
21 #include <keymaster/android_keymaster_utils.h>
22
23 #include "openssl_err.h"
24 #include "openssl_utils.h"
25 #include "rsa_keymaster1_key.h"
26
27 using std::unique_ptr;
28
29 namespace keymaster {
30
Begin(EVP_PKEY * rsa_key,const AuthorizationSet & input_params)31 keymaster_error_t RsaKeymaster1WrappedOperation::Begin(EVP_PKEY* rsa_key,
32 const AuthorizationSet& input_params) {
33 Keymaster1Engine::KeyData* key_data = engine_->GetData(rsa_key);
34 if (!key_data)
35 return KM_ERROR_UNKNOWN_ERROR;
36
37 // Copy the input params and substitute KM_DIGEST_NONE for whatever was specified. Also change
38 // KM_PAD_RSA_PSS and KM_PAD_OAEP to KM_PAD_NONE, if necessary. These are the params we'll pass
39 // to the hardware module. The regular Rsa*Operation classes will do software digesting and
40 // padding where we've told the HW not to.
41 //
42 // The reason we don't change KM_PAD_RSA_PKCS1_1_5_SIGN or KM_PAD_RSA_PKCS1_1_5_ENCRYPT to
43 // KM_PAD_NONE is because the hardware can perform those padding modes, since they don't involve
44 // digesting.
45 //
46 // We also cache in the key the padding value that we expect to be passed to the engine crypto
47 // operation. This just allows us to double-check that the correct padding value is reaching
48 // that layer.
49 AuthorizationSet begin_params(input_params);
50 int pos = begin_params.find(TAG_DIGEST);
51 if (pos == -1)
52 return KM_ERROR_UNSUPPORTED_DIGEST;
53 begin_params[pos].enumerated = KM_DIGEST_NONE;
54
55 pos = begin_params.find(TAG_PADDING);
56 if (pos == -1)
57 return KM_ERROR_UNSUPPORTED_PADDING_MODE;
58 switch (begin_params[pos].enumerated) {
59
60 case KM_PAD_RSA_PSS:
61 case KM_PAD_RSA_OAEP:
62 key_data->expected_openssl_padding = RSA_NO_PADDING;
63 begin_params[pos].enumerated = KM_PAD_NONE;
64 break;
65
66 case KM_PAD_RSA_PKCS1_1_5_ENCRYPT:
67 case KM_PAD_RSA_PKCS1_1_5_SIGN:
68 key_data->expected_openssl_padding = RSA_PKCS1_PADDING;
69 break;
70 }
71
72 return engine_->device()->begin(engine_->device(), purpose_, &key_data->key_material,
73 &begin_params, nullptr /* out_params */, &operation_handle_);
74 }
75
76 keymaster_error_t
PrepareFinish(EVP_PKEY * rsa_key,const AuthorizationSet & input_params)77 RsaKeymaster1WrappedOperation::PrepareFinish(EVP_PKEY* rsa_key,
78 const AuthorizationSet& input_params) {
79 Keymaster1Engine::KeyData* key_data = engine_->GetData(rsa_key);
80 if (!key_data) {
81 LOG_E("Could not get extended key data... not a Keymaster1Engine key?", 0);
82 return KM_ERROR_UNKNOWN_ERROR;
83 }
84 key_data->op_handle = operation_handle_;
85 key_data->finish_params.Reinitialize(input_params);
86
87 return KM_ERROR_OK;
88 }
89
Abort()90 keymaster_error_t RsaKeymaster1WrappedOperation::Abort() {
91 return engine_->device()->abort(engine_->device(), operation_handle_);
92 }
93
GetError(EVP_PKEY * rsa_key)94 keymaster_error_t RsaKeymaster1WrappedOperation::GetError(EVP_PKEY* rsa_key) {
95 Keymaster1Engine::KeyData* key_data = engine_->GetData(rsa_key); // key_data is owned by rsa
96 if (!key_data)
97 return KM_ERROR_UNKNOWN_ERROR;
98 return key_data->error;
99 }
100
GetEvpKey(const RsaKeymaster1Key & key,keymaster_error_t * error)101 static EVP_PKEY* GetEvpKey(const RsaKeymaster1Key& key, keymaster_error_t* error) {
102 if (!key.key()) {
103 *error = KM_ERROR_UNKNOWN_ERROR;
104 return nullptr;
105 }
106
107 UniquePtr<EVP_PKEY, EVP_PKEY_Delete> pkey(EVP_PKEY_new());
108 if (!key.InternalToEvp(pkey.get())) {
109 *error = KM_ERROR_UNKNOWN_ERROR;
110 return nullptr;
111 }
112 return pkey.release();
113 }
114
CreateOperation(const Key & key,const AuthorizationSet & begin_params,keymaster_error_t * error)115 Operation* RsaKeymaster1OperationFactory::CreateOperation(const Key& key,
116 const AuthorizationSet& begin_params,
117 keymaster_error_t* error) {
118 keymaster_digest_t digest;
119 if (!GetAndValidateDigest(begin_params, key, &digest, error))
120 return nullptr;
121
122 keymaster_padding_t padding;
123 if (!GetAndValidatePadding(begin_params, key, &padding, error))
124 return nullptr;
125
126 const RsaKeymaster1Key& rsa_km1_key(static_cast<const RsaKeymaster1Key&>(key));
127 unique_ptr<EVP_PKEY, EVP_PKEY_Delete> rsa(GetEvpKey(rsa_km1_key, error));
128 if (!rsa)
129 return nullptr;
130
131 switch (purpose_) {
132 case KM_PURPOSE_SIGN:
133 return new RsaKeymaster1Operation<RsaSignOperation>(digest, padding, rsa.release(),
134 engine_);
135 case KM_PURPOSE_DECRYPT:
136 return new RsaKeymaster1Operation<RsaDecryptOperation>(digest, padding, rsa.release(),
137 engine_);
138 default:
139 LOG_E("Bug: Pubkey operation requested. Those should be handled by normal RSA operations.",
140 0);
141 *error = KM_ERROR_UNSUPPORTED_PURPOSE;
142 return nullptr;
143 }
144 }
145
146 static const keymaster_digest_t supported_digests[] = {
147 KM_DIGEST_NONE, KM_DIGEST_MD5, KM_DIGEST_SHA1, KM_DIGEST_SHA_2_224,
148 KM_DIGEST_SHA_2_256, KM_DIGEST_SHA_2_384, KM_DIGEST_SHA_2_512};
149
150 const keymaster_digest_t*
SupportedDigests(size_t * digest_count) const151 RsaKeymaster1OperationFactory::SupportedDigests(size_t* digest_count) const {
152 *digest_count = array_length(supported_digests);
153 return supported_digests;
154 }
155
156 static const keymaster_padding_t supported_sig_padding[] = {
157 KM_PAD_NONE, KM_PAD_RSA_PKCS1_1_5_SIGN, KM_PAD_RSA_PSS,
158 };
159 static const keymaster_padding_t supported_crypt_padding[] = {
160 KM_PAD_NONE, KM_PAD_RSA_PKCS1_1_5_ENCRYPT, KM_PAD_RSA_OAEP,
161 };
162
163 const keymaster_padding_t*
SupportedPaddingModes(size_t * padding_mode_count) const164 RsaKeymaster1OperationFactory::SupportedPaddingModes(size_t* padding_mode_count) const {
165 switch (purpose_) {
166 case KM_PURPOSE_SIGN:
167 case KM_PURPOSE_VERIFY:
168 *padding_mode_count = array_length(supported_sig_padding);
169 return supported_sig_padding;
170 case KM_PURPOSE_ENCRYPT:
171 case KM_PURPOSE_DECRYPT:
172 *padding_mode_count = array_length(supported_crypt_padding);
173 return supported_crypt_padding;
174 default:
175 *padding_mode_count = 0;
176 return nullptr;
177 }
178 }
179
180 } // namespace keymaster
181