1 /*
2 * Copyright 2014 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 <openssl/bn.h>
18
19 #include "dsa_operation.h"
20 #include "openssl_utils.h"
21
22 namespace keymaster {
23
~DsaOperation()24 DsaOperation::~DsaOperation() {
25 if (dsa_key_ != NULL)
26 DSA_free(dsa_key_);
27 }
28
Update(const Buffer & input,Buffer *)29 keymaster_error_t DsaOperation::Update(const Buffer& input, Buffer* /* output */) {
30 switch (purpose()) {
31 default:
32 return KM_ERROR_UNIMPLEMENTED;
33 case KM_PURPOSE_SIGN:
34 case KM_PURPOSE_VERIFY:
35 return StoreData(input);
36 }
37 }
38
StoreData(const Buffer & input)39 keymaster_error_t DsaOperation::StoreData(const Buffer& input) {
40 if (!data_.reserve(data_.available_read() + input.available_read()) ||
41 !data_.write(input.peek_read(), input.available_read()))
42 return KM_ERROR_INVALID_INPUT_LENGTH;
43 return KM_ERROR_OK;
44 }
45
Finish(const Buffer &,Buffer * output)46 keymaster_error_t DsaSignOperation::Finish(const Buffer& /* signature */, Buffer* output) {
47 output->Reinitialize(DSA_size(dsa_key_));
48 unsigned int siglen;
49 if (!DSA_sign(0 /* type -- ignored */, data_.peek_read(), data_.available_read(),
50 output->peek_write(), &siglen, dsa_key_))
51 return KM_ERROR_UNKNOWN_ERROR;
52 output->advance_write(siglen);
53 return KM_ERROR_OK;
54 }
55
Finish(const Buffer & signature,Buffer *)56 keymaster_error_t DsaVerifyOperation::Finish(const Buffer& signature, Buffer* /* output */) {
57 if ((int)data_.available_read() != DSA_size(dsa_key_))
58 return KM_ERROR_INVALID_INPUT_LENGTH;
59
60 int result = DSA_verify(0 /* type -- ignored */, data_.peek_read(), data_.available_read(),
61 signature.peek_read(), signature.available_read(), dsa_key_);
62 if (result < 0)
63 return KM_ERROR_UNKNOWN_ERROR;
64 else if (result == 0)
65 return KM_ERROR_VERIFICATION_FAILED;
66 else
67 return KM_ERROR_OK;
68 }
69
70 } // namespace keymaster
71