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Shawn Willden0d560bf2014-12-15 17:44:02 -07001/*
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 "hmac_operation.h"
18
19#include <openssl/evp.h>
20#include <openssl/hmac.h>
21
Shawn Willden567a4a02014-12-31 12:14:46 -070022#include "openssl_err.h"
Shawn Willden63ac0432014-12-29 14:07:08 -070023#include "symmetric_key.h"
24
Shawn Willdend79791b2015-05-09 12:48:36 +000025#if defined(OPENSSL_IS_BORINGSSL)
Adam Langleyc3326552015-04-28 13:20:52 -070026#include <openssl/mem.h>
Shawn Willdend79791b2015-05-09 12:48:36 +000027typedef size_t openssl_size_t;
28#else
29typedef int openssl_size_t;
30#endif
31
Shawn Willden0d560bf2014-12-15 17:44:02 -070032namespace keymaster {
33
Shawn Willden3ed6d062015-04-15 13:39:38 -060034Operation* HmacOperationFactory::CreateOperation(const Key& key,
Shawn Willden09f25272015-04-15 13:49:49 -060035 const AuthorizationSet& begin_params,
Shawn Willden3ed6d062015-04-15 13:39:38 -060036 keymaster_error_t* error) {
Shawn Willden09f25272015-04-15 13:49:49 -060037 uint32_t tag_length = 0;
38 begin_params.GetTagValue(TAG_MAC_LENGTH, &tag_length);
Shawn Willden0c60f6f2015-04-27 23:40:10 -060039 if (tag_length % 8 != 0) {
40 LOG_E("MAC length %d nod a multiple of 8 bits", tag_length);
41 *error = KM_ERROR_UNSUPPORTED_MAC_LENGTH;
42 return nullptr;
43 }
Shawn Willden63ac0432014-12-29 14:07:08 -070044
Shawn Willden226746b2015-05-08 11:36:56 -060045 keymaster_digest_t digest;
46 if (!begin_params.GetTagValue(TAG_DIGEST, &digest)) {
47 LOG_E("%d digests specified in begin params", begin_params.GetTagCount(TAG_DIGEST));
48 *error = KM_ERROR_UNSUPPORTED_DIGEST;
49 return nullptr;
50 } else if (!key.authorizations().Contains(TAG_DIGEST, digest)) {
51 LOG_E("Digest %d was specified, but not authorized by key", digest);
52 *error = KM_ERROR_INCOMPATIBLE_DIGEST;
53 return nullptr;
54 }
Shawn Willden63ac0432014-12-29 14:07:08 -070055
56 const SymmetricKey* symmetric_key = static_cast<const SymmetricKey*>(&key);
Shawn Willden0c60f6f2015-04-27 23:40:10 -060057 UniquePtr<HmacOperation> op(new HmacOperation(purpose(), symmetric_key->key_data(),
58 symmetric_key->key_data_size(), digest,
59 tag_length / 8));
Shawn Willden09f25272015-04-15 13:49:49 -060060 if (!op.get())
Shawn Willden63ac0432014-12-29 14:07:08 -070061 *error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
Shawn Willden09f25272015-04-15 13:49:49 -060062 else
63 *error = op->error();
64
65 if (*error != KM_ERROR_OK)
66 return nullptr;
67
68 return op.release();
Shawn Willden63ac0432014-12-29 14:07:08 -070069}
70
71static keymaster_digest_t supported_digests[] = {KM_DIGEST_SHA1, KM_DIGEST_SHA_2_224,
72 KM_DIGEST_SHA_2_256, KM_DIGEST_SHA_2_384,
73 KM_DIGEST_SHA_2_512};
74const keymaster_digest_t* HmacOperationFactory::SupportedDigests(size_t* digest_count) const {
75 *digest_count = array_length(supported_digests);
76 return supported_digests;
77}
78
Shawn Willden567a4a02014-12-31 12:14:46 -070079HmacOperation::HmacOperation(keymaster_purpose_t purpose, const uint8_t* key_data,
80 size_t key_data_size, keymaster_digest_t digest, size_t tag_length)
81 : Operation(purpose), error_(KM_ERROR_OK), tag_length_(tag_length) {
Shawn Willden0d560bf2014-12-15 17:44:02 -070082 // Initialize CTX first, so dtor won't crash even if we error out later.
83 HMAC_CTX_init(&ctx_);
84
Shawn Willden09f25272015-04-15 13:49:49 -060085 const EVP_MD* md = nullptr;
Shawn Willden0d560bf2014-12-15 17:44:02 -070086 switch (digest) {
Shawn Willden09f25272015-04-15 13:49:49 -060087 case KM_DIGEST_NONE:
88 case KM_DIGEST_MD5:
89 error_ = KM_ERROR_UNSUPPORTED_DIGEST;
90 break;
Shawn Willden51d5e0e2014-12-18 10:44:03 -070091 case KM_DIGEST_SHA1:
92 md = EVP_sha1();
93 break;
Shawn Willden62c22862014-12-17 08:36:20 -070094 case KM_DIGEST_SHA_2_224:
95 md = EVP_sha224();
96 break;
Shawn Willden0d560bf2014-12-15 17:44:02 -070097 case KM_DIGEST_SHA_2_256:
98 md = EVP_sha256();
99 break;
Shawn Willden62c22862014-12-17 08:36:20 -0700100 case KM_DIGEST_SHA_2_384:
101 md = EVP_sha384();
102 break;
103 case KM_DIGEST_SHA_2_512:
104 md = EVP_sha512();
105 break;
Shawn Willden0d560bf2014-12-15 17:44:02 -0700106 }
107
Shawn Willden09f25272015-04-15 13:49:49 -0600108 if (md == nullptr) {
109 error_ = KM_ERROR_UNSUPPORTED_DIGEST;
Shawn Willden0d560bf2014-12-15 17:44:02 -0700110 return;
111 }
112
113 HMAC_Init_ex(&ctx_, key_data, key_data_size, md, NULL /* engine */);
114}
115
116HmacOperation::~HmacOperation() {
117 HMAC_CTX_cleanup(&ctx_);
118}
119
Shawn Willden111edb32015-02-05 22:44:24 -0700120keymaster_error_t HmacOperation::Begin(const AuthorizationSet& /* input_params */,
121 AuthorizationSet* /* output_params */) {
Shawn Willden0d560bf2014-12-15 17:44:02 -0700122 return error_;
123}
124
Shawn Willden6bfbff02015-02-06 19:48:24 -0700125keymaster_error_t HmacOperation::Update(const AuthorizationSet& /* additional_params */,
Shawn Willdended8e7d2015-06-01 15:29:12 -0600126 const Buffer& input, AuthorizationSet* /* output_params */,
127 Buffer* /* output */, size_t* input_consumed) {
Shawn Willden0d560bf2014-12-15 17:44:02 -0700128 if (!HMAC_Update(&ctx_, input.peek_read(), input.available_read()))
Shawn Willden567a4a02014-12-31 12:14:46 -0700129 return TranslateLastOpenSslError();
Shawn Willden0d560bf2014-12-15 17:44:02 -0700130 *input_consumed = input.available_read();
131 return KM_ERROR_OK;
132}
133
134keymaster_error_t HmacOperation::Abort() {
135 return KM_ERROR_OK;
136}
137
Shawn Willden6bfbff02015-02-06 19:48:24 -0700138keymaster_error_t HmacOperation::Finish(const AuthorizationSet& /* additional_params */,
Shawn Willdended8e7d2015-06-01 15:29:12 -0600139 const Buffer& signature,
140 AuthorizationSet* /* output_params */, Buffer* output) {
Shawn Willden0d560bf2014-12-15 17:44:02 -0700141 uint8_t digest[EVP_MAX_MD_SIZE];
142 unsigned int digest_len;
143 if (!HMAC_Final(&ctx_, digest, &digest_len))
Shawn Willden567a4a02014-12-31 12:14:46 -0700144 return TranslateLastOpenSslError();
Shawn Willden0d560bf2014-12-15 17:44:02 -0700145
146 switch (purpose()) {
147 case KM_PURPOSE_SIGN:
Shawn Willden09f25272015-04-15 13:49:49 -0600148 if (tag_length_ > digest_len)
149 return KM_ERROR_UNSUPPORTED_MAC_LENGTH;
150 if (!output->reserve(tag_length_) || !output->write(digest, tag_length_))
151 return KM_ERROR_MEMORY_ALLOCATION_FAILED;
Shawn Willden0d560bf2014-12-15 17:44:02 -0700152 return KM_ERROR_OK;
153 case KM_PURPOSE_VERIFY:
Shawn Willden09f25272015-04-15 13:49:49 -0600154 if (signature.available_read() > digest_len)
Shawn Willden0d560bf2014-12-15 17:44:02 -0700155 return KM_ERROR_INVALID_INPUT_LENGTH;
Shawn Willden09f25272015-04-15 13:49:49 -0600156 if (CRYPTO_memcmp(signature.peek_read(), digest, signature.available_read()) != 0)
Shawn Willden0d560bf2014-12-15 17:44:02 -0700157 return KM_ERROR_VERIFICATION_FAILED;
158 return KM_ERROR_OK;
159 default:
160 return KM_ERROR_UNSUPPORTED_PURPOSE;
161 }
162}
163
164} // namespace keymaster