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- /*
- * Copyright 2014 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
- #include "hmac_operation.h"
- #include <keymaster/new>
- #include <openssl/evp.h>
- #include <openssl/hmac.h>
- #include <keymaster/km_openssl/hmac_key.h>
- #include <keymaster/km_openssl/openssl_err.h>
- #include <keymaster/km_openssl/openssl_utils.h>
- #if defined(OPENSSL_IS_BORINGSSL)
- #include <openssl/mem.h>
- typedef size_t openssl_size_t;
- #else
- typedef int openssl_size_t;
- #endif
- namespace keymaster {
- OperationPtr HmacOperationFactory::CreateOperation(Key&& key, const AuthorizationSet& begin_params,
- keymaster_error_t* error) const {
- uint32_t min_mac_length_bits;
- if (!key.authorizations().GetTagValue(TAG_MIN_MAC_LENGTH, &min_mac_length_bits)) {
- LOG_E("HMAC key must have KM_TAG_MIN_MAC_LENGTH", 0);
- *error = KM_ERROR_INVALID_KEY_BLOB;
- return nullptr;
- }
- uint32_t mac_length_bits = UINT32_MAX;
- if (begin_params.GetTagValue(TAG_MAC_LENGTH, &mac_length_bits)) {
- if (purpose() == KM_PURPOSE_VERIFY) {
- LOG_E("MAC length may not be specified for verify", 0);
- *error = KM_ERROR_INVALID_ARGUMENT;
- return nullptr;
- }
- } else {
- if (purpose() == KM_PURPOSE_SIGN) {
- *error = KM_ERROR_MISSING_MAC_LENGTH;
- return nullptr;
- }
- }
- keymaster_digest_t digest;
- if (!key.authorizations().GetTagValue(TAG_DIGEST, &digest)) {
- LOG_E("%d digests found in HMAC key authorizations; must be exactly 1",
- begin_params.GetTagCount(TAG_DIGEST));
- *error = KM_ERROR_INVALID_KEY_BLOB;
- return nullptr;
- }
- UniquePtr<HmacOperation> op(new (std::nothrow) HmacOperation(
- move(key), purpose(), digest, mac_length_bits / 8, min_mac_length_bits / 8));
- if (!op.get())
- *error = KM_ERROR_MEMORY_ALLOCATION_FAILED;
- else
- *error = op->error();
- if (*error != KM_ERROR_OK) return nullptr;
- return move(op);
- }
- static keymaster_digest_t supported_digests[] = {KM_DIGEST_SHA1, KM_DIGEST_SHA_2_224,
- KM_DIGEST_SHA_2_256, KM_DIGEST_SHA_2_384,
- KM_DIGEST_SHA_2_512};
- const keymaster_digest_t* HmacOperationFactory::SupportedDigests(size_t* digest_count) const {
- *digest_count = array_length(supported_digests);
- return supported_digests;
- }
- HmacOperation::HmacOperation(Key&& key, keymaster_purpose_t purpose, keymaster_digest_t digest,
- size_t mac_length, size_t min_mac_length)
- : Operation(purpose, key.hw_enforced_move(), key.sw_enforced_move()), error_(KM_ERROR_OK),
- mac_length_(mac_length), min_mac_length_(min_mac_length) {
- // Initialize CTX first, so dtor won't crash even if we error out later.
- HMAC_CTX_init(&ctx_);
- const EVP_MD* md = nullptr;
- switch (digest) {
- case KM_DIGEST_NONE:
- case KM_DIGEST_MD5:
- error_ = KM_ERROR_UNSUPPORTED_DIGEST;
- break;
- case KM_DIGEST_SHA1:
- md = EVP_sha1();
- break;
- case KM_DIGEST_SHA_2_224:
- md = EVP_sha224();
- break;
- case KM_DIGEST_SHA_2_256:
- md = EVP_sha256();
- break;
- case KM_DIGEST_SHA_2_384:
- md = EVP_sha384();
- break;
- case KM_DIGEST_SHA_2_512:
- md = EVP_sha512();
- break;
- }
- if (md == nullptr) {
- error_ = KM_ERROR_UNSUPPORTED_DIGEST;
- return;
- }
- if (purpose == KM_PURPOSE_SIGN) {
- if (mac_length > EVP_MD_size(md) || mac_length < kMinHmacLengthBits / 8) {
- error_ = KM_ERROR_UNSUPPORTED_MAC_LENGTH;
- return;
- }
- if (mac_length < min_mac_length) {
- error_ = KM_ERROR_INVALID_MAC_LENGTH;
- return;
- }
- }
- KeymasterKeyBlob blob = key.key_material_move();
- HMAC_Init_ex(&ctx_, blob.key_material, blob.key_material_size, md, nullptr /* engine */);
- }
- HmacOperation::~HmacOperation() {
- HMAC_CTX_cleanup(&ctx_);
- }
- keymaster_error_t HmacOperation::Begin(const AuthorizationSet& /* input_params */,
- AuthorizationSet* /* output_params */) {
- auto rc = GenerateRandom(reinterpret_cast<uint8_t*>(&operation_handle_),
- (size_t)sizeof(operation_handle_));
- if (rc != KM_ERROR_OK) return rc;
- return error_;
- }
- keymaster_error_t HmacOperation::Update(const AuthorizationSet& /* additional_params */,
- const Buffer& input, AuthorizationSet* /* output_params */,
- Buffer* /* output */, size_t* input_consumed) {
- if (!HMAC_Update(&ctx_, input.peek_read(), input.available_read()))
- return TranslateLastOpenSslError();
- *input_consumed = input.available_read();
- return KM_ERROR_OK;
- }
- keymaster_error_t HmacOperation::Abort() {
- return KM_ERROR_OK;
- }
- keymaster_error_t HmacOperation::Finish(const AuthorizationSet& additional_params,
- const Buffer& input, const Buffer& signature,
- AuthorizationSet* /* output_params */, Buffer* output) {
- keymaster_error_t error = UpdateForFinish(additional_params, input);
- if (error != KM_ERROR_OK) return error;
- uint8_t digest[EVP_MAX_MD_SIZE];
- unsigned int digest_len;
- if (!HMAC_Final(&ctx_, digest, &digest_len)) return TranslateLastOpenSslError();
- switch (purpose()) {
- case KM_PURPOSE_SIGN:
- if (mac_length_ > digest_len) return KM_ERROR_UNSUPPORTED_MAC_LENGTH;
- if (!output->reserve(mac_length_) || !output->write(digest, mac_length_))
- return KM_ERROR_MEMORY_ALLOCATION_FAILED;
- return KM_ERROR_OK;
- case KM_PURPOSE_VERIFY: {
- size_t siglen = signature.available_read();
- if (siglen > digest_len || siglen < kMinHmacLengthBits / 8)
- return KM_ERROR_UNSUPPORTED_MAC_LENGTH;
- if (siglen < min_mac_length_) return KM_ERROR_INVALID_MAC_LENGTH;
- if (CRYPTO_memcmp(signature.peek_read(), digest, siglen) != 0)
- return KM_ERROR_VERIFICATION_FAILED;
- return KM_ERROR_OK;
- }
- default:
- return KM_ERROR_UNSUPPORTED_PURPOSE;
- }
- }
- } // namespace keymaster
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