| /* |
| * 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) { |
| 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 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, NULL /* 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 |