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/*
* Copyright 2021 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 "cppbor.h"
#include "keymaster/cppcose/cppcose.h"
#include <aidl/android/hardware/security/keymint/RpcHardwareInfo.h>
#include <android-base/properties.h>
#include <cppbor_parse.h>
#include <cstdint>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <keymaster/android_keymaster_utils.h>
#include <keymaster/logger.h>
#include <keymaster/remote_provisioning_utils.h>
#include <openssl/curve25519.h>
#include <remote_prov/remote_prov_utils.h>
namespace aidl::android::hardware::security::keymint::remote_prov {
namespace {
using ::keymaster::KeymasterBlob;
using ::keymaster::kStatusFailed;
using ::keymaster::kStatusInvalidEek;
using ::keymaster::StatusOr;
using ::testing::ElementsAreArray;
using byte_view = std::basic_string_view<uint8_t>;
struct KeyInfoEcdsa {
CoseKeyCurve curve;
byte_view pubKeyX;
byte_view pubKeyY;
bool operator==(const KeyInfoEcdsa& other) const {
return curve == other.curve && pubKeyX == other.pubKeyX && pubKeyY == other.pubKeyY;
}
};
// The production root signing key for Google ECDSA P256 Endpoint Encryption Key cert chains.
inline constexpr uint8_t kEcdsa256GeekRootX[] = {
0xf7, 0x14, 0x8a, 0xdb, 0x97, 0xf4, 0xcc, 0x53, 0xef, 0xd2, 0x64, 0x11, 0xc4, 0xe3, 0x75, 0x1f,
0x66, 0x1f, 0xa4, 0x71, 0x0c, 0x6c, 0xcf, 0xfa, 0x09, 0x46, 0x80, 0x74, 0x87, 0x54, 0xf2, 0xad};
inline constexpr uint8_t kEcdsa256GeekRootY[] = {
0x5e, 0x7f, 0x5b, 0xf6, 0xec, 0xe4, 0xf6, 0x19, 0xcc, 0xff, 0x13, 0x37, 0xfd, 0x0f, 0xa1, 0xc8,
0x93, 0xdb, 0x18, 0x06, 0x76, 0xc4, 0x5d, 0xe6, 0xd7, 0x6a, 0x77, 0x86, 0xc3, 0x2d, 0xaf, 0x8f};
// Hard-coded set of acceptable public COSE_Keys that can act as roots of EEK chains.
inline constexpr KeyInfoEcdsa kAuthorizedEcdsa256EekRoots[] = {
{CoseKeyCurve::P256, byte_view(kEcdsa256GeekRootX, sizeof(kEcdsa256GeekRootX)),
byte_view(kEcdsa256GeekRootY, sizeof(kEcdsa256GeekRootY))},
};
static ErrMsgOr<CoseKey> parseEcdh256(const bytevec& coseKey) {
auto key = CoseKey::parse(coseKey, EC2, ECDH_ES_HKDF_256, P256);
if (!key) return key;
auto& pubkey_x = key->getMap().get(cppcose::CoseKey::PUBKEY_X);
auto& pubkey_y = key->getMap().get(cppcose::CoseKey::PUBKEY_Y);
if (!pubkey_x || !pubkey_y || !pubkey_x->asBstr() || !pubkey_y->asBstr() ||
pubkey_x->asBstr()->value().size() != 32 || pubkey_y->asBstr()->value().size() != 32) {
return "Invalid P256 public key";
}
return key;
}
StatusOr<std::tuple<std::vector<uint8_t> /* EEK pubX */, std::vector<uint8_t> /* EEK pubY */,
std::vector<uint8_t> /* EEK ID */>>
validateAndExtractEcdsa256EekPubAndId(bool testMode,
const KeymasterBlob& endpointEncryptionCertChain) {
auto [item, newPos, errMsg] =
cppbor::parse(endpointEncryptionCertChain.begin(), endpointEncryptionCertChain.end());
if (!item || !item->asArray()) {
return kStatusFailed;
}
const cppbor::Array* certArr = item->asArray();
std::vector<uint8_t> lastPubKey;
for (size_t i = 0; i < certArr->size(); ++i) {
auto cosePubKey =
verifyAndParseCoseSign1(certArr->get(i)->asArray(), lastPubKey, {} /* AAD */);
if (!cosePubKey) {
return kStatusInvalidEek;
}
lastPubKey = *std::move(cosePubKey);
// In prod mode the first pubkey should match a well-known Google public key.
if (!testMode && i == 0) {
auto parsedPubKey = CoseKey::parse(lastPubKey);
if (!parsedPubKey) {
return kStatusFailed;
}
auto curve = parsedPubKey->getIntValue(CoseKey::CURVE);
if (!curve) {
return kStatusInvalidEek;
}
auto rawPubX = parsedPubKey->getBstrValue(CoseKey::PUBKEY_X);
if (!rawPubX) {
return kStatusInvalidEek;
}
auto rawPubY = parsedPubKey->getBstrValue(CoseKey::PUBKEY_Y);
if (!rawPubY) {
return kStatusInvalidEek;
}
KeyInfoEcdsa matcher = {static_cast<CoseKeyCurve>(*curve),
byte_view(rawPubX->data(), rawPubX->size()),
byte_view(rawPubY->data(), rawPubY->size())};
if (std::find(std::begin(kAuthorizedEcdsa256EekRoots),
std::end(kAuthorizedEcdsa256EekRoots),
matcher) == std::end(kAuthorizedEcdsa256EekRoots)) {
return kStatusInvalidEek;
}
}
}
auto eek = parseEcdh256(lastPubKey);
if (!eek) {
return kStatusInvalidEek;
}
return std::make_tuple(eek->getBstrValue(CoseKey::PUBKEY_X).value(),
eek->getBstrValue(CoseKey::PUBKEY_Y).value(),
eek->getBstrValue(CoseKey::KEY_ID).value());
}
TEST(RemoteProvUtilsTest, GenerateEekChainInvalidLength) {
ASSERT_FALSE(generateEekChain(RpcHardwareInfo::CURVE_25519, 1, /*eekId=*/{}));
}
TEST(RemoteProvUtilsTest, GenerateEekChain) {
bytevec kTestEekId = {'t', 'e', 's', 't', 'I', 'd', 0};
for (size_t length : {2, 3, 31}) {
auto get_eek_result = generateEekChain(RpcHardwareInfo::CURVE_25519, length, kTestEekId);
ASSERT_TRUE(get_eek_result) << get_eek_result.message();
auto& [chain, pubkey, privkey] = *get_eek_result;
auto validation_result = validateAndExtractEekPubAndId(
/*testMode=*/true, KeymasterBlob(chain.data(), chain.size()));
ASSERT_TRUE(validation_result.isOk());
auto& [eekPub, eekId] = *validation_result;
EXPECT_THAT(eekId, ElementsAreArray(kTestEekId));
EXPECT_THAT(eekPub, ElementsAreArray(pubkey));
}
}
TEST(RemoteProvUtilsTest, GetProdEekChain) {
auto chain = getProdEekChain(RpcHardwareInfo::CURVE_25519);
auto validation_result = validateAndExtractEekPubAndId(
/*testMode=*/false, KeymasterBlob(chain.data(), chain.size()));
ASSERT_TRUE(validation_result.isOk()) << "Error: " << validation_result.moveError();
auto& [eekPub, eekId] = *validation_result;
auto [geekCert, ignoredNewPos, error] =
cppbor::parse(kCoseEncodedGeekCert, sizeof(kCoseEncodedGeekCert));
ASSERT_NE(geekCert, nullptr) << "Error: " << error;
ASSERT_NE(geekCert->asArray(), nullptr);
auto& encodedGeekCoseKey = geekCert->asArray()->get(kCoseSign1Payload);
ASSERT_NE(encodedGeekCoseKey, nullptr);
ASSERT_NE(encodedGeekCoseKey->asBstr(), nullptr);
auto geek = CoseKey::parse(encodedGeekCoseKey->asBstr()->value());
ASSERT_TRUE(geek) << "Error: " << geek.message();
const std::vector<uint8_t> empty;
EXPECT_THAT(eekId, ElementsAreArray(geek->getBstrValue(CoseKey::KEY_ID).value_or(empty)));
EXPECT_THAT(eekPub, ElementsAreArray(geek->getBstrValue(CoseKey::PUBKEY_X).value_or(empty)));
}
TEST(RemoteProvUtilsTest, JsonEncodeCsr) {
cppbor::Array array;
array.add(1);
auto [json, error] = jsonEncodeCsrWithBuild(std::string("test"), array);
ASSERT_TRUE(error.empty()) << error;
std::string expected = R"({"build_fingerprint":")" +
::android::base::GetProperty("ro.build.fingerprint", /*default=*/"") +
R"(","csr":"gQE=","name":"test"})";
ASSERT_EQ(json, expected);
}
TEST(RemoteProvUtilsTest, GenerateEcdsaEekChainInvalidLength) {
ASSERT_FALSE(generateEekChain(RpcHardwareInfo::CURVE_P256, 1, /*eekId=*/{}));
}
TEST(RemoteProvUtilsTest, GenerateEcdsaEekChain) {
bytevec kTestEekId = {'t', 'e', 's', 't', 'I', 'd', 0};
for (size_t length : {2, 3, 31}) {
auto get_eek_result = generateEekChain(RpcHardwareInfo::CURVE_P256, length, kTestEekId);
ASSERT_TRUE(get_eek_result) << get_eek_result.message();
auto& [chain, pubkey, privkey] = *get_eek_result;
auto validation_result = validateAndExtractEcdsa256EekPubAndId(
/*testMode=*/true, KeymasterBlob(chain.data(), chain.size()));
ASSERT_TRUE(validation_result.isOk());
auto& [eekPubX, eekPubY, eekId] = *validation_result;
bytevec eekPub;
eekPub.insert(eekPub.begin(), eekPubX.begin(), eekPubX.end());
eekPub.insert(eekPub.end(), eekPubY.begin(), eekPubY.end());
EXPECT_THAT(eekId, ElementsAreArray(kTestEekId));
EXPECT_THAT(eekPub, ElementsAreArray(pubkey));
}
}
TEST(RemoteProvUtilsTest, GetProdEcdsaEekChain) {
auto chain = getProdEekChain(RpcHardwareInfo::CURVE_P256);
auto validation_result = validateAndExtractEcdsa256EekPubAndId(
/*testMode=*/false, KeymasterBlob(chain.data(), chain.size()));
ASSERT_TRUE(validation_result.isOk()) << "Error: " << validation_result.moveError();
auto& [eekPubX, eekPubY, eekId] = *validation_result;
auto [geekCert, ignoredNewPos, error] =
cppbor::parse(kCoseEncodedEcdsa256GeekCert, sizeof(kCoseEncodedEcdsa256GeekCert));
ASSERT_NE(geekCert, nullptr) << "Error: " << error;
ASSERT_NE(geekCert->asArray(), nullptr);
auto& encodedGeekCoseKey = geekCert->asArray()->get(kCoseSign1Payload);
ASSERT_NE(encodedGeekCoseKey, nullptr);
ASSERT_NE(encodedGeekCoseKey->asBstr(), nullptr);
auto geek = CoseKey::parse(encodedGeekCoseKey->asBstr()->value());
ASSERT_TRUE(geek) << "Error: " << geek.message();
const std::vector<uint8_t> empty;
EXPECT_THAT(eekId, ElementsAreArray(geek->getBstrValue(CoseKey::KEY_ID).value_or(empty)));
EXPECT_THAT(eekPubX, ElementsAreArray(geek->getBstrValue(CoseKey::PUBKEY_X).value_or(empty)));
EXPECT_THAT(eekPubY, ElementsAreArray(geek->getBstrValue(CoseKey::PUBKEY_Y).value_or(empty)));
}
} // namespace
} // namespace aidl::android::hardware::security::keymint::remote_prov
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