| // Copyright 2023 The Chromium Authors |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "crypto/unexportable_key.h" |
| |
| #include "base/check.h" |
| #include "crypto/sha2.h" |
| #include "crypto/signature_verifier.h" |
| #include "third_party/boringssl/src/include/openssl/bytestring.h" |
| #include "third_party/boringssl/src/include/openssl/ec.h" |
| #include "third_party/boringssl/src/include/openssl/ec_key.h" |
| #include "third_party/boringssl/src/include/openssl/ecdsa.h" |
| #include "third_party/boringssl/src/include/openssl/evp.h" |
| #include "third_party/boringssl/src/include/openssl/obj.h" |
| |
| namespace crypto { |
| |
| namespace { |
| |
| std::vector<uint8_t> CBBToVector(const CBB* cbb) { |
| return std::vector<uint8_t>(CBB_data(cbb), CBB_data(cbb) + CBB_len(cbb)); |
| } |
| |
| class SoftwareECDSA : public UnexportableSigningKey { |
| public: |
| explicit SoftwareECDSA(bssl::UniquePtr<EC_KEY> key) : key_(std::move(key)) {} |
| ~SoftwareECDSA() override = default; |
| |
| SignatureVerifier::SignatureAlgorithm Algorithm() const override { |
| return SignatureVerifier::SignatureAlgorithm::ECDSA_SHA256; |
| } |
| |
| std::vector<uint8_t> GetSubjectPublicKeyInfo() const override { |
| bssl::UniquePtr<EVP_PKEY> pkey(EVP_PKEY_new()); |
| CHECK(EVP_PKEY_set1_EC_KEY(pkey.get(), key_.get())); |
| |
| bssl::ScopedCBB cbb; |
| CHECK(CBB_init(cbb.get(), /*initial_capacity=*/128) && |
| EVP_marshal_public_key(cbb.get(), pkey.get())); |
| return CBBToVector(cbb.get()); |
| } |
| |
| std::vector<uint8_t> GetWrappedKey() const override { |
| bssl::ScopedCBB cbb; |
| CHECK( |
| CBB_init(cbb.get(), /*initial_capacity=*/128) && |
| EC_KEY_marshal_private_key(cbb.get(), key_.get(), |
| EC_PKEY_NO_PARAMETERS | EC_PKEY_NO_PUBKEY)); |
| return CBBToVector(cbb.get()); |
| } |
| |
| absl::optional<std::vector<uint8_t>> SignSlowly( |
| base::span<const uint8_t> data) override { |
| std::vector<uint8_t> ret(ECDSA_size(key_.get())); |
| std::array<uint8_t, kSHA256Length> digest = SHA256Hash(data); |
| unsigned int ret_size; |
| CHECK(ECDSA_sign(0, digest.data(), digest.size(), ret.data(), &ret_size, |
| key_.get())); |
| ret.resize(ret_size); |
| return ret; |
| } |
| |
| private: |
| bssl::UniquePtr<EC_KEY> key_; |
| }; |
| |
| class SoftwareProvider : public UnexportableKeyProvider { |
| public: |
| ~SoftwareProvider() override = default; |
| |
| absl::optional<SignatureVerifier::SignatureAlgorithm> SelectAlgorithm( |
| base::span<const SignatureVerifier::SignatureAlgorithm> |
| acceptable_algorithms) override { |
| for (auto algo : acceptable_algorithms) { |
| if (algo == SignatureVerifier::SignatureAlgorithm::ECDSA_SHA256) { |
| return algo; |
| } |
| } |
| |
| return absl::nullopt; |
| } |
| |
| std::unique_ptr<UnexportableSigningKey> GenerateSigningKeySlowly( |
| base::span<const SignatureVerifier::SignatureAlgorithm> |
| acceptable_algorithms) override { |
| if (!SelectAlgorithm(acceptable_algorithms)) { |
| return nullptr; |
| } |
| |
| bssl::UniquePtr<EC_KEY> key(EC_KEY_new_by_curve_name(NID_X9_62_prime256v1)); |
| CHECK(EC_KEY_generate_key(key.get())); |
| |
| return std::make_unique<SoftwareECDSA>(std::move(key)); |
| } |
| |
| std::unique_ptr<UnexportableSigningKey> FromWrappedSigningKeySlowly( |
| base::span<const uint8_t> wrapped_key) override { |
| bssl::UniquePtr<EC_GROUP> p256( |
| EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1)); |
| CBS cbs; |
| CBS_init(&cbs, wrapped_key.data(), wrapped_key.size()); |
| bssl::UniquePtr<EC_KEY> key(EC_KEY_parse_private_key(&cbs, p256.get())); |
| if (!key || CBS_len(&cbs) != 0) { |
| return nullptr; |
| } |
| return std::make_unique<SoftwareECDSA>(std::move(key)); |
| } |
| }; |
| |
| } // namespace |
| |
| std::unique_ptr<UnexportableKeyProvider> |
| GetSoftwareUnsecureUnexportableKeyProvider() { |
| return std::make_unique<SoftwareProvider>(); |
| } |
| |
| } // namespace crypto |