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- // Copyright 2015 The Chromium Authors. All rights reserved.
- // Use of this source code is governed by a BSD-style license that can be
- // found in the LICENSE file.
- #include <stdint.h>
- #include <memory>
- #include "components/webcrypto/algorithm_implementation.h"
- #include "components/webcrypto/algorithms/secret_key_util.h"
- #include "components/webcrypto/algorithms/util.h"
- #include "components/webcrypto/blink_key_handle.h"
- #include "components/webcrypto/status.h"
- #include "crypto/openssl_util.h"
- #include "third_party/blink/public/platform/web_crypto_algorithm_params.h"
- #include "third_party/blink/public/platform/web_crypto_key_algorithm.h"
- #include "third_party/boringssl/src/include/openssl/err.h"
- #include "third_party/boringssl/src/include/openssl/hkdf.h"
- namespace webcrypto {
- namespace {
- const blink::WebCryptoKeyUsageMask kValidUsages =
- blink::kWebCryptoKeyUsageDeriveKey | blink::kWebCryptoKeyUsageDeriveBits;
- class HkdfImplementation : public AlgorithmImplementation {
- public:
- HkdfImplementation() {}
- Status ImportKey(blink::WebCryptoKeyFormat format,
- base::span<const uint8_t> key_data,
- const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- blink::WebCryptoKey* key) const override {
- switch (format) {
- case blink::kWebCryptoKeyFormatRaw:
- return ImportKeyRaw(key_data, algorithm, extractable, usages, key);
- default:
- return Status::ErrorUnsupportedImportKeyFormat();
- }
- }
- Status ImportKeyRaw(base::span<const uint8_t> key_data,
- const blink::WebCryptoAlgorithm& algorithm,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- blink::WebCryptoKey* key) const {
- Status status = CheckKeyCreationUsages(kValidUsages, usages);
- if (status.IsError())
- return status;
- if (extractable)
- return Status::ErrorImportExtractableKdfKey();
- return CreateWebCryptoSecretKey(
- key_data,
- blink::WebCryptoKeyAlgorithm::CreateWithoutParams(
- blink::kWebCryptoAlgorithmIdHkdf),
- extractable, usages, key);
- }
- Status DeriveBits(const blink::WebCryptoAlgorithm& algorithm,
- const blink::WebCryptoKey& base_key,
- bool has_optional_length_bits,
- unsigned int optional_length_bits,
- std::vector<uint8_t>* derived_bytes) const override {
- crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
- if (!has_optional_length_bits)
- return Status::ErrorHkdfDeriveBitsLengthNotSpecified();
- if (optional_length_bits % 8)
- return Status::ErrorHkdfLengthNotWholeByte();
- const blink::WebCryptoHkdfParams* params = algorithm.HkdfParams();
- const EVP_MD* digest_algorithm = GetDigest(params->GetHash());
- if (!digest_algorithm)
- return Status::ErrorUnsupported();
- // Size output to fit length
- unsigned int derived_bytes_len = optional_length_bits / 8;
- derived_bytes->resize(derived_bytes_len);
- // Algorithm dispatch checks that the algorithm in |base_key| matches
- // |algorithm|.
- const std::vector<uint8_t>& raw_key = GetSymmetricKeyData(base_key);
- if (!HKDF(derived_bytes->data(), derived_bytes_len, digest_algorithm,
- raw_key.data(), raw_key.size(), params->Salt().data(),
- params->Salt().size(), params->Info().data(),
- params->Info().size())) {
- uint32_t error = ERR_get_error();
- if (ERR_GET_LIB(error) == ERR_LIB_HKDF &&
- ERR_GET_REASON(error) == HKDF_R_OUTPUT_TOO_LARGE) {
- return Status::ErrorHkdfLengthTooLong();
- }
- return Status::OperationError();
- }
- return Status::Success();
- }
- Status DeserializeKeyForClone(const blink::WebCryptoKeyAlgorithm& algorithm,
- blink::WebCryptoKeyType type,
- bool extractable,
- blink::WebCryptoKeyUsageMask usages,
- base::span<const uint8_t> key_data,
- blink::WebCryptoKey* key) const override {
- if (algorithm.ParamsType() != blink::kWebCryptoKeyAlgorithmParamsTypeNone ||
- type != blink::kWebCryptoKeyTypeSecret)
- return Status::ErrorUnexpected();
- // NOTE: Unlike ImportKeyRaw(), this does not enforce extractable==false.
- // This is intentional. Although keys cannot currently be created with
- // extractable==true, earlier implementations permitted this, so
- // de-serialization by structured clone should not reject them.
- return CreateWebCryptoSecretKey(key_data, algorithm, extractable, usages,
- key);
- }
- Status GetKeyLength(const blink::WebCryptoAlgorithm& key_length_algorithm,
- bool* has_length_bits,
- unsigned int* length_bits) const override {
- *has_length_bits = false;
- return Status::Success();
- }
- };
- } // namespace
- std::unique_ptr<AlgorithmImplementation> CreateHkdfImplementation() {
- return std::make_unique<HkdfImplementation>();
- }
- } // namespace webcrypto
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