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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 <openssl/err.h>
#include <openssl/hkdf.h>
#include "base/logging.h"
#include "base/stl_util.h"
#include "components/webcrypto/algorithm_implementation.h"
#include "components/webcrypto/crypto_data.h"
#include "components/webcrypto/openssl/key_openssl.h"
#include "components/webcrypto/openssl/util_openssl.h"
#include "components/webcrypto/status.h"
#include "components/webcrypto/webcrypto_util.h"
#include "crypto/openssl_util.h"
#include "third_party/WebKit/public/platform/WebCryptoAlgorithmParams.h"
#include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
namespace webcrypto {
namespace {
const blink::WebCryptoKeyUsageMask kValidUsages =
blink::WebCryptoKeyUsageDeriveKey | blink::WebCryptoKeyUsageDeriveBits;
class HkdfImplementation : public AlgorithmImplementation {
public:
HkdfImplementation() {}
Status VerifyKeyUsagesBeforeImportKey(
blink::WebCryptoKeyFormat format,
blink::WebCryptoKeyUsageMask usages) const override {
if (format != blink::WebCryptoKeyFormatRaw)
return Status::ErrorUnsupportedImportKeyFormat();
return CheckKeyCreationUsages(kValidUsages, usages, false);
}
Status ImportKeyRaw(const CryptoData& key_data,
const blink::WebCryptoAlgorithm& algorithm,
bool extractable,
blink::WebCryptoKeyUsageMask usages,
blink::WebCryptoKey* key) const override {
return CreateWebCryptoSecretKey(
key_data, blink::WebCryptoKeyAlgorithm::createWithoutParams(
blink::WebCryptoAlgorithmIdHkdf),
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();
const blink::WebCryptoHkdfParams* params = algorithm.hkdfParams();
const EVP_MD* digest_algorithm = GetDigest(params->hash().id());
if (!digest_algorithm)
return Status::ErrorUnsupported();
// Size output to fit length
unsigned int derived_bytes_len = NumBitsToBytes(optional_length_bits);
derived_bytes->resize(derived_bytes_len);
// Algorithm dispatch checks that the algorithm in |base_key| matches
// |algorithm|.
const std::vector<uint8_t>& raw_key =
SymKeyOpenSsl::Cast(base_key)->raw_key_data();
if (!HKDF(vector_as_array(derived_bytes), derived_bytes_len,
digest_algorithm, vector_as_array(&raw_key), 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();
}
TruncateToBitLength(optional_length_bits, derived_bytes);
return Status::Success();
}
Status SerializeKeyForClone(
const blink::WebCryptoKey& key,
blink::WebVector<uint8_t>* key_data) const override {
key_data->assign(SymKeyOpenSsl::Cast(key)->serialized_key_data());
return Status::Success();
}
Status DeserializeKeyForClone(const blink::WebCryptoKeyAlgorithm& algorithm,
blink::WebCryptoKeyType type,
bool extractable,
blink::WebCryptoKeyUsageMask usages,
const CryptoData& key_data,
blink::WebCryptoKey* key) const override {
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
AlgorithmImplementation* CreatePlatformHkdfImplementation() {
return new HkdfImplementation;
}
} // namespace webcrypto
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