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// Copyright 2015 The Chromium Authors
// 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 "base/containers/span.h"
#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/evp.h"
namespace webcrypto {
namespace {
const blink::WebCryptoKeyUsageMask kAllKeyUsages =
blink::kWebCryptoKeyUsageDeriveKey | blink::kWebCryptoKeyUsageDeriveBits;
class Pbkdf2Implementation : public AlgorithmImplementation {
public:
Pbkdf2Implementation() = default;
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(kAllKeyUsages, usages);
if (status.IsError())
return status;
if (extractable)
return Status::ErrorImportExtractableKdfKey();
const blink::WebCryptoKeyAlgorithm key_algorithm =
blink::WebCryptoKeyAlgorithm::CreateWithoutParams(
blink::kWebCryptoAlgorithmIdPbkdf2);
return CreateWebCryptoSecretKey(key_data, key_algorithm, extractable,
usages, key);
}
Status DeriveBits(const blink::WebCryptoAlgorithm& algorithm,
const blink::WebCryptoKey& base_key,
std::optional<unsigned int> length_bits,
std::vector<uint8_t>* derived_bytes) const override {
crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
if (!length_bits.has_value()) {
return Status::ErrorPbkdf2DeriveBitsLengthNotSpecified();
}
// Even though the RFC8018 states that length must be a "positive integer"
// the spec considers that it's better to avoid discontinuity in the allowed
// values of this parameter.
// https://github.com/w3c/webcrypto/issues/370
if (*length_bits % 8) {
return Status::ErrorPbkdf2InvalidLength();
}
const blink::WebCryptoPbkdf2Params* params = algorithm.Pbkdf2Params();
if (params->Iterations() == 0)
return Status::ErrorPbkdf2Iterations0();
const EVP_MD* digest_algorithm = GetDigest(params->GetHash());
if (!digest_algorithm)
return Status::ErrorUnsupported();
unsigned int keylen_bytes = *length_bits / 8;
derived_bytes->resize(keylen_bytes);
const std::vector<uint8_t>& password = GetSymmetricKeyData(base_key);
if (!PKCS5_PBKDF2_HMAC(
reinterpret_cast<const char*>(password.data()), password.size(),
params->Salt().data(), params->Salt().size(), params->Iterations(),
digest_algorithm, keylen_bytes, derived_bytes->data())) {
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,
std::optional<unsigned int>* length_bits) const override {
*length_bits = std::nullopt;
return Status::Success();
}
};
} // namespace
std::unique_ptr<AlgorithmImplementation> CreatePbkdf2Implementation() {
return std::make_unique<Pbkdf2Implementation>();
}
} // namespace webcrypto
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