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// Copyright 2014 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/hmac.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/jwk.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 "crypto/secure_util.h"
#include "third_party/WebKit/public/platform/WebCryptoAlgorithmParams.h"
#include "third_party/WebKit/public/platform/WebCryptoKeyAlgorithm.h"
namespace webcrypto {
namespace {
const blink::WebCryptoKeyUsageMask kAllKeyUsages =
blink::WebCryptoKeyUsageSign | blink::WebCryptoKeyUsageVerify;
Status SignHmac(const std::vector<uint8_t>& raw_key,
const blink::WebCryptoAlgorithm& hash,
const CryptoData& data,
std::vector<uint8_t>* buffer) {
crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
const EVP_MD* digest_algorithm = GetDigest(hash.id());
if (!digest_algorithm)
return Status::ErrorUnsupported();
size_t hmac_expected_length = EVP_MD_size(digest_algorithm);
buffer->resize(hmac_expected_length);
crypto::ScopedOpenSSLSafeSizeBuffer<EVP_MAX_MD_SIZE> hmac_result(
vector_as_array(buffer), hmac_expected_length);
unsigned int hmac_actual_length;
unsigned char* const success = HMAC(
digest_algorithm, vector_as_array(&raw_key), raw_key.size(), data.bytes(),
data.byte_length(), hmac_result.safe_buffer(), &hmac_actual_length);
if (!success || hmac_actual_length != hmac_expected_length)
return Status::OperationError();
return Status::Success();
}
class HmacImplementation : public AlgorithmImplementation {
public:
HmacImplementation() {}
Status GenerateKey(const blink::WebCryptoAlgorithm& algorithm,
bool extractable,
blink::WebCryptoKeyUsageMask usages,
GenerateKeyResult* result) const override {
Status status = CheckKeyCreationUsages(kAllKeyUsages, usages, false);
if (status.IsError())
return status;
const blink::WebCryptoHmacKeyGenParams* params =
algorithm.hmacKeyGenParams();
unsigned int keylen_bits = 0;
status = GetHmacKeyGenLengthInBits(params, &keylen_bits);
if (status.IsError())
return status;
return GenerateWebCryptoSecretKey(blink::WebCryptoKeyAlgorithm::createHmac(
params->hash().id(), keylen_bits),
extractable, usages, keylen_bits, result);
}
Status VerifyKeyUsagesBeforeImportKey(
blink::WebCryptoKeyFormat format,
blink::WebCryptoKeyUsageMask usages) const override {
switch (format) {
case blink::WebCryptoKeyFormatRaw:
case blink::WebCryptoKeyFormatJwk:
return CheckKeyCreationUsages(kAllKeyUsages, usages, false);
default:
return Status::ErrorUnsupportedImportKeyFormat();
}
}
Status ImportKeyRaw(const CryptoData& key_data,
const blink::WebCryptoAlgorithm& algorithm,
bool extractable,
blink::WebCryptoKeyUsageMask usages,
blink::WebCryptoKey* key) const override {
const blink::WebCryptoHmacImportParams* params =
algorithm.hmacImportParams();
unsigned int keylen_bits = 0;
Status status = GetHmacImportKeyLengthBits(params, key_data.byte_length(),
&keylen_bits);
if (status.IsError())
return status;
const blink::WebCryptoKeyAlgorithm key_algorithm =
blink::WebCryptoKeyAlgorithm::createHmac(params->hash().id(),
keylen_bits);
// If no bit truncation was requested, then done!
if ((keylen_bits % 8) == 0) {
return CreateWebCryptoSecretKey(key_data, key_algorithm, extractable,
usages, key);
}
// Otherwise zero out the unused bits in the key data before importing.
std::vector<uint8_t> modified_key_data(
key_data.bytes(), key_data.bytes() + key_data.byte_length());
TruncateToBitLength(keylen_bits, &modified_key_data);
return CreateWebCryptoSecretKey(CryptoData(modified_key_data),
key_algorithm, extractable, usages, key);
}
Status ImportKeyJwk(const CryptoData& key_data,
const blink::WebCryptoAlgorithm& algorithm,
bool extractable,
blink::WebCryptoKeyUsageMask usages,
blink::WebCryptoKey* key) const override {
const char* algorithm_name =
GetJwkHmacAlgorithmName(algorithm.hmacImportParams()->hash().id());
if (!algorithm_name)
return Status::ErrorUnexpected();
std::vector<uint8_t> raw_data;
Status status = ReadSecretKeyJwk(key_data, algorithm_name, extractable,
usages, &raw_data);
if (status.IsError())
return status;
return ImportKeyRaw(CryptoData(raw_data), algorithm, extractable, usages,
key);
}
Status ExportKeyRaw(const blink::WebCryptoKey& key,
std::vector<uint8_t>* buffer) const override {
*buffer = SymKeyOpenSsl::Cast(key)->raw_key_data();
return Status::Success();
}
Status ExportKeyJwk(const blink::WebCryptoKey& key,
std::vector<uint8_t>* buffer) const override {
SymKeyOpenSsl* sym_key = SymKeyOpenSsl::Cast(key);
const std::vector<uint8_t>& raw_data = sym_key->raw_key_data();
const char* algorithm_name =
GetJwkHmacAlgorithmName(key.algorithm().hmacParams()->hash().id());
if (!algorithm_name)
return Status::ErrorUnexpected();
WriteSecretKeyJwk(CryptoData(raw_data), algorithm_name, key.extractable(),
key.usages(), buffer);
return Status::Success();
}
Status Sign(const blink::WebCryptoAlgorithm& algorithm,
const blink::WebCryptoKey& key,
const CryptoData& data,
std::vector<uint8_t>* buffer) const override {
const blink::WebCryptoAlgorithm& hash =
key.algorithm().hmacParams()->hash();
return SignHmac(SymKeyOpenSsl::Cast(key)->raw_key_data(), hash, data,
buffer);
}
Status Verify(const blink::WebCryptoAlgorithm& algorithm,
const blink::WebCryptoKey& key,
const CryptoData& signature,
const CryptoData& data,
bool* signature_match) const override {
std::vector<uint8_t> result;
Status status = Sign(algorithm, key, data, &result);
if (status.IsError())
return status;
// Do not allow verification of truncated MACs.
*signature_match =
result.size() == signature.byte_length() &&
crypto::SecureMemEqual(vector_as_array(&result), signature.bytes(),
signature.byte_length());
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 {
return GetHmacKeyLength(key_length_algorithm, has_length_bits, length_bits);
}
};
} // namespace
AlgorithmImplementation* CreatePlatformHmacImplementation() {
return new HmacImplementation;
}
} // namespace webcrypto
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