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// Copyright 2014 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <vector>
#include "base/location.h"
#include "base/numerics/safe_math.h"
#include "components/webcrypto/algorithms/aes.h"
#include "components/webcrypto/blink_key_handle.h"
#include "components/webcrypto/status.h"
#include "crypto/openssl_util.h"
#include "third_party/boringssl/src/include/openssl/aes.h"
namespace webcrypto {
namespace {
class AesKwImplementation : public AesAlgorithm {
public:
AesKwImplementation()
: AesAlgorithm(blink::kWebCryptoKeyUsageWrapKey |
blink::kWebCryptoKeyUsageUnwrapKey,
"KW") {}
Status Encrypt(const blink::WebCryptoAlgorithm& algorithm,
const blink::WebCryptoKey& key,
base::span<const uint8_t> data,
std::vector<uint8_t>* buffer) const override {
crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
// These length checks are done in order to give a more specific
// error. These are not required for correctness.
if (data.size() < 16)
return Status::ErrorDataTooSmall();
if (data.size() % 8)
return Status::ErrorInvalidAesKwDataLength();
// Key import validates key sizes, so the bits computation will not
// overflow.
const std::vector<uint8_t>& raw_key = GetSymmetricKeyData(key);
AES_KEY aes_key;
if (AES_set_encrypt_key(raw_key.data(),
static_cast<unsigned>(raw_key.size() * 8),
&aes_key) < 0) {
return Status::OperationError();
}
// Key wrap's overhead is 8 bytes.
base::CheckedNumeric<size_t> length(data.size());
length += 8;
if (!length.IsValid())
return Status::ErrorDataTooLarge();
buffer->resize(length.ValueOrDie());
if (AES_wrap_key(&aes_key, nullptr /* default IV */, buffer->data(),
data.data(), data.size()) < 0) {
return Status::OperationError();
}
return Status::Success();
}
Status Decrypt(const blink::WebCryptoAlgorithm& algorithm,
const blink::WebCryptoKey& key,
base::span<const uint8_t> data,
std::vector<uint8_t>* buffer) const override {
crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
// These length checks are done in order to give a more specific
// error. These are not required for correctness.
if (data.size() < 24)
return Status::ErrorDataTooSmall();
if (data.size() % 8)
return Status::ErrorInvalidAesKwDataLength();
// Key import validates key sizes, so the bits computation will not
// overflow.
const std::vector<uint8_t>& raw_key = GetSymmetricKeyData(key);
AES_KEY aes_key;
if (AES_set_decrypt_key(raw_key.data(),
static_cast<unsigned>(raw_key.size() * 8),
&aes_key) < 0) {
return Status::OperationError();
}
// Key wrap's overhead is 8 bytes.
buffer->resize(data.size() - 8);
if (AES_unwrap_key(&aes_key, nullptr /* default IV */, buffer->data(),
data.data(), data.size()) < 0) {
return Status::OperationError();
}
return Status::Success();
}
};
} // namespace
std::unique_ptr<AlgorithmImplementation> CreateAesKwImplementation() {
return std::make_unique<AesKwImplementation>();
}
} // namespace webcrypto
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