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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 "components/webcrypto/algorithms/util.h"
#include "base/check_op.h"
#include "components/webcrypto/status.h"
#include "crypto/openssl_util.h"
#include "third_party/boringssl/src/include/openssl/aead.h"
#include "third_party/boringssl/src/include/openssl/bn.h"
#include "third_party/boringssl/src/include/openssl/digest.h"
namespace webcrypto {
const EVP_MD* GetDigest(const blink::WebCryptoAlgorithm& hash_algorithm) {
return GetDigest(hash_algorithm.Id());
}
const EVP_MD* GetDigest(blink::WebCryptoAlgorithmId id) {
switch (id) {
case blink::kWebCryptoAlgorithmIdSha1:
return EVP_sha1();
case blink::kWebCryptoAlgorithmIdSha256:
return EVP_sha256();
case blink::kWebCryptoAlgorithmIdSha384:
return EVP_sha384();
case blink::kWebCryptoAlgorithmIdSha512:
return EVP_sha512();
default:
return nullptr;
}
}
void TruncateToBitLength(size_t length_bits, std::vector<uint8_t>* bytes) {
size_t length_bytes = NumBitsToBytes(length_bits);
if (bytes->size() != length_bytes) {
CHECK_LT(length_bytes, bytes->size());
bytes->resize(length_bytes);
}
size_t remainder_bits = length_bits % 8;
// Zero any "unused bits" in the final byte.
if (remainder_bits)
bytes->back() &= ~((0xFF) >> remainder_bits);
}
Status CheckKeyCreationUsages(blink::WebCryptoKeyUsageMask all_possible_usages,
blink::WebCryptoKeyUsageMask actual_usages) {
if (!ContainsKeyUsages(all_possible_usages, actual_usages))
return Status::ErrorCreateKeyBadUsages();
return Status::Success();
}
bool ContainsKeyUsages(blink::WebCryptoKeyUsageMask a,
blink::WebCryptoKeyUsageMask b) {
return (a & b) == b;
}
Status AeadEncryptDecrypt(EncryptOrDecrypt mode,
base::span<const uint8_t> raw_key,
base::span<const uint8_t> data,
unsigned int tag_length_bytes,
base::span<const uint8_t> iv,
base::span<const uint8_t> additional_data,
const EVP_AEAD* aead_alg,
std::vector<uint8_t>* buffer) {
crypto::OpenSSLErrStackTracer err_tracer(FROM_HERE);
bssl::ScopedEVP_AEAD_CTX ctx;
if (!aead_alg)
return Status::ErrorUnexpected();
if (!EVP_AEAD_CTX_init(ctx.get(), aead_alg, raw_key.data(), raw_key.size(),
tag_length_bytes, nullptr)) {
return Status::OperationError();
}
size_t len;
int ok;
if (mode == DECRYPT) {
if (data.size() < tag_length_bytes)
return Status::ErrorDataTooSmall();
buffer->resize(data.size() - tag_length_bytes);
ok = EVP_AEAD_CTX_open(ctx.get(), buffer->data(), &len, buffer->size(),
iv.data(), iv.size(), data.data(), data.size(),
additional_data.data(), additional_data.size());
} else {
// No need to check for unsigned integer overflow here (seal fails if
// the output buffer is too small).
buffer->resize(data.size() + EVP_AEAD_max_overhead(aead_alg));
ok = EVP_AEAD_CTX_seal(ctx.get(), buffer->data(), &len, buffer->size(),
iv.data(), iv.size(), data.data(), data.size(),
additional_data.data(), additional_data.size());
}
if (!ok)
return Status::OperationError();
buffer->resize(len);
return Status::Success();
}
} // namespace webcrypto
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