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// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
//
// SPDX-License-Identifier: LGPL-2.1-or-later
#include "filesourceinfo.h"
#include "logging.h"
#ifdef Quotient_E2EE_ENABLED
# include "e2ee/qolmutils.h"
# include <QtCore/QCryptographicHash>
# include <openssl/evp.h>
#endif
using namespace Quotient;
QByteArray Quotient::decryptFile(const QByteArray& ciphertext,
const EncryptedFileMetadata& metadata)
{
#ifdef Quotient_E2EE_ENABLED
if (QByteArray::fromBase64(metadata.hashes["sha256"_ls].toLatin1())
!= QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
qCWarning(E2EE) << "Hash verification failed for file";
return {};
}
auto _key = metadata.key.k;
const auto keyBytes = QByteArray::fromBase64(
_key.replace(u'_', u'/').replace(u'-', u'+').toLatin1());
int length;
auto* ctx = EVP_CIPHER_CTX_new();
QByteArray plaintext(ciphertext.size() + EVP_MAX_BLOCK_LENGTH - 1, '\0');
EVP_DecryptInit_ex(
ctx, EVP_aes_256_ctr(), nullptr,
reinterpret_cast<const unsigned char*>(keyBytes.data()),
reinterpret_cast<const unsigned char*>(
QByteArray::fromBase64(metadata.iv.toLatin1()).data()));
EVP_DecryptUpdate(ctx, reinterpret_cast<unsigned char*>(plaintext.data()),
&length,
reinterpret_cast<const unsigned char*>(ciphertext.data()),
ciphertext.size());
EVP_DecryptFinal_ex(ctx,
reinterpret_cast<unsigned char*>(plaintext.data())
+ length,
&length);
EVP_CIPHER_CTX_free(ctx);
return plaintext.left(ciphertext.size());
#else
qWarning(MAIN) << "This build of libQuotient doesn't support E2EE, "
"cannot decrypt the file";
return ciphertext;
#endif
}
std::pair<EncryptedFileMetadata, QByteArray> Quotient::encryptFile(
const QByteArray& plainText)
{
#ifdef Quotient_E2EE_ENABLED
QByteArray k = getRandom(32);
auto kBase64 = k.toBase64();
QByteArray iv = getRandom(16);
JWK key = { "oct"_ls,
{ "encrypt"_ls, "decrypt"_ls },
"A256CTR"_ls,
QString(k.toBase64())
.replace(u'/', u'_')
.replace(u'+', u'-')
.left(kBase64.indexOf('=')),
true };
int length;
auto* ctx = EVP_CIPHER_CTX_new();
EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr,
reinterpret_cast<const unsigned char*>(k.data()),
reinterpret_cast<const unsigned char*>(iv.data()));
const auto blockSize = EVP_CIPHER_CTX_block_size(ctx);
QByteArray cipherText(plainText.size() + blockSize - 1, '\0');
EVP_EncryptUpdate(ctx, reinterpret_cast<unsigned char*>(cipherText.data()),
&length,
reinterpret_cast<const unsigned char*>(plainText.data()),
plainText.size());
EVP_EncryptFinal_ex(ctx,
reinterpret_cast<unsigned char*>(cipherText.data())
+ length,
&length);
EVP_CIPHER_CTX_free(ctx);
auto hash = QCryptographicHash::hash(cipherText, QCryptographicHash::Sha256)
.toBase64();
auto ivBase64 = iv.toBase64();
EncryptedFileMetadata efm = { {},
key,
ivBase64.left(ivBase64.indexOf('=')),
{ { QStringLiteral("sha256"),
hash.left(hash.indexOf('=')) } },
"v2"_ls };
return { efm, cipherText };
#else
return {};
#endif
}
void JsonObjectConverter<EncryptedFileMetadata>::dumpTo(QJsonObject& jo,
const EncryptedFileMetadata& pod)
{
addParam<>(jo, QStringLiteral("url"), pod.url);
addParam<>(jo, QStringLiteral("key"), pod.key);
addParam<>(jo, QStringLiteral("iv"), pod.iv);
addParam<>(jo, QStringLiteral("hashes"), pod.hashes);
addParam<>(jo, QStringLiteral("v"), pod.v);
}
void JsonObjectConverter<EncryptedFileMetadata>::fillFrom(const QJsonObject& jo,
EncryptedFileMetadata& pod)
{
fromJson(jo.value("url"_ls), pod.url);
fromJson(jo.value("key"_ls), pod.key);
fromJson(jo.value("iv"_ls), pod.iv);
fromJson(jo.value("hashes"_ls), pod.hashes);
fromJson(jo.value("v"_ls), pod.v);
}
void JsonObjectConverter<JWK>::dumpTo(QJsonObject& jo, const JWK& pod)
{
addParam<>(jo, QStringLiteral("kty"), pod.kty);
addParam<>(jo, QStringLiteral("key_ops"), pod.keyOps);
addParam<>(jo, QStringLiteral("alg"), pod.alg);
addParam<>(jo, QStringLiteral("k"), pod.k);
addParam<>(jo, QStringLiteral("ext"), pod.ext);
}
void JsonObjectConverter<JWK>::fillFrom(const QJsonObject& jo, JWK& pod)
{
fromJson(jo.value("kty"_ls), pod.kty);
fromJson(jo.value("key_ops"_ls), pod.keyOps);
fromJson(jo.value("alg"_ls), pod.alg);
fromJson(jo.value("k"_ls), pod.k);
fromJson(jo.value("ext"_ls), pod.ext);
}
template <typename... FunctorTs>
struct Overloads : FunctorTs... {
using FunctorTs::operator()...;
};
template <typename... FunctorTs>
Overloads(FunctorTs&&...) -> Overloads<FunctorTs...>;
QUrl Quotient::getUrlFromSourceInfo(const FileSourceInfo& fsi)
{
return std::visit(Overloads { [](const QUrl& url) { return url; },
[](const EncryptedFileMetadata& efm) {
return efm.url;
} },
fsi);
}
void Quotient::setUrlInSourceInfo(FileSourceInfo& fsi, const QUrl& newUrl)
{
std::visit(Overloads { [&newUrl](QUrl& url) { url = newUrl; },
[&newUrl](EncryptedFileMetadata& efm) {
efm.url = newUrl;
} },
fsi);
}
void Quotient::fillJson(QJsonObject& jo,
const std::array<QLatin1String, 2>& jsonKeys,
const FileSourceInfo& fsi)
{
// NB: Keeping variant_size_v out of the function signature for readability.
// NB2: Can't use jsonKeys directly inside static_assert as its value is
// unknown so the compiler cannot ensure size() is constexpr (go figure...)
static_assert(
std::variant_size_v<FileSourceInfo> == decltype(jsonKeys) {}.size());
jo.insert(jsonKeys[fsi.index()], toJson(fsi));
}
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