diff options
Diffstat (limited to 'lib/events/filesourceinfo.cpp')
| -rw-r--r-- | lib/events/filesourceinfo.cpp | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/lib/events/filesourceinfo.cpp b/lib/events/filesourceinfo.cpp new file mode 100644 index 00000000..a60d86d2 --- /dev/null +++ b/lib/events/filesourceinfo.cpp @@ -0,0 +1,163 @@ +// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org> +// +// SPDX-License-Identifier: LGPL-2.1-or-later + +#include "filesourceinfo.h" + +#include "logging.h" +#include "util.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 + auto k = RandomBuffer(32); + auto kBase64 = k.toBase64(QByteArray::Base64UrlEncoding + | QByteArray::OmitTrailingEquals); + auto iv = RandomBuffer(16); + JWK key = { + "oct"_ls, { "encrypt"_ls, "decrypt"_ls }, "A256CTR"_ls, kBase64, true + }; + + int length = -1; + auto* ctx = EVP_CIPHER_CTX_new(); + EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), nullptr, k.bytes(), iv.bytes()); + 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(QByteArray::OmitTrailingEquals); + auto ivBase64 = iv.toBase64(QByteArray::OmitTrailingEquals); + EncryptedFileMetadata efm = { + {}, key, ivBase64, { { QStringLiteral("sha256"), hash } }, "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); +} + +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)); +} |