Merge pull request #477 from TobiasFella/work/readencryptedmessages

1 files changed, 92 insertions, 0 deletions

diff --git a/lib/events/encryptedfile.cpp b/lib/events/encryptedfile.cpp
new file mode 100644
index 00000000..d4a517bd
--- /dev/null
+++ b/lib/events/encryptedfile.cpp
@@ -0,0 +1,92 @@
+// SPDX-FileCopyrightText: 2021 Carl Schwan <carlschwan@kde.org>
+//
+// SPDX-License-Identifier: LGPL-2.1-or-later
+
+#include "encryptedfile.h"
+#include "logging.h"
+
+#ifdef Quotient_E2EE_ENABLED
+#include <openssl/evp.h>
+#include <QtCore/QCryptographicHash>
+#endif
+
+using namespace Quotient;
+
+QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
+{
+#ifdef Quotient_E2EE_ENABLED
+    auto _key = key.k;
+    const auto keyBytes = QByteArray::fromBase64(
+        _key.replace(u'_', u'/').replace(u'-', u'+').toLatin1());
+    const auto sha256 = QByteArray::fromBase64(hashes["sha256"].toLatin1());
+    if (sha256
+        != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
+        qCWarning(E2EE) << "Hash verification failed for file";
+        return {};
+    }
+    {
+        int length;
+        auto* ctx = EVP_CIPHER_CTX_new();
+        QByteArray plaintext(ciphertext.size() + EVP_CIPHER_CTX_block_size(ctx)
+                                 - 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(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;
+    }
+#else
+    qWarning(MAIN) << "This build of libQuotient doesn't support E2EE, "
+                      "cannot decrypt the file";
+    return ciphertext;
+#endif
+}
+
+void JsonObjectConverter<EncryptedFile>::dumpTo(QJsonObject& jo,
+                                                const EncryptedFile& 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<EncryptedFile>::fillFrom(const QJsonObject& jo,
+                                                  EncryptedFile& 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);
+}