Move encryptFile/decryptFile out of EncryptedFileMetadata

These are not operations on EncryptedFileMetadata but rather on
a combination of EncryptedFileMetadata and ciphertext. If C++ had
multimethods these could be bound to such a combination.

6 files changed, 18 insertions, 17 deletions

diff --git a/autotests/testfilecrypto.cpp b/autotests/testfilecrypto.cpp
index b86114a4..29521060 100644
--- a/autotests/testfilecrypto.cpp
+++ b/autotests/testfilecrypto.cpp
@@ -12,8 +12,8 @@ using namespace Quotient;
 void TestFileCrypto::encryptDecryptData()
 {
     QByteArray data = "ABCDEF";
-    auto [file, cipherText] = EncryptedFileMetadata::encryptFile(data);
-    auto decrypted = file.decryptFile(cipherText);
+    auto [file, cipherText] = encryptFile(data);
+    auto decrypted = decryptFile(cipherText, file);
     // AES CTR produces ciphertext of the same size as the original
     QCOMPARE(cipherText.size(), data.size());
     QCOMPARE(decrypted.size(), data.size());
diff --git a/lib/events/filesourceinfo.cpp b/lib/events/filesourceinfo.cpp
index a64c7da8..43e8e44c 100644
--- a/lib/events/filesourceinfo.cpp
+++ b/lib/events/filesourceinfo.cpp
@@ -16,14 +16,15 @@
 
 using namespace Quotient;
 
-QByteArray EncryptedFileMetadata::decryptFile(const QByteArray& ciphertext) const
+QByteArray Quotient::decryptFile(const QByteArray& ciphertext,
+                                 const EncryptedFileMetadata& metadata)
 {
 #ifdef Quotient_E2EE_ENABLED
-    auto _key = key.k;
+    auto _key = metadata.key.k;
     const auto keyBytes = QByteArray::fromBase64(
         _key.replace(u'_', u'/').replace(u'-', u'+').toLatin1());
     const auto sha256 =
-        QByteArray::fromBase64(hashes["sha256"_ls].toLatin1());
+        QByteArray::fromBase64(metadata.hashes["sha256"_ls].toLatin1());
     if (sha256
         != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
         qCWarning(E2EE) << "Hash verification failed for file";
@@ -37,7 +38,7 @@ QByteArray EncryptedFileMetadata::decryptFile(const QByteArray& ciphertext) cons
             ctx, EVP_aes_256_ctr(), nullptr,
             reinterpret_cast<const unsigned char*>(keyBytes.data()),
             reinterpret_cast<const unsigned char*>(
-                QByteArray::fromBase64(iv.toLatin1()).data()));
+                QByteArray::fromBase64(metadata.iv.toLatin1()).data()));
         EVP_DecryptUpdate(
             ctx, reinterpret_cast<unsigned char*>(plaintext.data()), &length,
             reinterpret_cast<const unsigned char*>(ciphertext.data()),
@@ -56,7 +57,7 @@ QByteArray EncryptedFileMetadata::decryptFile(const QByteArray& ciphertext) cons
 #endif
 }
 
-std::pair<EncryptedFileMetadata, QByteArray> EncryptedFileMetadata::encryptFile(
+std::pair<EncryptedFileMetadata, QByteArray> Quotient::encryptFile(
     const QByteArray& plainText)
 {
 #ifdef Quotient_E2EE_ENABLED
diff --git a/lib/events/filesourceinfo.h b/lib/events/filesourceinfo.h
index 885601be..8f7e3cbe 100644
--- a/lib/events/filesourceinfo.h
+++ b/lib/events/filesourceinfo.h
@@ -45,12 +45,13 @@ public:
     QString iv;
     QHash<QString, QString> hashes;
     QString v;
-
-    static std::pair<EncryptedFileMetadata, QByteArray> encryptFile(
-        const QByteArray& plainText);
-    QByteArray decryptFile(const QByteArray& ciphertext) const;
 };
 
+QUOTIENT_API std::pair<EncryptedFileMetadata, QByteArray> encryptFile(
+    const QByteArray& plainText);
+QUOTIENT_API QByteArray decryptFile(const QByteArray& ciphertext,
+                                    const EncryptedFileMetadata& metadata);
+
 template <>
 struct QUOTIENT_API JsonObjectConverter<EncryptedFileMetadata> {
     static void dumpTo(QJsonObject& jo, const EncryptedFileMetadata& pod);
diff --git a/lib/jobs/downloadfilejob.cpp b/lib/jobs/downloadfilejob.cpp
index 85c235c7..032b24f2 100644
--- a/lib/jobs/downloadfilejob.cpp
+++ b/lib/jobs/downloadfilejob.cpp
@@ -128,7 +128,7 @@ BaseJob::Status DownloadFileJob::prepareResult()
             QByteArray encrypted = d->tempFile->readAll();
 
             EncryptedFileMetadata file = *d->encryptedFile;
-            const auto decrypted = file.decryptFile(encrypted);
+            const auto decrypted = decryptFile(encrypted, file);
             d->targetFile->write(decrypted);
             d->tempFile->remove();
         } else {
@@ -153,7 +153,7 @@ BaseJob::Status DownloadFileJob::prepareResult()
             const auto encrypted = d->tempFile->readAll();
 
             EncryptedFileMetadata file = *d->encryptedFile;
-            const auto decrypted = file.decryptFile(encrypted);
+            const auto decrypted = decryptFile(encrypted, file);
             d->tempFile->write(decrypted);
         } else {
 #endif
diff --git a/lib/mxcreply.cpp b/lib/mxcreply.cpp
index b7993ad5..4174cfd8 100644
--- a/lib/mxcreply.cpp
+++ b/lib/mxcreply.cpp
@@ -47,9 +47,9 @@ MxcReply::MxcReply(QNetworkReply* reply, Room* room, const QString &eventId)
         if(!d->m_encryptedFile.has_value()) {
             d->m_device = d->m_reply;
         } else {
-            EncryptedFileMetadata file = *d->m_encryptedFile;
             auto buffer = new QBuffer(this);
-            buffer->setData(file.decryptFile(d->m_reply->readAll()));
+            buffer->setData(
+                decryptFile(d->m_reply->readAll(), *d->m_encryptedFile));
             buffer->open(ReadOnly);
             d->m_device = buffer;
         }
diff --git a/lib/room.cpp b/lib/room.cpp
index 0cef1025..4cb01a39 100644
--- a/lib/room.cpp
+++ b/lib/room.cpp
@@ -2524,8 +2524,7 @@ void Room::uploadFile(const QString& id, const QUrl& localFilename,
         QFile file(localFilename.toLocalFile());
         file.open(QFile::ReadOnly);
         QByteArray data;
-        std::tie(fileMetadata, data) =
-            EncryptedFileMetadata::encryptFile(file.readAll());
+        std::tie(fileMetadata, data) = encryptFile(file.readAll());
         tempFile.write(data);
         tempFile.close();
         fileName = QFileInfo(tempFile).absoluteFilePath();