More cleanup, especially in EncryptedFile

For EncryptedFile:
- JSON converter bodies moved away to .cpp;
- instead of C-style casts, reinterpret_cast is used to convert from
  (const) char* to (const) unsigned char*;
- the size for the target plain text takes into account the case where
  the cipher block size can be larger than 1 (after reading
  https://www.openssl.org/docs/man1.1.1/man3/EVP_DecryptUpdate.html).
- file decryption is wrapped in #ifdef Quotient_E2EE_ENABLED, to avoid
  OpenSSL linking errors when compiling without E2EE.

4 files changed, 99 insertions, 57 deletions

diff --git a/lib/connection.cpp b/lib/connection.cpp
index 87fc8e2c..1ef2495d 100644
--- a/lib/connection.cpp
+++ b/lib/connection.cpp
@@ -2007,8 +2007,10 @@ void Connection::Private::loadOutdatedUserDevices()
                                     << device.algorithms;
                     continue;
                 }
-                if(!verifyIdentitySignature(device, device.deviceId, device.userId)) {
-                    qCWarning(E2EE) << "Failed to verify devicekeys signature. Skipping this device";
+                if (!verifyIdentitySignature(device, device.deviceId,
+                                             device.userId)) {
+                    qCWarning(E2EE) << "Failed to verify devicekeys signature. "
+                                       "Skipping this device";
                     continue;
                 }
                 deviceKeys[user][device.deviceId] = device;
@@ -2022,9 +2024,11 @@ void Connection::Private::loadOutdatedUserDevices()
 void Connection::Private::saveDevicesList()
 {
     q->database()->transaction();
-    auto query = q->database()->prepareQuery(QStringLiteral("DELETE FROM tracked_users"));
+    auto query = q->database()->prepareQuery(
+        QStringLiteral("DELETE FROM tracked_users"));
     q->database()->execute(query);
-    query.prepare(QStringLiteral("INSERT INTO tracked_users(matrixId) VALUES(:matrixId);"));
+    query.prepare(QStringLiteral(
+        "INSERT INTO tracked_users(matrixId) VALUES(:matrixId);"));
     for (const auto& user : trackedUsers) {
         query.bindValue(":matrixId", user);
         q->database()->execute(query);
@@ -2032,13 +2036,18 @@ void Connection::Private::saveDevicesList()
 
     query.prepare(QStringLiteral("DELETE FROM outdated_users"));
     q->database()->execute(query);
-    query.prepare(QStringLiteral("INSERT INTO outdated_users(matrixId) VALUES(:matrixId);"));
+    query.prepare(QStringLiteral(
+        "INSERT INTO outdated_users(matrixId) VALUES(:matrixId);"));
     for (const auto& user : outdatedUsers) {
         query.bindValue(":matrixId", user);
         q->database()->execute(query);
     }
 
-    query.prepare(QStringLiteral("INSERT INTO tracked_devices(matrixId, deviceId, curveKeyId, curveKey, edKeyId, edKey) VALUES(:matrixId, :deviceId, :curveKeyId, :curveKey, :edKeyId, :edKey);"));
+    query.prepare(QStringLiteral(
+        "INSERT INTO tracked_devices"
+        "(matrixId, deviceId, curveKeyId, curveKey, edKeyId, edKey) "
+        "VALUES(:matrixId, :deviceId, :curveKeyId, :curveKey, :edKeyId, :edKey);"
+        ));
     for (const auto& user : deviceKeys.keys()) {
         for (const auto& device : deviceKeys[user]) {
             auto keys = device.keys.keys();
diff --git a/lib/events/encryptedfile.cpp b/lib/events/encryptedfile.cpp
index dbb72af8..d4a517bd 100644
--- a/lib/events/encryptedfile.cpp
+++ b/lib/events/encryptedfile.cpp
@@ -5,27 +5,88 @@
 #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
+QByteArray EncryptedFile::decryptFile(const QByteArray& ciphertext) const
 {
-    QString _key = key.k;
-    auto keyBytes  = QByteArray::fromBase64(_key.replace(QLatin1Char('_'), QLatin1Char('/')).replace(QLatin1Char('-'), QLatin1Char('+')).toLatin1());
+#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)) {
+    if (sha256
+        != QCryptographicHash::hash(ciphertext, QCryptographicHash::Sha256)) {
         qCWarning(E2EE) << "Hash verification failed for file";
-        return QByteArray();
+        return {};
     }
-    QByteArray plaintext(ciphertext.size(), 0);
-    EVP_CIPHER_CTX *ctx;
-    int length;
-    ctx = EVP_CIPHER_CTX_new();
-    EVP_DecryptInit_ex(ctx, EVP_aes_256_ctr(), NULL, (const unsigned char *)keyBytes.data(), (const unsigned char *)QByteArray::fromBase64(iv.toLatin1()).data());
-    EVP_DecryptUpdate(ctx, (unsigned char *)plaintext.data(), &length, (const unsigned char *)ciphertext.data(), ciphertext.size());
-    EVP_DecryptFinal_ex(ctx, (unsigned char *)plaintext.data() + length, &length);
-    EVP_CIPHER_CTX_free(ctx);
-    return plaintext;
+    {
+        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);
 }
diff --git a/lib/events/encryptedfile.h b/lib/events/encryptedfile.h
index 43bafc49..0558563f 100644
--- a/lib/events/encryptedfile.h
+++ b/lib/events/encryptedfile.h
@@ -49,42 +49,14 @@ public:
 };
 
 template <>
-struct JsonObjectConverter<EncryptedFile> {
-    static void 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);
-    }
-    static void 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);
-    }
+struct QUOTIENT_API JsonObjectConverter<EncryptedFile> {
+    static void dumpTo(QJsonObject& jo, const EncryptedFile& pod);
+    static void fillFrom(const QJsonObject& jo, EncryptedFile& pod);
 };
 
 template <>
-struct JsonObjectConverter<JWK> {
-    static void 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);
-    }
-    static void 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);
-    }
+struct QUOTIENT_API JsonObjectConverter<JWK> {
+    static void dumpTo(QJsonObject& jo, const JWK& pod);
+    static void fillFrom(const QJsonObject& jo, JWK& pod);
 };
 } // namespace Quotient
diff --git a/lib/jobs/downloadfilejob.cpp b/lib/jobs/downloadfilejob.cpp
index 634e5fb9..d00fc5f4 100644
--- a/lib/jobs/downloadfilejob.cpp
+++ b/lib/jobs/downloadfilejob.cpp
@@ -127,7 +127,7 @@ BaseJob::Status DownloadFileJob::prepareResult()
             QByteArray encrypted = d->tempFile->readAll();
 
             EncryptedFile file = *d->encryptedFile;
-            auto decrypted = file.decryptFile(encrypted);
+            const auto decrypted = file.decryptFile(encrypted);
             d->targetFile->write(decrypted);
             d->tempFile->remove();
         } else {
@@ -149,10 +149,10 @@ BaseJob::Status DownloadFileJob::prepareResult()
 #ifdef Quotient_E2EE_ENABLED
         if (d->encryptedFile.has_value()) {
             d->tempFile->seek(0);
-            auto encrypted = d->tempFile->readAll();
+            const auto encrypted = d->tempFile->readAll();
 
             EncryptedFile file = *d->encryptedFile;
-            auto decrypted = file.decryptFile(encrypted);
+            const auto decrypted = file.decryptFile(encrypted);
             d->tempFile->write(decrypted);
         } else {
 #endif