Cleanup across E2EE code

Notably:
- simplified unnecessarily verbose constructs;
- formally aligned (no re-numeration was necessary)
  QOlmMessage::Type with corresponding OLM_ constants;
- dropped QOlmSession::encryptMessageType() because it's very
  sensitive to the order of calling with QOlmSession::encrypt()
  (and encrypt() itself already calls it and returns the message
  type);
- simplify the return type of pickle() calls that can only fail due to
  an internal error;
- replace const QString& with QStringView or const QByteArray&
  where appropriate;
- use '\0' where it was meant to be instead of '0'.

1 files changed, 14 insertions, 21 deletions

diff --git a/lib/events/filesourceinfo.cpp b/lib/events/filesourceinfo.cpp
index e8b6794b..6abe6a08 100644
--- a/lib/events/filesourceinfo.cpp
+++ b/lib/events/filesourceinfo.cpp
@@ -59,19 +59,15 @@ 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 k = getRandom(32);
+    auto kBase64 = k.toBase64(QByteArray::Base64UrlEncoding
+                              | QByteArray::OmitTrailingEquals);
+    auto iv = getRandom(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,
                        reinterpret_cast<const unsigned char*>(k.data()),
@@ -89,14 +85,11 @@ std::pair<EncryptedFileMetadata, QByteArray> Quotient::encryptFile(
     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 };
+                    .toBase64(QByteArray::OmitTrailingEquals);
+    auto ivBase64 = iv.toBase64(QByteArray::OmitTrailingEquals);
+    EncryptedFileMetadata efm = {
+        {}, key, ivBase64, { { QStringLiteral("sha256"), hash } }, "v2"_ls
+    };
     return { efm, cipherText };
 #else
     return {};