refactor: move SecureUtils::getCertLength -> TlsUtility, and use Qt to get the length of the key file

src/lib/gui/TlsUtility.cpp

@@ -61,7 +61,20 @@ bool isCertValid(const QString &certPath)
 
 int getCertKeyLength(const QString &certPath)
 {
-  return deskflow::getCertLength(certPath.toStdString());
+  QFile file(certPath);
+  if (!file.open(QFile::ReadOnly)) {
+    //: %1 will be replaced by the certificate path
+    qDebug() << QObject::tr("failed to read key from certificate file: %1").arg(certPath);
+    return -1;
+  }
+
+  const auto key = QSslKey(&file, QSsl::Rsa);
+  if (key.isNull()) {
+    //: %1 will be replaced by the certificate path
+    qDebug() << QObject::tr("failed to parse certificate file: %1").arg(certPath);
+    return -1;
+  }
+  return key.length();
 }
 
 QByteArray certFingerprint(const QString &certPath)

src/lib/gui/TlsUtility.h

@@ -29,7 +29,7 @@ bool isCertValid(const QString &certPath = Settings::value(Settings::Security::C
 /**
  * @brief Get the lenght of a key
  * @param certPath path of the file to check, when unset will use the value of Settings::Security::Certificate
- * @return the bitsize of the key
+ * @return the bitsize of the key or -1 if there was an error reading the file
  */
 int getCertKeyLength(const QString &certPath = Settings::value(Settings::Security::Certificate).toString());
 

src/lib/net/SecureUtils.cpp

@@ -118,34 +118,6 @@ void generatePemSelfSignedCert(const std::string &path, int keyLength)
   PEM_write_X509(fp, cert);
 }
 
-int getCertLength(const std::string &path)
-{
-  auto fp = fopenUtf8Path(path.c_str(), "r");
-  if (!fp) {
-    throw std::runtime_error("could not open certificate output path");
-    return -1;
-  }
-
-  EVP_PKEY *privateKey = PEM_read_PrivateKey(fp, nullptr, nullptr, nullptr);
-
-  fclose(fp);
-
-  if (!privateKey) {
-    throw std::runtime_error("could not open certificate");
-    return -1;
-  }
-
-  if (EVP_PKEY_base_id(privateKey) != EVP_PKEY_RSA) {
-    throw std::runtime_error("not an RSA key");
-    return -1;
-  }
-  int size = EVP_PKEY_get_bits(privateKey);
-
-  EVP_PKEY_free(privateKey);
-
-  return size;
-}
-
 QString formatSSLFingerprintColumns(const QByteArray &fingerprint)
 {
   auto kMaxColumns = 24;

src/lib/net/SecureUtils.h

@@ -30,7 +30,5 @@ Fingerprint pemFileCertFingerprint(const std::string &path, QCryptographicHash::
 
 void generatePemSelfSignedCert(const std::string &path, int keyLength = 2048);
 
-int getCertLength(const std::string &path);
-
 QString generateFingerprintArt(const QByteArray &rawDigest);
 } // namespace deskflow