/// <summary>
/// Process a transmitted message to import any signing certificates for subsequent S/MIME encryption.
/// </summary>
/// <param name="o">A ProcessMessageArguments object containing message parameters.</param>
private void ProcessMessage(object o)
{
ProcessMessageArguments arguments = (ProcessMessageArguments)o;
// Export the message to a local directory.
if (!string.IsNullOrEmpty(arguments.ExportDirectory))
{
string messageId = Functions.ReturnBetween(arguments.MessageText.ToLower(), "message-id: <", ">");
if (string.IsNullOrEmpty(messageId))
{
messageId = Guid.NewGuid().ToString();
}
string fileName = ProxyFunctions.GetExportFileName(arguments.ExportDirectory, messageId, arguments.InstanceId, arguments.UserName);
File.WriteAllText(fileName, arguments.MessageText);
}
// Only parse the message if it contains a known S/MIME content type.
string canonicalMessageText = arguments.MessageText.ToLower();
if (canonicalMessageText.IndexOf("application/x-pkcs7-signature") > -1 || canonicalMessageText.IndexOf("application/pkcs7-mime") > -1)
{
try
{
// Parse the message.
MailMessage message = new MailMessage(arguments.MessageText);
// If the message contains a signing certificate that we haven't processed on this session, import it.
foreach (X509Certificate2 cert in message.SmimeSigningCertificateChain)
{
if (cert != null && !SmimeCertificatesReceived.Contains(cert))
{
// Import the certificate to the Local Machine store.
ProxyFunctions.Log(LogWriter, SessionId, arguments.ConnectionId, "Importing certificate with Serial Number {" + cert.SerialNumber + "}.", Proxy.LogLevel.Information, LogLevel);
CertHelper.InstallWindowsCertificate(cert, StoreLocation.LocalMachine);
// Remember this ceriticate to avoid importing it again this session.
SmimeCertificatesReceived.Add(cert);
}
}
}
catch (Exception ex)
{
if (arguments.DebugMode || System.Diagnostics.Debugger.IsAttached)
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception while processing message: " + ex.ToString(), Proxy.LogLevel.Error, LogLevel);
}
else
{
ProxyFunctions.Log(LogWriter, SessionId, "Exception while processing message: " + ex.Message, Proxy.LogLevel.Error, LogLevel);
}
}
}
}
