private void HandleMessageEvent(Object mailItem)
{
try
{
SignMailItem((MailItem)mailItem);
}
catch (Exception ex)
{
Logger.LogError("Signing a mail item according to DKIM failed with an exception. Check the logged exception for details.\n" + ex);
}
finally
{
#if !EX_2007_SP3 //not supported in Exchange 2007
// This allows Transport poison detection to correclty handle this message
// if there is a crash on this thread.
agentAsyncContext.Resume();
#endif
agentAsyncContext.Complete();
agentAsyncContext = null;
}
}
private void OnOnSubmittedMessage(SubmittedMessageEventSource source, QueuedMessageEventArgs queuedMessageEventArgs)
{
lock (_fileLock)
{
AgentAsyncContext agentAsyncContext = null;
try
{
var mailItem = queuedMessageEventArgs.MailItem;
agentAsyncContext = GetAgentAsyncContext();
// check the sender whitelist
if (_exchangeAttachmentFilterConfig.SendersWhitelist.Any(
f => Regex.IsMatch(mailItem.FromAddress.ToString(), WildcardToRegex(f))))
{
return;
}
// maybe we will need list of recipients on single line...
var recipientList = new StringBuilder();
for (var i = 0; i < mailItem.Recipients.Count; i++)
{
recipientList.Append(i == 0 ? mailItem.Recipients[i].Address.ToString() : "; " + mailItem.Recipients[i].Address);
}
var removedAttachments = new List <Attachment>();
var strippedAttachments = new List <Attachment>();
var messageRejected = false;
var messageLogStringBuilder = new SysLogBuilder();
var mailItemStatusText =
$"[from: {mailItem.FromAddress}] [to: {recipientList}] [method: {mailItem.InboundDeliveryMethod}] [subject: {mailItem.Message.Subject}] [size: {mailItem.MimeStreamLength.ToString("N0")}]";
messageLogStringBuilder.Log(mailItemStatusText);
if (mailItem.Message.Attachments.Count == 0 && _exchangeAttachmentFilterConfig.LogAccepted)
{
messageLogStringBuilder.LogPadded(
"ACCEPTED: [reason: no attachments]");
}
else
{
foreach (var attachment in mailItem.Message.Attachments)
{
// It would be great idea to process only attachments with size greater
// than some threshold, 'cos infected files are always quite small (only few kB)
// But I am not sure how to get the attachment size here, ...
// if (any previous) attachment rejected the message then break the processing now
if (messageRejected)
{
break;
}
AttachmentFilterStatus attachmentStatus = null;
if (_exchangeAttachmentFilterConfig.DsnStripOriginalMessage)
{
// DSN has InboundDeliveryMethod equal to DeliveryMethod.File and FromAddress is equal to <>
// and DSN's original message is included as message/rfc822 attachment
if (mailItem.InboundDeliveryMethod == DeliveryMethod.File &&
mailItem.FromAddress.ToString() == "<>" &&
attachment.ContentType.ToLower().Equals("message/rfc822"))
{
attachmentStatus =
new AttachmentFilterStatus(AttachmentFilterStatusEnum.StripAttachment,
"DSN original message");
}
}
if (attachmentStatus == null)
{
// default file status (by extension)
attachmentStatus = FilenameFilterStatus(attachment.FileName);
// is it archive?
if (_exchangeAttachmentFilterConfig.ScanArchives && IsArchive(attachment.FileName))
{
var archiveStatus = ProcessArchiveStream(attachment.GetContentReadStream());
if (archiveStatus.Status > attachmentStatus.Status)
{
attachmentStatus = archiveStatus;
}
}
// is it OpenXml document?
if (_exchangeAttachmentFilterConfig.ScanOpenXmlDocuments &&
IsOpenXmlDocument(attachment.FileName))
{
var openXmlDocumentStatus =
ProcessOpenXmlDocumentStream(attachment.GetContentReadStream());
if (openXmlDocumentStatus.Status > attachmentStatus.Status)
{
attachmentStatus = openXmlDocumentStatus;
}
}
}
var attachmentStatusText =
$"[file: {attachment.FileName}] [type: {attachment.AttachmentType}] [content type:{attachment.ContentType}] [reason: {attachmentStatus.Reason}]";
switch (attachmentStatus.Status)
{
case AttachmentFilterStatusEnum.Accept:
if (_exchangeAttachmentFilterConfig.LogAccepted)
{
messageLogStringBuilder.LogPadded($"ACCEPTED: {attachmentStatusText}");
}
break;
case AttachmentFilterStatusEnum.RemoveAttachment:
// just mark this attachment for removement, but do not touch attachments collection now
// (we are in foreach loop and need to process them all)
removedAttachments.Add(attachment);
if (_exchangeAttachmentFilterConfig.LogRejectedOrRemoved)
{
messageLogStringBuilder.LogPadded($"REMOVED: {attachmentStatusText}");
}
break;
case AttachmentFilterStatusEnum.StripAttachment:
// just mark this attachment for removement, but do not touch attachments collection now
// (we are in foreach loop and need to process them all)
strippedAttachments.Add(attachment);
if (_exchangeAttachmentFilterConfig.LogRejectedOrRemoved)
{
messageLogStringBuilder.LogPadded($"STRIPPED: {attachmentStatusText}");
}
break;
case AttachmentFilterStatusEnum.RejectMessage:
// reject whole message
if (_exchangeAttachmentFilterConfig.LogRejectedOrRemoved)
{
messageLogStringBuilder.LogPadded($"REJECTED: {attachmentStatusText}");
}
messageRejected = true;
break;
}
}
}
if (messageLogStringBuilder.MessageCount > 1)
{
SysLog.Log(messageLogStringBuilder);
}
// reject the message?
if (messageRejected)
{
// delete the source message and do nothing more (we do not send DSN)...
source.Delete();
return;
}
// for every attachment we marked as being removed create new txt attachment with some info why it happened...
foreach (var removedAttachment in removedAttachments)
{
// new attachment filename
var newFileName =
$"{_exchangeAttachmentFilterConfig.RemovedAttachmentPrefix}{removedAttachment.FileName}.txt";
// add new attachment to the message...
var newAttachment = mailItem.Message.Attachments.Add(newFileName);
// ...and write content into it (info message)
var newAttachmentWriter = new StreamWriter(newAttachment.GetContentWriteStream());
newAttachmentWriter.WriteLine(removedAttachment.FileName);
newAttachmentWriter.WriteLine();
newAttachmentWriter.WriteLine(_exchangeAttachmentFilterConfig.RemovedAttachmentNewContent);
newAttachmentWriter.Flush();
newAttachmentWriter.Close();
}
// finally remove all attachments marked for removal
foreach (var removedAttachment in removedAttachments)
{
mailItem.Message.Attachments.Remove(removedAttachment);
}
// ...and stripped attachments, too
foreach (var strippedAttachment in strippedAttachments)
{
mailItem.Message.Attachments.Remove(strippedAttachment);
}
}
catch (IOException ex)
{
SysLog.Log("IOException: " + ex.Message);
}
catch (Exception ex)
{
SysLog.Log("Exception: " + ex.Message);
}
finally
{
agentAsyncContext?.Complete();
}
}
}
void RvScopiaMeeting_OnResolvedMessage(ResolvedMessageEventSource source, QueuedMessageEventArgs args){
this.emailMessage = args.MailItem.Message;
if (this.emailMessage == null || this.emailMessage.TnefPart == null) {
return;
}
long now = DateTime.UtcNow.Ticks;
SchedulingInfo schedulingInfo = new SchedulingInfo();
schedulingInfo.subject = args.MailItem.Message.Subject;
schedulingInfo.delegatorEmailAddr = args.MailItem.Message.From.NativeAddress;
RvLogger.DebugWrite("Enter transport agent, from: " + schedulingInfo.delegatorEmailAddr + ", subject: " + schedulingInfo.subject);
try
{
this.agentAsyncContext = this.GetAgentAsyncContext();
schedulingInfo.requestType = this.getRequestType(this.emailMessage.MapiMessageClass);
//Reject all meeting type except request and cancel.
if (RequestType.Other == schedulingInfo.requestType)
{
RvLogger.DebugWrite("Reject other request type: " + this.emailMessage.MapiMessageClass);
return;
}
RvMailParser parser = new RvMailParser(this);
try
{
parser.parseTnefSimple(args.MailItem, schedulingInfo);
}
catch (Exception exceptionParseMail)
{
RvLogger.DebugWrite("Fail to parse mail.");
RvLogger.DebugWrite(exceptionParseMail.Message);
RvLogger.DebugWrite(exceptionParseMail.StackTrace);
return;
}
//Reject forwarded appointment
if (!string.IsNullOrEmpty(schedulingInfo.subjectPrefix) && "FW:".Equals(schedulingInfo.subjectPrefix))
{
RvLogger.DebugWrite("Reject forward request type");
return;
}
if (schedulingInfo.recurrencePattern != null){
schedulingInfo.recurrenceHashInfo = RvScopiaMeeting.getHashString4Str(schedulingInfo.recurrencePattern.getStringForHash());
schedulingInfo.recurrencePattern.startDate = schedulingInfo.startDate;
schedulingInfo.recurrencePattern.endDate = schedulingInfo.endDate;
}
if (null == schedulingInfo.emailMessage) {
RvLogger.DebugWrite("null == schedulingInfo.emailMessage================================================");
return;
}
if (!isScopia(schedulingInfo))
{
RvLogger.DebugWrite("This is not a SCOPIA meeting");
return;
}
parseRecipentsChanged(schedulingInfo);
if (schedulingInfo.isRecipentsChanged)
if (schedulingInfo.requestType == RequestType.CancelMeeting)
{
schedulingInfo.requestType = RequestType.CreateMeeting;
schedulingInfo.isAddRecipents = false;
schedulingInfo.subject = schedulingInfo.subject.Substring(schedulingInfo.subjectPrefix.Length + 1);
Thread.Sleep(HOW_MANY_SECONDS_WAIT_FOR_FOLLOWING_REQUEST * 1000);
}else
schedulingInfo.isAddRecipents = true;
if (RvScopiaMeeting.SERVER_ACCOUNT.Equals(schedulingInfo.senderEmailAddr))
{
RvLogger.DebugWrite("Send a email back to notify the sender this mail is failed to send out.");
return;
}
//when modify a recurrence, to make sure the modified ocurrence request is later than the recurrence request.
if (schedulingInfo.meetingType == MeetingType.Ocurrence)
Thread.Sleep(HOW_MANY_SECONDS_WAIT_FOR_FOLLOWING_REQUEST * 1000);
icm.XmlApi.scheduleReportType result = changeMail(source, args, schedulingInfo, now);
if (null != result && result.Success && isCreateMeetingRequest(schedulingInfo))
{
Dictionary<string, byte[]> attachmentsdata = null;
if (this.emailMessage.Attachments.Count > 0)
{
attachmentsdata = new Dictionary<string, byte[]>(this.emailMessage.Attachments.Count);
for (int i = 0; i < this.emailMessage.Attachments.Count; i++)
{
Attachment attachment = this.emailMessage.Attachments[i];
Stream readStream = attachment.GetContentReadStream();
byte[] bytes = null;
if (readStream.Length > 0) {
bytes = new byte[readStream.Length];
readStream.Read(bytes, 0, bytes.Length);
} else
bytes = Encoding.ASCII.GetBytes(" ");
attachmentsdata.Add(attachment.FileName, bytes);
}
}
parser.changeBodyOfTnef(args.MailItem.Message.TnefPart, schedulingInfo);
if (attachmentsdata != null)
{
foreach (KeyValuePair<string, byte[]> attachmentdata in attachmentsdata)
{
Attachment attachment = this.emailMessage.Attachments.Add(attachmentdata.Key);
Stream attachmentStream = attachment.GetContentWriteStream();
attachmentStream.Write(attachmentdata.Value, 0, attachmentdata.Value.Length);
attachmentStream.Flush();
attachmentStream.Close();
}
}
}
}
catch (Exception ex)
{
RvLogger.DebugWrite(ex.Message);
RvLogger.DebugWrite(ex.StackTrace);
string baseFailCode = ex.Message;
sendBackAMail(source, schedulingInfo, baseFailCode);
}
finally
{
RvLogger.DebugWrite("Start to agentAsyncContext.Complete()================================================");
agentAsyncContext.Complete();
RvLogger.DebugWrite("Complete agentAsyncContext.Complete()================================================");
RvLogger.DebugWrite("Leave transport agent, from: " + schedulingInfo.delegatorEmailAddr + ", subject: " + schedulingInfo.subject);
}
}