Exiscan bug with multiple messages in one SMTP session
"Edgar Lovecraft" <[email protected]> Tue, 09 Nov 2004 22:41:09 -0600
| Newsgroups | gmane.mail.exim.user,gmane.mail.exim.exiscan.user |
|---|---|
| Message-ID | <jbm.20041109224109.6a4e0789@User21> |
I am re-posting this as I did not see any response to the first one... Perhaps I was not clear enough in my first posting which is below, but the internal exiscan variables are not behaving properly when there are multiple messages in a single SMTP transaction, thus a message with malformed MIME parts will be delivered on any subsequent DATA commands that are part of a single SMTP transaction. For example, I can have the first 'MAIL/RCPT/DATA' fail with a MIME error, and then ANY 'MAIL/RCPT/DATA' after that first failure, will ACCEPT any malformed message. So currently, they only way to avoid this, is to allow only one MAIL command per SMTP session. Anyone that can confirm this behavoir does/doesn't exist on their systems would be greatly appreciated. :) Here is the original message that I posted... ------ Here is the problem, on exim 4.43 with exiscan-acl-4.43-28.patch, a malformed message (in my example below there are bad base64 chars), passes the demime error checks the second time through on the same connection. To test, connect to your exim MTA with telnet, issue a standard SMTP transaction, feed the example below as the data, exiscan will reject the message (if you have the errors >=2 I believe), after the message is rejected, issue another "mail from" command, i used the exact same information for the mail from: and rcpt to: commands, and feed the message through a second time, this time it will pass the demime checks, or at least it does on my machines, yes machines, i have tested this on multiple exim/exiscan installs that I run. Just for calrity, here is a mock smtp transaction to exibit the problem: EHLO localhost.localdomain OK MAIL FROM:<user-at-my-domain.com> OK RCPT TO:<user-at-my-domain.com> OK DATA <--past the fake message below in--> . 550 Rejected, bad mime parts MAIL FROM:<user-at-my-domain.com> OK RCPT TO:<user-at-my-domain.com> OK DATA <--past the fake message below in a second time--> <--or any other message that has bad mime parts for that matter--> . OK <message_id> QUIT just remove the *'s before feeding the message in the SMTP DATA command. <BEGIN_FAKE_MESSAGE> *Message-ID: <[email protected]> *Received: from [69.102.13.153] by web11502.mail.yahoo.com via HTTP; * Thu, 04 Nov 2004 19:48:23 PDT *Date: Thu, 04 Nov 2004 19:48:23 -0700 (PDT) *From: Someone <[email protected]> *Subject: exiscan testing *To: Someone <[email protected]> *MIME-Version: 1.0 *Content-Type: multipart/alternative; * boundary="0-419322518-1098240503=:82280" * *--0-419322518-1098240503=:82280 *Content-Type: text/plain; charset=us-ascii *Content-Transfer-Encoding: base64 * *c29tZXRoaW5nIGlzIGhlc%%$$mU= * *--0-419322518-1098240503=:82280-- </END_FAKE_MESSAGE> -- --EAL-- -- -- ## List details at http://www.exim.org/mailman/listinfo/exim-users Exim details at http://www.exim.org/ ##