From: Art Cancro <ajc@citadel.org>
Date: Fri, 7 Jun 2002 22:10:51 +0000 (+0000)
Subject: * Added a new message function hook type EVT_SMTPSCAN which permits modules to
X-Git-Tag: v7.86~6381
X-Git-Url: https://code.citadel.org/?p=citadel.git;a=commitdiff_plain;h=9efc6048ae21ab4e374ac4d22a1e4c50740d48be

* Added a new message function hook type EVT_SMTPSCAN which permits modules to
  register hooks that can scan incoming SMTP messages and elect to reject them
  (due to virus or spam content, for example).
---

diff --git a/citadel/ChangeLog b/citadel/ChangeLog
index 2768183f4..0a8ba560f 100644
--- a/citadel/ChangeLog
+++ b/citadel/ChangeLog
@@ -1,4 +1,9 @@
  $Log$
+ Revision 591.36  2002/06/07 22:10:51  ajc
+ * Added a new message function hook type EVT_SMTPSCAN which permits modules to
+   register hooks that can scan incoming SMTP messages and elect to reject them
+   (due to virus or spam content, for example).
+
  Revision 591.35  2002/06/07 03:22:13  ajc
  * Added a module "serv_mrtg" which allows activity reporting to MRTG
    (http://www.mrtg.org) -- this will replace our stats program.
@@ -3692,3 +3697,4 @@ Sat Jul 11 00:20:48 EDT 1998 Nathan Bryant <bryant@cs.usm.maine.edu>
 
 Fri Jul 10 1998 Art Cancro <ajc@uncensored.citadel.org>
 	* Initial CVS import
+
diff --git a/citadel/serv_smtp.c b/citadel/serv_smtp.c
index 6617cc2c4..43896c280 100644
--- a/citadel/serv_smtp.c
+++ b/citadel/serv_smtp.c
@@ -457,6 +457,7 @@ void smtp_data(void) {
 	long msgnum;
 	char nowstamp[SIZ];
 	struct recptypes *valid;
+	int scan_errors;
 
 	if (strlen(SMTP->from) == 0) {
 		cprintf("503 Need MAIL command first.\r\n");
@@ -508,17 +509,35 @@ void smtp_data(void) {
 
 	/* Submit the message into the Citadel system. */
 	valid = validate_recipients(SMTP->recipients);
-	msgnum = CtdlSubmitMsg(msg, valid, "");
-	CtdlFreeMessage(msg);
-	phree(valid);
 
-	if (msgnum > 0L) {
-		cprintf("250 Message accepted.\r\n");
+	/* If there are modules that want to scan this message before final
+	 * submission (such as virus checkers or spam filters), call them now
+	 * and give them an opportunity to reject the message.
+	 */
+	scan_errors = PerformMessageHooks(msg, EVT_SMTPSCAN);
+
+	if (scan_errors > 0) {	/* We don't want this message! */
+
+		if (msg->cm_fields['0'] == NULL) {
+			msg->cm_fields['0'] = strdoop(
+				"Message rejected by filter");
+		}
+
+		cprintf("552 %s\r\n", msg->cm_fields['0']);
 	}
-	else {
-		cprintf("550 Internal delivery error\r\n");
+	
+	else {			/* Ok, we'll accept this message. */
+		msgnum = CtdlSubmitMsg(msg, valid, "");
+		if (msgnum > 0L) {
+			cprintf("250 Message accepted.\r\n");
+		}
+		else {
+			cprintf("550 Internal delivery error\r\n");
+		}
 	}
 
+	CtdlFreeMessage(msg);
+	phree(valid);
 	smtp_data_clear();	/* clear out the buffers now */
 }
 
diff --git a/citadel/server.h b/citadel/server.h
index c8cb89254..127be4c95 100644
--- a/citadel/server.h
+++ b/citadel/server.h
@@ -338,6 +338,7 @@ extern DLEXP struct MessageFunctionHook *MessageHookTable;
 #define EVT_BEFOREREAD	200
 #define EVT_BEFORESAVE	201
 #define EVT_AFTERSAVE	202
+#define EVT_SMTPSCAN	203	/* called before submitting a msg from SMTP */
 
 
 
diff --git a/citadel/techdoc/hack.txt b/citadel/techdoc/hack.txt
index 90bbe404a..af5ce2cd1 100644
--- a/citadel/techdoc/hack.txt
+++ b/citadel/techdoc/hack.txt
@@ -117,6 +117,11 @@ T	Date/Time	A 32-bit integer containing the date and time of
 U       Subject         Optional.  Developers may choose whether they wish to
                         generate or display subject fields.  Citadel/UX does
                         not generate them, but it does print them when found.
+0	Error		This field is typically never found in a message on
+			disk or in transit.  Message scanning modules are
+			expected to fill in this field when rejecting a message
+			with an explanation as to what happened (virus found,
+			message looks like spam, etc.)
   
 			EXAMPLE