From: Omar Polo <op@omarpolo.com>
Subject: smtpd: implement the report response for proc-filters too
To: tech@openbsd.org
Cc: Gilles CHEHADE <gilles@poolp.org>
Date: Fri, 09 Aug 2024 12:52:49 +0200

We don't seem to allow proc filters to report, unlike built-in ones.  We
document the report response thought, so I guess it's just an omission.

I'm attaching a diff that adds the missing bits, I've quickly tried with
a hacked version of Gilles' filter-kicker that does a report instead of
a disconnect and I can see the report being broadcasted.

This was reported by renegm on github:
<https://github.com/OpenSMTPD/OpenSMTPD/issues/1257>

Thoughts/clues?


Thanks,

Omar Polo

diff /usr/src
commit - 055349ebc95a6766143567ec24bc3f785a470f34
path + /usr/src
blob - 08db127c4c062f988b52fd483423388103bebacc
file + usr.sbin/smtpd/lka_filter.c
--- usr.sbin/smtpd/lka_filter.c
+++ usr.sbin/smtpd/lka_filter.c
@@ -47,6 +47,7 @@ static int	filter_builtins_data(struct filter_session 
 static int	filter_builtins_commit(struct filter_session *, struct filter *, uint64_t, const char *);
 
 static void	filter_result_proceed(uint64_t);
+static void	filter_result_report(uint64_t, const char *);
 static void	filter_result_junk(uint64_t);
 static void	filter_result_rewrite(uint64_t, const char *);
 static void	filter_result_reject(uint64_t, const char *);
@@ -657,6 +658,8 @@ lka_filter_process_response(const char *name, const ch
 			filter_result_reject(reqid, parameter);
 		else if (strncmp(response, "disconnect|", 11) == 0)
 			filter_result_disconnect(reqid, parameter);
+		else if (strncmp(response, "report|", 7) == 0)
+			filter_result_report(reqid, parameter);
 		else
 			fatalx("Invalid directive: %s", line);
 	}
@@ -957,6 +960,16 @@ filter_result_proceed(uint64_t reqid)
 }
 
 static void
+filter_result_report(uint64_t reqid, const char *param)
+{
+	m_create(p_dispatcher, IMSG_FILTER_SMTP_PROTOCOL, 0, 0, -1);
+	m_add_id(p_dispatcher, reqid);
+	m_add_int(p_dispatcher, FILTER_REPORT);
+	m_add_string(p_dispatcher, param);
+	m_close(p_dispatcher);
+}
+
+static void
 filter_result_junk(uint64_t reqid)
 {
 	m_create(p_dispatcher, IMSG_FILTER_SMTP_PROTOCOL, 0, 0, -1);
@@ -1633,6 +1646,9 @@ lka_report_smtp_filter_response(const char *direction,
 	case FILTER_PROCEED:
 		response_name = "proceed";
 		break;
+	case FILTER_REPORT:
+		response_name = "report";
+		break;
 	case FILTER_JUNK:
 		response_name = "junk";
 		break;
blob - b72d295918243c5c57959ee721fe3117562d44ea
file + usr.sbin/smtpd/smtp_session.c
--- usr.sbin/smtpd/smtp_session.c
+++ usr.sbin/smtpd/smtp_session.c
@@ -1026,6 +1026,7 @@ smtp_session_imsg(struct mproc *p, struct imsg *imsg)
 			filter_param = s->filter_param;
 			/* fallthrough */
 
+		case FILTER_REPORT:
 		case FILTER_REWRITE:
 			smtp_report_filter_response(s, s->filter_phase,
 			    filter_response,
blob - 6eddff3c72575c5bb29a1bf6788cfc4df950bb0a
file + usr.sbin/smtpd/smtpd.h
--- usr.sbin/smtpd/smtpd.h
+++ usr.sbin/smtpd/smtpd.h
@@ -1125,6 +1125,7 @@ struct filter_config {
 
 enum filter_status {
 	FILTER_PROCEED,
+	FILTER_REPORT,
 	FILTER_REWRITE,
 	FILTER_REJECT,
 	FILTER_DISCONNECT,