From: op <op@openbsd.org>
Date: Tue, 5 Dec 2023 13:38:25 +0000 (+0000)
Subject: reject headers that start with a space or tab
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a5bc80fb5b01fd00243844063b729cef2049cee2;p=openbsd

reject headers that start with a space or tab

If the first header starts with a space but still contains a colon
character, it is added to the body mail effectively appending it to the
Received header due to the folding rules.

Issue reported by Crystal Kolipe

ok millert@, giovanni@
---

diff --git a/usr.sbin/smtpd/rfc5322.c b/usr.sbin/smtpd/rfc5322.c
index a6f15056d59..79f55327de0 100644
--- a/usr.sbin/smtpd/rfc5322.c
+++ b/usr.sbin/smtpd/rfc5322.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rfc5322.c,v 1.3 2021/06/14 17:58:16 eric Exp $	*/
+/*	$OpenBSD: rfc5322.c,v 1.4 2023/12/05 13:38:25 op Exp $	*/
 
 /*
  * Copyright (c) 2018 Eric Faurot <eric@openbsd.org>
@@ -149,7 +149,8 @@ _rfc5322_next(struct rfc5322_parser *parser, struct rfc5322_result *res)
 
 	case RFC5322_NONE:
 	case RFC5322_HEADER_END:
-		if (line && (pos = strchr(line, ':'))) {
+		if (line && line[0] != ' ' && line[0] != '\t' &&
+		    (pos = strchr(line, ':'))) {
 			len = pos - line;
 			if (buf_grow(&parser->hdr, len + 1) == -1)
 				return -1;