delivery_lmtp does not know how to deal with LMTP servers returning

continuation lines, fix this.

reported and initial diff by parchd-1 @ github, ok sunil@

1 files changed, 29 insertions, 9 deletions

diff --git a/usr.sbin/smtpd/delivery_lmtp.c b/usr.sbin/smtpd/delivery_lmtp.c
index 9459b72163f..8df04f5dcb5 100644
--- a/usr.sbin/smtpd/delivery_lmtp.c
+++ b/usr.sbin/smtpd/delivery_lmtp.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: delivery_lmtp.c,v 1.15 2015/12/14 10:22:11 jung Exp $ */
+/* $OpenBSD: delivery_lmtp.c,v 1.16 2016/06/05 11:48:56 gilles Exp $ */
 
 /*
  * Copyright (c) 2013 Ashish SHUKLA <ashish.is@lostca.se>
@@ -36,6 +36,9 @@
 
 #include "smtpd.h"
 
+/* should be more than enough for any LMTP server */
+#define	MAX_CONTINUATIONS	100
+
 static int	inet_socket(char *);
 static int	lmtp_cmd(char **buf, size_t *, int, FILE *, const char *, ...)
 		    __attribute__((__format__ (printf, 5, 6)))
@@ -175,6 +178,7 @@ lmtp_cmd(char **buf, size_t *sz, int code, FILE *fp, const char *fmt, ...)
 	va_list	 ap;
 	char	*bufp;
 	ssize_t	 len;
+	size_t	 counter;
 
 	va_start(ap, fmt);
 	if (vfprintf(fp, fmt, ap) < 0)
@@ -187,14 +191,30 @@ lmtp_cmd(char **buf, size_t *sz, int code, FILE *fp, const char *fmt, ...)
 	if (fflush(fp) != 0)
 		err(1, "fflush");
 
-	if ((len = getline(buf, sz, fp)) == -1)
-		err(1, "getline");
-
-	bufp = *buf;
-	if (len >= 2 && bufp[len - 2] == '\r')
-		bufp[len - 2] = '\0';
-	else if (bufp[len - 1] == '\n')
-		bufp[len - 1] = '\0';
+	counter = 0;
+	do {
+		if ((len = getline(buf, sz, fp)) == -1)
+			err(1, "getline");
+		if (len < 4)
+			err(1, "line too short");
+
+		bufp = *buf;
+		if (len >= 2 && bufp[len - 2] == '\r')
+			bufp[len - 2] = '\0';
+		else if (bufp[len - 1] == '\n')
+			bufp[len - 1] = '\0';
+
+		if (bufp[3] == '\0' || bufp[3] == ' ')
+			break;
+		else if (bufp[3] == '-') {
+			if (counter == MAX_CONTINUATIONS)
+				errx(1, "LMTP server is sending too many continuations");
+			counter++;
+			continue;
+		}
+		else
+			errx(1, "invalid line");
+	} while (1);
 
 	return bufp[0] != code;
 }