From: Stephan Bosch <stephan.bosch@dovecot.fi>
Date: Mon, 3 Dec 2018 23:16:47 +0000 (+0100)
Subject: lib-smtp: client: Prevent sending an empty XCLIENT command when the first parameter... 
X-Git-Tag: 2.3.5~296
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5494f652d571c7eeb2a350cd8391121c7dcf5578;p=thirdparty%2Fdovecot%2Fcore.git

lib-smtp: client: Prevent sending an empty XCLIENT command when the first parameter is long.
---

diff --git a/src/lib-smtp/smtp-client-connection.c b/src/lib-smtp/smtp-client-connection.c
index 1390f29084..35da137e08 100644
--- a/src/lib-smtp/smtp-client-connection.c
+++ b/src/lib-smtp/smtp-client-connection.c
@@ -650,12 +650,15 @@ smtp_client_connection_xclient_add(struct smtp_client_connection *conn,
 	size_t prev_offset = str_len(str);
 	const char *new_field;
 
+	i_assert(prev_offset >= offset);
+
 	str_append_c(str, ' ');
 	str_append(str, field);
 	str_append_c(str, '=');
 	smtp_xtext_encode_cstr(str, value);
 
-	if (str_len(str) <= SMTP_CLIENT_BASE_LINE_LENGTH_LIMIT)
+	if (prev_offset == offset ||
+	    str_len(str) <= SMTP_CLIENT_BASE_LINE_LENGTH_LIMIT)
 		return;
 		
 	/* preserve field we just added */