From bf9ea4ea71b6e7d6f96d4d69c661621518787df5 Mon Sep 17 00:00:00 2001
From: Thomas Haller <thaller@redhat.com>
Date: Sun, 21 Jun 2020 22:40:17 +0200
Subject: [PATCH] shared: avoid copying empty string in
 nm_str_buf_append_printf()

(cherry picked from commit 081650eb67cf85e741d8e30babb9b7884b4fd36f)
---
 shared/nm-glib-aux/nm-shared-utils.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/shared/nm-glib-aux/nm-shared-utils.c b/shared/nm-glib-aux/nm-shared-utils.c
index e7b9b043b4..23577a0d7c 100644
--- a/shared/nm-glib-aux/nm-shared-utils.c
+++ b/shared/nm-glib-aux/nm-shared-utils.c
@@ -4948,7 +4948,12 @@ nm_str_buf_append_printf (NMStrBuf *strbuf,
 	nm_assert (l < G_MAXINT);
 
 	if ((gsize) l >= available) {
-		gsize l2 = ((gsize) l) + 1u;
+		gsize l2;
+
+		if (l == 0)
+			return;
+
+		l2 = ((gsize) l) + 1u;
 
 		nm_str_buf_maybe_expand (strbuf, l2, FALSE);