From 8d2e35b2d46fd9bfd23e7c3036d2bd116d2bb64a Mon Sep 17 00:00:00 2001
From: Finn Behrens <me@kloenk.de>
Date: Fri, 10 Nov 2023 11:15:58 +0100
Subject: [PATCH] client: display_completion_matches add 0-byte check

Check that enough space for newline and 0-byte is left in line.
This fixes a buffer overflow on specific completion results.

Reported-By: Leona Maroni <dev@leona.is>
---
 client/display.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/client/display.c b/client/display.c
index 8b06ff58..64125934 100644
--- a/client/display.c
+++ b/client/display.c
@@ -633,7 +633,7 @@ static void display_completion_matches(char **matches, int num_matches,
 	l_free(prompt);
 
 	for (index = 1, line_used = 0; matches[index]; index++) {
-		if ((line_used + max_length) > LINE_LEN) {
+		if ((line_used + max_length + 1) >= (LINE_LEN - 1)) {
 			strcpy(&line[line_used], "\n");
 
 			display_text(line);