From 46a60ec7950ed13715dc82fe0bcab17db740dfbc Mon Sep 17 00:00:00 2001
From: Bram Matthys <syzop@vulnscan.org>
Date: Mon, 11 Jun 2018 08:05:14 +0200
Subject: [PATCH] Fix OOB read (1 byte to the left)

---
 src/modules/m_mode.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/modules/m_mode.c b/src/modules/m_mode.c
index 5de32d04b..2a9bb30b5 100644
--- a/src/modules/m_mode.c
+++ b/src/modules/m_mode.c
@@ -695,7 +695,7 @@ void make_mode_str(aChannel *chptr, long oldm, Cmode_t oldem, long oldl, int pco
 		chptr->mode.extmode = oldem;
 	}
 	z = strlen(para_buf);
-	if (para_buf[z - 1] == ' ')
+	if ((z > 0) && (para_buf[z - 1] == ' '))
 		para_buf[z - 1] = '\0';
 	*x = '\0';
 	if (*mode_buf == '\0')