From 920cd815bafea084f68cc4309399aea77bd7f66b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Petr=20Men=C5=A1=C3=ADk?= <pemensik@redhat.com>
Date: Fri, 3 Sep 2021 14:11:42 +0200
Subject: [PATCH 03/15] Small safeguard to unexpected data

Make sure negative index is not used for comparison. It seems code in
option parsing does not allow it to be empty, but insist on it also in
this place.
---
 src/dhcp-common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/dhcp-common.c b/src/dhcp-common.c
index 73568a9..85b269a 100644
--- a/src/dhcp-common.c
+++ b/src/dhcp-common.c
@@ -88,7 +88,7 @@ int match_netid_wild(struct dhcp_netid *check, struct dhcp_netid *pool)
   for (; check; check = check->next)
     {
       const int check_len = strlen(check->net);
-      const int is_wc = (check->net[check_len - 1] == '*');
+      const int is_wc = (check_len > 0 && check->net[check_len - 1] == '*');
       
       /* '#' for not is for backwards compat. */
       if (check->net[0] != '!' && check->net[0] != '#')
-- 
2.31.1