From 775f258fbd1895ba669be22f108faf817247a47a Mon Sep 17 00:00:00 2001
From: Helge Deller <deller@gmx.de>
Date: Tue, 1 Oct 2019 17:06:05 +0200
Subject: [PATCH] kexec-tools: Fix possible out-of-bounds access in ifdown

Fix a possible out-of-bounds access in function ifdown():

ifdown.c: In function 'ifdown':
ifdown.c:56:4: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
   56 |    strncpy(ifr.ifr_name, ifp->if_name, IFNAMSIZ);

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Simon Horman <horms@verge.net.au>

diff --git a/kexec/ifdown.c b/kexec/ifdown.c
index 9679ad7..3ac19c1 100644
--- a/kexec/ifdown.c
+++ b/kexec/ifdown.c
@@ -53,7 +53,8 @@ int ifdown(void)
 			if (strchr(ifp->if_name, ':') != NULL)
 				continue;
 
-			strncpy(ifr.ifr_name, ifp->if_name, IFNAMSIZ);
+			strncpy(ifr.ifr_name, ifp->if_name, IFNAMSIZ-1);
+			ifr.ifr_name[IFNAMSIZ-1] = 0;
 			if (ioctl(fd, SIOCGIFFLAGS, &ifr) < 0) {
 				fprintf(stderr, "ifdown: shutdown ");
 				perror(ifp->if_name);
-- 
1.8.3.1