From a4fa9864bf1f15e007a3470b83a91076690a3222 Mon Sep 17 00:00:00 2001
From: Brooks Davis <brooks@FreeBSD.org>
Date: Tue, 27 Jan 2004 01:43:14 +0000
Subject: [PATCH] Use IFNAMSIZ instead of a magic value for the length of an
 interface name.

Prevent the kernel from potentially overflowing the interface name
variable.  The size argument of strlcpy is complex because the name is
not null-terminated in sdl_data.
---
 sbin/ifconfig/ifconfig.c | 7 ++++---
 sbin/ifconfig/ifconfig.h | 2 +-
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/sbin/ifconfig/ifconfig.c b/sbin/ifconfig/ifconfig.c
index 0e433a54cf46..0e6ae2b8c52b 100644
--- a/sbin/ifconfig/ifconfig.c
+++ b/sbin/ifconfig/ifconfig.c
@@ -113,7 +113,7 @@ struct	in6_aliasreq	in6_addreq =
 struct	sockaddr_in	netmask;
 struct	netrange	at_nr;		/* AppleTalk net range */
 
-char	name[32];
+char	name[IFNAMSIZ];
 int	flags;
 int	setaddr;
 int	setipdst;
@@ -596,8 +596,9 @@ main(int argc, char *argv[])
 			addrcount++;
 			next += nextifm->ifm_msglen;
 		}
-		strncpy(name, sdl->sdl_data, sdl->sdl_nlen);
-		name[sdl->sdl_nlen] = '\0';
+		strlcpy(name, sdl->sdl_data,
+		    sizeof(name) <= sdl->sdl_nlen ?
+		    sizeof(name) : sdl->sdl_nlen + 1);
 
 		if (all || namesonly) {
 			if (uponly)
diff --git a/sbin/ifconfig/ifconfig.h b/sbin/ifconfig/ifconfig.h
index 7430c691142e..622be5409772 100644
--- a/sbin/ifconfig/ifconfig.h
+++ b/sbin/ifconfig/ifconfig.h
@@ -36,7 +36,7 @@
 
 extern struct ifreq ifr;
 
-extern char name[32];	/* name of interface */
+extern char name[IFNAMSIZ];	/* name of interface */
 extern int allmedia;
 extern int supmedia;
 struct afswtch;