From a48d677f268433a839407df83dea02c34f221f05 Mon Sep 17 00:00:00 2001
From: Luiz Otavio O Souza <loos@FreeBSD.org>
Date: Sat, 5 Jul 2014 20:16:02 +0000
Subject: [PATCH] Check the number of returned entries before doing any access
 to ifm_ulist.

---
 sbin/etherswitchcfg/etherswitchcfg.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sbin/etherswitchcfg/etherswitchcfg.c b/sbin/etherswitchcfg/etherswitchcfg.c
index dd68e67c4ec9..f7f117ae3e2b 100644
--- a/sbin/etherswitchcfg/etherswitchcfg.c
+++ b/sbin/etherswitchcfg/etherswitchcfg.c
@@ -235,6 +235,8 @@ set_port_media(struct cfg *cfg, char *argv[])
 	p.es_ifmr.ifm_count = IFMEDIAREQ_NULISTENTRIES;
 	if (ioctl(cfg->fd, IOETHERSWITCHGETPORT, &p) != 0)
 		err(EX_OSERR, "ioctl(IOETHERSWITCHGETPORT)");
+	if (p.es_ifmr.ifm_count == 0)
+		return;
 	subtype = get_media_subtype(IFM_TYPE(ifm_ulist[0]), argv[1]);
 	p.es_ifr.ifr_media = (p.es_ifmr.ifm_current & IFM_IMASK) |
 	        IFM_TYPE(ifm_ulist[0]) | subtype;