From: Matthias Kaehlcke <mka@chromium.org>
Date: Tue, 25 Jul 2017 18:36:25 +0000 (-0700)
Subject: netpoll: Fix device name check in netpoll_setup()
X-Git-Tag: v4.9.161~20
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=64696ba9577f7742358cd7be42da2a4eb4877244;p=thirdparty%2Fkernel%2Fstable.git

netpoll: Fix device name check in netpoll_setup()

commit 0c3a8f8b8fabff4f3ad2dd7b95ae0e90cdd1aebb upstream.

Apparently netpoll_setup() assumes that netpoll.dev_name is a pointer
when checking if the device name is set:

if (np->dev_name) {
  ...

However the field is a character array, therefore the condition always
yields true. Check instead whether the first byte of the array has a
non-zero value.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 457f882b0f7ba..9b2d61120c0d7 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -666,7 +666,7 @@ int netpoll_setup(struct netpoll *np)
 	int err;
 
 	rtnl_lock();
-	if (np->dev_name) {
+	if (np->dev_name[0]) {
 		struct net *net = current->nsproxy->net_ns;
 		ndev = __dev_get_by_name(net, np->dev_name);
 	}