From 19c605df59761f2e65389ab444c5696aaf666cca Mon Sep 17 00:00:00 2001
From: Martin Willi <martin@strongswan.org>
Date: Fri, 13 May 2016 12:41:48 +0200
Subject: [PATCH] mac80211_hwsim: Add missing check for HWSIM_ATTR_SIGNAL

commit 62397da50bb20a6b812c949ef465d7e69fe54bb6 upstream.

A wmediumd that does not send this attribute causes a NULL pointer
dereference, as the attribute is accessed even if it does not exist.

The attribute was required but never checked ever since userspace frame
forwarding has been introduced. The issue gets more problematic once we
allow wmediumd registration from user namespaces.

Fixes: 7882513bacb1 ("mac80211_hwsim driver support userspace frame tx/rx")
Signed-off-by: Martin Willi <martin@strongswan.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
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