mac80211: fix IBSS presp allocation size

BugLink: http://bugs.launchpad.net/bugs/1702104

commit f1f3e9e2 upstream.

When VHT IBSS support was added, the size of the extra elements
wasn't considered in ieee80211_ibss_build_presp(), which makes
it possible that it would overrun the allocated buffer. Fix it
by allocating the necessary space.

Fixes: abcff6ef ("mac80211: add VHT support for IBSS")
Reported-by: Shaul Triebitz <shaul.triebitz@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

net/mac80211/ibss.c

@@ -66,6 +66,8 @@ ieee80211_ibss_build_presp(struct ieee80211_sub_if_data *sdata,
 		    2 + (IEEE80211_MAX_SUPP_RATES - 8) +
 		    2 + sizeof(struct ieee80211_ht_cap) +
 		    2 + sizeof(struct ieee80211_ht_operation) +
+		    2 + sizeof(struct ieee80211_vht_cap) +
+		    2 + sizeof(struct ieee80211_vht_operation) +
 		    ifibss->ie_len;
 	presp = kzalloc(sizeof(*presp) + frame_len, GFP_KERNEL);
 	if (!presp)