cfg80211: validate scan channels

Currently it is possible to request a scan on only
disabled channels, which could be problematic for
some drivers. Reject such scans, and also ignore
disabled channels that are given. This resuls in
the scan begin/end event only including channels
that are actually used.

This makes the mac80211 check for disabled channels
superfluous. At the same time, remove the no-IBSS
check from mac80211 -- nothing says that we should
not find any networks on channels that cannot be
used for an IBSS, even when operating in IBSS mode.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/net/wireless/scan.c b/net/wireless/scan.c
index 2e8c515f3c5c..e2d344ff6745 100644
--- a/net/wireless/scan.c
+++ b/net/wireless/scan.c
@@ -650,9 +650,15 @@ int cfg80211_wext_siwscan(struct net_device *dev,
         i = 0;
         for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
                 int j;
+
                 if (!wiphy->bands[band])
                         continue;
+
                 for (j = 0; j < wiphy->bands[band]->n_channels; j++) {
+                        /* ignore disabled channels */
+                        if (wiphy->bands[band]->channels[j].flags &
+                                                IEEE80211_CHAN_DISABLED)
+                                continue;
 
                         /* If we have a wireless request structure and the
                          * wireless request specifies frequencies, then search