[PATCH] nl80211: Disallow setting of HT for channel 14

[Masashi Honma]

This patch disables setting of HT20 and more for channel 14 because
the channel is only for IEEE 802.11b.

The patch for net/wireless/util.c was unit-tested.

The patch for net/wireless/chan.c was tested with iw command.

Before this patch.
$ sudo iw dev <ifname> set channel 14 HT20
$

After this patch.
$ sudo iw dev <ifname> set channel 14 HT20
kernel reports: invalid channel definition
command failed: Invalid argument (-22)
$

Signed-off-by: Masashi Honma <masashi.ho...@gmail.com>
---
 net/wireless/chan.c | 4 ++++
 net/wireless/util.c | 3 ++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index e851cafd8e2f..1212deb41361 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -204,6 +204,10 @@ bool cfg80211_chandef_valid(const struct cfg80211_chan_def 
*chandef)
                return false;
        }
 
+       /* channel 14 is only for IEEE 802.11b */
+       if (chandef->center_freq1 == 2484 && chandef->width > 
NL80211_CHAN_WIDTH_20_NOHT)
+               return false;
+
        if (cfg80211_chandef_is_edmg(chandef) &&
            !cfg80211_edmg_chandef_valid(chandef))
                return false;
diff --git a/net/wireless/util.c b/net/wireless/util.c
index 419eb12c1e93..063715df3950 100644
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -1559,7 +1559,8 @@ bool ieee80211_chandef_to_operating_class(struct 
cfg80211_chan_def *chandef,
        }
 
        if (freq == 2484) {
-               if (chandef->width > NL80211_CHAN_WIDTH_40)
+               /* channel 14 is only for IEEE 802.11b */
+               if (chandef->width > NL80211_CHAN_WIDTH_20_NOHT)
                        return false;
 
                *op_class = 82; /* channel 14 */
-- 
2.17.1