It was possible to connect STA when AP CSA was in
progress which clearly was a bug.
Deny attempts to increase chanctx refcount or
create chanctx.
This effectively denies starting a new interface
and radar detection while CSA is in progress.
Existing interfaces (including those with active
CSA) can be stopped though.
Signed-off-by: Michal Kazior <michal.kazior@xxxxxxxxx>
---
net/mac80211/chan.c | 7 +++++++
net/mac80211/ieee80211_i.h | 1 +
net/mac80211/util.c | 18 ++++++++++++++++++
3 files changed, 26 insertions(+)
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index f43613a..9057b66 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -517,6 +517,13 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
WARN_ON(sdata->dev && netif_carrier_ok(sdata->dev));
+ /* Do not allow an interface to bind to channel contexts during CSA as
+ * it would end up with the interface being dragged to a different
+ * channel once CSA completes. It's safe to unbind from channel
+ * contexts though. */
+ if (ieee80211_is_csa_active(local))
+ return -EBUSY;
+
mutex_lock(&local->chanctx_mtx);
__ieee80211_vif_release_channel(sdata);
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a6cda02..763a0ca 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1465,6 +1465,7 @@ int __ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev,
int ieee80211_channel_switch(struct wiphy *wiphy,
struct cfg80211_csa_settings *params,
int num_params);
+bool ieee80211_is_csa_active(struct ieee80211_local *local);
/* interface handling */
int ieee80211_iface_init(void);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 676dc09..3e77c41 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2775,3 +2775,21 @@ void ieee80211_recalc_dtim(struct ieee80211_local *local,
ps->dtim_count = dtim_count;
}
+
+bool ieee80211_is_csa_active(struct ieee80211_local *local)
+{
+ struct ieee80211_sub_if_data *sdata;
+
+ lockdep_assert_held(&local->mtx);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+ if (sdata->vif.csa_active) {
+ rcu_read_unlock();
+ return true;
+ }
+ }
+ rcu_read_unlock();
+
+ return false;
+}
--
1.8.4.rc3
--
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