mac80211: fix ieee80211_ioctl_giwrate

The ieee80211_ioctl_giwrate() ioctl handler doesn't rcu_read_lock()
its access to the sta table, fix it.

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

1 files changed, 12 insertions, 6 deletions

diff --git a/net/mac80211/ieee80211_ioctl.c b/net/mac80211/ieee80211_ioctl.c
index b047eebb6330..41130b303170 100644
--- a/net/mac80211/ieee80211_ioctl.c
+++ b/net/mac80211/ieee80211_ioctl.c
@@ -586,19 +586,25 @@ static int ieee80211_ioctl_giwrate(struct net_device *dev,
 
         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-        if (sdata->vif.type == IEEE80211_IF_TYPE_STA)
-                sta = sta_info_get(local, sdata->u.sta.bssid);
-        else
+        if (sdata->vif.type != IEEE80211_IF_TYPE_STA)
                 return -EOPNOTSUPP;
-        if (!sta)
-                return -ENODEV;
 
         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 
-        if (sta->txrate_idx < sband->n_bitrates)
+        rcu_read_lock();
+
+        sta = sta_info_get(local, sdata->u.sta.bssid);
+
+        if (sta && sta->txrate_idx < sband->n_bitrates)
                 rate->value = sband->bitrates[sta->txrate_idx].bitrate;
         else
                 rate->value = 0;
+
+        rcu_read_unlock();
+
+        if (!sta)
+                return -ENODEV;
+
         rate->value *= 100000;
 
         return 0;