cfg80211: fix locking for SIWFREQ

"cfg80211: validate channel settings across interfaces"
contained a locking bug -- in the managed-mode SIWFREQ
call it would end up running into a lock recursion.

This fixes it by not checking that particular interface
for a channel that it needs to stay on, which is as it
should be as that's the interface we're setting the
channel for.

Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Reported-by: Kalle Valo <kalle.valo@iki.fi>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Kalle Valo <kalle.valo@iki.fi>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 6 insertions, 4 deletions

diff --git a/net/wireless/chan.c b/net/wireless/chan.c
index bc00c9a06b3d..a46ac6c9b365 100644
--- a/net/wireless/chan.c
+++ b/net/wireless/chan.c
@@ -42,13 +42,14 @@ rdev_fixed_channel(struct cfg80211_registered_device *rdev,
 }
 
 int rdev_set_freq(struct cfg80211_registered_device *rdev,
+                  struct wireless_dev *for_wdev,
                   int freq, enum nl80211_channel_type channel_type)
 {
         struct ieee80211_channel *chan;
         struct ieee80211_sta_ht_cap *ht_cap;
         int result;
 
-        if (rdev_fixed_channel(rdev, NULL))
+        if (rdev_fixed_channel(rdev, for_wdev))
                 return -EBUSY;
 
         if (!rdev->ops->set_channel)
diff --git a/net/wireless/core.h b/net/wireless/core.h
index 639db52eeff7..f7be3a9b427e 100644
--- a/net/wireless/core.h
+++ b/net/wireless/core.h
@@ -374,6 +374,7 @@ struct ieee80211_channel *
 rdev_fixed_channel(struct cfg80211_registered_device *rdev,
                    struct wireless_dev *for_wdev);
 int rdev_set_freq(struct cfg80211_registered_device *rdev,
+                  struct wireless_dev *for_wdev,
                   int freq, enum nl80211_channel_type channel_type);
 
 #endif /* __NET_WIRELESS_CORE_H */
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index 667a87d307da..a8aaadeb6773 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -721,7 +721,7 @@ static int nl80211_set_wiphy(struct sk_buff *skb, struct genl_info *info)
                 freq = nla_get_u32(info->attrs[NL80211_ATTR_WIPHY_FREQ]);
 
                 mutex_lock(&rdev->devlist_mtx);
-                result = rdev_set_freq(rdev, freq, channel_type);
+                result = rdev_set_freq(rdev, NULL, freq, channel_type);
                 mutex_unlock(&rdev->devlist_mtx);
                 if (result)
                         goto bad_res;
diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index 17648dc79867..c44917492210 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -766,7 +766,7 @@ int cfg80211_wext_siwfreq(struct net_device *dev,
                 if (freq == 0)
                         return -EINVAL;
                 mutex_lock(&rdev->devlist_mtx);
-                err = rdev_set_freq(rdev, freq, NL80211_CHAN_NO_HT);
+                err = rdev_set_freq(rdev, NULL, freq, NL80211_CHAN_NO_HT);
                 mutex_unlock(&rdev->devlist_mtx);
                 return err;
         }
diff --git a/net/wireless/wext-sme.c b/net/wireless/wext-sme.c
index 907470063f22..d16cd9ea4d00 100644
--- a/net/wireless/wext-sme.c
+++ b/net/wireless/wext-sme.c
@@ -106,7 +106,7 @@ int cfg80211_mgd_wext_siwfreq(struct net_device *dev,
 
         /* SSID is not set, we just want to switch channel */
         if (chan && !wdev->wext.connect.ssid_len) {
-                err = rdev_set_freq(rdev, freq, NL80211_CHAN_NO_HT);
+                err = rdev_set_freq(rdev, wdev, freq, NL80211_CHAN_NO_HT);
                 goto out;
         }