cfg80211: fix interface combinations check

If a given interface combination doesn't contain
a required interface type then we missed checking
that and erroneously allowed it even though iface
type wasn't there at all. Add a check that makes
sure that all interface types are accounted for.

Cc: stable@kernel.org
Reported-by: Mohammed Shafi Shajakhan <mohammed@qca.qualcomm.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/wireless/util.c b/net/wireless/util.c
index 55d9946..8f2d68f 100644 (file)
--- a/net/wireless/util.c
+++ b/net/wireless/util.c
@@ -935,6 +935,7 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
                                  enum nl80211_iftype iftype)
 {
        struct wireless_dev *wdev_iter;
+       u32 used_iftypes = BIT(iftype);
        int num[NUM_NL80211_IFTYPES];
        int total = 1;
        int i, j;
@@ -961,6 +962,7 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
 
                num[wdev_iter->iftype]++;
                total++;
+               used_iftypes |= BIT(wdev_iter->iftype);
        }
        mutex_unlock(&rdev->devlist_mtx);
 
@@ -970,6 +972,7 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
        for (i = 0; i < rdev->wiphy.n_iface_combinations; i++) {
                const struct ieee80211_iface_combination *c;
                struct ieee80211_iface_limit *limits;
+               u32 all_iftypes = 0;
 
                c = &rdev->wiphy.iface_combinations[i];
 
@@ -984,6 +987,7 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
                        if (rdev->wiphy.software_iftypes & BIT(iftype))
                                continue;
                        for (j = 0; j < c->n_limits; j++) {
+                               all_iftypes |= limits[j].types;
                                if (!(limits[j].types & BIT(iftype)))
                                        continue;
                                if (limits[j].max < num[iftype])
@@ -991,7 +995,20 @@ int cfg80211_can_change_interface(struct cfg80211_registered_device *rdev,
                                limits[j].max -= num[iftype];
                        }
                }
-               /* yay, it fits */
+
+               /*
+                * Finally check that all iftypes that we're currently
+                * using are actually part of this combination. If they
+                * aren't then we can't use this combination and have
+                * to continue to the next.
+                */
+               if ((all_iftypes & used_iftypes) != used_iftypes)
+                       goto cont;
+
+               /*
+                * This combination covered all interface types and
+                * supported the requested numbers, so we're good.
+                */
                kfree(limits);
                return 0;
  cont: