mac80211: verify IBSS in interface combinations

Drivers shouldn't attempt to advertise support
for more than one IBSS interface since mac80211
doesn't support that. Check and return an error
from ieee80211_register_hw() in that case.

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

1 files changed, 17 insertions, 3 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 0d7b08db8e56..96ab1302a099 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -752,11 +752,25 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
         hw->wiphy->interface_modes |= BIT(NL80211_IFTYPE_MONITOR);
         hw->wiphy->software_iftypes |= BIT(NL80211_IFTYPE_MONITOR);
 
-        /* mac80211 doesn't support more than 1 channel */
-        for (i = 0; i < hw->wiphy->n_iface_combinations; i++)
-                if (hw->wiphy->iface_combinations[i].num_different_channels > 1)
+        /*
+         * mac80211 doesn't support more than 1 channel, and also not more
+         * than one IBSS interface
+         */
+        for (i = 0; i < hw->wiphy->n_iface_combinations; i++) {
+                const struct ieee80211_iface_combination *c;
+                int j;
+
+                c = &hw->wiphy->iface_combinations[i];
+
+                if (c->num_different_channels > 1)
                         return -EINVAL;
 
+                for (j = 0; j < c->n_limits; j++)
+                        if ((c->limits[j].types & BIT(NL80211_IFTYPE_ADHOC)) &&
+                            c->limits[j].max > 1)
+                                return -EINVAL;
+        }
+
 #ifndef CONFIG_MAC80211_MESH
         /* mesh depends on Kconfig, but drivers should set it if they want */
         local->hw.wiphy->interface_modes &= ~BIT(NL80211_IFTYPE_MESH_POINT);