mac80211: fix memory leak in register_hw() error path

Move the internal scan request allocation below the last
sanity check in ieee80211_register_hw() to avoid leaking
memory if the sanity check actually triggers.
Reported-by: ZHAO Gang <gamerh2o@gmail.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/main.c

@@ -846,17 +846,6 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 		/* TODO: consider VHT for RX chains, hopefully it's the same */
 	}
 
-	local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) +
-				      sizeof(void *) * channels, GFP_KERNEL);
-	if (!local->int_scan_req)
-		return -ENOMEM;
-
-	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
-		if (!local->hw.wiphy->bands[band])
-			continue;
-		local->int_scan_req->rates[band] = (u32) -1;
-	}
-
 	/* if low-level driver supports AP, we also support VLAN */
 	if (local->hw.wiphy->interface_modes & BIT(NL80211_IFTYPE_AP)) {
 		hw->wiphy->interface_modes |= BIT(NL80211_IFTYPE_AP_VLAN);
@@ -880,6 +869,17 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
 				return -EINVAL;
 	}
 
+	local->int_scan_req = kzalloc(sizeof(*local->int_scan_req) +
+				      sizeof(void *) * channels, GFP_KERNEL);
+	if (!local->int_scan_req)
+		return -ENOMEM;
+
+	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+		if (!local->hw.wiphy->bands[band])
+			continue;
+		local->int_scan_req->rates[band] = (u32) -1;
+	}
+
 #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);