iwlwifi: don't allow the FW to return invalid ch indices

If the FW returns an invalid channels count in response to an MCC request,
make sure we don't reference invalid indices in the channels array.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/iwlwifi/iwl-nvm-parse.c

@@ -743,10 +743,15 @@ iwl_parse_nvm_mcc_info(struct device *dev, const struct iwl_cfg *cfg,
 	int center_freq, prev_center_freq = 0;
 	int valid_rules = 0;
 	bool new_rule;
+	int max_num_ch = cfg->device_family == IWL_DEVICE_FAMILY_8000 ?
+			 IWL_NUM_CHANNELS_FAMILY_8000 : IWL_NUM_CHANNELS;
 
 	if (WARN_ON_ONCE(num_of_ch > NL80211_MAX_SUPP_REG_RULES))
 		return ERR_PTR(-EINVAL);
 
+	if (WARN_ON(num_of_ch > max_num_ch))
+		num_of_ch = max_num_ch;
+
 	IWL_DEBUG_DEV(dev, IWL_DL_LAR, "building regdom for %d channels\n",
 		      num_of_ch);