iwlwifi: disallow MFP with software crypto

When software crypto is enabled, it isn't safe
to enable MFP since the firmware interprets some
management packets, and with MFP it would do so
without proper validation.
Reviewed-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Reviewed-by: Assaf Krauss <assaf.krauss@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/iwlwifi/dvm/mac80211.c

@@ -168,8 +168,13 @@ int iwlagn_mac_setup_register(struct iwl_priv *priv,
 		hw->flags |= IEEE80211_HW_SUPPORTS_DYNAMIC_SMPS |
 			     IEEE80211_HW_SUPPORTS_STATIC_SMPS;
 
-	/* enable 11w if the uCode advertise */
-	if (capa->flags & IWL_UCODE_TLV_FLAGS_MFP)
+	/*
+	 * Enable 11w if advertised by firmware and software crypto
+	 * is not enabled (as the firmware will interpret some mgmt
+	 * packets, so enabling it with software crypto isn't safe)
+	 */
+	if (priv->fw->ucode_capa.flags & IWL_UCODE_TLV_FLAGS_MFP &&
+	    !iwlwifi_mod_params.sw_crypto)
 		hw->flags |= IEEE80211_HW_MFP_CAPABLE;
 
 	hw->sta_data_size = sizeof(struct iwl_station_priv);