wifi: iwlwifi: disable certain features for fips_enabled

When fips_enabled is set, keys will not be given to the
hardware by mac80211 since the hardware isn't certified.
In this case, various features cannot work correctly as
the firmware needs to handle frames, but it then cannot
since no keys are available.

Disable features:
 - WoWLAN since no keys etc.
 - MFP since some frames need to be handled in firmware
 - EHT/6GHz since MFP is required

Also restrict A-MSDU size since A-MSDUs cannot be split
up by hardware and thus need to fit into the RX buffers
in one piece.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250723094230.329fade58a27.I0be27dd329643cc5fdf79a8c8b8f6d2e6fb5c175@changeid

1 files changed, 21 insertions, 4 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c b/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c
index 4424443d2328..a67b9572aac3 100644
--- a/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c
+++ b/drivers/net/wireless/intel/iwlwifi/iwl-nvm-parse.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2016-2017 Intel Deutschland GmbH
  */
 #include <linux/types.h>
+#include <linux/fips.h>
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/etherdevice.h>
@@ -543,16 +544,22 @@ static void iwl_init_vht_hw_capab(struct iwl_trans *trans,
 	else
 		vht_cap->cap |= IEEE80211_VHT_CAP_TX_ANTENNA_PATTERN;
 
+	/*
+	 * With fips_enabled crypto is done by software, so the HW cannot
+	 * split up A-MSDUs and the real limit that was set applies.
+	 * Note that EHT doesn't honour this (HE copies the VHT value),
+	 * but EHT is also entirely disabled for fips_enabled.
+	 */
 	switch (iwlwifi_mod_params.amsdu_size) {
 	case IWL_AMSDU_DEF:
-		if (trans->mac_cfg->mq_rx_supported)
+		if (trans->mac_cfg->mq_rx_supported && !fips_enabled)
 			vht_cap->cap |=
 				IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454;
 		else
 			vht_cap->cap |= IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_3895;
 		break;
 	case IWL_AMSDU_2K:
-		if (trans->mac_cfg->mq_rx_supported)
+		if (trans->mac_cfg->mq_rx_supported && !fips_enabled)
 			vht_cap->cap |=
 				IEEE80211_VHT_CAP_MAX_MPDU_LENGTH_11454;
 		else
@@ -909,7 +916,9 @@ iwl_nvm_fixup_sband_iftd(struct iwl_trans *trans,
 	bool slow_pcie = (!trans->mac_cfg->integrated &&
 			  trans->info.pcie_link_speed < PCI_EXP_LNKSTA_CLS_8_0GB);
 
-	if (!data->sku_cap_11be_enable || iwlwifi_mod_params.disable_11be)
+	/* EHT needs WPA3/MFP so cannot do it for fips_enabled */
+	if (!data->sku_cap_11be_enable || iwlwifi_mod_params.disable_11be ||
+	    fips_enabled)
 		iftype_data->eht_cap.has_eht = false;
 
 	/* Advertise an A-MPDU exponent extension based on
@@ -1197,11 +1206,19 @@ static void iwl_init_sbands(struct iwl_trans *trans,
 	n_used += iwl_init_sband_channels(data, sband, n_channels,
 					  NL80211_BAND_6GHZ);
 
-	if (data->sku_cap_11ax_enable && !iwlwifi_mod_params.disable_11ax)
+	/*
+	 * 6 GHz requires WPA3 which requires MFP, which FW cannot do
+	 * when fips_enabled, so don't advertise any 6 GHz channels to
+	 * avoid spending time on scanning those channels and perhaps
+	 * even finding APs there that cannot be used.
+	 */
+	if (!fips_enabled && data->sku_cap_11ax_enable &&
+	    !iwlwifi_mod_params.disable_11ax)
 		iwl_init_he_hw_capab(trans, data, sband, tx_chains, rx_chains,
 				     fw);
 	else
 		sband->n_channels = 0;
+
 	if (n_channels != n_used)
 		IWL_ERR_DEV(dev, "NVM: used only %d of %d channels\n",
 			    n_used, n_channels);