wifi: iwlwifi: mvm: don't set the MFP flag for the GTK

jira LE-1907
cve CVE-2024-27434
Rebuild_History Non-Buildable kernel-5.14.0-427.31.1.el9_4
commit-author Emmanuel Grumbach <emmanuel.grumbach@intel.com>
commit e35f316

The firmware doesn't need the MFP flag for the GTK, it can even make the
firmware crash. in case the AP is configured with: group cipher TKIP and
MFPC. We would send the GTK with cipher = TKIP and MFP which is of course
not possible.

Fixes: 5c75a20 ("wifi: iwlwifi: mvm: support new key API")
	Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
	Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://msgid.link/20240206175739.2f2c602ab3c6.If13b2e2fa532381d985c07df130bee1478046c89@changeid
	Signed-off-by: Johannes Berg <johannes.berg@intel.com>
(cherry picked from commit e35f316)
	Signed-off-by: Jonathan Maple <jmaple@ciq.com>

Author: PlaidCat

drivers/net/wireless/intel/iwlwifi/mvm/mld-key.c

@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /*
- * Copyright (C) 2022 - 2023 Intel Corporation
+ * Copyright (C) 2022 - 2024 Intel Corporation
  */
 #include <linux/kernel.h>
 #include <net/mac80211.h>
@@ -62,11 +62,13 @@ u32 iwl_mvm_get_sec_flags(struct iwl_mvm *mvm,
 			  struct ieee80211_key_conf *keyconf)
 {
 	struct iwl_mvm_vif *mvmvif = iwl_mvm_vif_from_mac80211(vif);
+	bool pairwise = keyconf->flags & IEEE80211_KEY_FLAG_PAIRWISE;
+	bool igtk = keyconf->keyidx == 4 || keyconf->keyidx == 5;
 	u32 flags = 0;
 
 	lockdep_assert_held(&mvm->mutex);
 
-	if (!(keyconf->flags & IEEE80211_KEY_FLAG_PAIRWISE))
+	if (!pairwise)
 		flags |= IWL_SEC_KEY_FLAG_MCAST_KEY;
 
 	switch (keyconf->cipher) {
@@ -96,12 +98,14 @@ u32 iwl_mvm_get_sec_flags(struct iwl_mvm *mvm,
 	if (!sta && vif->type == NL80211_IFTYPE_STATION)
 		sta = mvmvif->ap_sta;
 
-	/* Set the MFP flag also for an AP interface where the key is an IGTK
-	 * key as in such a case the station would always be NULL
+	/*
+	 * If we are installing an iGTK (in AP or STA mode), we need to tell
+	 * the firmware this key will en/decrypt MGMT frames.
+	 * Same goes if we are installing a pairwise key for an MFP station.
+	 * In case we're installing a groupwise key (which is not an iGTK),
+	 * then, we will not use this key for MGMT frames.
 	 */
-	if ((!IS_ERR_OR_NULL(sta) && sta->mfp) ||
-	    (vif->type == NL80211_IFTYPE_AP &&
-	     (keyconf->keyidx == 4 || keyconf->keyidx == 5)))
+	if ((!IS_ERR_OR_NULL(sta) && sta->mfp && pairwise) || igtk)
 		flags |= IWL_SEC_KEY_FLAG_MFP;
 
 	return flags;