Subject: [PATCH] wifi: ieee80211: correctly mark FTM frames non-bufferable
From: Johannes Berg <[email-masked]>
Date: Wed, 29 Mar 2023 16:46:26 +0200

The checks of whether or not a frame is bufferable were not
taking into account that some action frames aren't, such as
FTM. Check this, which requires some changes to the function
ieee80211_is_bufferable_mmpdu() since we need the whole skb
for the checks now.

Signed-off-by: Johannes Berg <[email-masked]>
Reviewed-by: Greenman, Gregory <[email-masked]>
Reviewed-by: Peer, Ilan <[email-masked]>
---

--- a/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/tx.c
@@ -555,8 +555,9 @@ static void iwl_mvm_skb_prepare_status(s
 
 static int iwl_mvm_get_ctrl_vif_queue(struct iwl_mvm *mvm,
 				      struct ieee80211_tx_info *info,
-				      struct ieee80211_hdr *hdr)
+				      struct sk_buff *skb)
 {
+	struct ieee80211_hdr *hdr = (void *)skb->data;
 	struct iwl_mvm_vif *mvmvif =
 		iwl_mvm_vif_from_mac80211(info->control.vif);
 	__le16 fc = hdr->frame_control;
@@ -575,7 +576,7 @@ static int iwl_mvm_get_ctrl_vif_queue(st
 		 * reason 7 ("Class 3 frame received from nonassociated STA").
 		 */
 		if (ieee80211_is_mgmt(fc) &&
-		    (!ieee80211_is_bufferable_mmpdu(fc) ||
+		    (!ieee80211_is_bufferable_mmpdu(skb) ||
 		     ieee80211_is_deauth(fc) || ieee80211_is_disassoc(fc)))
 			return mvm->probe_queue;
 
@@ -693,7 +694,7 @@ int iwl_mvm_tx_skb_non_sta(struct iwl_mv
 			else
 				sta_id = mvmvif->mcast_sta.sta_id;
 
-			queue = iwl_mvm_get_ctrl_vif_queue(mvm, &info, hdr);
+			queue = iwl_mvm_get_ctrl_vif_queue(mvm, &info, skb);
 		} else if (info.control.vif->type == NL80211_IFTYPE_MONITOR) {
 			queue = mvm->snif_queue;
 			sta_id = mvm->snif_sta.sta_id;
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -738,20 +738,6 @@ static inline bool ieee80211_is_any_null
 }
 
 /**
- * ieee80211_is_bufferable_mmpdu - check if frame is bufferable MMPDU
- * @fc: frame control field in little-endian byteorder
- */
-static inline bool ieee80211_is_bufferable_mmpdu(__le16 fc)
-{
-	/* IEEE 802.11-2012, definition of "bufferable management frame";
-	 * note that this ignores the IBSS special case. */
-	return ieee80211_is_mgmt(fc) &&
-	       (ieee80211_is_action(fc) ||
-		ieee80211_is_disassoc(fc) ||
-		ieee80211_is_deauth(fc));
-}
-
-/**
  * ieee80211_is_first_frag - check if IEEE80211_SCTL_FRAG is not set
  * @seq_ctrl: frame sequence control bytes in little-endian byteorder
  */
@@ -3672,6 +3658,44 @@ static inline u8 *ieee80211_get_DA(struc
 }
 
 /**
+ * ieee80211_is_bufferable_mmpdu - check if frame is bufferable MMPDU
+ * @skb: the skb to check, starting with the 802.11 header
+ */
+static inline bool ieee80211_is_bufferable_mmpdu(struct sk_buff *skb)
+{
+	struct ieee80211_mgmt *mgmt = (void *)skb->data;
+	__le16 fc = mgmt->frame_control;
+
+	/*
+	 * IEEE 802.11 REVme D2.0 definition of bufferable MMPDU;
+	 * note that this ignores the IBSS special case.
+	 */
+	if (!ieee80211_is_mgmt(fc))
+		return false;
+
+	if (ieee80211_is_disassoc(fc) || ieee80211_is_deauth(fc))
+		return true;
+
+	if (!ieee80211_is_action(fc))
+		return false;
+
+	if (skb->len < offsetofend(typeof(*mgmt), u.action.u.ftm.action_code))
+		return true;
+
+	/* action frame - additionally check for non-bufferable FTM */
+
+	if (mgmt->u.action.category != WLAN_CATEGORY_PUBLIC &&
+	    mgmt->u.action.category != WLAN_CATEGORY_PROTECTED_DUAL_OF_ACTION)
+		return true;
+
+	if (mgmt->u.action.u.ftm.action_code == WLAN_PUB_ACTION_FTM_REQUEST ||
+	    mgmt->u.action.u.ftm.action_code == WLAN_PUB_ACTION_FTM)
+		return false;
+
+	return true;
+}
+
+/**
  * _ieee80211_is_robust_mgmt_frame - check if frame is a robust management frame
  * @hdr: the frame (buffer must include at least the first octet of payload)
  */
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -487,7 +487,7 @@ ieee80211_tx_h_unicast_ps_buf(struct iee
 		int ac = skb_get_queue_mapping(tx->skb);
 
 		if (ieee80211_is_mgmt(hdr->frame_control) &&
-		    !ieee80211_is_bufferable_mmpdu(hdr->frame_control)) {
+		    !ieee80211_is_bufferable_mmpdu(tx->skb)) {
 			info->flags |= IEEE80211_TX_CTL_NO_PS_BUFFER;
 			return TX_CONTINUE;
 		}
@@ -1283,7 +1283,7 @@ static struct txq_info *ieee80211_get_tx
 	if (!(info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP) &&
 	    unlikely(!ieee80211_is_data_present(hdr->frame_control))) {
 		if ((!ieee80211_is_mgmt(hdr->frame_control) ||
-		     ieee80211_is_bufferable_mmpdu(hdr->frame_control) ||
+		     ieee80211_is_bufferable_mmpdu(skb) ||
 		     vif->type == NL80211_IFTYPE_STATION) &&
 		    sta && sta->uploaded) {
 			/*