release/5.2.40/mac80211-fix-wrong-160-80-80-MHz-setting.patch

From 15e40c33f4856f808bc3a967fa837347e1d6e3da Mon Sep 17 00:00:00 2001
From: Shay Bar <shay.bar@celeno.com>
Date: Mon, 10 Feb 2020 15:07:28 +0200
Subject: [PATCH] mac80211: fix wrong 160/80+80 MHz setting
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commit 33181ea7f5a62a17fbe55f0f73428ecb5e686be8 upstream.

Before this patch, STA's would set new width of 160/80+80 MHz based on AP capability only.
This is wrong because STA may not support > 80MHz BW.
Fix is to verify STA has 160/80+80 MHz capability before increasing its width to > 80MHz.

The "support_80_80" and "support_160" setting is based on:
"Table 9-272 — Setting of the Supported Channel Width Set subfield and Extended NSS BW
Support subfield at a STA transmitting the VHT Capabilities Information field"
From "Draft P802.11REVmd_D3.0.pdf"

Signed-off-by: Aviad Brikman <aviad.brikman@celeno.com>
Signed-off-by: Shay Bar <shay.bar@celeno.com>
Link: https://lore.kernel.org/r/20200210130728.23674-1-shay.bar@celeno.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index c9a35ebcbfae..cf1952193712 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2936,10 +2936,22 @@ bool ieee80211_chandef_vht_oper(struct ieee80211_hw *hw,
 	int cf0, cf1;
 	int ccfs0, ccfs1, ccfs2;
 	int ccf0, ccf1;
+	u32 vht_cap;
+	bool support_80_80 = false;
+	bool support_160 = false;
 
 	if (!oper || !htop)
 		return false;
 
+	vht_cap = hw->wiphy->bands[chandef->chan->band]->vht_cap.cap;
+	support_160 = (vht_cap & (IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_MASK |
+				  IEEE80211_VHT_CAP_EXT_NSS_BW_MASK));
+	support_80_80 = ((vht_cap &
+			 IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160_80PLUS80MHZ) ||
+			(vht_cap & IEEE80211_VHT_CAP_SUPP_CHAN_WIDTH_160MHZ &&
+			 vht_cap & IEEE80211_VHT_CAP_EXT_NSS_BW_MASK) ||
+			((vht_cap & IEEE80211_VHT_CAP_EXT_NSS_BW_MASK) >>
+				    IEEE80211_VHT_CAP_EXT_NSS_BW_SHIFT > 1));
 	ccfs0 = oper->center_freq_seg0_idx;
 	ccfs1 = oper->center_freq_seg1_idx;
 	ccfs2 = (le16_to_cpu(htop->operation_mode) &
@@ -2967,10 +2979,10 @@ bool ieee80211_chandef_vht_oper(struct ieee80211_hw *hw,
 			unsigned int diff;
 
 			diff = abs(ccf1 - ccf0);
-			if (diff == 8) {
+			if ((diff == 8) && support_160) {
 				new.width = NL80211_CHAN_WIDTH_160;
 				new.center_freq1 = cf1;
-			} else if (diff > 8) {
+			} else if ((diff > 8) && support_80_80) {
 				new.width = NL80211_CHAN_WIDTH_80P80;
 				new.center_freq2 = cf1;
 			}
-- 
2.7.4