wifi: cfg80211/mac80211: check EHT capability size correctly

For AP/non-AP the EHT MCS/NSS subfield size differs, the
4-octet subfield is only used for 20 MHz-only non-AP STA.
Pass an argument around everywhere to be able to parse it
properly.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/ieee80211.h

@@ -2886,7 +2886,8 @@ ieee80211_he_spr_size(const u8 *he_spr_ie)
 /* Calculate 802.11be EHT capabilities IE Tx/Rx EHT MCS NSS Support Field size */
 static inline u8
 ieee80211_eht_mcs_nss_size(const struct ieee80211_he_cap_elem *he_cap,
-			   const struct ieee80211_eht_cap_elem_fixed *eht_cap)
+			   const struct ieee80211_eht_cap_elem_fixed *eht_cap,
+			   bool from_ap)
 {
 	u8 count = 0;
 
@@ -2907,7 +2908,10 @@ ieee80211_eht_mcs_nss_size(const struct ieee80211_he_cap_elem *he_cap,
 	if (eht_cap->phy_cap_info[0] & IEEE80211_EHT_PHY_CAP0_320MHZ_IN_6GHZ)
 		count += 3;
 
-	return count ? count : 4;
+	if (count)
+		return count;
+
+	return from_ap ? 3 : 4;
 }
 
 /* 802.11be EHT PPE Thresholds */
@@ -2943,7 +2947,8 @@ ieee80211_eht_ppe_size(u16 ppe_thres_hdr, const u8 *phy_cap_info)
 }
 
 static inline bool
-ieee80211_eht_capa_size_ok(const u8 *he_capa, const u8 *data, u8 len)
+ieee80211_eht_capa_size_ok(const u8 *he_capa, const u8 *data, u8 len,
+			   bool from_ap)
 {
 	const struct ieee80211_eht_cap_elem_fixed *elem = (const void *)data;
 	u8 needed = sizeof(struct ieee80211_eht_cap_elem_fixed);
@@ -2952,7 +2957,8 @@ ieee80211_eht_capa_size_ok(const u8 *he_capa, const u8 *data, u8 len)
 		return false;
 
 	needed += ieee80211_eht_mcs_nss_size((const void *)he_capa,
-					     (const void *)data);
+					     (const void *)data,
+					     from_ap);
 	if (len < needed)
 		return false;
 

net/mac80211/eht.c

@@ -30,7 +30,9 @@ ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data *sdata,
 		return;
 
 	mcs_nss_size = ieee80211_eht_mcs_nss_size(he_cap_ie_elem,
-						  &eht_cap_ie_elem->fixed);
+						  &eht_cap_ie_elem->fixed,
+						  sdata->vif.type ==
+							NL80211_IFTYPE_STATION);
 
 	eht_total_size += mcs_nss_size;
 

net/mac80211/ieee80211_i.h

@@ -2185,6 +2185,8 @@ static inline void ieee80211_tx_skb(struct ieee80211_sub_if_data *sdata,
  *	for that non-transmitting BSS is returned
  * @link_id: the link ID to parse elements for, if a STA profile
  *	is present in the multi-link element, or -1 to ignore
+ * @from_ap: frame is received from an AP (currently used only
+ *	for EHT capabilities parsing)
  */
 struct ieee80211_elems_parse_params {
 	const u8 *start;
@@ -2194,6 +2196,7 @@ struct ieee80211_elems_parse_params {
 	u32 crc;
 	struct cfg80211_bss *bss;
 	int link_id;
+	bool from_ap;
 };
 
 struct ieee802_11_elems *
@@ -2514,7 +2517,8 @@ u8 ieee80211_ie_len_eht_cap(struct ieee80211_sub_if_data *sdata, u8 iftype);
 u8 *ieee80211_ie_build_eht_cap(u8 *pos,
 			       const struct ieee80211_sta_he_cap *he_cap,
 			       const struct ieee80211_sta_eht_cap *eht_cap,
-			       u8 *end);
+			       u8 *end,
+			       bool for_ap);
 
 void
 ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data *sdata,

net/mac80211/mlme.c

@@ -746,11 +746,13 @@ static void ieee80211_add_eht_ie(struct ieee80211_sub_if_data *sdata,
 	eht_cap_size =
 		2 + 1 + sizeof(eht_cap->eht_cap_elem) +
 		ieee80211_eht_mcs_nss_size(&he_cap->he_cap_elem,
-					   &eht_cap->eht_cap_elem) +
+					   &eht_cap->eht_cap_elem,
+					   false) +
 		ieee80211_eht_ppe_size(eht_cap->eht_ppe_thres[0],
 				       eht_cap->eht_cap_elem.phy_cap_info);
 	pos = skb_put(skb, eht_cap_size);
-	ieee80211_ie_build_eht_cap(pos, he_cap, eht_cap, pos + eht_cap_size);
+	ieee80211_ie_build_eht_cap(pos, he_cap, eht_cap, pos + eht_cap_size,
+				   false);
 }
 
 static void ieee80211_assoc_add_rates(struct sk_buff *skb,
@@ -3912,6 +3914,7 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 		.len = elem_len,
 		.bss = cbss,
 		.link_id = link == &sdata->deflink ? -1 : link->link_id,
+		.from_ap = true,
 	};
 	bool is_6ghz = cbss->channel->band == NL80211_BAND_6GHZ;
 	bool is_s1g = cbss->channel->band == NL80211_BAND_S1GHZ;
@@ -4580,6 +4583,11 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 	bool is_6ghz = cbss->channel->band == NL80211_BAND_6GHZ;
 	bool is_5ghz = cbss->channel->band == NL80211_BAND_5GHZ;
 	struct ieee80211_bss *bss = (void *)cbss->priv;
+	struct ieee80211_elems_parse_params parse_params = {
+		.bss = cbss,
+		.link_id = -1,
+		.from_ap = true,
+	};
 	struct ieee802_11_elems *elems;
 	const struct cfg80211_bss_ies *ies;
 	int ret;
@@ -4589,7 +4597,9 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 	rcu_read_lock();
 
 	ies = rcu_dereference(cbss->ies);
-	elems = ieee802_11_parse_elems(ies->data, ies->len, false, cbss);
+	parse_params.start = ies->data;
+	parse_params.len = ies->len;
+	elems = ieee802_11_parse_elems_full(&parse_params);
 	if (!elems) {
 		rcu_read_unlock();
 		return -ENOMEM;
@@ -4944,6 +4954,11 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 	struct ieee80211_mgd_assoc_data *assoc_data = ifmgd->assoc_data;
 	u16 capab_info, status_code, aid;
+	struct ieee80211_elems_parse_params parse_params = {
+		.bss = NULL,
+		.link_id = -1,
+		.from_ap = true,
+	};
 	struct ieee802_11_elems *elems;
 	int ac;
 	const u8 *elem_start;
@@ -4998,7 +5013,9 @@ static void ieee80211_rx_mgmt_assoc_resp(struct ieee80211_sub_if_data *sdata,
 		return;
 
 	elem_len = len - (elem_start - (u8 *)mgmt);
-	elems = ieee802_11_parse_elems(elem_start, elem_len, false, NULL);
+	parse_params.start = elem_start;
+	parse_params.len = elem_len;
+	elems = ieee802_11_parse_elems_full(&parse_params);
 	if (!elems)
 		goto notify_driver;
 
@@ -5363,6 +5380,10 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	u32 ncrc = 0;
 	u8 *bssid, *variable = mgmt->u.beacon.variable;
 	u8 deauth_buf[IEEE80211_DEAUTH_FRAME_LEN];
+	struct ieee80211_elems_parse_params parse_params = {
+		.link_id = -1,
+		.from_ap = true,
+	};
 
 	sdata_assert_lock(sdata);
 
@@ -5381,6 +5402,9 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	if (baselen > len)
 		return;
 
+	parse_params.start = variable;
+	parse_params.len = len - baselen;
+
 	rcu_read_lock();
 	chanctx_conf = rcu_dereference(link->conf->chanctx_conf);
 	if (!chanctx_conf) {
@@ -5399,8 +5423,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	if (ifmgd->assoc_data && ifmgd->assoc_data->need_beacon &&
 	    !WARN_ON(sdata->vif.valid_links) &&
 	    ieee80211_rx_our_beacon(bssid, ifmgd->assoc_data->link[0].bss)) {
-		elems = ieee802_11_parse_elems(variable, len - baselen, false,
-					       ifmgd->assoc_data->link[0].bss);
+		parse_params.bss = ifmgd->assoc_data->link[0].bss;
+		elems = ieee802_11_parse_elems_full(&parse_params);
 		if (!elems)
 			return;
 
@@ -5466,9 +5490,10 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_link_data *link,
 	 */
 	if (!ieee80211_is_s1g_beacon(hdr->frame_control))
 		ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
-	elems = ieee802_11_parse_elems_crc(variable, len - baselen,
-					   false, care_about_ies, ncrc,
-					   link->u.mgd.bss);
+	parse_params.bss = link->u.mgd.bss;
+	parse_params.filter = care_about_ies;
+	parse_params.crc = ncrc;
+	elems = ieee802_11_parse_elems_full(&parse_params);
 	if (!elems)
 		return;
 	ncrc = elems->crc;

net/mac80211/util.c

@@ -954,9 +954,11 @@ void ieee80211_queue_delayed_work(struct ieee80211_hw *hw,
 }
 EXPORT_SYMBOL(ieee80211_queue_delayed_work);
 
-static void ieee80211_parse_extension_element(u32 *crc,
+static void
+ieee80211_parse_extension_element(u32 *crc,
 				  const struct element *elem,
-					      struct ieee802_11_elems *elems)
+				  struct ieee802_11_elems *elems,
+				  struct ieee80211_elems_parse_params *params)
 {
 	const void *data = elem->data + 1;
 	u8 len;
@@ -1013,7 +1015,8 @@ static void ieee80211_parse_extension_element(u32 *crc,
 		break;
 	case WLAN_EID_EXT_EHT_CAPABILITY:
 		if (ieee80211_eht_capa_size_ok(elems->he_cap,
-					       data, len)) {
+					       data, len,
+					       params->from_ap)) {
 			elems->eht_cap = data;
 			elems->eht_cap_len = len;
 		}
@@ -1385,7 +1388,7 @@ _ieee802_11_parse_elems_full(struct ieee80211_elems_parse_params *params,
 		case WLAN_EID_EXTENSION:
 			ieee80211_parse_extension_element(calc_crc ?
 								&crc : NULL,
-							  elem, elems);
+							  elem, elems, params);
 			break;
 		case WLAN_EID_S1G_CAPABILITIES:
 			if (elen >= sizeof(*elems->s1g_capab))
@@ -2025,7 +2028,8 @@ static int ieee80211_build_preq_ies_band(struct ieee80211_sub_if_data *sdata,
 	    cfg80211_any_usable_channels(local->hw.wiphy, BIT(sband->band),
 					 IEEE80211_CHAN_NO_HE |
 					 IEEE80211_CHAN_NO_EHT)) {
-		pos = ieee80211_ie_build_eht_cap(pos, he_cap, eht_cap, end);
+		pos = ieee80211_ie_build_eht_cap(pos, he_cap, eht_cap, end,
+						 sdata->vif.type == NL80211_IFTYPE_AP);
 		if (!pos)
 			goto out_err;
 	}
@@ -4770,6 +4774,7 @@ u8 ieee80211_ie_len_eht_cap(struct ieee80211_sub_if_data *sdata, u8 iftype)
 	const struct ieee80211_sta_he_cap *he_cap;
 	const struct ieee80211_sta_eht_cap *eht_cap;
 	struct ieee80211_supported_band *sband;
+	bool is_ap;
 	u8 n;
 
 	sband = ieee80211_get_sband(sdata);
@@ -4781,8 +4786,12 @@ u8 ieee80211_ie_len_eht_cap(struct ieee80211_sub_if_data *sdata, u8 iftype)
 	if (!he_cap || !eht_cap)
 		return 0;
 
+	is_ap = iftype == NL80211_IFTYPE_AP ||
+		iftype == NL80211_IFTYPE_P2P_GO;
+
 	n = ieee80211_eht_mcs_nss_size(&he_cap->he_cap_elem,
-				       &eht_cap->eht_cap_elem);
+				       &eht_cap->eht_cap_elem,
+				       is_ap);
 	return 2 + 1 +
 	       sizeof(he_cap->he_cap_elem) + n +
 	       ieee80211_eht_ppe_size(eht_cap->eht_ppe_thres[0],
@@ -4793,7 +4802,8 @@ u8 ieee80211_ie_len_eht_cap(struct ieee80211_sub_if_data *sdata, u8 iftype)
 u8 *ieee80211_ie_build_eht_cap(u8 *pos,
 			       const struct ieee80211_sta_he_cap *he_cap,
 			       const struct ieee80211_sta_eht_cap *eht_cap,
-			       u8 *end)
+			       u8 *end,
+			       bool for_ap)
 {
 	u8 mcs_nss_len, ppet_len;
 	u8 ie_len;
@@ -4804,7 +4814,8 @@ u8 *ieee80211_ie_build_eht_cap(u8 *pos,
 		return orig_pos;
 
 	mcs_nss_len = ieee80211_eht_mcs_nss_size(&he_cap->he_cap_elem,
-						 &eht_cap->eht_cap_elem);
+						 &eht_cap->eht_cap_elem,
+						 for_ap);
 	ppet_len = ieee80211_eht_ppe_size(eht_cap->eht_ppe_thres[0],
 					  eht_cap->eht_cap_elem.phy_cap_info);
 

net/wireless/core.c

@@ -860,6 +860,9 @@ int wiphy_register(struct wiphy *wiphy)
 
 		for (i = 0; i < sband->n_iftype_data; i++) {
 			const struct ieee80211_sband_iftype_data *iftd;
+			bool has_ap, has_non_ap;
+			u32 ap_bits = BIT(NL80211_IFTYPE_AP) |
+				      BIT(NL80211_IFTYPE_P2P_GO);
 
 			iftd = &sband->iftype_data[i];
 
@@ -879,6 +882,19 @@ int wiphy_register(struct wiphy *wiphy)
 			else
 				have_he = have_he &&
 					  iftd->he_cap.has_he;
+
+			has_ap = iftd->types_mask & ap_bits;
+			has_non_ap = iftd->types_mask & ~ap_bits;
+
+			/*
+			 * For EHT 20 MHz STA, the capabilities format differs
+			 * but to simplify, don't check 20 MHz but rather check
+			 * only if AP and non-AP were mentioned at the same time,
+			 * reject if so.
+			 */
+			if (WARN_ON(iftd->eht_cap.has_eht &&
+				    has_ap && has_non_ap))
+				return -EINVAL;
 		}
 
 		if (WARN_ON(!have_he && band == NL80211_BAND_6GHZ))

net/wireless/nl80211.c

@@ -1820,10 +1820,15 @@ nl80211_send_iftype_data(struct sk_buff *msg,
 	if (eht_cap->has_eht && he_cap->has_he) {
 		u8 mcs_nss_size, ppe_thresh_size;
 		u16 ppe_thres_hdr;
+		bool is_ap;
+
+		is_ap = iftdata->types_mask & BIT(NL80211_IFTYPE_AP) ||
+			iftdata->types_mask & BIT(NL80211_IFTYPE_P2P_GO);
 
 		mcs_nss_size =
 			ieee80211_eht_mcs_nss_size(&he_cap->he_cap_elem,
-						   &eht_cap->eht_cap_elem);
+						   &eht_cap->eht_cap_elem,
+						   is_ap);
 
 		ppe_thres_hdr = get_unaligned_le16(&eht_cap->eht_ppe_thres[0]);
 		ppe_thresh_size =
@@ -5668,7 +5673,7 @@ static int nl80211_calculate_ap_params(struct cfg80211_ap_settings *params)
 		params->eht_cap = (void *)(cap->data + 1);
 		if (!ieee80211_eht_capa_size_ok((const u8 *)params->he_cap,
 						(const u8 *)params->eht_cap,
-						cap->datalen - 1))
+						cap->datalen - 1, true))
 			return -EINVAL;
 	}
 	cap = cfg80211_find_ext_elem(WLAN_EID_EXT_EHT_OPERATION, ies, ies_len);
@@ -6897,7 +6902,8 @@ static int nl80211_set_station_tdls(struct genl_info *info,
 
 			if (!ieee80211_eht_capa_size_ok((const u8 *)params->link_sta_params.he_capa,
 							(const u8 *)params->link_sta_params.eht_capa,
-							params->link_sta_params.eht_capa_len))
+							params->link_sta_params.eht_capa_len,
+							false))
 				return -EINVAL;
 		}
 	}
@@ -7208,7 +7214,8 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info)
 
 			if (!ieee80211_eht_capa_size_ok((const u8 *)params.link_sta_params.he_capa,
 							(const u8 *)params.link_sta_params.eht_capa,
-							params.link_sta_params.eht_capa_len))
+							params.link_sta_params.eht_capa_len,
+							false))
 				return -EINVAL;
 		}
 	}
@@ -15968,7 +15975,8 @@ nl80211_add_mod_link_station(struct sk_buff *skb, struct genl_info *info,
 
 			if (!ieee80211_eht_capa_size_ok((const u8 *)params.he_capa,
 							(const u8 *)params.eht_capa,
-							params.eht_capa_len))
+							params.eht_capa_len,
+							false))
 				return -EINVAL;
 		}
 	}