mac80211: mlme: validate peer HE supported rates

We validate that AP has mandatory rates set in HE capabilities.

Also we make sure AP is consistent with itself on rates set in HE basic
rates required joining the BSS and rates set in HE capabilities.
Signed-off-by: Mordechay Goodstein <mordechay.goodstein@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20220202104617.7023450fdf16.I194df59252097ba25a0a543456d4350f1607a538@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/mlme.c

@@ -5006,6 +5006,104 @@ static u8 ieee80211_max_rx_chains(struct ieee80211_sub_if_data *sdata,
 	return chains;
 }
 
+static bool
+ieee80211_verify_peer_he_mcs_support(struct ieee80211_sub_if_data *sdata,
+				     const struct cfg80211_bss_ies *ies,
+				     const struct ieee80211_he_operation *he_op)
+{
+	const struct element *he_cap_elem;
+	const struct ieee80211_he_cap_elem *he_cap;
+	struct ieee80211_he_mcs_nss_supp *he_mcs_nss_supp;
+	u16 mcs_80_map_tx, mcs_80_map_rx;
+	u16 ap_min_req_set;
+	int mcs_nss_size;
+	int nss;
+
+	he_cap_elem = cfg80211_find_ext_elem(WLAN_EID_EXT_HE_CAPABILITY,
+					     ies->data, ies->len);
+
+	/* invalid HE IE */
+	if (!he_cap_elem || he_cap_elem->datalen < 1 + sizeof(*he_cap)) {
+		sdata_info(sdata,
+			   "Invalid HE elem, Disable HE\n");
+		return false;
+	}
+
+	/* skip one byte ext_tag_id */
+	he_cap = (void *)(he_cap_elem->data + 1);
+	mcs_nss_size = ieee80211_he_mcs_nss_size(he_cap);
+
+	/* invalid HE IE */
+	if (he_cap_elem->datalen < 1 + sizeof(*he_cap) + mcs_nss_size) {
+		sdata_info(sdata,
+			   "Invalid HE elem with nss size, Disable HE\n");
+		return false;
+	}
+
+	/* mcs_nss is right after he_cap info */
+	he_mcs_nss_supp = (void *)(he_cap + 1);
+
+	mcs_80_map_tx = le16_to_cpu(he_mcs_nss_supp->tx_mcs_80);
+	mcs_80_map_rx = le16_to_cpu(he_mcs_nss_supp->rx_mcs_80);
+
+	/* P802.11-REVme/D0.3
+	 * 27.1.1 Introduction to the HE PHY
+	 * ...
+	 * An HE STA shall support the following features:
+	 * ...
+	 * Single spatial stream HE-MCSs 0 to 7 (transmit and receive) in all
+	 * supported channel widths for HE SU PPDUs
+	 */
+	if ((mcs_80_map_tx & 0x3) == IEEE80211_HE_MCS_NOT_SUPPORTED ||
+	    (mcs_80_map_rx & 0x3) == IEEE80211_HE_MCS_NOT_SUPPORTED) {
+		sdata_info(sdata,
+			   "Missing mandatory rates for 1 Nss, rx 0x%x, tx 0x%x, disable HE\n",
+			   mcs_80_map_tx, mcs_80_map_rx);
+		return false;
+	}
+
+	if (!he_op)
+		return true;
+
+	ap_min_req_set = le16_to_cpu(he_op->he_mcs_nss_set);
+
+	/* make sure the AP is consistent with itself
+	 *
+	 * P802.11-REVme/D0.3
+	 * 26.17.1 Basic HE BSS operation
+	 *
+	 * A STA that is operating in an HE BSS shall be able to receive and
+	 * transmit at each of the <HE-MCS, NSS> tuple values indicated by the
+	 * Basic HE-MCS And NSS Set field of the HE Operation parameter of the
+	 * MLME-START.request primitive and shall be able to receive at each of
+	 * the <HE-MCS, NSS> tuple values indicated by the Supported HE-MCS and
+	 * NSS Set field in the HE Capabilities parameter of the MLMESTART.request
+	 * primitive
+	 */
+	for (nss = 8; nss > 0; nss--) {
+		u8 ap_op_val = (ap_min_req_set >> (2 * (nss - 1))) & 3;
+		u8 ap_rx_val;
+		u8 ap_tx_val;
+
+		if (ap_op_val == IEEE80211_HE_MCS_NOT_SUPPORTED)
+			continue;
+
+		ap_rx_val = (mcs_80_map_rx >> (2 * (nss - 1))) & 3;
+		ap_tx_val = (mcs_80_map_tx >> (2 * (nss - 1))) & 3;
+
+		if (ap_rx_val == IEEE80211_HE_MCS_NOT_SUPPORTED ||
+		    ap_tx_val == IEEE80211_HE_MCS_NOT_SUPPORTED ||
+		    ap_rx_val < ap_op_val || ap_tx_val < ap_op_val) {
+			sdata_info(sdata,
+				   "Invalid rates for %d Nss, rx %d, tx %d oper %d, disable HE\n",
+				   nss, ap_rx_val, ap_rx_val, ap_op_val);
+			return false;
+		}
+	}
+
+	return true;
+}
+
 static bool
 ieee80211_verify_sta_he_mcs_support(struct ieee80211_sub_if_data *sdata,
 				    struct ieee80211_supported_band *sband,
@@ -5191,7 +5289,8 @@ static int ieee80211_prep_channel(struct ieee80211_sub_if_data *sdata,
 			}
 		}
 
-		if (!ieee80211_verify_sta_he_mcs_support(sdata, sband, he_oper))
+		if (!ieee80211_verify_peer_he_mcs_support(sdata, ies, he_oper) ||
+		    !ieee80211_verify_sta_he_mcs_support(sdata, sband, he_oper))
 			ifmgd->flags |= IEEE80211_STA_DISABLE_HE;
 	}