wifi: cfg80211: check extended MLD capa/ops in assoc

Check that additionally extended MLD capa/ops for the MLD is
consistent, i.e. the same value is reported by all affiliated
APs/links.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250101070249.e29f42c7ae21.Ib2cdce608321ad154e4b13103cc315c3e3cb6b2b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

include/linux/ieee80211.h

@@ -4961,6 +4961,7 @@ struct ieee80211_multi_link_elem {
 #define IEEE80211_MLC_BASIC_PRES_EML_CAPA		0x0080
 #define IEEE80211_MLC_BASIC_PRES_MLD_CAPA_OP		0x0100
 #define IEEE80211_MLC_BASIC_PRES_MLD_ID			0x0200
+#define IEEE80211_MLC_BASIC_PRES_EXT_MLD_CAPA_OP	0x0400
 
 #define IEEE80211_MED_SYNC_DELAY_DURATION		0x00ff
 #define IEEE80211_MED_SYNC_DELAY_SYNC_OFDM_ED_THRESH	0x0f00
@@ -5226,6 +5227,47 @@ static inline u16 ieee80211_mle_get_mld_capa_op(const u8 *data)
 	return get_unaligned_le16(common);
 }
 
+/**
+ * ieee80211_mle_get_ext_mld_capa_op - returns the extended MLD capabilities
+ *	and operations.
+ * @data: pointer to the multi-link element
+ * Return: the extended MLD capabilities and operations field value from
+ *	the multi-link element, or 0 if not present
+ *
+ * The element is assumed to be of the correct type (BASIC) and big enough,
+ * this must be checked using ieee80211_mle_type_ok().
+ */
+static inline u16 ieee80211_mle_get_ext_mld_capa_op(const u8 *data)
+{
+	const struct ieee80211_multi_link_elem *mle = (const void *)data;
+	u16 control = le16_to_cpu(mle->control);
+	const u8 *common = mle->variable;
+
+	/*
+	 * common points now at the beginning of
+	 * ieee80211_mle_basic_common_info
+	 */
+	common += sizeof(struct ieee80211_mle_basic_common_info);
+
+	if (!(control & IEEE80211_MLC_BASIC_PRES_EXT_MLD_CAPA_OP))
+		return 0;
+
+	if (control & IEEE80211_MLC_BASIC_PRES_LINK_ID)
+		common += 1;
+	if (control & IEEE80211_MLC_BASIC_PRES_BSS_PARAM_CH_CNT)
+		common += 1;
+	if (control & IEEE80211_MLC_BASIC_PRES_MED_SYNC_DELAY)
+		common += 2;
+	if (control & IEEE80211_MLC_BASIC_PRES_EML_CAPA)
+		common += 2;
+	if (control & IEEE80211_MLC_BASIC_PRES_MLD_CAPA_OP)
+		common += 2;
+	if (control & IEEE80211_MLC_BASIC_PRES_MLD_ID)
+		common += 1;
+
+	return get_unaligned_le16(common);
+}
+
 /**
  * ieee80211_mle_get_mld_id - returns the MLD ID
  * @data: pointer to the multi-link element
@@ -5298,6 +5340,8 @@ static inline bool ieee80211_mle_size_ok(const u8 *data, size_t len)
 			common += 2;
 		if (control & IEEE80211_MLC_BASIC_PRES_MLD_ID)
 			common += 1;
+		if (control & IEEE80211_MLC_BASIC_PRES_EXT_MLD_CAPA_OP)
+			common += 2;
 		break;
 	case IEEE80211_ML_CONTROL_TYPE_PREQ:
 		common += sizeof(struct ieee80211_mle_preq_common_info);

net/wireless/mlme.c

@@ -352,6 +352,13 @@ cfg80211_mlme_check_mlo_compat(const struct ieee80211_multi_link_elem *mle_a,
 		return -EINVAL;
 	}
 
+	if (ieee80211_mle_get_ext_mld_capa_op((const u8 *)mle_a) !=
+	    ieee80211_mle_get_ext_mld_capa_op((const u8 *)mle_b)) {
+		NL_SET_ERR_MSG(extack,
+			       "extended link MLD capabilities/ops mismatch");
+		return -EINVAL;
+	}
+
 	return 0;
 }