nl80211: use NLA_POLICY_RANGE(NLA_BINARY, ...) for a few attributes

We have a few attributes with minimum and maximum lengths that are
not the same, use the new feature of being able to specify both in
the policy to validate them, removing code and allowing this to be
advertised to userspace in the policy export.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://lore.kernel.org/r/20200819085642.8f12ffa14f33.I9d948d59870e521febcd79bb4a986b1de1dca47b@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

net/wireless/nl80211.c

@@ -574,14 +574,20 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_CSA_C_OFF_BEACON] = { .type = NLA_BINARY },
 	[NL80211_ATTR_CSA_C_OFF_PRESP] = { .type = NLA_BINARY },
 	[NL80211_ATTR_STA_SUPPORTED_CHANNELS] = NLA_POLICY_MIN_LEN(2),
-	[NL80211_ATTR_STA_SUPPORTED_OPER_CLASSES] = { .type = NLA_BINARY },
+	/*
+	 * The value of the Length field of the Supported Operating
+	 * Classes element is between 2 and 253.
+	 */
+	[NL80211_ATTR_STA_SUPPORTED_OPER_CLASSES] =
+		NLA_POLICY_RANGE(NLA_BINARY, 2, 253),
 	[NL80211_ATTR_HANDLE_DFS] = { .type = NLA_FLAG },
 	[NL80211_ATTR_OPMODE_NOTIF] = { .type = NLA_U8 },
 	[NL80211_ATTR_VENDOR_ID] = { .type = NLA_U32 },
 	[NL80211_ATTR_VENDOR_SUBCMD] = { .type = NLA_U32 },
 	[NL80211_ATTR_VENDOR_DATA] = { .type = NLA_BINARY },
-	[NL80211_ATTR_QOS_MAP] = { .type = NLA_BINARY,
-				   .len = IEEE80211_QOS_MAP_LEN_MAX },
+	[NL80211_ATTR_QOS_MAP] = NLA_POLICY_RANGE(NLA_BINARY,
+						  IEEE80211_QOS_MAP_LEN_MIN,
+						  IEEE80211_QOS_MAP_LEN_MAX),
 	[NL80211_ATTR_MAC_HINT] = NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN),
 	[NL80211_ATTR_WIPHY_FREQ_HINT] = { .type = NLA_U32 },
 	[NL80211_ATTR_TDLS_PEER_CAPABILITY] = { .type = NLA_U32 },
@@ -636,9 +642,10 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 	[NL80211_ATTR_TXQ_LIMIT] = { .type = NLA_U32 },
 	[NL80211_ATTR_TXQ_MEMORY_LIMIT] = { .type = NLA_U32 },
 	[NL80211_ATTR_TXQ_QUANTUM] = { .type = NLA_U32 },
-	[NL80211_ATTR_HE_CAPABILITY] = { .type = NLA_BINARY,
-					 .len = NL80211_HE_MAX_CAPABILITY_LEN },
-
+	[NL80211_ATTR_HE_CAPABILITY] =
+		NLA_POLICY_RANGE(NLA_BINARY,
+				 NL80211_HE_MIN_CAPABILITY_LEN,
+				 NL80211_HE_MAX_CAPABILITY_LEN),
 	[NL80211_ATTR_FTM_RESPONDER] =
 		NLA_POLICY_NESTED(nl80211_ftm_responder_policy),
 	[NL80211_ATTR_TIMEOUT] = NLA_POLICY_MIN(NLA_U32, 1),
@@ -5852,13 +5859,6 @@ static int nl80211_parse_sta_channel_info(struct genl_info *info,
 		 nla_data(info->attrs[NL80211_ATTR_STA_SUPPORTED_OPER_CLASSES]);
 		params->supported_oper_classes_len =
 		  nla_len(info->attrs[NL80211_ATTR_STA_SUPPORTED_OPER_CLASSES]);
-		/*
-		 * The value of the Length field of the Supported Operating
-		 * Classes element is between 2 and 253.
-		 */
-		if (params->supported_oper_classes_len < 2 ||
-		    params->supported_oper_classes_len > 253)
-			return -EINVAL;
 	}
 	return 0;
 }
@@ -5881,9 +5881,6 @@ static int nl80211_set_station_tdls(struct genl_info *info,
 			nla_data(info->attrs[NL80211_ATTR_HE_CAPABILITY]);
 		params->he_capa_len =
 			nla_len(info->attrs[NL80211_ATTR_HE_CAPABILITY]);
-
-		if (params->he_capa_len < NL80211_HE_MIN_CAPABILITY_LEN)
-			return -EINVAL;
 	}
 
 	err = nl80211_parse_sta_channel_info(info, params);
@@ -6142,10 +6139,6 @@ static int nl80211_new_station(struct sk_buff *skb, struct genl_info *info)
 			nla_data(info->attrs[NL80211_ATTR_HE_CAPABILITY]);
 		params.he_capa_len =
 			nla_len(info->attrs[NL80211_ATTR_HE_CAPABILITY]);
-
-		/* max len is validated in nla policy */
-		if (params.he_capa_len < NL80211_HE_MIN_CAPABILITY_LEN)
-			return -EINVAL;
 	}
 
 	if (info->attrs[NL80211_ATTR_HE_6GHZ_CAPABILITY])
@@ -13545,8 +13538,7 @@ static int nl80211_set_qos_map(struct sk_buff *skb,
 		pos = nla_data(info->attrs[NL80211_ATTR_QOS_MAP]);
 		len = nla_len(info->attrs[NL80211_ATTR_QOS_MAP]);
 
-		if (len % 2 || len < IEEE80211_QOS_MAP_LEN_MIN ||
-		    len > IEEE80211_QOS_MAP_LEN_MAX)
+		if (len % 2)
 			return -EINVAL;
 
 		qos_map = kzalloc(sizeof(struct cfg80211_qos_map), GFP_KERNEL);