cfg80211/mac80211: improve ad-hoc multicast rate handling

- store the multicast rate as an index instead of the rate value
  (reduces cpu overhead in a hotpath)
- validate the rate values (must match a bitrate in at least one sband)

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 33 insertions, 3 deletions

diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
index b15eb77195d..8734efa663d 100644
--- a/net/wireless/nl80211.c
+++ b/net/wireless/nl80211.c
@@ -3600,6 +3600,34 @@ static int nl80211_disassociate(struct sk_buff *skb, struct genl_info *info)
 				      local_state_change);
 }
 
+static bool
+nl80211_parse_mcast_rate(struct cfg80211_registered_device *rdev,
+			 int mcast_rate[IEEE80211_NUM_BANDS],
+			 int rateval)
+{
+	struct wiphy *wiphy = &rdev->wiphy;
+	bool found = false;
+	int band, i;
+
+	for (band = 0; band < IEEE80211_NUM_BANDS; band++) {
+		struct ieee80211_supported_band *sband;
+
+		sband = wiphy->bands[band];
+		if (!sband)
+			continue;
+
+		for (i = 0; i < sband->n_bitrates; i++) {
+			if (sband->bitrates[i].bitrate == rateval) {
+				mcast_rate[band] = i + 1;
+				found = true;
+				break;
+			}
+		}
+	}
+
+	return found;
+}
+
 static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 {
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
@@ -3683,9 +3711,11 @@ static int nl80211_join_ibss(struct sk_buff *skb, struct genl_info *info)
 				return -EINVAL;
 		}
 	}
-	if (info->attrs[NL80211_ATTR_MCAST_RATE])
-		ibss.mcast_rate =
-			nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE]);
+
+	if (info->attrs[NL80211_ATTR_MCAST_RATE] &&
+	    !nl80211_parse_mcast_rate(rdev, ibss.mcast_rate,
+			nla_get_u32(info->attrs[NL80211_ATTR_MCAST_RATE])))
+		return -EINVAL;
 
 	if (ibss.privacy && info->attrs[NL80211_ATTR_KEYS]) {
 		connkeys = nl80211_parse_connkeys(rdev,