[PATCH AUTOSEL 4.19 18/29] mac80211: fix possible sta leak

[Sasha Levin]

From: Johannes Berg <johannes.berg@xxxxxxxxx>

[ Upstream commit 5fd2f91ad483baffdbe798f8a08f1b41442d1e24 ]

If TDLS station addition is rejected, the sta memory is leaked.
Avoid this by moving the check before the allocation.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7ed5285396c2 ("mac80211: don't initiate TDLS connection if station is not associated to AP")
Link: https://lore.kernel.org/r/20190801073033.7892-1-johannes@xxxxxxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/mac80211/cfg.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 40c5102234679..a48e83b19cfa7 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1471,6 +1471,11 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev,
 	if (is_multicast_ether_addr(mac))
 		return -EINVAL;
 
+	if (params->sta_flags_set & BIT(NL80211_STA_FLAG_TDLS_PEER) &&
+	    sdata->vif.type == NL80211_IFTYPE_STATION &&
+	    !sdata->u.mgd.associated)
+		return -EINVAL;
+
 	sta = sta_info_alloc(sdata, mac, GFP_KERNEL);
 	if (!sta)
 		return -ENOMEM;
@@ -1478,10 +1483,6 @@ static int ieee80211_add_station(struct wiphy *wiphy, struct net_device *dev,
 	if (params->sta_flags_set & BIT(NL80211_STA_FLAG_TDLS_PEER))
 		sta->sta.tdls = true;
 
-	if (sta->sta.tdls && sdata->vif.type == NL80211_IFTYPE_STATION &&
-	    !sdata->u.mgd.associated)
-		return -EINVAL;
-
 	err = sta_apply_parameters(local, sta, params);
 	if (err) {
 		sta_info_free(local, sta);
-- 
2.20.1