mac80211: fix possible sta leak

BugLink: https://bugs.launchpad.net/bugs/1843338
commit 5fd2f91ad483baffdbe798f8a08f1b41442d1e24 upstream.

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

Cc: stable@vger.kernel.org
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@sipsolutions.net
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 150dd2160cefb2c2866b473aadbd64d8f6e69ff4..8168c667d91d92390576576a4125c8679c2db8a5 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1459,6 +1459,11 @@ 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;
@@ -1466,10 +1471,6 @@ 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);