[PATCH] cfg80211: fix wext-compat memory leak

From: stefan . seyfried
Date: Sun Sep 30 2018 - 06:53:19 EST


From: Stefan Seyfried <seife+kernel@xxxxxxxxxxxxxx>

cfg80211_wext_giwrate and sinfo.pertid might allocate sinfo.pertid via
rdev_get_station(), but never release it

Signed-off-by: Stefan Seyfried <seife+kernel@xxxxxxxxxxxxxx>
---
net/wireless/wext-compat.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/net/wireless/wext-compat.c b/net/wireless/wext-compat.c
index 167f7025ac98..f462336aac1c 100644
--- a/net/wireless/wext-compat.c
+++ b/net/wireless/wext-compat.c
@@ -1277,12 +1277,16 @@ static int cfg80211_wext_giwrate(struct net_device *dev,
err = rdev_get_station(rdev, dev, addr, &sinfo);
if (err)
return err;
-
if (!(sinfo.filled & BIT_ULL(NL80211_STA_INFO_TX_BITRATE)))
return -EOPNOTSUPP;

rate->value = 100000 * cfg80211_calculate_bitrate(&sinfo.txrate);

+ /* sta_set_sinfo(), called from ieee80211_get_station(), called from
+ * rdev_get_station via rdev->ops->get_station, allocates pertid struct
+ * which we do not use here. */
+ kfree(sinfo.pertid);
+
return 0;
}

@@ -1293,7 +1297,7 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
struct cfg80211_registered_device *rdev = wiphy_to_rdev(wdev->wiphy);
/* we are under RTNL - globally locked - so can use static structs */
static struct iw_statistics wstats;
- static struct station_info sinfo;
+ static struct station_info sinfo = {};
u8 bssid[ETH_ALEN];

if (dev->ieee80211_ptr->iftype != NL80211_IFTYPE_STATION)
@@ -1352,6 +1356,9 @@ static struct iw_statistics *cfg80211_wireless_stats(struct net_device *dev)
if (sinfo.filled & BIT_ULL(NL80211_STA_INFO_TX_FAILED))
wstats.discard.retries = sinfo.tx_failed;

+ /* see cfg80211_wext_giwrate() above */
+ kfree(sinfo.pertid);
+
return &wstats;
}

--
2.19.0