[PATCH][-next] rtlwifi: kfree entry until after entry->bssid has been accessed

From: Colin King
Date: Fri Jun 30 2017 - 06:08:58 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

The current code kfree's entry and then dereferences it by accessing
entry->bssid. Avoid the dereference-after-free by moving the kfree
after the access to entry->bssid.

Detected by CoverityScan, CID#1448600 ("Read from pointer after free")

Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/net/wireless/realtek/rtlwifi/base.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/base.c b/drivers/net/wireless/realtek/rtlwifi/base.c
index e36ee592c660..208f56297a75 100644
--- a/drivers/net/wireless/realtek/rtlwifi/base.c
+++ b/drivers/net/wireless/realtek/rtlwifi/base.c
@@ -1735,12 +1735,12 @@ void rtl_scan_list_expire(struct ieee80211_hw *hw)
continue;

list_del(&entry->list);
- kfree(entry);
rtlpriv->scan_list.num--;

RT_TRACE(rtlpriv, COMP_SCAN, DBG_LOUD,
"BSSID=%pM is expire in scan list (total=%d)\n",
entry->bssid, rtlpriv->scan_list.num);
+ kfree(entry);
}

spin_unlock_irqrestore(&rtlpriv->locks.scan_list_lock, flags);
--
2.11.0