From: Colin Ian King <colin.king@canonical.com>
Date: Fri, 30 Jun 2017 10:08:43 +0000 (+0100)
Subject: rtlwifi: kfree entry until after entry->bssid has been accessed
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=d0116f6f7b306bc2d1bfc98d7c7c80fe5f468c20;p=openwrt%2Fstaging%2Fblogic.git

rtlwifi: kfree entry until after entry->bssid has been accessed

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@canonical.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
---

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);