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rtlwifi: kfree entry until after entry->bssid has been accessed
authorColin Ian King <colin.king@canonical.com>
Fri, 30 Jun 2017 10:08:43 +0000 (11:08 +0100)
committerKalle Valo <kvalo@codeaurora.org>
Thu, 27 Jul 2017 10:58:18 +0000 (13:58 +0300)
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>
drivers/net/wireless/realtek/rtlwifi/base.c

index e36ee59..208f562 100644 (file)
@@ -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);