From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5483C35242 for ; Sat, 8 Feb 2020 18:31:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 80D3921775 for ; Sat, 8 Feb 2020 18:31:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728098AbgBHSaS (ORCPT ); Sat, 8 Feb 2020 13:30:18 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33960 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727650AbgBHS3m (ORCPT ); Sat, 8 Feb 2020 13:29:42 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1j0UrH-0003dw-NW; Sat, 08 Feb 2020 18:29:35 +0000 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1j0UrG-000CMh-E8; Sat, 08 Feb 2020 18:29:34 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Greg Kroah-Hartman" , "Dan Carpenter" , "Pan Bian" Date: Sat, 08 Feb 2020 18:19:52 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 053/148] staging: rtl8192e: fix potential use after free In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Pan Bian commit b7aa39a2ed0112d07fc277ebd24a08a7b2368ab9 upstream. The variable skb is released via kfree_skb() when the return value of _rtl92e_tx is not zero. However, after that, skb is accessed again to read its length, which may result in a use after free bug. This patch fixes the bug by moving the release operation to where skb is never used later. Signed-off-by: Pan Bian Reviewed-by: Dan Carpenter Link: https://lore.kernel.org/r/1572965351-6745-1-git-send-email-bianpan2016@163.com Signed-off-by: Greg Kroah-Hartman [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings --- drivers/staging/rtl8192e/rtl8192e/rtl_core.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/staging/rtl8192e/rtl8192e/rtl_core.c +++ b/drivers/staging/rtl8192e/rtl8192e/rtl_core.c @@ -1884,8 +1884,6 @@ void rtl8192_hard_data_xmit(struct sk_bu memcpy((unsigned char *)(skb->cb), &dev, sizeof(dev)); skb_push(skb, priv->rtllib->tx_headroom); ret = rtl8192_tx(dev, skb); - if (ret != 0) - kfree_skb(skb); if (queue_index != MGNT_QUEUE) { priv->rtllib->stats.tx_bytes += (skb->len - @@ -1893,6 +1891,9 @@ void rtl8192_hard_data_xmit(struct sk_bu priv->rtllib->stats.tx_packets++; } + if (ret != 0) + kfree_skb(skb); + return; }