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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 1A375C2BC73 for ; Wed, 4 Dec 2019 18:00:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E104B215F2 for ; Wed, 4 Dec 2019 18:00:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575482417; bh=QbBuGS/coJEwh6RluN11VrD758/GAztJk087GoksdZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lgxQt8FVg7jOEZTvxEyvwfl4zsBLFnxCWqTE5BNfNJ005RcCrqbYmsTC94NZ1gvud Fq5WUR1xiAsXhDfJQGoYDNvO9jx+IXN7hhjr477AZejp1NsvRazaHOudMk1hMdFzlR EOrjF9rZL5qsBZ7Uu/UrsqPlukIOK5euWOSIos+Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729294AbfLDSAP (ORCPT ); Wed, 4 Dec 2019 13:00:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:38406 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728236AbfLDSAO (ORCPT ); Wed, 4 Dec 2019 13:00:14 -0500 Received: from localhost (unknown [217.68.49.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 896432081B; Wed, 4 Dec 2019 18:00:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575482414; bh=QbBuGS/coJEwh6RluN11VrD758/GAztJk087GoksdZc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qSTbBVdWEDwo5vHPMuLsfKv6HGxCButCwjVETvSVLs6fuWn+jcIDaMSvty96opA5C rOF1hZaxclClpZc/DdgGCCt9hkl0GnCtsTGjcL8MmdPE9/ugAdzDuLMxufzB5notPk w4Yqs+r76GFYH0s8JaxGKTodlbQEg+4b2RdoiFRk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pan Bian , Dan Carpenter Subject: [PATCH 4.4 77/92] staging: rtl8192e: fix potential use after free Date: Wed, 4 Dec 2019 18:50:17 +0100 Message-Id: <20191204174334.879073522@linuxfoundation.org> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20191204174327.215426506@linuxfoundation.org> References: <20191204174327.215426506@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 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 Cc: stable Link: https://lore.kernel.org/r/1572965351-6745-1-git-send-email-bianpan2016@163.com Signed-off-by: Greg Kroah-Hartman --- 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 @@ -1631,14 +1631,15 @@ static void _rtl92e_hard_data_xmit(struc memcpy((unsigned char *)(skb->cb), &dev, sizeof(dev)); skb_push(skb, priv->rtllib->tx_headroom); ret = _rtl92e_tx(dev, skb); - if (ret != 0) - kfree_skb(skb); if (queue_index != MGNT_QUEUE) { priv->rtllib->stats.tx_bytes += (skb->len - priv->rtllib->tx_headroom); priv->rtllib->stats.tx_packets++; } + + if (ret != 0) + kfree_skb(skb); } static int _rtl92e_hard_start_xmit(struct sk_buff *skb, struct net_device *dev)