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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 7C66FC3A5A1 for ; Wed, 28 Aug 2019 03:53:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E6A620856 for ; Wed, 28 Aug 2019 03:53:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726278AbfH1Dw4 (ORCPT ); Tue, 27 Aug 2019 23:52:56 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:54434 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726227AbfH1Dw4 (ORCPT ); Tue, 27 Aug 2019 23:52:56 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 6AA2F153BA913; Tue, 27 Aug 2019 20:52:55 -0700 (PDT) Date: Tue, 27 Aug 2019 20:52:54 -0700 (PDT) Message-Id: <20190827.205254.561639753689757462.davem@davemloft.net> To: loyou85@gmail.com Cc: edumazet@google.com, dsterba@suse.com, dbanerje@akamai.com, fw@strlen.de, davej@codemonkey.org.uk, tglx@linutronix.de, matwey@sai.msu.ru, sakari.ailus@linux.intel.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, xiaojunzhao141@gmail.com Subject: Re: [PATCH v3] net: fix skb use after free in netpoll From: David Miller In-Reply-To: <1566801964-14691-1-git-send-email-loyou85@gmail.com> References: <20190825.232003.1145950065287854577.davem@davemloft.net> <1566801964-14691-1-git-send-email-loyou85@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Tue, 27 Aug 2019 20:52:55 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Feng Sun Date: Mon, 26 Aug 2019 14:46:04 +0800 > After commit baeababb5b85d5c4e6c917efe2a1504179438d3b > ("tun: return NET_XMIT_DROP for dropped packets"), > when tun_net_xmit drop packets, it will free skb and return NET_XMIT_DROP, > netpoll_send_skb_on_dev will run into following use after free cases: > 1. retry netpoll_start_xmit with freed skb; > 2. queue freed skb in npinfo->txq. > queue_process will also run into use after free case. > > hit netpoll_send_skb_on_dev first case with following kernel log: ... > Signed-off-by: Feng Sun > Signed-off-by: Xiaojun Zhao Applied and queued up for -stable.