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=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 95767C433DB for ; Tue, 5 Jan 2021 10:52:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 54A2D22581 for ; Tue, 5 Jan 2021 10:52:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729274AbhAEKw1 (ORCPT ); Tue, 5 Jan 2021 05:52:27 -0500 Received: from mx2.suse.de ([195.135.220.15]:60328 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728919AbhAEKw1 (ORCPT ); Tue, 5 Jan 2021 05:52:27 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609843899; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=ctvgyyVLZwmab3QcFSKJMVqA4L0pIOmLRRQPugBuOjA=; b=dOi2ZlD73n5Gj8nhG2gCLg7GfoHsZIMlE565LwSspgL27LwmpOxKFHdOMUokOc2uQrQGLH RdnY3l25/m5wlVlveEUJwV7JVBpJzDURvMOQcJDjiELHLWaUQz6JjIliO1FUn6QA/Y7DAW BQJAUcC/RKKsdfsytrTGilDfrGGHUjA= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 90025AD0B; Tue, 5 Jan 2021 10:51:39 +0000 (UTC) Message-ID: Subject: Re: =?UTF-8?Q?=E5=9B=9E=E5=A4=8D=3A?= KASAN: use-after-free Read in service_outstanding_interrupt From: Oliver Neukum To: "Zhang, Qiang" , syzbot , "andreyknvl@google.com" , "gregkh@linuxfoundation.org" , "gustavoars@kernel.org" , "ingrassia@epigenesys.com" , "lee.jones@linaro.org" , "linux-kernel@vger.kernel.org" , "linux-usb@vger.kernel.org" , "penguin-kernel@I-love.SAKURA.ne.jp" , "syzkaller-bugs@googlegroups.com" Date: Tue, 05 Jan 2021 11:51:31 +0100 In-Reply-To: References: <000000000000994d2a05b6b49959@google.com> ,<6a56df508f597d38746878e80e1f159a556d3152.camel@suse.com> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, den 05.01.2021, 04:50 +0000 schrieb Zhang, Qiang: > > ________________________________________ > 发件人: Oliver Neukum > 发送时间: 2021年1月5日 0:28 > 收件人: syzbot; andreyknvl@google.com; gregkh@linuxfoundation.org; gustavoars@kernel.org; ingrassia@epigenesys.com; lee.jones@linaro.org; linux-kernel@vger.kernel.org; linux-usb@vger.kernel.org; penguin-kernel@I-love.SAKURA.ne.jp; syzkaller-bugs@googlegroups.com > 主题: Re: KASAN: use-after-free Read in service_outstanding_interrupt > > Am Donnerstag, den 17.12.2020, 19:21 -0800 schrieb syzbot: > > syzbot has found a reproducer for the following issue on: > > > > HEAD commit: 5e60366d Merge tag 'fallthrough-fixes-clang-5.11-rc1' of g.. > > git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing > > console output: https://syzkaller.appspot.com/x/log.txt?x=12c5b623500000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=5cea7506b7139727 > > dashboard link: https://syzkaller.appspot.com/bug?extid=9e04e2df4a32fb661daf > > compiler: gcc (GCC) 10.1.0-syz 20200507 > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=175adf07500000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1672680f500000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: >syzbot+9e04e2df4a32fb661daf@syzkaller.appspotmail.com > > > > #syz test: https://github.com/google/kasan.git 5e60366d > > > > Hello Oliver > > this use-after-free still exists，It can be seen from calltrace that it is > usb_device's object has been released when disconnect, > can add a reference count to usb_device's object to avoid this problem Hi, thanks for your analysis. I think you are correct in your analysis, but I am afraid your fix is not correct. The driver is submitting an URB to a disconnected device. Your fix would prevent a crash, which is definitely good, but we still cannot do that, because the device may be owned by another driver or usbfs at that time. Regards Oliver