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=-10.7 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 7045EC433B4 for ; Thu, 22 Apr 2021 06:55:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2A6FD6145B for ; Thu, 22 Apr 2021 06:55:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234734AbhDVGzn (ORCPT ); Thu, 22 Apr 2021 02:55:43 -0400 Received: from mout02.posteo.de ([185.67.36.142]:58981 "EHLO mout02.posteo.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229629AbhDVGzJ (ORCPT ); Thu, 22 Apr 2021 02:55:09 -0400 X-Greylist: delayed 428 seconds by postgrey-1.27 at vger.kernel.org; Thu, 22 Apr 2021 02:55:09 EDT Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 57C8C2400FC for ; Thu, 22 Apr 2021 08:47:24 +0200 (CEST) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4FQnzH0cm6z6tmV; Thu, 22 Apr 2021 08:47:22 +0200 (CEST) Subject: Re: [PATCH 120/190] Revert "tty: atmel_serial: fix a potential NULL pointer dereference" To: Jiri Slaby , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Cc: Kangjie Lu , Richard Genoud , stable References: <20210421130105.1226686-1-gregkh@linuxfoundation.org> <20210421130105.1226686-121-gregkh@linuxfoundation.org> <57f44dfa-a502-ee4f-6d53-0ab7cba00e1b@kernel.org> From: Richard Genoud Message-ID: Date: Thu, 22 Apr 2021 06:47:20 +0000 MIME-Version: 1.0 In-Reply-To: <57f44dfa-a502-ee4f-6d53-0ab7cba00e1b@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Language: fr-FR Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 22/04/2021 à 07:18, Jiri Slaby a écrit : > On 21. 04. 21, 14:59, Greg Kroah-Hartman wrote: >> This reverts commit c85be041065c0be8bc48eda4c45e0319caf1d0e5. >> >> Commits from @umn.edu addresses have been found to be submitted in "bad >> faith" to try to test the kernel community's ability to review "known >> malicious" changes.  The result of these submissions can be found in a >> paper published at the 42nd IEEE Symposium on Security and Privacy >> entitled, "Open Source Insecurity: Stealthily Introducing >> Vulnerabilities via Hypocrite Commits" written by Qiushi Wu (University >> of Minnesota) and Kangjie Lu (University of Minnesota). >> >> Because of this, all submissions from this group must be reverted from >> the kernel tree and will need to be re-reviewed again to determine if >> they actually are a valid fix.  Until that work is complete, remove this >> change to ensure that no problems are being introduced into the >> codebase. >> >> Cc: Kangjie Lu >> Cc: Richard Genoud >> Cc: stable >> Cc: Greg Kroah-Hartman >> Signed-off-by: Greg Kroah-Hartman >> --- >>   drivers/tty/serial/atmel_serial.c | 4 ---- >>   1 file changed, 4 deletions(-) >> >> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c >> index a24e5c2b30bc..9786d8e5f04f 100644 >> --- a/drivers/tty/serial/atmel_serial.c >> +++ b/drivers/tty/serial/atmel_serial.c >> @@ -1256,10 +1256,6 @@ static int atmel_prepare_rx_dma(struct uart_port *port) >>                        sg_dma_len(&atmel_port->sg_rx)/2, >>                        DMA_DEV_TO_MEM, >>                        DMA_PREP_INTERRUPT); >> -    if (!desc) { >> -        dev_err(port->dev, "Preparing DMA cyclic failed\n"); >> -        goto chan_err; >> -    } > > I cannot find anything malicious in the original fix: > * port->dev is valid for dev_err > * dmaengine_prep_dma_cyclic returns NULL in case of error > * chan_err invokes atmel_release_rx_dma which undoes the previous initialization code. > > Hence a NACK from me for the revert. I agree with your NACK. Back at the time (march 2019), I reviewed the changed and asked for a 2nd version and I didn't found anything suspicious. But the more eyes, the better. cf http://lkml.iu.edu/hypermail/linux/kernel/1903.1/05858.html > >>       desc->callback = atmel_complete_rx_dma; >>       desc->callback_param = port; >>       atmel_port->desc_rx = desc; >> > >