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=-11.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 96514C433E2 for ; Tue, 15 Sep 2020 17:52:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5735B206B6 for ; Tue, 15 Sep 2020 17:52:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727904AbgIORwZ (ORCPT ); Tue, 15 Sep 2020 13:52:25 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:51518 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727872AbgIORdL (ORCPT ); Tue, 15 Sep 2020 13:33:11 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212]) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1kIEXS-00033S-SU; Tue, 15 Sep 2020 17:14:42 +0000 Subject: Re: [PATCH] media: rc: fix check on dev->min_timeout for LIRC_GET_MIN_TIMEOUT ioctl To: Sean Young Cc: Mauro Carvalho Chehab , Maxim Levitsky , linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200915153608.35154-1-colin.king@canonical.com> <20200915171256.GA681@gofer.mess.org> From: Colin Ian King Message-ID: Date: Tue, 15 Sep 2020 18:14:42 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.2.1 MIME-Version: 1.0 In-Reply-To: <20200915171256.GA681@gofer.mess.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 15/09/2020 18:12, Sean Young wrote: > On Tue, Sep 15, 2020 at 04:36:08PM +0100, Colin King wrote: >> From: Colin Ian King >> >> Currently the LIRC_GET_MIN_TIMEOUT is checking for a null dev->max_timeout >> and then accessing dev->min_timeout, hence we may have a potential null >> pointer dereference issue. This looks like a cut-n-paste typo, fix it >> by checking on dev->min_timeout before accessing it. > > max_timeout and min_timeout are both u32, not pointers. So, the commit > message is wrong: there is no null pointer dereference issue. > > Every driver which has max_timeout also has min_timeout set (I've checked > for this). So technically this is not wrong, but maybe it looks wrong? Oops. I totally misread the analysis report. My bad. > > Thanks, > > Sean >> >> Addresses-Coverity: ("Copy-paste error") >> Fixes: e589333f346b ("V4L/DVB: IR: extend interfaces to support more device settings") >> Signed-off-by: Colin Ian King >> --- >> drivers/media/rc/lirc_dev.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c >> index 220363b9a868..d230c21e1d31 100644 >> --- a/drivers/media/rc/lirc_dev.c >> +++ b/drivers/media/rc/lirc_dev.c >> @@ -533,7 +533,7 @@ static long lirc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) >> >> /* Generic timeout support */ >> case LIRC_GET_MIN_TIMEOUT: >> - if (!dev->max_timeout) >> + if (!dev->min_timeout) >> ret = -ENOTTY; >> else >> val = dev->min_timeout; >> -- >> 2.27.0