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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 43BAFC38145 for ; Thu, 8 Sep 2022 20:30:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229755AbiIHUaR (ORCPT ); Thu, 8 Sep 2022 16:30:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44046 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229464AbiIHUaO (ORCPT ); Thu, 8 Sep 2022 16:30:14 -0400 Received: from mx01.omp.ru (mx01.omp.ru [90.154.21.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 260655E56A; Thu, 8 Sep 2022 13:30:13 -0700 (PDT) Received: from [192.168.1.103] (31.173.81.50) by msexch01.omp.ru (10.188.4.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.986.14; Thu, 8 Sep 2022 23:30:04 +0300 Subject: Re: [PATCH] usb: gadget: rndis: Avoid dereference before NULL check To: Jim Lin , , CC: , , Aniruddha TVS Rao References: <20220908175615.5095-1-jilin@nvidia.com> From: Sergey Shtylyov Organization: Open Mobile Platform Message-ID: Date: Thu, 8 Sep 2022 23:30:04 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: <20220908175615.5095-1-jilin@nvidia.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [31.173.81.50] X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 5.9.20, Database issued on: 09/08/2022 19:43:21 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 172645 [Sep 08 2022] X-KSE-AntiSpam-Info: Version: 5.9.20.0 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 498 498 840112829f78e8dd3e3ddbbff8b15d552f4973a3 X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.81.50 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.81.50 in (user) dbl.spamhaus.org} X-KSE-AntiSpam-Info: 127.0.0.199:7.1.2;omp.ru:7.1.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;31.173.81.50:7.1.2 X-KSE-AntiSpam-Info: ApMailHostAddress: 31.173.81.50 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 09/08/2022 19:45:00 X-KSE-AttachmentFiltering-Interceptor-Info: protection disabled X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 9/8/2022 7:02:00 PM X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/8/22 8:56 PM, Jim Lin wrote: > NULL check is performed after params->dev is dereferenced in > dev_get_stats. > Fixed by adding a NULL check before dereferencing params->dev and > removing subsequent NULL checks for it. You've beaten me to send such a patch... :-) > > Signed-off-by: Aniruddha TVS Rao > Signed-off-by: Jim Lin > --- > drivers/usb/gadget/function/rndis.c | 37 ++++++++++++----------------- > 1 file changed, 15 insertions(+), 22 deletions(-) > > diff --git a/drivers/usb/gadget/function/rndis.c b/drivers/usb/gadget/function/rndis.c > index 64de9f1b874c..d2f18f34c8e5 100644 > --- a/drivers/usb/gadget/function/rndis.c > +++ b/drivers/usb/gadget/function/rndis.c > @@ -198,6 +198,9 @@ static int gen_ndis_query_resp(struct rndis_params *params, u32 OID, u8 *buf, > outbuf = (__le32 *)&resp[1]; > resp->InformationBufferOffset = cpu_to_le32(16); > > + if (!params->dev) > + return -ENODEV; > + Hm, isn't this checked at the start of rndis_query_response(), this function's only caller? [...] MBR, Sergey