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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 7EA18C76194 for ; Thu, 25 Jul 2019 15:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6189C2238C for ; Thu, 25 Jul 2019 15:52:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389637AbfGYPwF (ORCPT ); Thu, 25 Jul 2019 11:52:05 -0400 Received: from mx2.suse.de ([195.135.220.15]:46322 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387765AbfGYPwE (ORCPT ); Thu, 25 Jul 2019 11:52:04 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 906EAAFBE; Thu, 25 Jul 2019 15:52:03 +0000 (UTC) Date: Thu, 25 Jul 2019 17:52:03 +0200 Message-ID: From: Takashi Iwai To: "Jia-Ju Bai" Cc: , , , , , Subject: Re: [PATCH] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() In-Reply-To: <20190725082733.15234-1-baijiaju1990@gmail.com> References: <20190725082733.15234-1-baijiaju1990@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 25 Jul 2019 10:27:33 +0200, Jia-Ju Bai wrote: > > In build_adc_controls(), there is an if statement on line 773 to check > whether ak->adc_info is NULL: > if (! ak->adc_info || > ! ak->adc_info[mixer_ch].switch_name) > > When ak->adc_info is NULL, it is used on line 792: > knew.name = ak->adc_info[mixer_ch].selector_name; > > Thus, a possible null-pointer dereference may occur. > > To fix this bug, referring to lines 773 and 774, ak->adc_info > and ak->adc_info[mixer_ch].selector_name are checked before being used. > > This bug is found by a static analysis tool STCheck written by us. > > Signed-off-by: Jia-Ju Bai > --- > sound/i2c/other/ak4xxx-adda.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/sound/i2c/other/ak4xxx-adda.c b/sound/i2c/other/ak4xxx-adda.c > index 5f59316f982a..9a891470e84a 100644 > --- a/sound/i2c/other/ak4xxx-adda.c > +++ b/sound/i2c/other/ak4xxx-adda.c > @@ -775,11 +775,13 @@ static int build_adc_controls(struct snd_akm4xxx *ak) > return err; > > memset(&knew, 0, sizeof(knew)); > - knew.name = ak->adc_info[mixer_ch].selector_name; > - if (!knew.name) { > + if (! ak->adc_info || > + ! ak->adc_info[mixer_ch].selector_name) { > knew.name = "Capture Channel"; > knew.index = mixer_ch + ak->idx_offset * 2; > } > + else > + knew.name = ak->adc_info[mixer_ch].selector_name; > > knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER; > knew.info = ak4xxx_capture_source_info; The code change itself looks good, but please follow the standard coding style. In short: please run checkpatch.pl, fix errors (some warnings may be ignored) and resubmit. thanks, Takashi