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,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 6F1CCC43461 for ; Thu, 17 Sep 2020 17:29:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22CF52220E for ; Thu, 17 Sep 2020 17:29:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726361AbgIQR3g convert rfc822-to-8bit (ORCPT ); Thu, 17 Sep 2020 13:29:36 -0400 Received: from mslow2.mail.gandi.net ([217.70.178.242]:36266 "EHLO mslow2.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726400AbgIQR1o (ORCPT ); Thu, 17 Sep 2020 13:27:44 -0400 X-Greylist: delayed 2484 seconds by postgrey-1.27 at vger.kernel.org; Thu, 17 Sep 2020 13:27:43 EDT Received: from relay8-d.mail.gandi.net (unknown [217.70.183.201]) by mslow2.mail.gandi.net (Postfix) with ESMTP id EA76B3B3CE0 for ; Thu, 17 Sep 2020 16:30:39 +0000 (UTC) X-Originating-IP: 91.224.148.103 Received: from xps13 (unknown [91.224.148.103]) (Authenticated sender: miquel.raynal@bootlin.com) by relay8-d.mail.gandi.net (Postfix) with ESMTPSA id E6D0F1BF217; Thu, 17 Sep 2020 16:30:02 +0000 (UTC) Date: Thu, 17 Sep 2020 18:30:01 +0200 From: Miquel Raynal To: Evgeny Novikov Cc: Richard Weinberger , Vignesh Raghavendra , Matthias Brugger , Boris Brezillon , "Gustavo A. R. Silva" , Masahiro Yamada , Stephen Boyd , linux-mtd@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, ldv-project@linuxtesting.org Subject: Re: [PATCH] mtd: rawnand: mtk: avoid underflow in mtk_nfc_nand_chip_init() Message-ID: <20200917183001.393245e8@xps13> In-Reply-To: <20200916194045.6378-1-novikov@ispras.ru> References: <20200916194045.6378-1-novikov@ispras.ru> Organization: Bootlin X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Evgeny, Evgeny Novikov wrote on Wed, 16 Sep 2020 22:40:45 +0300: > If of_get_property() will set nsels to negative values the driver may Is this really a possible case? Looking at the OF code, I don't think it can ever happen... > allocate insufficient memory for chip. Moreover, there may be underflow > for devm_kzalloc(). This can result in various bad consequences later. > The patch causes mtk_nfc_nand_chip_init() to fail for negative values of > nsels. > > Found by Linux Driver Verification project (linuxtesting.org). > > Signed-off-by: Evgeny Novikov > --- > drivers/mtd/nand/raw/mtk_nand.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mtd/nand/raw/mtk_nand.c b/drivers/mtd/nand/raw/mtk_nand.c > index ad1b55dab211..df98a2eec240 100644 > --- a/drivers/mtd/nand/raw/mtk_nand.c > +++ b/drivers/mtd/nand/raw/mtk_nand.c > @@ -1376,7 +1376,7 @@ static int mtk_nfc_nand_chip_init(struct device *dev, struct mtk_nfc *nfc, > return -ENODEV; > > nsels /= sizeof(u32); > - if (!nsels || nsels > MTK_NAND_MAX_NSELS) { > + if (nsels <= 0 || nsels > MTK_NAND_MAX_NSELS) { > dev_err(dev, "invalid reg property size %d\n", nsels); > return -EINVAL; > } Thanks, Miquèl