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 3F228C77B7A for ; Wed, 7 Jun 2023 08:09:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238969AbjFGIJO (ORCPT ); Wed, 7 Jun 2023 04:09:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55096 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238665AbjFGIJL (ORCPT ); Wed, 7 Jun 2023 04:09:11 -0400 Received: from relay6-d.mail.gandi.net (relay6-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::226]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 395D710EC for ; Wed, 7 Jun 2023 01:09:07 -0700 (PDT) X-GND-Sasl: miquel.raynal@bootlin.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1686125346; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Uvksj9+UTvDgflRsg73N5TFFbYS+sBxliu8X8GLsizk=; b=G59dKWV0vhixhK+7vErxEEZ4NfcDztQRB6cB2HMGjROdt1v88OIGFy+8wrGrQv7FsgbzJf 2tk+pv6vqg1HIedGRioquJpX3vymzXs16pxp/r667GQXf+G9gxCaK7Kf+UNkwNlYuuMn1O A57Jtz0psOH3fWW8tE8v+pIb/zObc3o7A+W3qs/sEPO7oHwBv2uAiKwwL0FwPZ4GnfucgV EYmY+k/nNjiWprnS7mBaA4Wrj4WAdQ2pnytjHUyIKfQHGqP6oMulZ0Imp/KXJXqXrQm4LD qzfBY7o3uxkC+qFTG11SNmABBplJpAHAdf9w+u85OAVBP8kffmdgvmuO7y1Q7A== X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com X-GND-Sasl: miquel.raynal@bootlin.com Received: by mail.gandi.net (Postfix) with ESMTPSA id 71A6EC0009; Wed, 7 Jun 2023 08:09:03 +0000 (UTC) Date: Wed, 7 Jun 2023 10:09:02 +0200 From: Miquel Raynal To: William Zhang Cc: Broadcom Kernel List , Linux MTD List , f.fainelli@gmail.com, rafal@milecki.pl, kursad.oney@broadcom.com, joel.peshkin@broadcom.com, computersforpeace@gmail.com, anand.gore@broadcom.com, dregan@mail.com, kamal.dasu@broadcom.com, tomer.yacoby@broadcom.com, dan.beygelman@broadcom.com, Florian Fainelli , linux-kernel@vger.kernel.org, Vignesh Raghavendra , Richard Weinberger , Kamal Dasu Subject: Re: [PATCH 04/12] mtd: rawnand: brcmnand: Fix potential out-of-bounds access in oob write Message-ID: <20230607100902.4df2bc27@xps-13> In-Reply-To: <20230606231252.94838-5-william.zhang@broadcom.com> References: <20230606231252.94838-1-william.zhang@broadcom.com> <20230606231252.94838-5-william.zhang@broadcom.com> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi William, william.zhang@broadcom.com wrote on Tue, 6 Jun 2023 16:12:44 -0700: > When the oob buffer length is not in multiple of words, the oob write > function does out-of-bounds read on the oob source buffer at the last > iteration. Fix that by always checking length limit on the oob buffer > read and fill with 0xff when reaching the end of the buffer to the oob > registers. >=20 > Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom S= TB NAND controller") > Signed-off-by: William Zhang > Reviewed-by: Florian Fainelli > --- >=20 > drivers/mtd/nand/raw/brcmnand/brcmnand.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/mtd/nand/raw/brcmnand/brcmnand.c b/drivers/mtd/nand/= raw/brcmnand/brcmnand.c > index 20832857c4aa..d920e88c7f5b 100644 > --- a/drivers/mtd/nand/raw/brcmnand/brcmnand.c > +++ b/drivers/mtd/nand/raw/brcmnand/brcmnand.c > @@ -1486,10 +1486,10 @@ static int write_oob_to_regs(struct brcmnand_cont= roller *ctrl, int i, > =20 > for (j =3D 0; j < tbytes; j +=3D 4) > oob_reg_write(ctrl, j, > - (oob[j + 0] << 24) | > - (oob[j + 1] << 16) | > - (oob[j + 2] << 8) | > - (oob[j + 3] << 0)); > + (((j < tbytes) ? oob[j] : 0xff) << 24) | > + (((j + 1 < tbytes) ? oob[j + 1] : 0xff) << 16) | > + (((j + 2 < tbytes) ? oob[j + 2] : 0xff) << 8) | > + ((j + 3 < tbytes) ? oob[j + 3] : 0xff)); This is a lot of additional operations which most of the time are not relevant. I would instead got for one less iteration in the for loop when there is unaligned data, and then dedicated if/else to fill the missing bytes. > return tbytes; > } > =20 Thanks, Miqu=C3=A8l