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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 2CFC2C433E0 for ; Tue, 26 May 2020 07:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D55E320787 for ; Tue, 26 May 2020 07:52:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590479557; bh=AifSerfqz073RNCBrNqnnbcnsc2XfSSlPfQgof4KSyc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=UiFIZV4EouBoCBsGjtevej6mc2cinxkNuJc5R2Glf3DQrSshjUAj5Xf5w37Uc4Pn3 Z8MKJ9Vv7n14Lhkj4hgaL4LBXoCE45eM9DR2QhCcViuSDQZIi1UgoJvj8h4GJRVFkZ bsd6RO4ifrP2s+bUFSyCGds5HYSa0+JwhLtOUrHs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731524AbgEZHwh (ORCPT ); Tue, 26 May 2020 03:52:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:35210 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726048AbgEZHwh (ORCPT ); Tue, 26 May 2020 03:52:37 -0400 Received: from localhost (unknown [151.48.148.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C063420776; Tue, 26 May 2020 07:52:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590479556; bh=AifSerfqz073RNCBrNqnnbcnsc2XfSSlPfQgof4KSyc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=b8fXBdI1RUIH8NDfL3m84zZgEBrAV0IJXbcozZeUuqFkQQDHi7px6uMwPa64jcCOt ehMgAlZbTIx1J5jV3vlQvnRwcZpnzE1ShmnicDZrPy7cHL/HBm/d/KB4xRzp8EfRu9 H/JzgqluLhzcQlJXmJeaENg91pIxC4F1oO6tVWTM= Date: Tue, 26 May 2020 09:52:30 +0200 From: Lorenzo Bianconi To: Jonathan Cameron Cc: linux-iio@vger.kernel.org, Jonathan Cameron , Lars-Peter Clausen , Lorenzo Bianconi Subject: Re: [PATCH 10/25] iio:humidity:hts221 Fix alignment and data leak issues Message-ID: <20200526075230.GA339643@localhost.localdomain> References: <20200525170628.503283-1-jic23@kernel.org> <20200525170628.503283-11-jic23@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="LZvS9be/3tNcYl/X" Content-Disposition: inline In-Reply-To: <20200525170628.503283-11-jic23@kernel.org> Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org --LZvS9be/3tNcYl/X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable > From: Jonathan Cameron >=20 > One of a class of bugs pointed out by Lars in a recent review. > iio_push_to_buffers_with_timestamp assumes the buffer used is aligned > to the size of the timestamp (8 bytes). This is not guaranteed in > this driver which uses an array of smaller elements on the stack. > As Lars also noted this anti pattern can involve a leak of data to > userspace and that indeed can happen here. We close both issues by > moving to a suitable structure in the iio_priv() data. > This data is allocated with kzalloc so no data can leak > apart from previous readings. >=20 > Fixes: e4a70e3e7d84 ("iio: humidity: add support to hts221 rh/temp combo = device") > Reported-by: Lars-Peter Clausen > Signed-off-by: Jonathan Cameron > Cc: Lorenzo Bianconi Hi Jonathan, I guess you can drop HTS221_DATA_SIZE now since it seems no longer used. Acked-by: Lorenzo Bianconi > --- > drivers/iio/humidity/hts221.h | 5 +++++ > drivers/iio/humidity/hts221_buffer.c | 9 +++++---- > 2 files changed, 10 insertions(+), 4 deletions(-) >=20 > diff --git a/drivers/iio/humidity/hts221.h b/drivers/iio/humidity/hts221.h > index 7c650df77556..6ad579ca9cef 100644 > --- a/drivers/iio/humidity/hts221.h > +++ b/drivers/iio/humidity/hts221.h > @@ -39,6 +39,11 @@ struct hts221_hw { > =20 > bool enabled; > u8 odr; > + /* Ensure natural alignment of timestamp */ > + struct { > + __le16 channels[2]; > + s64 ts; > + } scan; > }; > =20 > extern const struct dev_pm_ops hts221_pm_ops; > diff --git a/drivers/iio/humidity/hts221_buffer.c b/drivers/iio/humidity/= hts221_buffer.c > index 21c6c160462d..59ede9860185 100644 > --- a/drivers/iio/humidity/hts221_buffer.c > +++ b/drivers/iio/humidity/hts221_buffer.c > @@ -160,7 +160,6 @@ static const struct iio_buffer_setup_ops hts221_buffe= r_ops =3D { > =20 > static irqreturn_t hts221_buffer_handler_thread(int irq, void *p) > { > - u8 buffer[ALIGN(2 * HTS221_DATA_SIZE, sizeof(s64)) + sizeof(s64)]; > struct iio_poll_func *pf =3D p; > struct iio_dev *iio_dev =3D pf->indio_dev; > struct hts221_hw *hw =3D iio_priv(iio_dev); > @@ -170,18 +169,20 @@ static irqreturn_t hts221_buffer_handler_thread(int= irq, void *p) > /* humidity data */ > ch =3D &iio_dev->channels[HTS221_SENSOR_H]; > err =3D regmap_bulk_read(hw->regmap, ch->address, > - buffer, HTS221_DATA_SIZE); > + &hw->scan.channels[0], > + sizeof(hw->scan.channels[0])); > if (err < 0) > goto out; > =20 > /* temperature data */ > ch =3D &iio_dev->channels[HTS221_SENSOR_T]; > err =3D regmap_bulk_read(hw->regmap, ch->address, > - buffer + HTS221_DATA_SIZE, HTS221_DATA_SIZE); > + &hw->scan.channels[1], > + sizeof(hw->scan.channels[1])); > if (err < 0) > goto out; > =20 > - iio_push_to_buffers_with_timestamp(iio_dev, buffer, > + iio_push_to_buffers_with_timestamp(iio_dev, &hw->scan, > iio_get_time_ns(iio_dev)); > =20 > out: > --=20 > 2.26.2 >=20 --LZvS9be/3tNcYl/X Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCXszKvAAKCRA6cBh0uS2t rJ2KAP0cN11RgdgvizvVYCpW+k4beelKu1CQOymmq108Tib0dgD+NjAd2YYUjbf5 0J2ZzjMqHn/GswvdMSTE1bNFrUub4gk= =pYGL -----END PGP SIGNATURE----- --LZvS9be/3tNcYl/X--