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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 C4F4CC43381 for ; Mon, 18 Mar 2019 11:20:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F36120857 for ; Mon, 18 Mar 2019 11:20:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727271AbfCRLUa (ORCPT ); Mon, 18 Mar 2019 07:20:30 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:59933 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727012AbfCRLU3 (ORCPT ); Mon, 18 Mar 2019 07:20:29 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id 0AFBD8056F; Mon, 18 Mar 2019 12:20:20 +0100 (CET) Date: Mon, 18 Mar 2019 12:20:28 +0100 From: Pavel Machek To: Rasmus Villemoes Cc: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Jacek Anaszewski , LKML , linux-leds@vger.kernel.org Subject: Re: [PATCH v2 1/6] leds: netdev trigger: use memcpy in device_name_store Message-ID: <20190318112027.GA6101@amd> References: <20190313202615.22883-1-linux@rasmusvillemoes.dk> <20190314140619.3309-1-linux@rasmusvillemoes.dk> <20190314140619.3309-2-linux@rasmusvillemoes.dk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wRRV7LY7NUeQGEoC" Content-Disposition: inline In-Reply-To: <20190314140619.3309-2-linux@rasmusvillemoes.dk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --wRRV7LY7NUeQGEoC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu 2019-03-14 15:06:14, Rasmus Villemoes wrote: > If userspace doesn't end the input with a newline (which can easily > happen if the write happens from a C program that does write(fd, > iface, strlen(iface))), we may end up including garbage from a > previous, longer value in the device_name. For example >=20 > # cat device_name >=20 > # printf 'eth12' > device_name > # cat device_name > eth12 > # printf 'eth3' > device_name > # cat device_name > eth32 >=20 > I highly doubt anybody is relying on this behaviour, so switch to > simply copying the bytes (we've already checked that size is < > IFNAMSIZ) and unconditionally zero-terminate it; of course, we also > still have to strip a trailing newline. >=20 > This is also preparation for future patches. >=20 > Signed-off-by: Rasmus Villemoes Acked-by: Pavel Machek --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --wRRV7LY7NUeQGEoC Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlyPfvsACgkQMOfwapXb+vKOvgCgqiyTfYd0+V2ObT2VRP6kXG3J upAAn17RsHq8Gx6/q0Ui7GNZEKg1GBfd =ZsZF -----END PGP SIGNATURE----- --wRRV7LY7NUeQGEoC--