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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 DDB48C433EF for ; Mon, 9 Sep 2019 10:54:38 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 2E26621920 for ; Mon, 9 Sep 2019 10:54:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ssi.gouv.fr header.i=@ssi.gouv.fr header.b="bsPrfe3f" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2E26621920 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ssi.gouv.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-16884-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 19651 invoked by uid 550); 9 Sep 2019 10:54:30 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 19628 invoked from network); 9 Sep 2019 10:54:30 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ssi.gouv.fr; s=20160407; t=1568026458; bh=lsE8Nf8H8eP9Ra9FaOYEExhywlR7G0uudTTjxz1hvFc=; h=Subject:To:CC:References:From:Date:In-Reply-To:From:Subject; b=bsPrfe3facITGSy7DMYPy8YYzwh1VjblL+C13Jn98z/Ykyq4WF4HusFGQluS1lRBd QYYlffK04WUyhAEq8eXB0G3SbxesMMAAm5maeRLiYC+OGgwGm/UFnzGlEJmS5yTjgv eDWHr12JCE7LIy1AnpTqixcRdqDzgwzq7JGzTrSFVJXeir6LdPgy/jMps6OeNW1+Ba aChlFqI2Rwdfl7KYY82HfNbR9YLCc/r3WdWUMbTIopvQs4RYI2ecpdxUeyJYeoZrak hYdIFTmBcuxxlC16cK/J4YqCEyLJQ1AbFThzUt7fkCISGm2XqYe9FM8OenXBMO8HEi fKi53bdY2BZXA== Subject: Re: [PATCH v2 1/5] fs: Add support for an O_MAYEXEC flag on sys_open() To: James Morris CC: Jeff Layton , Florian Weimer , =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= , , Aleksa Sarai , Alexei Starovoitov , Al Viro , Andy Lutomirski , Christian Heimes , Daniel Borkmann , Eric Chiang , Jan Kara , Jann Horn , Jonathan Corbet , Kees Cook , Matthew Garrett , Matthew Wilcox , Michael Kerrisk , Mimi Zohar , =?UTF-8?Q?Philippe_Tr=c3=a9buchet?= , Scott Shell , Sean Christopherson , Shuah Khan , Song Liu , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , Yves-Alexis Perez , , , , References: <20190906152455.22757-1-mic@digikod.net> <20190906152455.22757-2-mic@digikod.net> <87ef0te7v3.fsf@oldenburg2.str.redhat.com> <75442f3b-a3d8-12db-579a-2c5983426b4d@ssi.gouv.fr> <1fbf54f6-7597-3633-a76c-11c4b2481add@ssi.gouv.fr> <5a59b309f9d0603d8481a483e16b5d12ecb77540.camel@kernel.org> <49e98ece-e85f-3006-159b-2e04ba67019e@ssi.gouv.fr> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= Message-ID: <073cb831-7c6b-1882-9b7d-eb810a2ef955@ssi.gouv.fr> Date: Mon, 9 Sep 2019 12:54:16 +0200 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:52.0) Gecko/20100101 Thunderbird/52.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 09/09/2019 12:12, James Morris wrote: > On Mon, 9 Sep 2019, Micka=C3=ABl Sala=C3=BCn wrote: > >> >> On 06/09/2019 21:03, James Morris wrote: >>> On Fri, 6 Sep 2019, Jeff Layton wrote: >>> >>>> The fact that open and openat didn't vet unknown flags is really a bug= . >>>> >>>> Too late to fix it now, of course, and as Aleksa points out, we've >>>> worked around that in the past. Now though, we have a new openat2 >>>> syscall on the horizon. There's little need to continue these sorts of >>>> hacks. >>>> >>>> New open flags really have no place in the old syscalls, IMO. >>> >>> Agree here. It's unfortunate but a reality and Linus will reject any su= ch >>> changes which break existing userspace. >> >> Do you mean that adding new flags to open(2) is not possible? >> >> Does it means that unspecified behaviors are definitely part of the >> Linux specification and can't be fixed? > > This is my understanding. > >> >> As I said, O_MAYEXEC should be ignored if it is not supported by the >> kernel, which perfectly fit with the current open(2) flags behavior, and >> should also behave the same with openat2(2). > > The problem here is programs which are already using the value of > O_MAYEXEC, which will break. Hence, openat2(2). Well, it still depends on the sysctl, which doesn't enforce anything by default, hence doesn't break existing behavior, and this unused flags could be fixed/removed or reported by sysadmins or distro developers. -- Micka=C3=ABl Sala=C3=BCn Les donn=C3=A9es =C3=A0 caract=C3=A8re personnel recueillies et trait=C3=A9= es dans le cadre de cet =C3=A9change, le sont =C3=A0 seule fin d=E2=80=99ex= =C3=A9cution d=E2=80=99une relation professionnelle et s=E2=80=99op=C3=A8re= nt dans cette seule finalit=C3=A9 et pour la dur=C3=A9e n=C3=A9cessaire =C3= =A0 cette relation. Si vous souhaitez faire usage de vos droits de consulta= tion, de rectification et de suppression de vos donn=C3=A9es, veuillez cont= acter contact.rgpd@sgdsn.gouv.fr. Si vous avez re=C3=A7u ce message par err= eur, nous vous remercions d=E2=80=99en informer l=E2=80=99exp=C3=A9diteur e= t de d=C3=A9truire le message. 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