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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 E71F8C4727E for ; Wed, 23 Sep 2020 18:49:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A31F7206DB for ; Wed, 23 Sep 2020 18:49:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="j6zFoRR/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726858AbgIWSte (ORCPT ); Wed, 23 Sep 2020 14:49:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45482 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726460AbgIWSte (ORCPT ); Wed, 23 Sep 2020 14:49:34 -0400 Received: from mail-qt1-x844.google.com (mail-qt1-x844.google.com [IPv6:2607:f8b0:4864:20::844]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3841CC0613CE; Wed, 23 Sep 2020 11:49:34 -0700 (PDT) Received: by mail-qt1-x844.google.com with SMTP id y11so779462qtn.9; Wed, 23 Sep 2020 11:49:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=RkpPiL5sLMoQ72Z4SVPCyIzaZVEUsKD6IONs26Z9oQ4=; b=j6zFoRR/TNHPnYOJYg/v6yC5mOjqz6GhBvNdUdw/ZZY3Z659h4thQrXUvmYYNs/dMc 9AtbSQc1r9/KTQ+OdnHEMcrYOKmjexHp+zLAowzXW60xVUgp32upPori8ocBAUEa2r3r RBgGigmHJn+mG8rh+rrSfDqq2SdthMmzakAE8uf56Ks1STHFgtkyEvVJSTmUDeKd4JlH Cx+3SJd1aI9By0RJ0GJTBMtFDnsq45jEHay9VWPh2LaXhf87zwX1sup1iq4GFW7bYwHN wYZuJxH556l/n/M+2V+a2YdPh4IkzEbo9S36Kf5zviplDX4eWHJkLL/e8sUM7P5GbZLv 8Ccw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=RkpPiL5sLMoQ72Z4SVPCyIzaZVEUsKD6IONs26Z9oQ4=; b=dUYeTO293gYaaqNb5QY1CAxzysue013cNtGWDEbX/qPCgeAuN8dX5ow7pR/MBc2qyN Fvlsha7nrvoddkJIVG/VQIFJWB3layfykHnz8wTsTT9xZza0zIg6BFISjdN9R0Yuh+13 t5XilUwLTqq4NSK0jl1isZctxhr6xrHaOGzpXZPMXKFqWAAu7lF9UJMWtwwWrg3rDC6q IyVflyHaInlZdYFZIZ0BjEELl3UQy8pf6+lVJ227a8Cj2p81TL7jtvlFY+HoE5grPZaZ tTd6tlsrgSr2C3Z62MFmI6lGRVulvElWrsUmDzQija7gQfl5Rp4ZUB9tBiwmDY2yVV/7 oePg== X-Gm-Message-State: AOAM531c8/RUS3QgJnipt9vrddG/HBzvwgqbUD5Fq6kMG0a8QN+Yox69 6rLqmahsS0W6uU9jpD2jRMSNTLsmOPw= X-Google-Smtp-Source: ABdhPJwkH8cFnD08Pdj7anSenqn2tvNw6QetwTg2I4xIrVuO/X572JBB17yMeOLN0zGx1aVaPRH8zA== X-Received: by 2002:aed:3203:: with SMTP id y3mr1556830qtd.278.1600886973396; Wed, 23 Sep 2020 11:49:33 -0700 (PDT) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id r187sm518764qkc.63.2020.09.23.11.49.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Sep 2020 11:49:32 -0700 (PDT) Sender: Arvind Sankar From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Wed, 23 Sep 2020 14:49:30 -0400 To: Solar Designer Cc: Florian Weimer , Pavel Machek , madvenka@linux.microsoft.com, kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, oleg@redhat.com, x86@kernel.org, luto@kernel.org, David.Laight@ACULAB.COM, mark.rutland@arm.com, mic@digikod.net, Rich Felker Subject: Re: [PATCH v2 0/4] [RFC] Implement Trampoline File Descriptor Message-ID: <20200923184930.GA1352963@rani.riverdale.lan> References: <20200922215326.4603-1-madvenka@linux.microsoft.com> <20200923081426.GA30279@amd> <20200923091456.GA6177@openwall.com> <87wo0ko8v0.fsf@oldenburg2.str.redhat.com> <20200923181136.GA8846@openwall.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200923181136.GA8846@openwall.com> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Wed, Sep 23, 2020 at 08:11:36PM +0200, Solar Designer wrote: > On Wed, Sep 23, 2020 at 04:39:31PM +0200, Florian Weimer wrote: > > * Solar Designer: > > > > > While I share my opinion here, I don't mean that to block Madhavan's > > > work. I'd rather defer to people more knowledgeable in current userland > > > and ABI issues/limitations and plans on dealing with those, especially > > > to Florian Weimer. I haven't seen Florian say anything specific for or > > > against Madhavan's proposal, and I'd like to. (Have I missed that?) > > [...] > > I think it's unnecessary for the libffi use case. > [...] > > > I don't know if kernel support could > > make sense in this context, but it would be a completely different > > patch. > > Thanks. Are there currently relevant use cases where the proposed > trampfd would be useful and likely actually made use of by userland - > e.g., specific userland project developers saying they'd use it, or > Madhavan intending to develop and contribute userland patches? > > Alexander The trampoline it provides in this version can be implemented completely in userspace. The kernel part of it is essentially just providing a way to do text relocations without needing a WX mapping, but the text relocations would be unnecessary in the first place if the trampoline was position-independent code.