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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 94861C433E7 for ; Tue, 1 Sep 2020 18:56:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 774692065F for ; Tue, 1 Sep 2020 18:56:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="iu/mivde" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729352AbgIASxL (ORCPT ); Tue, 1 Sep 2020 14:53:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57376 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731240AbgIASxD (ORCPT ); Tue, 1 Sep 2020 14:53:03 -0400 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9E489C061247 for ; Tue, 1 Sep 2020 11:53:02 -0700 (PDT) Received: by mail-pf1-x444.google.com with SMTP id w7so1343138pfi.4 for ; Tue, 01 Sep 2020 11:53:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DW1zJLlrp+b/X5DsaUJywWHpm9f8YdypCEJotWWzal8=; b=iu/mivdeQ6AWpfUigREEipYqDA+JBPragzl35o9Nu9ycwxuP1pT/n/GUj28IBjGlJy tASUZD6UQpFduus8RxIUHnWDo/ii2QxBTb8+/rddFmc7Q2BvQtdvriL4oOcAbvX3fTik a3CX0t1k/eCXUbO98m4G5hAHF2rr9hmEGAwHw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DW1zJLlrp+b/X5DsaUJywWHpm9f8YdypCEJotWWzal8=; b=E1JTHOL1n+Sn5ebUP81L9D2zmvz6A/UzDKoCZj59TtZRV8C4+LcT4LlAOvkkVZu9y2 WDoQVqi/Gi0lE9IA1Zkd5FxnEw3vKM4+PQZ5PjrKJNzAASSpDzdMWbrbpUjK3bY4e1DC xuqtJ1+Rsh1gaXAq4YR+6FhpJZSyM07inWwBpq1u78vxY7pcX2EHgU4twV8mAUlTC63Z HE2WuJqA0uqco5pGCFXhzxPfpTjZFcwroHjeMP7YM6K7NutLyXbG+X/sYKLHZ7ooF5hb bge3x6SpaY70tDOQav/EkT45tv5J7HY7tRUPy5yAz4YGFFrcHF/M1UTcxpc0eqRinyro zG7A== X-Gm-Message-State: AOAM530q8JzLjdEQyaF7aaQ51H6pRuJlnrA0H3n5EjNDYHrmaut9LZ4j EHXtjAdp/UwVbiVTx32nBbF23A== X-Google-Smtp-Source: ABdhPJw/YsKunmr1Z0dpXo1/zK3rMUMV+IlY1oP54bh4p+BaEO8LJP6shIZse5erSoELJy0YDj4+Gg== X-Received: by 2002:a65:4187:: with SMTP id a7mr2642045pgq.102.1598986382061; Tue, 01 Sep 2020 11:53:02 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id m19sm2192249pjq.18.2020.09.01.11.53.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Sep 2020 11:53:01 -0700 (PDT) Date: Tue, 1 Sep 2020 11:52:59 -0700 From: Kees Cook To: Christoph Hellwig Cc: Linus Torvalds , Al Viro , Michael Ellerman , the arch/x86 maintainers , Linux Kernel Mailing List , linux-fsdevel , linux-arch , linuxppc-dev Subject: Re: [PATCH 05/10] lkdtm: disable set_fs-based tests for !CONFIG_SET_FS Message-ID: <202009011152.335EE467@keescook> References: <20200827150030.282762-1-hch@lst.de> <20200827150030.282762-6-hch@lst.de> <20200829092406.GB8833@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200829092406.GB8833@lst.de> Sender: linux-arch-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Sat, Aug 29, 2020 at 11:24:06AM +0200, Christoph Hellwig wrote: > On Thu, Aug 27, 2020 at 11:06:28AM -0700, Linus Torvalds wrote: > > On Thu, Aug 27, 2020 at 8:00 AM Christoph Hellwig wrote: > > > > > > Once we can't manipulate the address limit, we also can't test what > > > happens when the manipulation is abused. > > > > Just remove these tests entirely. > > > > Once set_fs() doesn't exist on x86, the tests no longer make any sense > > what-so-ever, because test coverage will be basically zero. > > > > So don't make the code uglier just to maintain a fiction that > > something is tested when it isn't really. > > Sure fine with me unless Kees screams. If we don't have set_fs, we don't need the tests. :) -- Kees Cook