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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6230AC433F5 for ; Wed, 11 May 2022 19:03:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346559AbiEKTDm (ORCPT ); Wed, 11 May 2022 15:03:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241347AbiEKTDk (ORCPT ); Wed, 11 May 2022 15:03:40 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0B11861296 for ; Wed, 11 May 2022 12:03:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id B8FEDB8260A for ; Wed, 11 May 2022 19:03:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4C577C340EE for ; Wed, 11 May 2022 19:03:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652295816; bh=sgS8I586wmxDsWEfk8EYenY4Nf+IiynsiclSqvw9c1I=; h=In-Reply-To:References:Date:From:To:Cc:Subject:From; b=APM+OUuxz0Q71LKdL40gVite+fbwNKwg6+VMNJLoq/G6tlH1XJbvRYImhu+2++Umi JsOeeZFuukrZVpnHB7HXoe1NrSLDWxH/RLqopHOMjeeVHSZpLUiMgjWNb7LW75o6BX QRTx7oIxDHvPsEVw7sugtR6TtZC83Y2u/KzGScwYZBYIsXxmKIXZfPazja0bRPMhAi 3qbwb3bvfTnibHOz/Z1/VTrQnIxJRM3Yxp/zmyeqCNnwHxLjoR299kQpjQNAGf+bnB lZ9NfJuKXaAKp4FIomshX2MjRHBnx8ZulNzODN2Kc6jrm2882UyovgNnlC0iGZYCi7 gCph4X0krdV0A== Received: from compute2.internal (compute2.nyi.internal [10.202.2.46]) by mailauth.nyi.internal (Postfix) with ESMTP id 1D84A27C0054; Wed, 11 May 2022 15:03:35 -0400 (EDT) Received: from imap48 ([10.202.2.98]) by compute2.internal (MEProxy); Wed, 11 May 2022 15:03:35 -0400 X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvfedrgeehgdduvdelucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehn ugihucfnuhhtohhmihhrshhkihdfuceolhhuthhosehkvghrnhgvlhdrohhrgheqnecugg ftrfgrthhtvghrnhepvdfhuedvtdfhudffhfekkefftefghfeltdelgeffteehueegjeff udehgfetiefhnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrh homheprghnugihodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdduudeiudek heeifedvqddvieefudeiiedtkedqlhhuthhopeepkhgvrhhnvghlrdhorhhgsehlihhnuh igrdhluhhtohdruhhs X-ME-Proxy: Received: by mailuser.nyi.internal (Postfix, from userid 501) id B961331A005D; Wed, 11 May 2022 15:03:34 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.7.0-alpha0-591-gfe6c3a2700-fm-20220427.001-gfe6c3a27 Mime-Version: 1.0 Message-Id: <7c87b9f7-0a26-41cf-ba34-3dbd37caa2b8@www.fastmail.com> In-Reply-To: <87o803dijt.fsf@oldenburg.str.redhat.com> References: <898932fe61db6a9d61bc2458fa2f6049f1ca9f5c.1652290558.git.luto@kernel.org> <87o803dijt.fsf@oldenburg.str.redhat.com> Date: Wed, 11 May 2022 12:03:14 -0700 From: "Andy Lutomirski" To: "Florian Weimer" Cc: "the arch/x86 maintainers" , "Linux Kernel Mailing List" , "Kees Cook" Subject: Re: [PATCH] x86/vsyscall: Remove CONFIG_LEGACY_VSYSCALL_EMULATE Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 11, 2022, at 11:35 AM, Florian Weimer wrote: > * Andy Lutomirski: > >> CONFIG_LEGACY_VSYSCALL_EMULATE is, as far as I know, only needed for the >> combined use of exotic and outdated debugging mechanisms with outdated >> binaries. At this point, no one should be using it. We would like to >> implement dynamic switching of vsyscalls, but this is much more >> complicated to support in EMULATE mode than XONLY mode. >> >> So let's force all the distros off of EMULATE mode. If anyone actually >> needs it, they can set vsyscall=emulate, and we can then get away with >> refusing to support newer security models if that option is set. >> >> Cc: x86@kernel.org >> Cc: Kees Cook >> Cc: Florian Weimer >> Signed-off-by: Andy Lutomirski > > Sounds a good idea to me. > > Acked-by: Florian Weimer > > Regarding the mechanics, is it customary to remove the actual code (the > EMULATE enum constant) in later commits? > Might be several versions later. This patch intentionally still supports booting with vsyscall=emulate.