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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0AFAC04FFE for ; Tue, 14 May 2024 22:48:54 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E0A8B6B00B6; Tue, 14 May 2024 18:48:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id DBA248D004F; Tue, 14 May 2024 18:48:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C81AD6B00BD; Tue, 14 May 2024 18:48:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id A9F196B00B6 for ; Tue, 14 May 2024 18:48:53 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id D022C80185 for ; Tue, 14 May 2024 22:48:51 +0000 (UTC) X-FDA: 82118492862.25.95F81D7 Received: from cvs.openbsd.org (cvs.openbsd.org [199.185.137.3]) by imf08.hostedemail.com (Postfix) with ESMTP id CE3EE160014 for ; Tue, 14 May 2024 22:48:49 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=openbsd.org header.s=selector1 header.b=DXKecPN0; dmarc=none; spf=pass (imf08.hostedemail.com: domain of deraadt@openbsd.org designates 199.185.137.3 as permitted sender) smtp.mailfrom=deraadt@openbsd.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1715726930; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=mXdASnI1I+5GDxYcK2eWYLdQpu5/XexM+6ywcwiN6VY=; b=hC8dSkgA1RT1nSEpt1ktLtM6F5Edmjwb2HaSSWdokyO+zPvLh4MfWW5v6ahf6rXWA+ZkAQ Bk1qzPCqSFHztt+BNnG3YLw8+yLidQsnnXGLqq17UjeVdkkYxJxHTia2zx7u7stFsv/9vG xtz0/FolrgwE3NITrrNYnh/Ge9B3oUs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1715726930; a=rsa-sha256; cv=none; b=mL56SoU7M6GLDfuN6hjUV7QL7j1wOt0AC383432XQAq17b9txD0hh6LfKeThUwWHCFANY0 sdR9QxALNZIbiDzd7HQVJmb1C0FVDUev5S+QPF86yaa9PpzEysrarXZqpkWE8l19c3z1/t fSGOixi4ZezcTZ4Ux0MMIqOOiaDDSPo= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=openbsd.org header.s=selector1 header.b=DXKecPN0; dmarc=none; spf=pass (imf08.hostedemail.com: domain of deraadt@openbsd.org designates 199.185.137.3 as permitted sender) smtp.mailfrom=deraadt@openbsd.org DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; s=selector1; bh=lUUbtboFXA JWCE0W1VokJb8/yl3D0BpWZ8xnDFVZ9qM=; h=date:references:in-reply-to: subject:cc:to:from; d=openbsd.org; b=DXKecPN04dCt3ZGgyElWyQpUlSl8jxRlY fFmJmAonBF+5KpsNWHrZwtZLRNElrmyFepY+8i/Z1yYp6+xsR2NPvp22BIvChLbSA5tuWS L86bhYwLO9mbdcbd5MUKwgx0zrriBeTE5NTzNdm7wU+JAaxFvYez/GuEHF/1kfs9q2CbRt WZlubKV/MDKp30IHhP5MgV/YrT+UCm+zetoZ7L58Wrk+Tdie9BX4HIJrPq7TKoqTjbNgK1 D8wl0W+5bf5Yjcs1fc359iBaktIk3EM/C7cMwOyXGf5J0ybBHf4/BT7VNAcYrBpnwjZiPl rAJdmEb0IiNvnAemTgraO883ggLaA== Received: from cvs.openbsd.org (localhost [127.0.0.1]) by cvs.openbsd.org (OpenSMTPD) with ESMTP id 907e0c43; Tue, 14 May 2024 16:48:47 -0600 (MDT) From: "Theo de Raadt" To: Matthew Wilcox cc: Jonathan Corbet , Andrew Morton , jeffxu@chromium.org, keescook@chromium.org, jannh@google.com, sroettger@google.com, gregkh@linuxfoundation.org, torvalds@linux-foundation.org, usama.anjum@collabora.com, Liam.Howlett@oracle.com, surenb@google.com, merimus@google.com, rdunlap@infradead.org, jeffxu@google.com, jorgelo@chromium.org, groeck@chromium.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, pedro.falcato@gmail.com, dave.hansen@intel.com, linux-hardening@vger.kernel.org Subject: Re: [PATCH v10 0/5] Introduce mseal In-reply-to: References: <20240415163527.626541-1-jeffxu@chromium.org> <20240514104646.e6af4292f19b834777ec1e32@linux-foundation.org> <871q646rea.fsf@meer.lwn.net> Comments: In-reply-to Matthew Wilcox message dated "Tue, 14 May 2024 22:28:17 +0100." MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <57526.1715726927.1@cvs.openbsd.org> Date: Tue, 14 May 2024 16:48:47 -0600 Message-ID: <56001.1715726927@cvs.openbsd.org> X-Stat-Signature: fuiamte5bhxod9tb3jn3n1tw66861i3y X-Rspamd-Queue-Id: CE3EE160014 X-Rspam-User: X-Rspamd-Server: rspam01 X-HE-Tag: 1715726929-554860 X-HE-Meta: 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 uB6XNxkz SnZQ+guojuyLlEG6GAdD44j6shGBlA5jVXFk/v2L9JqjrEmQmwn2IqVC26ens5JnSUWwhuceMVj4FBvVzoWZ0qrifwVFNtbgyzWP32kltHs6mFhtINihISOwG5flexvGcS6EFAfe7dzrr25ubuAbBBgWiDldfKz/oyE2XbY30T8aY9PFeoe6GYsCHvVAnpTqGQPUoyXl5CVAgg2pCNAIhQMRCMjAqxkiwyniwC0z3j8pfX6NyL8AixAE5s/yvok73YmvH8coGrMj5jzs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000301, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Matthew Wilcox wrote: > > Not taking a position on merging, but I have to ask: are we convinced at > > this point that mseal() isn't a chrome-only system call? Did we ever > > see the glibc patches that were promised? > > I think _this_ version of mseal() is OpenBSD's mimmutable() with a > basically unused extra 'flags' argument. As such, we have an existance > proof that it's useful beyond Chrome. Yes, it is close enough. > I think Liam still had concerns around the > walk-the-vmas-twice-to-error-out-early part of the implementation? > Although we can always fix the implementation later; changing the API > is hard. Yes I am a bit worried about the point Liam brings up -- we've discussed it privately at length. Matthew, to keep it short I have a different viewpoint: Some of the Linux m* system calls have non-conforming, partial-work-then-return-error behaviour. I cannot find anything like this in any system call in any other operating system, and I believe there is a defacto rule against doing this, and Linux has an optimization which violating this, and I think it could be fixed with fairly minor expense, and can't imagine it affecting a single application. I worry that the non-atomicity will one day be used by an attacker.