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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5DBF5C004C0 for ; Mon, 23 Oct 2023 15:18:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=pM/9GDG6SvD5jwJ3gzKShISOf3fj/ZsIM8YNaNYkaNU=; b=oDw1byaYR38mThjxRC6TJZgGmN kH37JH8lUxKI0XoeRh/K8vi0bnaByhy8JQaJY3KmyicUbo1XgEz6nx9zSRLwxeKD2UH8qlCj7QRq2 orzdv8MU0BAD+Otj+4ZeFxPhEPRfr7fJ/+p3KqjczkiuEI90nUABVC5FUyXxjR2JY1PRYxbVCst8F cKibtlAFkEA814ZNMJrbUuWC7Qh+qFz1BjPePVHwQCQq4e7cfpxUbb+hTbX6hAWVknsgPy7gYSr80 8NNz375HYR5NZplcSGKJtG/M58DH8tAFrgV4hn1VCJtbmTkVmL3/ArLHGzlHA58cHS+5hboivJkFH WsMr8PZw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1quwhZ-007fiR-13; Mon, 23 Oct 2023 15:18:45 +0000 Received: from ams.source.kernel.org ([2604:1380:4601:e00::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1quwhX-007fhY-0H for linux-nvme@lists.infradead.org; Mon, 23 Oct 2023 15:18:44 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by ams.source.kernel.org (Postfix) with ESMTP id 3CBA8B81E72; Mon, 23 Oct 2023 15:18:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 12463C433C9; Mon, 23 Oct 2023 15:18:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1698074319; bh=MioXTG7udluvSetup3O78g2HsJEJGk9gLWyJfEWeILA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LJx2CfV/+FJCiVWBI6EsJhxvDLnqzg/b1qllHt7cMwV3PatGJp5gmRHX6iK/jxiez kRurmaMakEqIWoXrL6DvCBETjyyl0Fyy2X4MyY514jhXPyeevItuZzXmYsk2bXv4cY XYCMCInK0g7H2QENhVjX8YksIEBN6OBBnK+VoB8N/fUtxE/MZzypLmDez03xQpMmt3 URfJbBTtg8BGWvGAo0j1BIChnWdR3OWKYg1YtQsX7AwDj5s8PpC4SGk29PWG803Y7j 4fzCaoz5+yk2CApd13vd9KnriggdZpxWoB/tOEuhm+3XvBqpQrfBCa2VG0UJorH4qN 9ZYepcPt3pwCw== Date: Mon, 23 Oct 2023 09:18:36 -0600 From: Keith Busch To: Christoph Hellwig Cc: Kanchan Joshi , axboe@kernel.dk, sagi@grimberg.me, linux-nvme@lists.infradead.org, gost.dev@samsung.com, vincentfu@gmail.com, stable@vger.kernel.org Subject: Re: [PATCH v2] nvme: remove unprivileged passthrough support Message-ID: References: <20231016060519.231880-1-joshi.k@samsung.com> <20231019050411.GA14044@lst.de> <20231023054456.GB11272@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231023054456.GB11272@lst.de> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231023_081843_260690_A4BBAF5C X-CRM114-Status: GOOD ( 11.56 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Oct 23, 2023 at 07:44:56AM +0200, Christoph Hellwig wrote: > Yes, you need someone with root access to change the device node > persmissions. But we allowed that under the assumption it is safe > to do so, which it turns out it is not. Okay, iiuc, while we have to opt-in to allow this hole, we need another option for users to set to allow this usage because it's not safe. Here are two options I have considered for unpriveledged access, please let me know if you have others or thoughts. Restrict access for processes with CAP_SYS_RAWIO, which can be granted to non-root users. This cap is already used in scsi subsystem, too. A per nvme-generic namespace sysfs attribute that only root can toggle that would override any caps and just rely on access permissions.