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 6321CC00A8F for ; Tue, 24 Oct 2023 07:08:10 +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=qHl/gTL2TD8JhbGUTV/3Jap8t1AfGGr5PHeWNdjOgng=; b=lcJutiBWCHTtQ1WBAq72AxUQjl lV3GZpntRe9HE6zKOu0ASJZxyjKqI2Bg+J0IEwYtn/qcRigP4ZjQLq1pBjlIEn2VQMmvKU9ALnCKi KHO+RsrAQhSyPyEEQEUftOlYp170toyMG44iejtvSM7/XbOpKzgpJP/tyF7fSMf+VHjcwjgYbl1mq lPBm/qruGQHS+SnKFQn56+g+V3T2g7fB/psCvyNvyU7RW056msY3nVvqqUbGvn4MGNtw/zO+sdIHy RgdwW+lQzrn3T1DKpIOu0kS0XSwwBqXECg5ol+2+kE9CVQBDJtDiky0WB9adf6yuZWB5FVUbii9QZ kkVKFYNw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qvBWI-0092aF-0B; Tue, 24 Oct 2023 07:08:06 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qvBWF-0092ZW-2t for linux-nvme@lists.infradead.org; Tue, 24 Oct 2023 07:08:05 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 312F767373; Tue, 24 Oct 2023 09:08:00 +0200 (CEST) Date: Tue, 24 Oct 2023 09:07:59 +0200 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , 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: <20231024070759.GE9847@lst.de> 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: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231024_000804_080274_F69896BD X-CRM114-Status: GOOD ( 19.23 ) 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 09:18:36AM -0600, Keith Busch wrote: > 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. Well, that's sensible in general. > A per nvme-generic namespace sysfs attribute that only root can toggle > that would override any caps and just rely on access permissions. And that I'm not confident about as long as we can only use the broken PRP scheme on NVMe.