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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 CEC7FC43441 for ; Fri, 16 Nov 2018 09:32:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 95861208E7 for ; Fri, 16 Nov 2018 09:32:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="j4CO4YKj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 95861208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389442AbeKPToA (ORCPT ); Fri, 16 Nov 2018 14:44:00 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:54836 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727398AbeKPTn7 (ORCPT ); Fri, 16 Nov 2018 14:43:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=gTOHMOgDgIt+FDacDVfbF70kBQv2VWQ17SzLI5mmeHY=; b=j4CO4YKje4Xy1/kL18npqk+HK Z6AqzNINVVv5T5z6nX/BU0nD6aT3V3RhEJrlWMU0UtXWvNtQ758DQ8OVOWF8oIdKIVCe/9EqRsmOj RTWOzY+t+X4OkNQv+Z0M11oCF9cIx78oHT5XV4NsJHYP3XCsLiCOvmDa2L+ppT74Qqg/DpZA+S0SM kQmXR3vkQwkhzInM6gm0NCKZwkjjGp87T9j9HPMc1MFz6h7xXE+nRWISdSe7nFmOKDR+yqwpqFRUm t9JG6HZmolbE/wdPuPQi/cg9bY7WX3zxytwNi0fyYWFUUtY/RLQhHa2n8/jb02znyk/NW1cLTQYp+ 0wOZB2huw==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gNaUD-0008Gy-FI; Fri, 16 Nov 2018 09:32:25 +0000 Date: Fri, 16 Nov 2018 01:32:25 -0800 From: Christoph Hellwig To: Paolo Bonzini Cc: Christoph Hellwig , "Theodore Y. Ts'o" , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Hannes Reinecke , "Martin K. Petersen" , James Bottomley Subject: Re: [PATCH 0/3] SG_IO command filtering via sysfs Message-ID: <20181116093225.GA17033@infradead.org> References: <1541867733-7836-1-git-send-email-pbonzini@redhat.com> <20181111131445.GB25441@infradead.org> <20181111134241.GA2447@thunk.org> <20181112082013.GA9307@infradead.org> <79d7d4b2-e9b3-00b4-2ad0-789888f7ee36@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <79d7d4b2-e9b3-00b4-2ad0-789888f7ee36@redhat.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 12, 2018 at 11:17:29AM +0100, Paolo Bonzini wrote: > > Well, that's what we have the security_file_ioctl() LSM hook for so that > > your security model can arbitrate access to ioctls. > > Doesn't that have TOC-TOU races by design? If you want to look at the command - yes. If you just want to filter read vs write vs ioctl, no. > Also, what about SG_IO giving write access to files that are only opened > read-only (and only have read permissions)? Allowing SG_IO on read-only permissions sounds like a reall bad idea, filtering or not.