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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no 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 2F1BBC433E2 for ; Thu, 10 Sep 2020 20:08:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFDA7221E2 for ; Thu, 10 Sep 2020 20:08:19 +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="oalS+ESh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726976AbgIJUIM (ORCPT ); Thu, 10 Sep 2020 16:08:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726901AbgIJUF6 (ORCPT ); Thu, 10 Sep 2020 16:05:58 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7BBD9C061573; Thu, 10 Sep 2020 13:05:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=c2OmDmw3CBNdMhbSUreC74RlMC1GtRl7G6wTRWdIDhg=; b=oalS+EShumiM+wP4ntMj+va6+Q Nh1j9337AoOX5aS6ehlDvYBnbeH5wAQR/9ls36am10xynQpwjAzNspdirI5ohbUmCjgytsp6ExJhu 61TqiAGlfQvDFqi1JocYtyt1E3SBqZt+RHR5ElNE0185BXyGVupHaZe0djMdV/ttf1KoyzZ8hdeFJ z0CoXaDzfHr5fh5hlf6Gt1AywT/4OZMjRpww4aVwjYJG+OoB5dzIFkkHg42E79TUXRRyuDmQBueyp KAqaQ+Hi5YPbc5abQpTeFLdmAJTJqOQETXvwfl9CDwTes6XA46M10L1IXyJSp5ODcSg+CifPThbbA V4gIP2hA==; Received: from willy by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kGSpD-0003dj-CF; Thu, 10 Sep 2020 20:05:43 +0000 Date: Thu, 10 Sep 2020 21:05:43 +0100 From: Matthew Wilcox To: Al Viro Cc: =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= , Mimi Zohar , linux-kernel@vger.kernel.org, Aleksa Sarai , Alexei Starovoitov , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , Christian Brauner , Christian Heimes , Daniel Borkmann , Deven Bowers , Dmitry Vyukov , Eric Biggers , Eric Chiang , Florian Weimer , James Morris , Jan Kara , Jann Horn , Jonathan Corbet , Kees Cook , Lakshmi Ramasubramanian , Matthew Garrett , Michael Kerrisk , Miklos Szeredi , Philippe =?iso-8859-1?Q?Tr=E9buchet?= , Scott Shell , Sean Christopherson , Shuah Khan , Steve Dower , Steve Grubb , Tetsuo Handa , Thibaut Sautereau , Vincent Strubel , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC PATCH v9 0/3] Add introspect_access(2) (was O_MAYEXEC) Message-ID: <20200910200543.GY6583@casper.infradead.org> References: <20200910164612.114215-1-mic@digikod.net> <20200910170424.GU6583@casper.infradead.org> <880bb4ee-89a2-b9b0-747b-0f779ceda995@digikod.net> <20200910184033.GX6583@casper.infradead.org> <20200910200010.GF1236603@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200910200010.GF1236603@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 10, 2020 at 09:00:10PM +0100, Al Viro wrote: > On Thu, Sep 10, 2020 at 07:40:33PM +0100, Matthew Wilcox wrote: > > On Thu, Sep 10, 2020 at 08:38:21PM +0200, Mickaël Salaün wrote: > > > There is also the use case of noexec mounts and file permissions. From > > > user space point of view, it doesn't matter which kernel component is in > > > charge of defining the policy. The syscall should then not be tied with > > > a verification/integrity/signature/appraisal vocabulary, but simply an > > > access control one. > > > > permission()? > > int lsm(int fd, const char *how, char *error, int size); > > Seriously, this is "ask LSM to apply special policy to file"; let's > _not_ mess with flags, etc. for that; give it decent bandwidth > and since it's completely opaque for the rest of the kernel, > just a pass a string to be parsed by LSM as it sees fit. Hang on, it does have some things which aren't BD^W^WLSM. It lets the interpreter honour the mount -o noexec option. I presume it's not easily defeated by cat /home/salaun/bin/bad.pl | perl -