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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 27C53C43613 for ; Fri, 21 Jun 2019 13:13:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 050C52083B for ; Fri, 21 Jun 2019 13:12:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726750AbfFUNM6 (ORCPT ); Fri, 21 Jun 2019 09:12:58 -0400 Received: from mx1.redhat.com ([209.132.183.28]:37930 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726250AbfFUNM6 (ORCPT ); Fri, 21 Jun 2019 09:12:58 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 71A2F81123; Fri, 21 Jun 2019 13:12:48 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-57.rdu2.redhat.com [10.10.120.57]) by smtp.corp.redhat.com (Postfix) with ESMTP id 4F4191001B05; Fri, 21 Jun 2019 13:12:44 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <20190621094757.zijugn6cfulmchnf@brauner.io> References: <20190621094757.zijugn6cfulmchnf@brauner.io> <155905626142.1662.18430571708534506785.stgit@warthog.procyon.org.uk> <155905627927.1662.13276277442207649583.stgit@warthog.procyon.org.uk> To: Christian Brauner Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk, raven@themaw.net, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com Subject: Re: [PATCH 02/25] vfs: Allow fsinfo() to query what's in an fs_context [ver #13] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <21651.1561122763.1@warthog.procyon.org.uk> Date: Fri, 21 Jun 2019 14:12:43 +0100 Message-ID: <21652.1561122763@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 21 Jun 2019 13:12:58 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christian Brauner wrote: > > static int vfs_fsinfo_fd(unsigned int fd, struct fsinfo_kparams *params) > > { > > struct fd f = fdget_raw(fd); > > You're using fdget_raw() which means you want to allow O_PATH fds but > below you're checking whether the f_ops correspond to > fscontext_fops. If it's an O_PATH It can't be. The only way to get an fs_context fd is from fsopen() or fspick() - neither of which allow O_PATH to be specified. If you tried to go through /proc/pid/fd with open(O_PATH), I think you'd get the symlink, not the target. David