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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 996CDC04FE1 for ; Thu, 27 Jul 2023 09:13:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231209AbjG0JN3 convert rfc822-to-8bit (ORCPT ); Thu, 27 Jul 2023 05:13:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40412 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234079AbjG0JNC (ORCPT ); Thu, 27 Jul 2023 05:13:02 -0400 Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [185.58.86.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DEA3F7D80 for ; Thu, 27 Jul 2023 02:01:15 -0700 (PDT) Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) by relay.mimecast.com with ESMTP with both STARTTLS and AUTH (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id uk-mta-59-jWjmQDvBMMi6NLEiZstNIw-1; Thu, 27 Jul 2023 10:01:12 +0100 X-MC-Unique: jWjmQDvBMMi6NLEiZstNIw-1 Received: from AcuMS.Aculab.com (10.202.163.4) by AcuMS.aculab.com (10.202.163.4) with Microsoft SMTP Server (TLS) id 15.0.1497.48; Thu, 27 Jul 2023 10:01:06 +0100 Received: from AcuMS.Aculab.com ([::1]) by AcuMS.aculab.com ([::1]) with mapi id 15.00.1497.048; Thu, 27 Jul 2023 10:01:06 +0100 From: David Laight To: 'Aleksa Sarai' , Alexey Gladkov CC: LKML , Arnd Bergmann , "linux-api@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "viro@zeniv.linux.org.uk" , "James.Bottomley@hansenpartnership.com" , "acme@kernel.org" , "alexander.shishkin@linux.intel.com" , "axboe@kernel.dk" , "benh@kernel.crashing.org" , "borntraeger@de.ibm.com" , "bp@alien8.de" , "catalin.marinas@arm.com" , "christian@brauner.io" , "dalias@libc.org" , "davem@davemloft.net" , "deepa.kernel@gmail.com" , "deller@gmx.de" , "dhowells@redhat.com" , "fenghua.yu@intel.com" , "fweimer@redhat.com" , "geert@linux-m68k.org" , "glebfm@altlinux.org" , "gor@linux.ibm.com" , "hare@suse.com" , "hpa@zytor.com" , "ink@jurassic.park.msu.ru" , "jhogan@kernel.org" , "kim.phillips@arm.com" , "ldv@altlinux.org" , "linux-alpha@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-ia64@vger.kernel.org" , "linux-m68k@lists.linux-m68k.org" , "linux-mips@vger.kernel.org" , "linux-parisc@vger.kernel.org" , "linux-s390@vger.kernel.org" , "linux-sh@vger.kernel.org" , "linux@armlinux.org.uk" , "linuxppc-dev@lists.ozlabs.org" , "luto@kernel.org" , "mattst88@gmail.com" , "mingo@redhat.com" , "monstr@monstr.eu" , "mpe@ellerman.id.au" , "namhyung@kernel.org" , "paulus@samba.org" , "peterz@infradead.org" , "ralf@linux-mips.org" , "sparclinux@vger.kernel.org" , "stefan@agner.ch" , "tglx@linutronix.de" , "tony.luck@intel.com" , "tycho@tycho.ws" , "will@kernel.org" , "x86@kernel.org" , "ysato@users.sourceforge.jp" , Palmer Dabbelt Subject: RE: [PATCH v4 2/5] fs: Add fchmodat2() Thread-Topic: [PATCH v4 2/5] fs: Add fchmodat2() Thread-Index: AQHZvxZDeKGBJJpK+0qJRy2agWp2qK/NUtoA Date: Thu, 27 Jul 2023 09:01:06 +0000 Message-ID: References: In-Reply-To: Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org From: Aleksa Sarai > Sent: 25 July 2023 17:36 ... > We almost certainly want to support AT_EMPTY_PATH at the same time. > Otherwise userspace will still need to go through /proc when trying to > chmod a file handle they have. That can't be allowed. Just because a process has a file open and write access to the directory that contains it doesn't mean they are allowed to change the file permissions. They also need directory search access from a directory they have open through to the containing directory. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)