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=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 8EBD4C433E1 for ; Mon, 25 May 2020 19:37:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7FE5320723 for ; Mon, 25 May 2020 19:37:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390139AbgEYThy convert rfc822-to-8bit (ORCPT ); Mon, 25 May 2020 15:37:54 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:45912 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389985AbgEYThy (ORCPT ); Mon, 25 May 2020 15:37:54 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-232-sTToDJtAOvqxCcC2xDEG0A-1; Mon, 25 May 2020 20:37:50 +0100 X-MC-Unique: sTToDJtAOvqxCcC2xDEG0A-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Mon, 25 May 2020 20:37:49 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Mon, 25 May 2020 20:37:49 +0100 From: David Laight To: 'Christoph Hellwig' , Marcelo Ricardo Leitner CC: Vlad Yasevich , Neil Horman , "David S. Miller" , Jakub Kicinski , "linux-sctp@vger.kernel.org" , "netdev@vger.kernel.org" Subject: RE: do a single memdup_user in sctp_setsockopt Thread-Topic: do a single memdup_user in sctp_setsockopt Thread-Index: AQHWL5hibpEyDKsV4UyRPKuzFFnyuaizvkKggAGHkhuAA+6CkA== Date: Mon, 25 May 2020 19:37:49 +0000 Message-ID: <38061a608f294766846e23170bdf0177@AcuMS.aculab.com> References: <20200521174724.2635475-1-hch@lst.de> <348217b7a3e14c1fa4868e47362be9c5@AcuMS.aculab.com> <20200522143623.GA386664@localhost.localdomain> <20200523071929.GA10466@lst.de> In-Reply-To: <20200523071929.GA10466@lst.de> Accept-Language: en-GB, en-US Content-Language: 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-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: 'Christoph Hellwig' > Sent: 23 May 2020 08:19 ... > Alternatively I'll also happily only do a partial conversion for what > I need for the kernel_setsockopt removal and let you and Dave decided > what you guys prefer for the rest. I presume the justification for removing kernel_[sg]etsockopt() is that you want to get rid of set_fs(KERNEL_DS). (Which I believe is only a flag to access_ok()?) In any case I'm not against that at all. To do that you also need to solve the problem of the BPF 'hook' in setsockopt() that can also need to pass a kernel buffer through. I don't see a rush to remove kernel_[sg]etsockopt() until you have a solution for the BPF hook. Especially since, until set_fs() is removed, any driver can (and probably will) just implement their own version. I think you may end up with the protocols being able to export either [sg]etsockopt() functions or kernel_[sg]setsockopt() functions and some paths erroring if the required function is absent. But even that isn't trivial given the broken nature of one sctp option - where the returned length has to be invalid! I'm going to post a V3 of my big patch - I spotted an error. I'll include a different (smaller) patch in 0/1 that generates exactly the same object code but is easier to review. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)