From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Date: Thu, 21 May 2020 10:46:33 +0000 Message-ID: References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20200521091150.GA8401@lst.de> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: 'Christoph Hellwig' Cc: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" l List-Id: ceph-devel.vger.kernel.org From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 10:46:33 +0000 Subject: [Cluster-devel] remove kernel_setsockopt and kernel_getsockopt v2 In-Reply-To: <20200521091150.GA8401@lst.de> References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> Message-ID: List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) 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 B6366C433E0 for ; Thu, 21 May 2020 10:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F05C20814 for ; Thu, 21 May 2020 10:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728947AbgEUKqi convert rfc822-to-8bit (ORCPT ); Thu, 21 May 2020 06:46:38 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]:52898 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728889AbgEUKqi (ORCPT ); Thu, 21 May 2020 06:46:38 -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-221-qFd0NAKZNGeARFK-F-oKaQ-1; Thu, 21 May 2020 11:46:34 +0100 X-MC-Unique: qFd0NAKZNGeARFK-F-oKaQ-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; Thu, 21 May 2020 11:46:33 +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; Thu, 21 May 2020 11:46:33 +0100 From: David Laight To: 'Christoph Hellwig' CC: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , "Marcelo Ricardo Leitner" , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "linux-cifs@vger.kernel.org" , "cluster-devel@redhat.com" , "ocfs2-devel@oss.oracle.com" , "netdev@vger.kernel.org" , "linux-sctp@vger.kernel.org" , "ceph-devel@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-nfs@vger.kernel.org" Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Topic: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Index: AQHWL0EWFDRlmpM/90uRt9jvD36P/KiyKtMAgAAFoACAACnvQA== Date: Thu, 21 May 2020 10:46:33 +0000 Message-ID: References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> In-Reply-To: <20200521091150.GA8401@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: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) 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=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 D383BC433DF for ; Thu, 21 May 2020 10:47:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 998E320814 for ; Thu, 21 May 2020 10:47:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="cD7JmQXR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 998E320814 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=ACULAB.COM Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=0Iqr/rw7456hve/mWkp9fSan2IlaFkOaaOWtuimh1FI=; b=cD7JmQXRkGinUE vk5JZGLnGo92m2geBw7UO23ZyIIc+mMRc4LkRgG7tLHBsdQ3nRvFupNwDn14N63U0GV+EPPdqgrT2 UpiVhEyDtqaedTPI9W0Ue85Z9tAHM5y5ecuoISm8eFMC9q9P+JDa3f6zJBZJ4jaqwOfupMhKDpg+D k/tY23ee2SkwIwVkyx9kbf5XYqXmPWi1bSZP5ZGkMCvsqLIANwE2jXjUP4RV1TWD4zdrRdH1J2HkF lcY1dzWZ+03sJ1BDLd83nmzERvvVn8zC4k1GsES1JVzPBM+3ggnL4DLFnMqsah4z0mGKgeFmGA4H7 NaWK7jnh+FtE/Z9sDQ7Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbijN-00055u-Up; Thu, 21 May 2020 10:47:17 +0000 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jbiil-00051C-Mr for linux-nvme@lists.infradead.org; Thu, 21 May 2020 10:46:41 +0000 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-221-qFd0NAKZNGeARFK-F-oKaQ-1; Thu, 21 May 2020 11:46:34 +0100 X-MC-Unique: qFd0NAKZNGeARFK-F-oKaQ-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; Thu, 21 May 2020 11:46:33 +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; Thu, 21 May 2020 11:46:33 +0100 From: David Laight To: 'Christoph Hellwig' Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Topic: remove kernel_setsockopt and kernel_getsockopt v2 Thread-Index: AQHWL0EWFDRlmpM/90uRt9jvD36P/KiyKtMAgAAFoACAACnvQA== Date: Thu, 21 May 2020 10:46:33 +0000 Message-ID: References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> In-Reply-To: <20200521091150.GA8401@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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200521_034640_036121_025640C1 X-CRM114-Status: GOOD ( 11.80 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Marcelo Ricardo Leitner , Eric Dumazet , "linux-nvme@lists.infradead.org" , "linux-sctp@vger.kernel.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "drbd-dev@lists.linbit.com" , "linux-cifs@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-rdma@vger.kernel.org" , "cluster-devel@redhat.com" , Alexey Kuznetsov , Jakub Kicinski , "ceph-devel@vger.kernel.org" , "linux-nfs@vger.kernel.org" , Neil Horman , Hideaki YOSHIFUJI , "netdev@vger.kernel.org" , Vlad Yasevich , "linux-kernel@vger.kernel.org" , Jon Maloy , Ying Xue , "David S. Miller" , "ocfs2-devel@oss.oracle.com" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 10:46:33 +0000 Subject: RE: remove kernel_setsockopt and kernel_getsockopt v2 Message-Id: List-Id: References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> In-Reply-To: <20200521091150.GA8401@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Christoph Hellwig' Cc: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Laight Date: Thu, 21 May 2020 10:46:33 +0000 Subject: [Ocfs2-devel] remove kernel_setsockopt and kernel_getsockopt v2 In-Reply-To: <20200521091150.GA8401@lst.de> References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'Christoph Hellwig' Cc: "David S. Miller" , Jakub Kicinski , Eric Dumazet , Alexey Kuznetsov , Hideaki YOSHIFUJI , Vlad Yasevich , Neil Horman , Marcelo Ricardo Leitner , Jon Maloy , Ying Xue , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-rdma@vger.kernel.org" , "linux-nvme@lists.infradead.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. > > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales) From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id D1AAC420421 for ; Sat, 13 Jun 2020 11:58:26 +0200 (CEST) Received: by mail-wr1-f41.google.com with SMTP id l11so12301602wru.0 for ; Sat, 13 Jun 2020 02:58:26 -0700 (PDT) Received: from soda.linbit (62-99-137-214.static.upcbusiness.at. [62.99.137.214]) by smtp.gmail.com with ESMTPSA id p7sm14383155wro.26.2020.06.13.02.58.25 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Sat, 13 Jun 2020 02:58:25 -0700 (PDT) Resent-Message-ID: <20200613095823.GS4222@soda.linbit> Received: from eu-smtp-delivery-151.mimecast.com (eu-smtp-delivery-151.mimecast.com [146.101.78.151]) by mail19.linbit.com (LINBIT Mail Daemon) with ESMTP id 87C674203D6 for ; Thu, 21 May 2020 12:46:36 +0200 (CEST) From: David Laight To: 'Christoph Hellwig' Message-ID: References: <20200520195509.2215098-1-hch@lst.de> <138a17dfff244c089b95f129e4ea2f66@AcuMS.aculab.com> <20200521091150.GA8401@lst.de> In-Reply-To: <20200521091150.GA8401@lst.de> Content-Language: en-US MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: Marcelo Ricardo Leitner , Eric Dumazet , "linux-nvme@lists.infradead.org" , "linux-sctp@vger.kernel.org" , "target-devel@vger.kernel.org" , "linux-afs@lists.infradead.org" , "drbd-dev@lists.linbit.com" , "linux-cifs@vger.kernel.org" , "rds-devel@oss.oracle.com" , "linux-rdma@vger.kernel.org" , "cluster-devel@redhat.com" , Alexey Kuznetsov , Jakub Kicinski , "ceph-devel@vger.kernel.org" , "linux-nfs@vger.kernel.org" , Neil Horman , Hideaki YOSHIFUJI , "netdev@vger.kernel.org" , Vlad Yasevich , "linux-kernel@vger.kernel.org" , Jon Maloy , Ying Xue , "David S. Miller" , "ocfs2-devel@oss.oracle.com" Subject: Re: [Drbd-dev] remove kernel_setsockopt and kernel_getsockopt v2 List-Id: "*Coordination* of development, patches, contributions -- *Questions* \(even to developers\) go to drbd-user, please." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Date: Sat, 13 Jun 2020 10:17:17 -0000 From: 'Christoph Hellwig' > Sent: 21 May 2020 10:12 ... > > I worried about whether getsockopt() should read the entire > > user buffer first. SCTP needs the some of it often (including a > > sockaddr_storage in one case), TCP needs it once. > > However the cost of reading a few words is small, and a big > > buffer probably needs setting to avoid leaking kernel > > memory if the structure has holes or fields that don't get set. > > Reading from userspace solves both issues. >=20 > As mention in the thread on the last series: That was my first idea, but > we have way to many sockopts, especially in obscure protocols that just > hard code the size. The chance of breaking userspace in a way that can't > be fixed without going back to passing user pointers to get/setsockopt > is way to high to commit to such a change unfortunately. Right the syscall stubs probably can't do it. But the per-protocol ones can for the main protocols. I posted a patch for SCTP yesterday that removes 800 lines of source and 8k of object code. Even that needs a horrid bodge for one request where the length returned has to be less than the data copied! =09David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1= PT, UK Registration No: 1397386 (Wales)