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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 DA969C4332E for ; Fri, 8 Jan 2021 11:51:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AB99B239E7 for ; Fri, 8 Jan 2021 11:51:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726505AbhAHLvT convert rfc822-to-8bit (ORCPT ); Fri, 8 Jan 2021 06:51:19 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.86.151]:39616 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726520AbhAHLvH (ORCPT ); Fri, 8 Jan 2021 06:51:07 -0500 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-227-JrkSGbMLN9-FUY2lxHNdvQ-1; Fri, 08 Jan 2021 11:49:28 +0000 X-MC-Unique: JrkSGbMLN9-FUY2lxHNdvQ-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; Fri, 8 Jan 2021 11:49:27 +0000 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; Fri, 8 Jan 2021 11:49:27 +0000 From: David Laight To: 'Christoph Hellwig' , Alexander Viro CC: Andrew Morton , Jens Axboe , Arnd Bergmann , David Howells , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mips@vger.kernel.org" , "linux-parisc@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-s390@vger.kernel.org" , "sparclinux@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-aio@kvack.org" , "io-uring@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , "netdev@vger.kernel.org" , "keyrings@vger.kernel.org" , "linux-security-module@vger.kernel.org" Subject: RE: [PATCH 05/11] iov_iter: merge the compat case into rw_copy_check_uvector Thread-Topic: [PATCH 05/11] iov_iter: merge the compat case into rw_copy_check_uvector Thread-Index: AQHWkCRUvpDO9SBAlU68E+WeFLSma6oeR04A Date: Fri, 8 Jan 2021 11:49:27 +0000 Message-ID: <7167a94511a84f30b18733d56007a7a5@AcuMS.aculab.com> References: <20200921143434.707844-1-hch@lst.de> <20200921143434.707844-6-hch@lst.de> In-Reply-To: <20200921143434.707844-6-hch@lst.de> 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 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com 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: io-uring@vger.kernel.org From: Christoph Hellwig > Sent: 21 September 2020 15:34 > > Stop duplicating the iovec verify code, and instead add add a > __import_iovec helper that does the whole verify and import, but takes > a bool compat to decided on the native or compat layout. This also > ends up massively simplifying the calling conventions. > > Signed-off-by: Christoph Hellwig > --- > lib/iov_iter.c | 195 ++++++++++++++++++------------------------------- > 1 file changed, 70 insertions(+), 125 deletions(-) > > diff --git a/lib/iov_iter.c b/lib/iov_iter.c > index a64867501a7483..8bfa47b63d39aa 100644 > --- a/lib/iov_iter.c > +++ b/lib/iov_iter.c > @@ -10,6 +10,7 @@ > #include > #include > #include > +#include > > #define PIPE_PARANOIA /* for now */ > > @@ -1650,43 +1651,76 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags) > } > EXPORT_SYMBOL(dup_iter); > > -static ssize_t rw_copy_check_uvector(int type, > - const struct iovec __user *uvector, unsigned long nr_segs, > - unsigned long fast_segs, struct iovec *fast_pointer, > - struct iovec **ret_pointer) > +static int compat_copy_iovecs_from_user(struct iovec *iov, > + const struct iovec __user *uvector, unsigned long nr_segs) > +{ > + const struct compat_iovec __user *uiov = > + (const struct compat_iovec __user *)uvector; > + unsigned long i; > + int ret = -EFAULT; > + > + if (!user_access_begin(uvector, nr_segs * sizeof(*uvector))) > + return -EFAULT; I little bit late, but the above isn't quite right. It should be sizeof(*iouv) - the length is double what it should be. Not that access_ok() can fail for compat addresses and the extra length won't matter for architectures that need the address/length to open an address hole into userspace. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)