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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 097E4C2D0DB for ; Fri, 24 Jan 2020 15:46:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCC752071E for ; Fri, 24 Jan 2020 15:46:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389136AbgAXPqF convert rfc822-to-8bit (ORCPT ); Fri, 24 Jan 2020 10:46:05 -0500 Received: from eu-smtp-delivery-151.mimecast.com ([207.82.80.151]:36811 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389093AbgAXPqE (ORCPT ); Fri, 24 Jan 2020 10:46:04 -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-112-9-3BgZ-WNk6HIrS3qU3ecA-1; Fri, 24 Jan 2020 15:46:01 +0000 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, 24 Jan 2020 15:46:00 +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, 24 Jan 2020 15:46:00 +0000 From: David Laight To: "linux-kernel@vger.kernel.org" , netdev Subject: [PATCH 2/3] Use _copy_from_user() to read SG iovec array. Thread-Topic: [PATCH 2/3] Use _copy_from_user() to read SG iovec array. Thread-Index: AdXSzKSRXs42kspQS5CbFYOlJPFGSg== Date: Fri, 24 Jan 2020 15:46:00 +0000 Message-ID: <04fbf8632f83496d819f27bb353dbf39@AcuMS.aculab.com> 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-MC-Unique: 9-3BgZ-WNk6HIrS3qU3ecA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The code has either just validated that the size fits in a caller supplied fixed size buffer or has used kmalloc() to allocate a buffer. So avoid the non-trivial cost of the HARDENED_USERCOPY checks by calling _copy_from_user() instead of copy_from_user(). Signed-off-by: David Laight --- fs/read_write.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/read_write.c b/fs/read_write.c index 441d9ca..0241d68 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -795,7 +795,7 @@ ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, goto out; } } - if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { + if (_copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { ret = -EFAULT; goto out; } -- 1.8.1.2 - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)