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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 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 17952C34022 for ; Mon, 17 Feb 2020 22:15:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EB51320801 for ; Mon, 17 Feb 2020 22:15:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726069AbgBQWPm (ORCPT ); Mon, 17 Feb 2020 17:15:42 -0500 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:55162 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725966AbgBQWPm (ORCPT ); Mon, 17 Feb 2020 17:15:42 -0500 Received: from dread.disaster.area (pa49-179-138-28.pa.nsw.optusnet.com.au [49.179.138.28]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id 8AE837E9C6E; Tue, 18 Feb 2020 09:15:39 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1j3ofz-0003Q2-0u; Tue, 18 Feb 2020 09:15:39 +1100 Date: Tue, 18 Feb 2020 09:15:39 +1100 From: Dave Chinner To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org, Allison Collins , Chandan Rajendra , "Darrick J . Wong" Subject: Re: [PATCH 05/31] xfs: use strndup_user in XFS_IOC_ATTRMULTI_BY_HANDLE Message-ID: <20200217221538.GJ10776@dread.disaster.area> References: <20200217125957.263434-1-hch@lst.de> <20200217125957.263434-6-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200217125957.263434-6-hch@lst.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=W5xGqiek c=1 sm=1 tr=0 a=zAxSp4fFY/GQY8/esVNjqw==:117 a=zAxSp4fFY/GQY8/esVNjqw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=l697ptgUJYAA:10 a=pGLkceISAAAA:8 a=yPCof4ZbAAAA:8 a=7-415B0cAAAA:8 a=QMJNcwjdRDogb9IiVAAA:9 a=jgZg2VXXFmi3iGAR:21 a=btIgfXDAKQXfHWRP:21 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Mon, Feb 17, 2020 at 01:59:31PM +0100, Christoph Hellwig wrote: > Simplify the user copy code by using strndup_user. This means that we > now do one memory allocation per operation instead of one per ioctl, > but memory allocations are cheap compared to the actual file system > operations. > > Signed-off-by: Christoph Hellwig > Reviewed-by: Chandan Rajendra > Reviewed-by: Darrick J. Wong > --- > fs/xfs/xfs_ioctl.c | 17 +++++------------ > fs/xfs/xfs_ioctl32.c | 17 +++++------------ > 2 files changed, 10 insertions(+), 24 deletions(-) > > diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c > index b806003caacd..bb490a954c0b 100644 > --- a/fs/xfs/xfs_ioctl.c > +++ b/fs/xfs/xfs_ioctl.c > @@ -448,11 +448,6 @@ xfs_attrmulti_by_handle( > goto out_dput; > } > > - error = -ENOMEM; > - attr_name = kmalloc(MAXNAMELEN, GFP_KERNEL); > - if (!attr_name) > - goto out_kfree_ops; > - > error = 0; > for (i = 0; i < am_hreq.opcount; i++) { > if ((ops[i].am_flags & ATTR_ROOT) && > @@ -462,12 +457,11 @@ xfs_attrmulti_by_handle( > } > ops[i].am_flags &= ~ATTR_KERNEL_FLAGS; > > - ops[i].am_error = strncpy_from_user((char *)attr_name, > - ops[i].am_attrname, MAXNAMELEN); > - if (ops[i].am_error == 0 || ops[i].am_error == MAXNAMELEN) > - error = -ERANGE; > - if (ops[i].am_error < 0) > + attr_name = strndup_user(ops[i].am_attrname, MAXNAMELEN); > + if (IS_ERR(attr_name)) { > + ops[i].am_error = PTR_ERR(attr_name); > break; > + } This changes the error returned for an invalid attr name length from -ERANGE to either -EINVAL or -EFAULT. Can you please document that in the commit message. This change requires updates to the path_to_handle(3) man page shipped in xfsprogs in the xfslibs-dev package (xfsprogs::man/man3/handle.3) to document the differences in return values. Cheers, Dave. -- Dave Chinner david@fromorbit.com