From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751957AbdGGPW0 (ORCPT ); Fri, 7 Jul 2017 11:22:26 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:56278 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751866AbdGGPWY (ORCPT ); Fri, 7 Jul 2017 11:22:24 -0400 Date: Fri, 7 Jul 2017 16:22:15 +0100 From: Al Viro To: Michael Ellerman Cc: torvalds@linux-fondation.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH] fs/fcntl: Fix F_GET/SETLK etc. for compat processes Message-ID: <20170707152215.GE10672@ZenIV.linux.org.uk> References: <1499431731-27058-1-git-send-email-mpe@ellerman.id.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1499431731-27058-1-git-send-email-mpe@ellerman.id.au> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 07, 2017 at 10:48:51PM +1000, Michael Ellerman wrote: > Commit 8c6657cb50cb ("Switch flock copyin/copyout primitives to > copy_{from,to}_user()") added copy_flock_fields(from, to), but then in all cases > called it with arguments of (to, from). eg: > > static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl) > { > struct compat_flock fl; > > if (copy_from_user(&fl, ufl, sizeof(struct compat_flock))) > return -EFAULT; > copy_flock_fields(*kfl, fl); > return 0; > } > > We are reading the compat_flock ufl from userspace, into flock kfl. First we > copy all of ufl into fl on the stack, and then we want to assign each field of > fl to kfl. So we are copying from fl and to kfl. But as written the > copy_flock_fields() macro takes the arguments in the other order. > > copy_to/from_user() take "to" as the first argument, so change the order of > arguments in the copy_flock_fields() macro, rather than changing the callers. D'oh... Acked-by: Al Viro