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 7A8E6C83004 for ; Tue, 28 Apr 2020 19:36:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2B9DA22208 for ; Tue, 28 Apr 2020 19:36:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2B9DA22208 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ED1F78E0008; Tue, 28 Apr 2020 15:36:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E81E58E0001; Tue, 28 Apr 2020 15:36:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DBD6B8E0008; Tue, 28 Apr 2020 15:36:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0131.hostedemail.com [216.40.44.131]) by kanga.kvack.org (Postfix) with ESMTP id C41AC8E0001 for ; Tue, 28 Apr 2020 15:36:49 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 802B452D0 for ; Tue, 28 Apr 2020 19:36:49 +0000 (UTC) X-FDA: 76758271338.18.thing05_58a38e5065e46 X-HE-Tag: thing05_58a38e5065e46 X-Filterd-Recvd-Size: 2374 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf31.hostedemail.com (Postfix) with ESMTP for ; Tue, 28 Apr 2020 19:36:48 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3D459C14; Tue, 28 Apr 2020 12:36:48 -0700 (PDT) Received: from C02TF0J2HF1T.local (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EC1933F68F; Tue, 28 Apr 2020 12:36:44 -0700 (PDT) Date: Tue, 28 Apr 2020 20:36:41 +0100 From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: Will Deacon , Vincenzo Frascino , Szabolcs Nagy , Richard Earnshaw , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , linux-mm@kvack.org, linux-arch@vger.kernel.org, Alexander Viro Subject: Re: [PATCH v3 20/23] fs: Allow copy_mount_options() to access user-space in a single pass Message-ID: <20200428193641.GA35158@C02TF0J2HF1T.local> References: <20200421142603.3894-1-catalin.marinas@arm.com> <20200421142603.3894-21-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200421142603.3894-21-catalin.marinas@arm.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Apr 21, 2020 at 03:26:00PM +0100, Catalin Marinas wrote: > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -3025,13 +3025,16 @@ void *copy_mount_options(const void __user * data) > if (!copy) > return ERR_PTR(-ENOMEM); > > - size = PAGE_SIZE - offset_in_page(data); > + size = PAGE_SIZE; > + if (!arch_has_exact_copy_from_user(size)) > + size -= offset_in_page(data); > > - if (copy_from_user(copy, data, size)) { > + if (copy_from_user(copy, data, size) == size) { > kfree(copy); > return ERR_PTR(-EFAULT); > } > if (size != PAGE_SIZE) { > + WARN_ON(1); > if (copy_from_user(copy + size, data + size, PAGE_SIZE - size)) > memset(copy + size, 0, PAGE_SIZE - size); > } Argh, this WARN_ON should not be here at all. It's something I added to make check that I don't reach this part in arm64. Will remove in v4. -- Catalin