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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 74AC2C433E0 for ; Mon, 15 Jun 2020 12:34:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46B152076A for ; Mon, 15 Jun 2020 12:34:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="EzjEXnsQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729963AbgFOMe4 (ORCPT ); Mon, 15 Jun 2020 08:34:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729955AbgFOMez (ORCPT ); Mon, 15 Jun 2020 08:34:55 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60522C061A0E; Mon, 15 Jun 2020 05:34:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Transfer-Encoding :Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=7PZDg4jCzPxW5YIwZz6jai72YNhUOSrV8NAAvOuS8uI=; b=EzjEXnsQNJmyEoGtItnWE3dbp8 O/Bso1kmXi5hV9UUaupbb5CH//hiui1DrLy5TxJ73AcaBq1m9m35Him7FyIZ3oifaXa6XLWOTjn9N SdW38NDwmhYxG4WK7RTmzZlY4He+nh8/awLJoDa0ceCvBZMij51jN0zYfVgz4GjVVmqAhxd8JQMV4 pXsLBKiA6fy/GoolVDrkTUXTGRnqD9g8QFTyvfPvpFJXiRFKluo8YPGtdo0tPxFryq1txM6JkvjGq 0k+am2VfuJyRMYzaBQyOY551WtFuYvucjplW9PXYFf6u3qN10DMGJ7BhfDLStqyTfMUBsZcEpXaFx i+5Y4bvQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkoJz-0003d6-Pq; Mon, 15 Jun 2020 12:34:39 +0000 Date: Mon, 15 Jun 2020 05:34:39 -0700 From: Matthew Wilcox To: Christoph Hellwig Cc: Al Viro , Linus Torvalds , Ian Kent , David Howells , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: Re: [PATCH 05/13] fs: check FMODE_WRITE in __kernel_write Message-ID: <20200615123439.GT8681@bombadil.infradead.org> References: <20200615121257.798894-1-hch@lst.de> <20200615121257.798894-6-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200615121257.798894-6-hch@lst.de> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Jun 15, 2020 at 02:12:49PM +0200, Christoph Hellwig wrote: > We still need to check if the fѕ is open write, even for the low-level > helper. Do we need the analogous check for FMODE_READ in the __kernel_read() patch? > @@ -505,6 +505,8 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t > const char __user *p; > ssize_t ret; > > + if (!(file->f_mode & FMODE_WRITE)) > + return -EBADF; > if (!(file->f_mode & FMODE_CAN_WRITE)) > return -EINVAL; > > -- > 2.26.2 >