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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 0F502C433DF for ; Fri, 31 Jul 2020 05:33:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DD0DD22B3F for ; Fri, 31 Jul 2020 05:33:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596173617; bh=SrMzJYfTMQLBsXyhVjLLCmvenkRswzPK65sqy1cHK2g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rCfGaNqMBQboudYicb90BbWf1KagaHXVsuOjDJ7rajtPzRnslmdbYVQ1I0TAGS5hc ru5SPna6mqA56s6AErWsSUkVr0ED7C8NVYqY8UeCkrs0si7prxvGDVlDkIP3UgKMOJ 1ybm0yRy2xtxss0R/pHI/d1k3w6aM7uy2ipPu55s= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731067AbgGaFdh (ORCPT ); Fri, 31 Jul 2020 01:33:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:38516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726972AbgGaFdh (ORCPT ); Fri, 31 Jul 2020 01:33:37 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D6D79208E4; Fri, 31 Jul 2020 05:33:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1596173616; bh=SrMzJYfTMQLBsXyhVjLLCmvenkRswzPK65sqy1cHK2g=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=FwnmgM0LtXhYrZbihPSWdfHqpy+DSzZ09TwFtOWT8N9S6rPrAdA2tKlVwkYDVpYI7 /WGlgrGBWt6dS8efzXij7J2/2EIt43xsBoMyJbQjG+ff8WnhikCXp0JZMHcr82mxWq +EWy9cKwBRc78VgQG7aPqhbBW+dx32cNhinrGwQk= Date: Fri, 31 Jul 2020 07:33:33 +0200 From: Greg Kroah-Hartman To: Leon Romanovsky Cc: Peilin Ye , Santosh Shilimkar , "David S. Miller" , Jakub Kicinski , Dan Carpenter , Arnd Bergmann , linux-kernel-mentees@lists.linuxfoundation.org, netdev@vger.kernel.org, linux-rdma@vger.kernel.org, rds-devel@oss.oracle.com, linux-kernel@vger.kernel.org Subject: Re: [Linux-kernel-mentees] [PATCH net] rds: Prevent kernel-infoleak in rds_notify_queue_get() Message-ID: <20200731053333.GB466103@kroah.com> References: <20200730192026.110246-1-yepeilin.cs@gmail.com> <20200731045301.GI75549@unreal> <20200731053306.GA466103@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200731053306.GA466103@kroah.com> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Jul 31, 2020 at 07:33:06AM +0200, Greg Kroah-Hartman wrote: > On Fri, Jul 31, 2020 at 07:53:01AM +0300, Leon Romanovsky wrote: > > On Thu, Jul 30, 2020 at 03:20:26PM -0400, Peilin Ye wrote: > > > rds_notify_queue_get() is potentially copying uninitialized kernel stack > > > memory to userspace since the compiler may leave a 4-byte hole at the end > > > of `cmsg`. > > > > > > In 2016 we tried to fix this issue by doing `= { 0 };` on `cmsg`, which > > > unfortunately does not always initialize that 4-byte hole. Fix it by using > > > memset() instead. > > > > Of course, this is the difference between "{ 0 }" and "{}" initializations. > > Really? Neither will handle structures with holes in it, try it and > see. And if true, where in the C spec does it say that? thanks, greg k-h