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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, T_DKIMWL_WL_HIGH,USER_AGENT_MUTT 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 89080C636D8 for ; Mon, 10 Jun 2019 14:23:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6291220859 for ; Mon, 10 Jun 2019 14:23:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560176607; bh=A90YY0XScEWebv7Wa6OalV1D5wbhdju9RVpdpcHWqU4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=cduf89+ylMSbTuO1efu4eNqY29sr7n5oFa9FghiX8yBV4c6DZZDoh5QiNWHztUvDO 8CrGpMlRfSw4wtA1Xw0mYdcKOfRJ1I81RY+IzTPqhErRBAP6m8SdUxGhop46lsC7UI bEKYgcQCR9UF6ogShINENUAWP4e9sq2FnLcssSlw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390708AbfFJOX0 (ORCPT ); Mon, 10 Jun 2019 10:23:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:55034 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403788AbfFJOX0 (ORCPT ); Mon, 10 Jun 2019 10:23:26 -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 5F54B207E0; Mon, 10 Jun 2019 14:23:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560176605; bh=A90YY0XScEWebv7Wa6OalV1D5wbhdju9RVpdpcHWqU4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qd8G1NTbPOEvGugSZVmVm8H25EuH9qwztLE4UVT+TXnRwkifwY6An3zPfp13vG0/q UafexcVizdk1Sri1xgonAcETAjX5qzFGy/MYIsa/ZlWCkXxSHcCzpw8c00bso+xHcL 6V/z90ocdyGAKeLAjCWXPSOFEdGIIVfNM2x5pD3w= Date: Mon, 10 Jun 2019 16:23:23 +0200 From: Greg Kroah-Hartman To: Michal Kubecek Cc: stable@vger.kernel.org, Pavel Machek , linux-kernel@vger.kernel.org, Vivien Didelot , "David S. Miller" Subject: Re: [PATCH 4.19 01/51] ethtool: fix potential userspace buffer overflow Message-ID: <20190610142323.GD5937@kroah.com> References: <20190609164127.123076536@linuxfoundation.org> <20190609164127.215699992@linuxfoundation.org> <20190610082112.GA8783@amd> <20190610084229.GA31797@unicorn.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190610084229.GA31797@unicorn.suse.cz> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Mon, Jun 10, 2019 at 10:42:29AM +0200, Michal Kubecek wrote: > On Mon, Jun 10, 2019 at 10:21:12AM +0200, Pavel Machek wrote: > > Hi! > > > > > From: Vivien Didelot > > > > > > [ Upstream commit 0ee4e76937d69128a6a66861ba393ebdc2ffc8a2 ] > > > > > > ethtool_get_regs() allocates a buffer of size ops->get_regs_len(), > > > and pass it to the kernel driver via ops->get_regs() for filling. > > > > > > There is no restriction about what the kernel drivers can or cannot do > > > with the open ethtool_regs structure. They usually set regs->version > > > and ignore regs->len or set it to the same size as ops->get_regs_len(). > > > > > > But if userspace allocates a smaller buffer for the registers dump, > > > we would cause a userspace buffer overflow in the final copy_to_user() > > > call, which uses the regs.len value potentially reset by the driver. > > > > > > To fix this, make this case obvious and store regs.len before calling > > > ops->get_regs(), to only copy as much data as requested by userspace, > > > up to the value returned by ops->get_regs_len(). > > > > > > While at it, remove the redundant check for non-null regbuf. > > > > Mainline differs from 4.19-stable here, and while the non-null check > > is redundant in -mainline, it does not seem to be redundant in > > -stable. > > > > In stable, if get_regs_len() returns < 0, we'll pass it to vzalloc. > > Right. :-( > > I guess we should also pick commit f9fc54d313fa ("ethtool: check the > return value of get_regs_len") to stable branches before 5.0. Now queued up, thanks. greg k-h