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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 414EAC43387 for ; Sat, 22 Dec 2018 23:07:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 179302192C for ; Sat, 22 Dec 2018 23:07:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392925AbeLVXHY (ORCPT ); Sat, 22 Dec 2018 18:07:24 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:40480 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731156AbeLVXHX (ORCPT ); Sat, 22 Dec 2018 18:07:23 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::cf9]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id E4DFA14A8F325; Sat, 22 Dec 2018 15:07:22 -0800 (PST) Date: Sat, 22 Dec 2018 15:07:22 -0800 (PST) Message-Id: <20181222.150722.1493687829239836271.davem@davemloft.net> To: gustavo@embeddedor.com Cc: ast@kernel.org, daniel@iogearbox.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] net: core: Fix Spectre v1 vulnerability From: David Miller In-Reply-To: <20181221204901.GA30045@embeddedor> References: <20181221204901.GA30045@embeddedor> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sat, 22 Dec 2018 15:07:23 -0800 (PST) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Gustavo A. R. Silva" Date: Fri, 21 Dec 2018 14:49:01 -0600 > flen is indirectly controlled by user-space, hence leading to > a potential exploitation of the Spectre variant 1 vulnerability. > > This issue was detected with the help of Smatch: > > net/core/filter.c:1101 bpf_check_classic() warn: potential spectre issue 'filter' [w] > > Fix this by sanitizing flen before using it to index filter at line 1101: > > switch (filter[flen - 1].code) { > > and through pc at line 1040: > > const struct sock_filter *ftest = &filter[pc]; > > Notice that given that speculation windows are large, the policy is > to kill the speculation on the first load and not worry if it can be > completed with a dependent load/store [1]. > > [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 > > Signed-off-by: Gustavo A. R. Silva BPF folks, I'll take this directly. Applied and queued up for -stable, thanks.