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=-9.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 73E94C433DF for ; Sat, 22 Aug 2020 15:45:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4869020658 for ; Sat, 22 Aug 2020 15:45:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RYEZJ7+v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728211AbgHVPpg (ORCPT ); Sat, 22 Aug 2020 11:45:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727899AbgHVPpf (ORCPT ); Sat, 22 Aug 2020 11:45:35 -0400 Received: from mail-ot1-x341.google.com (mail-ot1-x341.google.com [IPv6:2607:f8b0:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BE08CC061573 for ; Sat, 22 Aug 2020 08:45:35 -0700 (PDT) Received: by mail-ot1-x341.google.com with SMTP id t7so3944899otp.0 for ; Sat, 22 Aug 2020 08:45:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=BOUMiCXf9j7Wt8uOl48K1yzTZg6ycoY2LCI3OS07QwU=; b=RYEZJ7+vYiZXk9huKRDhpEe5/bIaYN7b6sN+feZsU2Si+P1uDBxv6lVE3wPV1ztAFP bjezMJHG3S46TfQsy/vSdYqxmreJty4sk3a9idOD69SpPUOANUJa+hpBHnwLBdmM0TXo 4cdXOB3HlhfQ/yrIKP5xefEFds2FRNkslosQyyifowZ7JFZSA5u1UVgH0nV3b1/MTUOV hn8h18/X1LJL54IN/UsBu+052NRH5zl5JMTtm2RMtNEDcrbSuEcIeOyEFIQoZzK9sZnB 59sdNWLfTKh8QqZ9bAfIBiZuQNTEJ1TROCBrvbydP7Hg4Gp59i9BAC/Q8NPCbeTzaehG pB1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=BOUMiCXf9j7Wt8uOl48K1yzTZg6ycoY2LCI3OS07QwU=; b=rbyOwkpfpo4sagvfEGrrVwSgIeD9kp6kcDbKj65RC41SnhlVxt90FnJO0hGBup1L5o 1ylWqSKKWbyRhQiuz5SgcPnm4XZZwl5nCPhXhkQ0Gxh10HcwXJHDpgFxQpO3DCmivw9K BNxMi8eb5bASYHfrnfweWP6CGXo/N+tvAcVuB0quAeUtg8BolWfmM7RhPqLfg/O9LC96 HSkYN6+P8F2+w9idaYxoREgR9txPRjzKfJUB6WCVAJ40q5jvZr+fGWx7VYJXzPb3DLrp Zv3SD/g3WSMnB/lrFN8QlBOVVwvW6LuqgfL/V4dSnAKNyYly3L7lIkyM3wcsbdjQiLYH V6KQ== X-Gm-Message-State: AOAM530DQjzZaUBEe8QsaTLF5oMnVOe06F8VfKUAWWLWytx54MIUj7T5 EPXu0MXionDPY6OGS9f6sOU= X-Google-Smtp-Source: ABdhPJyTKEfbC9AHlbf4MivzlLGBeWpIYZs5IQUBN/OW06XMV3Bv7y2pF9afGp5u/zarC0bZilGJvA== X-Received: by 2002:a9d:ed0:: with SMTP id 74mr5186078otj.269.1598111135144; Sat, 22 Aug 2020 08:45:35 -0700 (PDT) Received: from Davids-MacBook-Pro.local ([2601:284:8202:10b0:a888:bc35:d7d6:9aca]) by smtp.googlemail.com with ESMTPSA id 95sm189330otw.26.2020.08.22.08.45.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 22 Aug 2020 08:45:34 -0700 (PDT) Subject: Re: [PATCH net v2] net: nexthop: don't allow empty NHA_GROUP To: Nikolay Aleksandrov , netdev@vger.kernel.org Cc: davem@davemloft.net, syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com References: <20200822103340.184978-1-nikolay@cumulusnetworks.com> <20200822120636.194237-1-nikolay@cumulusnetworks.com> From: David Ahern Message-ID: <197f8d43-d6fa-e701-92ba-81148fc139a5@gmail.com> Date: Sat, 22 Aug 2020 09:45:13 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <20200822120636.194237-1-nikolay@cumulusnetworks.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/22/20 6:06 AM, Nikolay Aleksandrov wrote: > Currently the nexthop code will use an empty NHA_GROUP attribute, but it > requires at least 1 entry in order to function properly. Otherwise we > end up derefencing null or random pointers all over the place due to not > having any nh_grp_entry members allocated, nexthop code relies on having at > least the first member present. Empty NHA_GROUP doesn't make any sense so > just disallow it. > Also add a WARN_ON for any future users of nexthop_create_group(). > ... > > CC: David Ahern > Fixes: 430a049190de ("nexthop: Add support for nexthop groups") > Reported-by: syzbot+a61aa19b0c14c8770bd9@syzkaller.appspotmail.com > Signed-off-by: Nikolay Aleksandrov > --- > Tested on 5.3 and latest -net by adding a nexthop with an empty NHA_GROUP > (purposefully broken iproute2) and then adding a route which uses it. > > v2: no changes, include stack trace in commit message > > net/ipv4/nexthop.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > Reviewed-by: David Ahern Thanks, Nik