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=-5.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 73EABC4CECF for ; Mon, 23 Sep 2019 15:53:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4BBFF2089F for ; Mon, 23 Sep 2019 15:53:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="sCLm/MJT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732812AbfIWPxB (ORCPT ); Mon, 23 Sep 2019 11:53:01 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:33654 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728464AbfIWPxA (ORCPT ); Mon, 23 Sep 2019 11:53:00 -0400 Received: by mail-pf1-f194.google.com with SMTP id q10so9399797pfl.0 for ; Mon, 23 Sep 2019 08:53:00 -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=LvVgVoijm4LqeTHNewjLvUao2avklYCb3x3l0rgxnGM=; b=sCLm/MJTXTL1D6tNJmJEnfxoBmlKkb1llSFTUWWsnyUbY0WWdiXcNH9RvkVpa3QAtG SkWgHIJthxL6Df6l1i68eT+0XBEZvDRWf5ANCjMfwWOqpgL91uSO69zi/4ukJGgzbbNg ZrLmDwErsfY4ZjJjkfqK+jJT3ggkKWhtj9T9SPFKIpaf/1tQd3/53jij1GyXqtUNcsfM 0dTiwrJDJEaQaevsDntInK7xkGI3Y4V/02U8YLlxV3JKG6MhUXrmLlOXSyv/j9WT4Je9 eSUU+TQ9tqnMCMiVUQmkoVdjqNgQhxOnj01oc9zb0XW1aw/VHWl1TXP2jH51tP8TCxtk /x6w== 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=LvVgVoijm4LqeTHNewjLvUao2avklYCb3x3l0rgxnGM=; b=RysynCDTYxPXnhFY4ze9Qubt7LETndvRLWu7vAL8zeMU8fTrbExEjM8PQmKsEQySdi 8ge2sM8cM2L0Tr8rBq1UQGr/767zSMhHQctzLt2FRzGDnZM8i3+OVCKgYWP7YvytWiYE ktpDNNDd19XOiF5vZhvBia5RlSgbftqgAIwwRSWuVVj2tmr7+ZZmE5tVedkcQDAr3mnz fER6bp7vh7QrpN5uSYfZbqUb7yxKePowpJ3n5zdaL3rl/pxmhR3HitHz+9uIFM0H8x1N SHzY355oIXMjbdjdSawqZ4PkAi3NQHZ2udyQuY5xVl0O2ItV+lb8zL2mphmLN1XL55+Z fvkA== X-Gm-Message-State: APjAAAUJ8R7Arrsz6d3eIuOLA9bcvs76sOhueXRGC7rvB5ykKuNizeDn ajBx8EJ688caG0iGVjJCnKQMSayY X-Google-Smtp-Source: APXvYqzf2EWIWILO8RnYLOPgJc+yCXsN6CwrgHumxccBcit9mrklxGWc7/axT0/VpFHKms4EKnhiUQ== X-Received: by 2002:a62:ac13:: with SMTP id v19mr282377pfe.202.1569253980032; Mon, 23 Sep 2019 08:53:00 -0700 (PDT) Received: from ?IPv6:2620:15c:2c1:200:55c7:81e6:c7d8:94b? ([2620:15c:2c1:200:55c7:81e6:c7d8:94b]) by smtp.gmail.com with ESMTPSA id o35sm9719180pgm.29.2019.09.23.08.52.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 23 Sep 2019 08:52:59 -0700 (PDT) Subject: Re: [PATCH net] sch_netem: fix a divide by zero in tabledist() To: Jakub Kicinski , Eric Dumazet Cc: "David S . Miller" , netdev , Eric Dumazet , syzbot References: <20190918150539.135042-1-edumazet@google.com> <20190920191516.073d88b6@cakuba.netronome.com> From: Eric Dumazet Message-ID: <722331f3-55f8-868f-0f52-60e17e28e862@gmail.com> Date: Mon, 23 Sep 2019 08:52:58 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190920191516.073d88b6@cakuba.netronome.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 9/20/19 7:15 PM, Jakub Kicinski wrote: > On Wed, 18 Sep 2019 08:05:39 -0700, Eric Dumazet wrote: >> syzbot managed to crash the kernel in tabledist() loading >> an empty distribution table. >> >> t = dist->table[rnd % dist->size]; >> >> Simply return an error when such load is attempted. >> >> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") >> Signed-off-by: Eric Dumazet >> Reported-by: syzbot > > Applied, queued, thank you! > Note that another divide by zero seems possible in the same function, if sigma = 0x8000000 2*sigma becomes zero, and we have yet another issue in : if (dist == NULL) return ((rnd % (2 * sigma)) + mu) - sigma;