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=-14.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,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 6852BC433ED for ; Fri, 2 Apr 2021 17:49:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44A0D61056 for ; Fri, 2 Apr 2021 17:49:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235990AbhDBRtv (ORCPT ); Fri, 2 Apr 2021 13:49:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33168 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234275AbhDBRtu (ORCPT ); Fri, 2 Apr 2021 13:49:50 -0400 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B4D18C0613E6; Fri, 2 Apr 2021 10:49:48 -0700 (PDT) Received: by mail-wr1-x432.google.com with SMTP id i18so1871849wrm.5; Fri, 02 Apr 2021 10:49:48 -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=6/S7y9C8nRxZmjQeY8wpCEGGx7d5w2nUI9mEHAzOyr4=; b=EKJRA9qiti7P9cUGyyz4nzgoW4eR1olaGPIr8PtEys12m9EmxxXJqBe73YBwGzSwbN TqnMm1GU6uCV7ISWh57RMLiE9Ns0bhZFqdMfvBlyWc2uJSssoMYy5dJQqQG/O5jTTUSL EmppftdLqPklLWp/IQTtjH3du7sMMkpmxFUp8OsPqP4GqU6/7pxl4nxo5uMb5Hv56YKx jj+6/MIjAaAxQwSSp9q/8cKbR+b4rgDqA0vkE1lKlv/KSaowHakhJuS7DfxTXycaPSFf lspjUzd5LR5ojUcP+ZYseL07LH/jtqnI6Z6Q7PHO5BPuxJH9Z29JMCWZTwzk3dXE6kKd 2Hqw== 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=6/S7y9C8nRxZmjQeY8wpCEGGx7d5w2nUI9mEHAzOyr4=; b=aKyEqFWKDtzxl/TJgcQ+UrJrRphR33Mvnen7cU0b67l43RO/q3qeOhTryaZjA9MJiw yiuBFLEOGfpWzH+f3cOiQBj0ZujtwTggY+G4jF3EbX0yuGW+i4AqduLAgmMGcw0MXhvT 9n+zE29pGTbXNqJgA7KtIQdPnkfNRROnU3u6x4TXhmKh+ILNBkI9baZ+FKjLyGm/YYnH jLPThcoWFBkcsc8PtC4/7nCnQn8SSv5fjlNi1GBP1dxo9CKfvDk0LxMGbMFT/P6HkBkH l2L0KcOWbuLnan91dpVXUjPxETWqu7LoD+Wp4J2uMTdpcjXidgmV41Ium7c46CX4VyQv NP3g== X-Gm-Message-State: AOAM5304M45/IxK0SrqvcymoLQAx+MJxtmcgYyv16uQQlWYcim86bid/ cQigAtcFR381v8anpdxzZWAaLIkI24g= X-Google-Smtp-Source: ABdhPJw8bkMpDdw4laVwoNHLaRMSJeXL7Ze2yJGqxwMYXo9ucLuObt0MlgbVEIMpRMBhG9soE6lzvw== X-Received: by 2002:a5d:6106:: with SMTP id v6mr16696092wrt.268.1617385786821; Fri, 02 Apr 2021 10:49:46 -0700 (PDT) Received: from [192.168.1.101] ([37.166.24.151]) by smtp.gmail.com with ESMTPSA id h8sm15305784wrt.94.2021.04.02.10.49.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 02 Apr 2021 10:49:45 -0700 (PDT) Subject: Re: [PATCH] net: initialize local variables in net/ipv6/mcast.c and net/ipv4/igmp.c To: Phillip Potter , davem@davemloft.net Cc: yoshfuji@linux-ipv6.org, dsahern@kernel.org, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20210402173617.895-1-phil@philpotter.co.uk> From: Eric Dumazet Message-ID: Date: Fri, 2 Apr 2021 19:49:44 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210402173617.895-1-phil@philpotter.co.uk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 4/2/21 7:36 PM, Phillip Potter wrote: > Use memset to initialize two local buffers in net/ipv6/mcast.c, > and another in net/ipv4/igmp.c. Fixes a KMSAN found uninit-value > bug reported by syzbot at: > https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51 According to this link, the bug no longer triggers. Please explain why you think it is still there. > > Reported-by: syzbot+001516d86dbe88862cec@syzkaller.appspotmail.com > Signed-off-by: Phillip Potter > --- > net/ipv4/igmp.c | 2 ++ > net/ipv6/mcast.c | 4 ++++ > 2 files changed, 6 insertions(+) > > diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c > index 7b272bbed2b4..bc8e358a9a2a 100644 > --- a/net/ipv4/igmp.c > +++ b/net/ipv4/igmp.c > @@ -1131,6 +1131,8 @@ static void ip_mc_filter_add(struct in_device *in_dev, __be32 addr) > char buf[MAX_ADDR_LEN]; > struct net_device *dev = in_dev->dev; > > + memset(buf, 0, sizeof(buf)); > + > /* Checking for IFF_MULTICAST here is WRONG-WRONG-WRONG. > We will get multicast token leakage, when IFF_MULTICAST > is changed. This check should be done in ndo_set_rx_mode > diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c > index 6c8604390266..ad90dc28f318 100644 > --- a/net/ipv6/mcast.c > +++ b/net/ipv6/mcast.c > @@ -658,6 +658,8 @@ static void igmp6_group_added(struct ifmcaddr6 *mc) > struct net_device *dev = mc->idev->dev; > char buf[MAX_ADDR_LEN]; > > + memset(buf, 0, sizeof(buf)); > + > if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) < > IPV6_ADDR_SCOPE_LINKLOCAL) > return; > @@ -694,6 +696,8 @@ static void igmp6_group_dropped(struct ifmcaddr6 *mc) > struct net_device *dev = mc->idev->dev; > char buf[MAX_ADDR_LEN]; > > + memset(buf, 0, sizeof(buf)); > + > if (IPV6_ADDR_MC_SCOPE(&mc->mca_addr) < > IPV6_ADDR_SCOPE_LINKLOCAL) > return; >