From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 35E3921105; Thu, 15 Aug 2024 02:51:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723690307; cv=none; b=uHi+WRTTcwhp6UaDCesZFLgp1kh9b2sK9IyGgHJUgBGcrJJDR559bepLzeeDfl3QjgOedSbTqWNv+qmEEUbNaIYqPhXLtbOD8Day3tcGW9dc0rWO3MRMMp0t/mT6gF4kmO6VlRQ8vLd245ApIUTabqe48mszWgVsxwUomRO9HLc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723690307; c=relaxed/simple; bh=XB/OFRNrquH4mpAQclpCYONQ3pgQikjiRXZkuOQFGbY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qFIIxuR/nJzpZ+g4hiWgWEjy/SBKFWsLl0tFJx1qhGTi9zz8oNlHJ2I16vmjOvv/jSkmILrJoSqOFMzl8eyC3zYegPLuFOSHBr/uMKwA7tzTVISVc/lQj4/Q8A74+MSXIvmn1k+6d07xvOi43dIhZkRgwXKPg1CgnChnHiCHWRQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=gzMr9WFg; arc=none smtp.client-ip=115.124.30.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="gzMr9WFg" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1723690296; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=UT+txWt3od0RrNF4QQo+/QHyhZ0lGG/Ah9rRkU+1xw0=; b=gzMr9WFgES9x9PlGozMcMstCl9PeCHhCgJy4hrQU9LSow0qKN7EgiphrR53+/DqYm2Fy9kWfHxlvjXtty7LtsOwbIw7H0yy8gHpsR+jFypg7vArV7/04E5VKGU1h5lVEPq/KTZRWCQGu8PXfoHBTZ1FzPCUjrwSrgNwrTvDK/rA= Received: from 30.32.126.52(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0WCv-Oun_1723690294) by smtp.aliyun-inc.com; Thu, 15 Aug 2024 10:51:35 +0800 Message-ID: <9db86945-c889-4c0f-adcf-119a9cbeb0cc@linux.alibaba.com> Date: Thu, 15 Aug 2024 10:51:33 +0800 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net,v4] net/smc: prevent NULL pointer dereference in txopt_get To: Jeongjun Park , wintera@linux.ibm.com, gbayer@linux.ibm.com, guwen@linux.alibaba.com, jaka@linux.ibm.com, tonylu@linux.alibaba.com, wenjia@linux.ibm.com Cc: davem@davemloft.net, dust.li@linux.alibaba.com, edumazet@google.com, kuba@kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org, pabeni@redhat.com References: <64c2d755-eb4b-42fa-befb-c4afd7e95f03@linux.ibm.com> <20240814150558.46178-1-aha310510@gmail.com> Content-Language: en-US From: "D. Wythe" In-Reply-To: <20240814150558.46178-1-aha310510@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 8/14/24 11:05 PM, Jeongjun Park wrote: > Alexandra Winter wrote: >> On 14.08.24 15:11, D. Wythe wrote: >>> struct smc_sock { /* smc sock container */ >>> - struct sock sk; >>> + union { >>> + struct sock sk; >>> + struct inet_sock inet; >>> + }; >> >> I don't see a path where this breaks, but it looks risky to me. >> Is an smc_sock always an inet_sock as well? Then can't you go with smc_sock->inet_sock->sk ? >> Or only in the IPPROTO SMC case, and in the AF_SMC case it is not an inet_sock? There is no smc_sock->inet_sock->sk before. And this part here was to make smc_sock also be an inet_sock. For IPPROTO_SMC, smc_sock should be an inet_sock, but it is not before. So, the initialization of certain fields in smc_sock(for example, clcsk) will overwrite modifications made to the inet_sock part in inet(6)_create. For AF_SMC,  the only problem is that  some space will be wasted. Since AF_SMC don't care the inet_sock part. However, make the use of sock by AF_SMC and IPPROTO_SMC separately for the sake of avoid wasting some space is a little bit extreme. > hmm... then how about changing it to something like this? > > @@ -283,7 +283,7 @@ struct smc_connection { > }; > > struct smc_sock { /* smc sock container */ > - struct sock sk; > + struct inet_sock inet; > struct socket *clcsock; /* internal tcp socket */ > void (*clcsk_state_change)(struct sock *sk); Don't. > /* original stat_change fct. */ > @@ -327,7 +327,7 @@ struct smc_sock { /* smc sock container */ > * */ > }; > > -#define smc_sk(ptr) container_of_const(ptr, struct smc_sock, sk) > +#define smc_sk(ptr) container_of_const(ptr, struct smc_sock, inet.sk) > > static inline void smc_init_saved_callbacks(struct smc_sock *smc) > { > > It is definitely not normal to make the first member of smc_sock as sock. > > Therefore, I think it would be appropriate to modify it to use inet_sock > as the first member like other protocols (sctp, dccp) and access sk in a > way like &smc->inet.sk. > > Although this fix would require more code changes, we tested the bug and > confirmed that it was not triggered and the functionality was working > normally. > > What do you think? > > Regards, > Jeongjun Park