From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: Re: [PATCH v2] netfilter: properly initialize xt_table_info structure Date: Thu, 31 May 2018 10:51:16 +0200 Message-ID: <20180531085116.GA17729@kroah.com> References: <20180517085951.2wxvcg5herkjaxda@unicorn.suse.cz> <20180517093410.GB17597@kroah.com> <20180517100908.GA3150@kroah.com> <20180517132012.GA29160@kroah.com> <20180518092756.odlyvxcpgbuistqq@breakpoint.cc> <20180526145449.GA10379@kroah.com> <20180531082436.ffd6gkbuk6xpm47y@breakpoint.cc> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: peter pi , Jan Engelhardt , Eric Dumazet , Greg Hackmann , Pablo Neira Ayuso , Jozsef Kadlecsik , Michal Kubecek , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org To: Florian Westphal Return-path: Content-Disposition: inline In-Reply-To: <20180531082436.ffd6gkbuk6xpm47y@breakpoint.cc> Sender: netdev-owner@vger.kernel.org List-Id: netfilter-devel.vger.kernel.org On Thu, May 31, 2018 at 10:24:36AM +0200, Florian Westphal wrote: > peter pi wrote: > > Hi Greg, I applied this patch on 4.4 and tested it on my Pixel 2, it seems > > the problem still exists, > > What is the problem exactly? The problem is that kernel data is being sent to userspace due to an uncleared buffer that was allocated and then copied to userspace. This can be reproduced by dumping the current set of iptables rules. Peter had an example reproducing script that he used to specifically show this. Peter, can you provide that? I thought that initializing this buffer to zero would solve the problem, but I guess I cleared the wrong buffer :( thanks, greg k-h