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=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT 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 4C440C4646D for ; Wed, 8 Aug 2018 08:25:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A7A8216F6 for ; Wed, 8 Aug 2018 08:25:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0A7A8216F6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727266AbeHHKnv (ORCPT ); Wed, 8 Aug 2018 06:43:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:32806 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726979AbeHHKnu (ORCPT ); Wed, 8 Aug 2018 06:43:50 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 5E8FDAD49; Wed, 8 Aug 2018 08:25:12 +0000 (UTC) Date: Wed, 8 Aug 2018 10:25:11 +0200 From: Michal Hocko To: Vlastimil Babka Cc: Florian Westphal , Georgi Nikolov , Andrew Morton , "David S. Miller" , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] netfilter/x_tables: do not fail xt_alloc_table_info too easilly Message-ID: <20180808082511.GF27972@dhcp22.suse.cz> References: <20180807195400.23687-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 08-08-18 10:16:01, Vlastimil Babka wrote: > On 08/07/2018 09:54 PM, Michal Hocko wrote: > > From: Michal Hocko > > > > eacd86ca3b03 ("net/netfilter/x_tables.c: use kvmalloc() > > in xt_alloc_table_info()") has unintentionally fortified > > xt_alloc_table_info allocation when __GFP_RETRY has been dropped from > > the vmalloc fallback. Later on there was a syzbot report that this > > can lead to OOM killer invocations when tables are too large and > > 0537250fdc6c ("netfilter: x_tables: make allocation less aggressive") > > has been merged to restore the original behavior. Georgi Nikolov however > > noticed that he is not able to install his iptables anymore so this can > > be seen as a regression. > > > > The primary argument for 0537250fdc6c was that this allocation path > > shouldn't really trigger the OOM killer and kill innocent tasks. On the > > other hand the interface requires root and as such should allow what the > > admin asks for. Root inside a namespaces makes this more complicated > > because those might be not trusted in general. If they are not then such > > namespaces should be restricted anyway. Therefore drop the __GFP_NORETRY > > and replace it by __GFP_ACCOUNT to enfore memcg constrains on it. > > > > Fixes: 0537250fdc6c ("netfilter: x_tables: make allocation less aggressive") > > Reported-by: Georgi Nikolov > > Suggested-by: Vlastimil Babka > > Acked-by: Florian Westphal > > Signed-off-by: Michal Hocko > > Acked-by: Vlastimil Babka Thanks! > IIRC According to Florian there are more places like this in the > netfilter code? Well, this is more for netfilter guys. I can only give a general guidance that generally untrusted allocations triggered from userspace should be a subject of kmem accounting. -- Michal Hocko SUSE Labs