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=-6.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BE045C33CB7 for ; Fri, 31 Jan 2020 23:17:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8FEC7217BA for ; Fri, 31 Jan 2020 23:17:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="PLoXMCEd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727180AbgAaXRf (ORCPT ); Fri, 31 Jan 2020 18:17:35 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:43144 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727156AbgAaXRf (ORCPT ); Fri, 31 Jan 2020 18:17:35 -0500 Received: by mail-oi1-f196.google.com with SMTP id p125so8948941oif.10; Fri, 31 Jan 2020 15:17:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lddKnZfH3lxsqX+cctMtAF3GKo7RkvSibOmZGG8SAIs=; b=PLoXMCEda9R3gUvpKaNePwsEU/qVq4fAUarhKcls49k95JxuiiKVH1X2z+Qn1pVSn7 nKtXcynoUA+ICqsCo2uQjtrZNjNJeM1fzatWmB6ncYYs8Ululfp2I1nWUNpcLaP/lANq Z6iJGNgsM8FnRszEBi4FJkRCpPr8onpI3CgLwLco8SFhyIbnIiS+K7eWtVbSTpo7kS1Y lCX3/tT37J2kMWlsvxeyxqi6D2/UnucI0HiuZ/nzA0KEME8WkSJsscKvUf46jgYL3dN/ z2NmaTiVfGrmDWLrrPrLjDhN4mhwVd04ETJrWhdqI1nY48HZD5x+sYYL3WeUpbYCENIS XpTA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lddKnZfH3lxsqX+cctMtAF3GKo7RkvSibOmZGG8SAIs=; b=Ln4MbrLUaEns8w6kFRWFVWLZ9Tkt5/3zkeTIstPg67vAR9A4AyTo36c2TLBZ5PXkcY 1o4EHS1oxYmkhljzroWD9kllYsFlU0tHqBOq6QsyU+YWPA5e5u9AugTexMMb0xJJwegh CVco2jwW9HXXoM5bvsKbjUhminIFbpCo96b3jTsGBLjOXxHK0XrLbigQzOAD1D4KWP6I y6xje+YXXjFCZnbNzKQ48UEGuAmfIxkGggtN+c+RxiaSTfcbQK1mWDCW0+RR8np+zK5h 8IBZHhJt9ngMb906pIk+Deds7kmRsaOLlYhq7C6GqFlchhKMNtknds9FlOOkjwJX5l3M wvOQ== X-Gm-Message-State: APjAAAVl95F/mo78q9KHej+ggpJ215O3vNDlBZGT9wJ12XU0HdKC/gax AN++SV1B9DDCIow7c1LiU+RPb6oTy7aNoo/VF4QAjewn X-Google-Smtp-Source: APXvYqwAFpx2ptMnWs0Qup1u24eWLus5feskSUgyrC6DdLdqvtC5Dfx5F/ZlpNNgVqkO4XsFrbGDgFtXdZ0dbS6OuaM= X-Received: by 2002:aca:1e11:: with SMTP id m17mr8062026oic.5.1580512654439; Fri, 31 Jan 2020 15:17:34 -0800 (PST) MIME-Version: 1.0 References: <20200131205216.22213-1-xiyou.wangcong@gmail.com> <20200131205216.22213-2-xiyou.wangcong@gmail.com> <20200131220856.GK795@breakpoint.cc> In-Reply-To: <20200131220856.GK795@breakpoint.cc> From: Cong Wang Date: Fri, 31 Jan 2020 15:17:23 -0800 Message-ID: Subject: Re: [Patch nf 1/3] xt_hashlimit: avoid OOM for user-controlled vmalloc To: Florian Westphal Cc: Linux Kernel Network Developers , NetFilter , syzbot , Pablo Neira Ayuso , Jozsef Kadlecsik Content-Type: text/plain; charset="UTF-8" Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jan 31, 2020 at 2:08 PM Florian Westphal wrote: > > Cong Wang wrote: > > The hashtable size could be controlled by user, so use flags > > GFP_USER | __GFP_NOWARN to avoid OOM warning triggered by user-space. > > > > Also add __GFP_NORETRY to avoid retrying, as this is just a > > best effort and the failure is already handled gracefully. > > > > Reported-and-tested-by: syzbot+adf6c6c2be1c3a718121@syzkaller.appspotmail.com > > Cc: Pablo Neira Ayuso > > Cc: Jozsef Kadlecsik > > Cc: Florian Westphal > > Signed-off-by: Cong Wang > > --- > > net/netfilter/xt_hashlimit.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c > > index bccd47cd7190..885a266d8e57 100644 > > --- a/net/netfilter/xt_hashlimit.c > > +++ b/net/netfilter/xt_hashlimit.c > > @@ -293,8 +293,9 @@ static int htable_create(struct net *net, struct hashlimit_cfg3 *cfg, > > if (size < 16) > > size = 16; > > } > > - /* FIXME: don't use vmalloc() here or anywhere else -HW */ > > - hinfo = vmalloc(struct_size(hinfo, hash, size)); > > + /* FIXME: don't use __vmalloc() here or anywhere else -HW */ > > + hinfo = __vmalloc(struct_size(hinfo, hash, size), > > + GFP_USER | __GFP_NOWARN | __GFP_NORETRY, PAGE_KERNEL); > > Rationale looks sane, wonder if it makes sense to drop Haralds comment > though, I don't see what other solution other than vmalloc could be used > here. I will remove it. Thanks.