From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pablo Neira Ayuso Subject: Re: [PATCH] netfilter: don't permit unprivileged writes to global state via sysctls Date: Thu, 20 Oct 2016 20:22:24 +0200 Message-ID: <20161020182224.GA10999@salvia> References: <1474669264-3283-1-git-send-email-jann@thejh.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , Alexey Kuznetsov , James Morris , Hideaki YOSHIFUJI , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org To: Jann Horn Return-path: Content-Disposition: inline In-Reply-To: <1474669264-3283-1-git-send-email-jann@thejh.net> Sender: netfilter-devel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sat, Sep 24, 2016 at 12:21:04AM +0200, Jann Horn wrote: > This prevents the modification of nf_conntrack_max in unprivileged network > namespaces. For unprivileged network namespaces, ip_conntrack_max is kept > as a readonly sysctl in order to minimize potential compatibility issues. > > This patch should apply cleanly to the net tree. For the record: This patch looks good to me, but this legacy ip_conntrack sysctl code is now gone. I don't know what is the procedure to get this to -stable branches now that this cannot be pushed upstream. > Signed-off-by: Jann Horn > --- > net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c > index ae1a71a..a639e94 100644 > --- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c > +++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c > @@ -358,6 +358,9 @@ static int ipv4_init_net(struct net *net) > if (!in->ctl_table) > return -ENOMEM; > > + if (net->user_ns != &init_user_ns) > + in->ctl_table[0].mode = 0444; > + > in->ctl_table[0].data = &nf_conntrack_max; > in->ctl_table[1].data = &net->ct.count; > in->ctl_table[2].data = &nf_conntrack_htable_size; > -- > 2.1.4 >