From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:43496 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752348AbeA2UEk (ORCPT ); Mon, 29 Jan 2018 15:04:40 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kevin Cernekee , Pablo Neira Ayuso , Michal Kubecek Subject: [PATCH 4.9 20/66] netfilter: nfnetlink_cthelper: Add missing permission checks Date: Mon, 29 Jan 2018 13:56:44 +0100 Message-Id: <20180129123840.892707494@linuxfoundation.org> In-Reply-To: <20180129123839.842860149@linuxfoundation.org> References: <20180129123839.842860149@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kevin Cernekee commit 4b380c42f7d00a395feede754f0bc2292eebe6e5 upstream. The capability check in nfnetlink_rcv() verifies that the caller has CAP_NET_ADMIN in the namespace that "owns" the netlink socket. However, nfnl_cthelper_list is shared by all net namespaces on the system. An unprivileged user can create user and net namespaces in which he holds CAP_NET_ADMIN to bypass the netlink_net_capable() check: $ nfct helper list nfct v1.4.4: netlink error: Operation not permitted $ vpnns -- nfct helper list { .name = ftp, .queuenum = 0, .l3protonum = 2, .l4protonum = 6, .priv_data_len = 24, .status = enabled, }; Add capable() checks in nfnetlink_cthelper, as this is cleaner than trying to generalize the solution. Signed-off-by: Kevin Cernekee Signed-off-by: Pablo Neira Ayuso Acked-by: Michal Kubecek Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nfnetlink_cthelper.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/net/netfilter/nfnetlink_cthelper.c +++ b/net/netfilter/nfnetlink_cthelper.c @@ -17,6 +17,7 @@ #include #include #include +#include #include #include @@ -392,6 +393,9 @@ static int nfnl_cthelper_new(struct net struct nfnl_cthelper *nlcth; int ret = 0; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE]) return -EINVAL; @@ -595,6 +599,9 @@ static int nfnl_cthelper_get(struct net struct nfnl_cthelper *nlcth; bool tuple_set = false; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (nlh->nlmsg_flags & NLM_F_DUMP) { struct netlink_dump_control c = { .dump = nfnl_cthelper_dump_table, @@ -661,6 +668,9 @@ static int nfnl_cthelper_del(struct net struct nfnl_cthelper *nlcth, *n; int j = 0, ret; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (tb[NFCTH_NAME]) helper_name = nla_data(tb[NFCTH_NAME]);