From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932332AbdL1RSj (ORCPT ); Thu, 28 Dec 2017 12:18:39 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:59095 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754205AbdL1ROP (ORCPT ); Thu, 28 Dec 2017 12:14:15 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Kevin Cernekee" , "Pablo Neira Ayuso" Date: Thu, 28 Dec 2017 17:05:44 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 188/204] netfilter: nfnetlink_cthelper: Add missing permission checks In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.52-rc1 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 Signed-off-by: Ben Hutchings --- 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 @@ -295,6 +296,9 @@ nfnl_cthelper_new(struct sock *nfnl, str struct nf_conntrack_tuple tuple; int ret = 0, i; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!tb[NFCTH_NAME] || !tb[NFCTH_TUPLE]) return -EINVAL; @@ -509,6 +513,9 @@ nfnl_cthelper_get(struct sock *nfnl, str struct nf_conntrack_tuple tuple; 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, @@ -581,6 +588,9 @@ nfnl_cthelper_del(struct sock *nfnl, str bool tuple_set = false, found = false; int i, j = 0, ret; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (tb[NFCTH_NAME]) helper_name = nla_data(tb[NFCTH_NAME]);