From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48578 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752766AbeA2UGj (ORCPT ); Mon, 29 Jan 2018 15:06:39 -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 4.4 40/74] netfilter: xt_osf: Add missing permission checks Date: Mon, 29 Jan 2018 13:56:45 +0100 Message-Id: <20180129123849.389817535@linuxfoundation.org> In-Reply-To: <20180129123847.507563674@linuxfoundation.org> References: <20180129123847.507563674@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Kevin Cernekee commit 916a27901de01446bcf57ecca4783f6cff493309 upstream. The capability check in nfnetlink_rcv() verifies that the caller has CAP_NET_ADMIN in the namespace that "owns" the netlink socket. However, xt_osf_fingers 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: vpnns -- nfnl_osf -f /tmp/pf.os vpnns -- nfnl_osf -f /tmp/pf.os -d These non-root operations successfully modify the systemwide OS fingerprint list. Add new capable() checks so that they can't. Signed-off-by: Kevin Cernekee Signed-off-by: Pablo Neira Ayuso Acked-by: Michal Kubecek Signed-off-by: Greg Kroah-Hartman --- net/netfilter/xt_osf.c | 7 +++++++ 1 file changed, 7 insertions(+) --- a/net/netfilter/xt_osf.c +++ b/net/netfilter/xt_osf.c @@ -19,6 +19,7 @@ #include #include +#include #include #include #include @@ -69,6 +70,9 @@ static int xt_osf_add_callback(struct so struct xt_osf_finger *kf = NULL, *sf; int err = 0; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!osf_attrs[OSF_ATTR_FINGER]) return -EINVAL; @@ -112,6 +116,9 @@ static int xt_osf_remove_callback(struct struct xt_osf_finger *sf; int err = -ENOENT; + if (!capable(CAP_NET_ADMIN)) + return -EPERM; + if (!osf_attrs[OSF_ATTR_FINGER]) return -EINVAL;