rtnetlink: add restricted rtnl groups for ipv4 and ipv6 mroute
Add RTNLGRP_{IPV4,IPV6}_MROUTE_R as two new restricted groups for the
NETLINK_ROUTE family.
Binding to these groups specifically requires CAP_NET_ADMIN to allow
multicast of sensitive messages (e.g. mroute cache reports).
Suggested-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: Julien Gomes <julien@arista.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 3aa5784..4aefa5a 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -4218,6 +4218,18 @@
rtnl_unlock();
}
+static int rtnetlink_bind(struct net *net, int group)
+{
+ switch (group) {
+ case RTNLGRP_IPV4_MROUTE_R:
+ case RTNLGRP_IPV6_MROUTE_R:
+ if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
+ return -EPERM;
+ break;
+ }
+ return 0;
+}
+
static int rtnetlink_event(struct notifier_block *this, unsigned long event, void *ptr)
{
struct net_device *dev = netdev_notifier_info_to_dev(ptr);
@@ -4252,6 +4264,7 @@
.input = rtnetlink_rcv,
.cb_mutex = &rtnl_mutex,
.flags = NL_CFG_F_NONROOT_RECV,
+ .bind = rtnetlink_bind,
};
sk = netlink_kernel_create(net, NETLINK_ROUTE, &cfg);