Commit 8b7c36d8 authored Jan 29, 2015 by Pablo Neira Committed by David S. Miller Jan 30, 2015

netlink: fix wrong subscription bitmask to group mapping in



The subscription bitmask passed via struct sockaddr_nl is converted to
the group number when calling the netlink_bind() and netlink_unbind()
callbacks.

The conversion is however incorrect since bitmask (1 << 0) needs to be
mapped to group number 1. Note that you cannot specify the group number 0
(usually known as _NONE) from setsockopt() using NETLINK_ADD_MEMBERSHIP
since this is rejected through -EINVAL.

This problem became noticeable since 97840cb6 ("netfilter: nfnetlink:
fix insufficient validation in nfnetlink_bind") when binding to bitmask
(1 << 0) in ctnetlink.

Reported-by: Andre Tomt <andre@tomt.net>
Reported-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 3cdaa5be

net/netlink/af_netlink.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -1438,7 +1438,7 @@ static void netlink_undo_bind(int group, long unsigned int groups,

		for (undo = 0; undo < group; undo++)
		if (test_bit(undo, &groups))
		nlk->netlink_unbind(sock_net(sk), undo);
		nlk->netlink_unbind(sock_net(sk), undo + 1);
		}

		static int netlink_bind(struct socket sock, struct sockaddr addr,
		@@ -1476,7 +1476,7 @@ static int netlink_bind(struct socket sock, struct sockaddr addr,
		for (group = 0; group < nlk->ngroups; group++) {
		if (!test_bit(group, &groups))
		continue;
		err = nlk->netlink_bind(net, group);
		err = nlk->netlink_bind(net, group + 1);
		if (!err)
		continue;
		netlink_undo_bind(group, groups, sk);