From 8b7c36d810c61ab16997f4387fc16291410700f8 Mon Sep 17 00:00:00 2001 From: Pablo Neira Date: Thu, 29 Jan 2015 10:51:53 +0100 Subject: [PATCH] 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 97840cb ("netfilter: nfnetlink: fix insufficient validation in nfnetlink_bind") when binding to bitmask (1 << 0) in ctnetlink. Reported-by: Andre Tomt Reported-by: Ivan Delalande Signed-off-by: Pablo Neira Ayuso Signed-off-by: David S. Miller --- net/netlink/af_netlink.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 02fdde28dada..75532efa51cd 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -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); -- 2.20.1