From: Tim Beale timbeale@catalyst.net.nz
[ Upstream commit 82ba25c6de200d7a9e9c970c998cdd6dfa8637ae ]
By default, packets received in another VRF should not be passed to an unbound socket in the default VRF. This patch updates the IPv4 UDP multicast logic to match the unicast VRF logic (in compute_score()), as well as the IPv6 mcast logic (in __udp_v6_is_mcast_sock()).
The particular case I noticed was DHCP discover packets going to the 255.255.255.255 address, which are handled by __udp4_lib_mcast_deliver(). The previous code meant that running multiple different DHCP server or relay agent instances across VRFs did not work correctly - any server/relay agent in the default VRF received DHCP discover packets for all other VRFs.
Fixes: 6da5b0f027a8 ("net: ensure unbound datagram socket to be chosen when not in a VRF") Signed-off-by: Tim Beale timbeale@catalyst.net.nz Reviewed-by: David Ahern dsahern@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/udp.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -538,8 +538,7 @@ static inline bool __udp_is_mcast_sock(s (inet->inet_dport != rmt_port && inet->inet_dport) || (inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) || ipv6_only_sock(sk) || - (sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif && - sk->sk_bound_dev_if != sdif)) + !udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if, dif, sdif)) return false; if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif)) return false;