openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

udp: only choose unbound UDP socket for multicast when not in a VRF 

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: 6da5b0f027 ("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>
This commit is contained in:
Tim Beale 2019-06-04 13:56:23 +12:00 committed by David S. Miller
parent 2b66552eb2
commit 82ba25c6de
1 changed files with 1 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/ipv4/udp.c
View File

@ -538,8 +538,7 @@ static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
(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;