Re: nft ingress won't work on wireless ?

[sean darcy <seandarcy2@gmail.com>]

On 3/9/20 3:50 PM, Pablo Neira Ayuso wrote:
> On Mon, Mar 09, 2020 at 09:36:40AM -0400, sean darcy wrote:
>> Fedora 31. nftables-0.9.1-3.fc31.x86_64
>>
>> The same ingress rule works on the ethernet port, but not on wireless.
>>
>> This works:
>>
>>
>> cat  ipv4-netdev-asterisk
>> # /opt/nftables/ipv4-filter-asterisk
> 
> flush ruleset is fine here? More comments below.
> 
>> include "/opt/nftables/whitelist1"
>> include "/opt/nftables/ip.blacklist1"
>>
>> table netdev netdev1 {
>>         set whitelist {
>>                  type ipv4_addr
>>                  flags interval
>>                  auto-merge
>>                  elements = $whitelist_ips
>>          }
>>
>>          set blacklist {
>>                  type ipv4_addr
>>                  flags interval
>>                  auto-merge
>>                  elements = $blacklist_ips
>>          }
>>
>>          chain ingress1 {
>> 		type filter hook ingress device enp5s0 priority 0; policy accept;
>>                  udp dport { 6000-31000 } accept comment  rtp_ports
>>                  #accept whitelist
>>                  ip saddr @whitelist accept
>>                  tcp dport { 3478, 5349, 554, 5222, 5269, 19294 } counter
>> accept comment "stun stun-tls rtsp and gv"
>>                  udp dport { 3478, 4893, 19295, 19302 } counter accept
>> comment "stun and gv"
>>                  #drop blacklist
>>                  ip saddr @blacklist counter drop
>>          }
>> }
>>
>>
>> But if I change the device in the ingress1 chain to wlp4s0, which exists:
>>
>>   ifconfig | grep -A 1 wlp4s0
>> wlp4s0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
>>          inet 10.0.0.61  netmask 255.255.255.0  broadcast 10.0.0.255
>>
>> it fails.
>>
>> nft[4158]: In file included from /opt/nftables/whitelist1:39:2-39:
>> nft[4158]:                  from
>> /opt/nftables/ipv4-netdev-asterisk-wlp4s0:6:1-35:
>> nft[4158]:                  from /etc/sysconfig/nftables.conf:17:1-52:
>> nft[4158]: /opt/nftables/ip.blacklist1:1124:15-22: Error: Could not process
>> rule: Device or resource busy
>> systemd[1]: nftables.service: Main process exited, code=exited,
>> status=1/FAILURE
>>
>> Just to repeat: the only change is the device. The other files are all the
>> same.
> 
> Are you re-using your existing 'ingress1' chain?
> 
> I mean:
> 
> # nft add table netdev x
> # nft add chain netdev x x { type filter hook ingress device eth0 priority 0\; }
> # nft add chain netdev x x { type filter hook ingress device wlan0 priority 0\; }
> Error: Could not process rule: Device or resource busy
> add chain netdev x x { type filter hook ingress device wlan0 priority 0; }
> 
> If you try to update the chain 'x' to use device 'wlan0' (different
> device), then nft reports that this chain is already busy.
> 

I'm not using nft from the command line. I'm restarting nft altogether 
using systemd.

systemctl stop nftables
[change the device in ingress1]
systemctl start nftables

cat /usr/lib/systemd/system/nftables.service
[Unit]
Description=Netfilter Tables
Documentation=man:nft(8)
Wants=network-pre.target
Before=network-pre.target

[Service]
Type=oneshot
ProtectSystem=full
ProtectHome=true
ExecStart=/sbin/nft -f /etc/sysconfig/nftables.conf
ExecReload=/sbin/nft 'flush ruleset; include 
"/etc/sysconfig/nftables.conf";'
ExecStop=/sbin/nft flush ruleset
RemainAfterExit=yes

[Install]
WantedBy=multi-user.target


sean