Rootless VPN-client broken

[ersonp]

Describe the bug
When a visor is started as non-root and the vpn-client is given permission via sudo setcap 'cap_net_admin+p' ./apps/vpn-client starting and stopping the vpn-client gives RTNETLINK answers: Operation not permitted error every second try. And works with no issues half the time.

Environment information:

• OS: e.g. Linux
• Platform: Linux 5.13.0-41-generic x86_64

Steps to Reproduce
Steps to reproduce the behavior:

1. Run sudo setcap 'cap_net_admin+p' ./apps/vpn-client
2. Start Visor ./skywire-visor -c skywire-config.json
3. Start and stop vpn-client multiple times
4. See error

Actual behavior
on vpn-client start

[2022-05-13T11:49:28+05:30] INFO [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Request processed. _elapsed="1.250974264s" _method="Dial" _received="11:49AM" input=022cfaa6aeda9a332d70309424d03c0880d82e3cd104201819d91cc4ad59dd1552:44 output=&{ConnID:2 LocalPort:49154}
[2022-05-13T11:49:28+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Dialed 022cfaa6aeda9a332d70309424d03c0880d82e3cd104201819d91cc4ad59dd1552:44
[2022-05-13T11:49:28+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Sending client hello: {[192.168.0.116 172.17.0.1 175.0.0.1 174.0.0.1 192.168.0.1] }
2022/05/13 11:49:29 [erson-69/ah1iSB2tme-000009] "GET http://localhost:8000/api/visors/021b09a8563898b6299dba3c90067c2a0fce77e07b52a5ce7f4035321842c97955/summary HTTP/1.1" from [::1]:34390 - 200 3286B in 2.316357ms
2022/05/13 11:49:29 [erson-69/ah1iSB2tme-000010] "GET http://localhost:8000/api/visors/021b09a8563898b6299dba3c90067c2a0fce77e07b52a5ce7f4035321842c97955/apps/vpn-client/connections HTTP/1.1" from [::1]:34392 - 200 125B in 164.211µs
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Got server hello: {OK 172.16.0.4 172.16.0.3}Performed handshake with 022cfaa6aeda9a332d70309424d03c0880d82e3cd104201819d91cc4ad59dd1552:44
[2022-05-13T11:49:29+05:30] INFO (STDERR) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: RTNETLINK answers: Operation not permitted
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Local TUN IP: 172.16.0.4
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Local TUN gateway: 172.16.0.3
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: CREATING TUN INTERFACE
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Allocated TUN utun4: <nil>
[2022-05-13T11:49:29+05:30] INFO (STDOUT) [proc:vpn-client:b3cd239e8d494e00b2e1870a2f157e99]: Setting up TUN device with: 172.16.0.4 and Gateway 172.16.0.3error serving app conn: error setting up TUN utun4: error setting gateway for interface: error running command "ip r add 172.16.0.4 via 172.16.0.3": exit status 2: RTNETLINK answers: Operation not permitted

on vpn-clieent stop

[2022-05-13T11:38:15+05:30] INFO (STDERR) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: time="2022-05-13T11:38:15+05:30" level=info msg="Closing TUN"
[2022-05-13T11:38:15+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Error resending traffic from TUN utun4 to VPN server: io: read/write on closed pipe
[2022-05-13T11:38:16+05:30] INFO (STDERR) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: RTNETLINK answers: Operation not permitted
2022/05/13 11:38:16 [erson-69/ia4Tz9utDB-000490] "PUT http://localhost:8000/api/visors/021b09a8563898b6299dba3c90067c2a0fce77e07b52a5ce7f4035321842c97955/apps/vpn-client HTTP/1.1" from [::1]:34362 - 200 175B in 1.022295419s
2022/05/13 11:38:16 [erson-69/ia4Tz9utDB-000491] "GET http://localhost:8000/api/visors/021b09a8563898b6299dba3c90067c2a0fce77e07b52a5ce7f4035321842c97955/summary HTTP/1.1" from [::1]:34364 - 200 2159B in 2.304324ms
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Error resending traffic from VPN server to TUN utun4: read tun: file already closed
[2022-05-13T11:38:16+05:30] INFO (STDERR) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: RTNETLINK answers: Operation not permitted
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 192.53.112.166
[2022-05-13T11:38:16+05:30] INFO (STDERR) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: 2022/05/13 11:38:15 rpc.Serve: accept:accept tcp 127.0.0.1:35061: use of closed network connection
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Error removing direct route to 192.53.112.166: error running command "ip r del 192.53.112.166/32 via 192.168.0.1": exit status 2: RTNETLINK answers: Operation not permitted
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]:
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 192.53.112.61
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Error removing direct route to 192.53.112.61: error running command "ip r del 192.53.112.61/32 via 192.168.0.1": exit status 2: RTNETLINK answers: Operation not permitted
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]:
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 192.53.112.183
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 192.53.112.186
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 194.5.192.160
[2022-05-13T11:38:16+05:30] INFO (STDOUT) [proc:vpn-client:a9ff9c40ed2f426f8da9115eccea4ee1]: Removing direct route to 139.162.141.220

[ersonp]

This works

sudo chown root ./apps/vpn-client
sudo chmod 4755 ./apps/vpn-client

[mrpalide]

Actually same situation reported here as bug, and they decided to solve this by root access to process, same as we do with

sudo chown root ./apps/vpn-client
sudo chmod 4755 ./apps/vpn-client

So, because its bug in fact, we can do same solution and close this issue.