vyos-op-run: T7901: skip permission checks if the user is root

[dmbaturin]

Change summary

A user with effective UID 0 is allowed do to everything, so permission checks make no sense in that case. Since root will never normally be in any operator groups, this fixes an issue with non-existent group lookup after sudo su and similar.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

Related PR(s)

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[sever-sever]

Works fine in my tests
Other errors are not related to the fix

root@r14:/home/vyos# show int
Invalid command [show int]: "int" is not a valid argument for command [show]
root@r14:/home/vyos# show interfaces
Codes: S - State, L - Link, u - Up, D - Down, A - Admin Down
Interface    IP Address         MAC                VRF        MTU  S/L    Description
-----------  -----------------  -----------------  -------  -----  -----  -------------
dum0         192.0.2.1/32       9e:a7:c9:85:fb:1d  default   1500  u/u
eth0         192.168.122.14/24  52:54:00:8d:67:6e  default   1500  u/u
eth1         10.0.0.1/30        52:54:00:f4:d5:cd  default   1500  u/u
eth2         -                  52:54:00:b5:3a:46  default   1500  u/u
eth3         10.0.3.1/30        52:54:00:6c:c4:3e  default   1500  u/u
lo           127.0.0.1/8        00:00:00:00:00:00  default  65536  u/u
             ::1/128
root@r14:/home/vyos# 
root@r14:/home/vyos# ping 127.0.0.1
Internal error: Node with type "tagNode" must not have a <virtualTagNode> child
root@r14:/home/vyos# 
root@r14:/home/vyos# exit
exit
vyos@r14:~$ ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.021 ms
^C
--- 127.0.0.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.021/0.021/0.021/0.000 ms
vyos@r14:~$ sudo su
root@r14:/home/vyos# 
root@r14:/home/vyos# 
root@r14:/home/vyos# ping 127.0.0.1
Internal error: Node with type "tagNode" must not have a <virtualTagNode> child
root@r14:/home/vyos# 
root@r14:/home/vyos# /usr/bin/ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.020 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.026 ms
^C
--- 127.0.0.1 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1042ms
rtt min/avg/max/mdev = 0.020/0.023/0.026/0.003 ms
root@r14:/home/vyos# 

[jestabro]

Logic is clear; basic tests show that the errors reported in T7901 and T7808 are resolved, other than the newly uncovered error with ping, a separate issue.