Libpam with OpenVPN on Ubuntu 18.04

Ubuntu Version: 18.04
OpenVPN Version: 2.4.4
google-authenticator-libpam Version: Ubuntu pacakge version 20170702-1 (Which appears to be created from git hash 00065df)

I'm trying to set up 2fa with OpenVPN using google authenticator. In the OpenVPN server config I have the following line:

`plugin /usr/lib/x86_64-linux-gnu/openvpn/plugins/openvpn-plugin-auth-pam.so openvpn`

Then in /etc/pam.d/openvpn I have:

`auth required /lib/x86_64-linux-gnu/security/pam_google_authenticator.so`

When I try logging into the openvpn server I see the following error in /var/auth.log:

`openvpn(pam_google_authenticator)[20005]: Failed to read "/home/david/.google_authenticator" for "david"`

Doing a ls -l on /home/david/.google_authenticator:

`-r-------- 1 david users 129 May 22 19:19 /home/david/.google_authenticator`

From doing a strace on the openvpn process, I see:

`setfsuid(1002) = 0`
`setfsuid(1002) = 1002`
`openat(AT_FDCWD, "/home/david/.google_authenticator", O_RDONLY) = -1 EACCES (Permission denied)`

Ok so for some reason due to permissions, it can't access the file even though user id 1002 corresponds to the user david.

Also I have google authenticator pam module set up with ssh. When I try connecting through SSH, it works just fine. Here's the strace from sshd:

`[pid 20034] setfsuid(1002) = 0`
`[pid 20034] setfsuid(1002) = 1002`
`[pid 20034] openat(AT_FDCWD, "/home/david/.google_authenticator", O_RDONLY) = 4`

I have no idea why the openat system call fails from the openvpn process.