kern/52223: mount_portal(8) no longer works

[n54%gmx.com@localhost]

>Number:         52223
>Category:       kern
>Synopsis:       mount_portal(8) no longer works
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue May 09 11:40:00 +0000 2017
>Originator:     Kamil Rytarowski
>Release:        NetBSD 7.99.66 amd64
>Organization:
TNF
>Environment:
NetBSD compaq 7.99.66 NetBSD 7.99.66 (GENERIC) #10: Fri Mar 24 18:43:32 CET 2017  root@chieftec:/public/netbsd-root/sys/arch/amd64/compile/GENERIC amd64

Confirmed on 7.99.71.
>Description:
mount_portal(8) no longer works.

Tested file, rfilter, wfilter, tcp -- all these modes seem to be broken.
>How-To-Repeat:
# mount_portal /usr/share/examples/mount_portal/fs.1.conf /mnt/
# cat /mnt/fs/etc/rc.conf  
cat: /mnt/fs/etc/rc.conf: Operation not permitted
>Fix:
N/A