lib/52297: lib/libc/gen/setdomainname_test changes the nisdomain and fails to clean up

[asomers%freebsd.org@localhost]

>Number:         52297
>Category:       lib
>Synopsis:       lib/libc/gen/setdomainname_test changes the nisdomain and fails to clean up
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jun 14 00:00:00 +0000 2017
>Originator:     Alan Somers
>Release:        
>Organization:
>Environment:
>Description:
I discovered this problem in FreeBSD via the ATF tests imported from NetBSD, and from inspection I can see that the bug affects NetBSD too.

If you run either setdomainname_test:setdomainname_limit or setdomainname_test:setdomainname_basic, it will change the system's nisdomain and fail to clean it up.  The former leave the nisdomain blank, while the latter sets it to a bunch of dashes.  This is a problem, because if the tests are run on a system that uses NIS, logins will become impossible.

The bug affects both 12.0-CURRENT and 11.1-BETA1

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219967
>How-To-Repeat:
On an nis client, run these three commands.  The output of the third should equal the first, but it doesn't.

[alans@stealthy /usr/tests/lib/libc/gen]$ domainname 
eng-nis2
[alans@stealthy /usr/tests/lib/libc/gen]$ sudo kyua debug setdomainname_test:setdomainname_basic
setdomainname_test:setdomainname_basic  ->  passed
[alans@stealthy /usr/tests/lib/libc/gen]$ domainname 
--------------------------------------------------------------------

>Fix:
https://reviews.freebsd.org/D11188