misc/37923: krb5 ccache unlinked when using xdm and pam

[j+nbsd%2008.salmi.ch@localhost]

>Number:         37923
>Category:       misc
>Synopsis:       krb5 ccache unlinked when using xdm and pam
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 30 13:55:00 +0000 2008
>Originator:     Jukka Salmi
>Release:        NetBSD 4.99.50
>Organization:
>Environment:
System: NetBSD moray.salmi.ch 4.99.50 NetBSD 4.99.50 (GENERIC.NOACPI) #0: Mon 
Jan 28 06:08:03 CET 2008 
build%moray.salmi.ch@localhost:/b/build/nbsd/c/i386/sys/arch/i386/compile/GENERIC.NOACPI
 i386
Architecture: i386
Machine: i386
>Description:
When using Kerberos V authentication with PAM, logging in using xdm(1)
succeeds, but for some strange reason the credentials cache file is
unlinked during login, leaving you without a TGT.
However, logging in using login(1) also succeeds, but the credentials
cache is _not_ unlinked (as expected), preserving your recently acquired
TGT.

>How-To-Repeat:
On a system using krb5 authentication, log in using login(1) and run
klist(1) to see your TGT. Then log out, and log in using xdm(1), run
klist(1) and wonder why it prints

        klist: No ticket file: /tmp/krb5cc_1000

or similar. And indeed there will be no credentials cache file.

>Fix: