Insecure /tmp handling in isdnlog

[dentoir <edtx xs4all nl>]

The isdnlog program (provided by isdn4k-utils.tar.gz) creates a
root-owned temp file called /tmp/isdnctrl (or /tmp/isdnctrl0) and
no checking for symbolic links is done. The file is opened append only,
a user can make a symbolic from /tmp/isdnctrl to any file and mess
things up.

example: ln -s /var/spool/mail/root /tmp/isdnctrl

-- dentoir
Fart Foundation
Security through immaturity