Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!mtndew!friedl From: friedl@mtndew.Tustin.CA.US (Stephen J. Friedl) Newsgroups: comp.unix.internals Subject: Re: Preventing date rollback Message-ID: <588@mtndew.Tustin.CA.US> Date: 7 Dec 90 04:41:18 GMT References: Distribution: comp Organization: VSI*FAX Tech Ctr, Tustin, CA Lines: 25 In article , richard@dataspan.dataspan.UUCP (Richard "Tiger" Melville) writes: > Many of the software products our company sells rely on a licence file which > specifies the duration of time the software is licensed for. The software > then refuses to run when the period has expired. It is, however, possible > to roll back the date on a machine and fool the licence manager software. Many sites will not want to set their date back a year (messes up too many other things), but you can often do it on a per-process basis by setting a timezone with a *huge* hour offset. For instance, I can set my clock back one year by changing TZ=PST8PDT into TZ=PST8768PDT # (24 * 365) + 8 = 8768 Smart software will detect this and refuse to believe a crazy TZ like this. Steve -- Stephen J. Friedl, KA8CMY / 3B2-kind-of-guy / Tustin, CA / 3B2-kind-of-guy +1 714 544 6561 / friedl@mtndew.Tustin.CA.US / {uunet,attmail}!mtndew!friedl "If it doesn't core dump, ship it" - Gary W. Keefe, on product development