🚀 go-pugleaf

In article <9...@dftsrv.gsfc.nasa.gov>, fast...@dftnic.gsfc.nasa.gov (John 'Fast-Eddie' McMahon) writes:
> I worked on a VM/370 system where the student users were forced into a
> restricted shell based on EXEC programs.  This restricted shell prevented the
> major method to copy programs which was to link/access another students user
> disk and do a copy command.  However, it didn't stop anyone who knew something
> about VM/CMS, or was willing to experiment.

This reminds me. Back in the old days of VMS, you could hit ^Y if you were
really fast before it executed the login file. Here at USU, things like
checking to make certain that your account actually has money it are done
in the login file. In those days you could log in anyway by hitting ^Y before
the login file got to its first command, $SET NOCONTROLY.

One facility for which I worked did a lot of real-time device driver type
munging of the system. It was therefore important for them to be able to
easily and quickly shut down the machine. They installed an account called
SHUTDOWN that had no password. Of course, the first instruction in the 
login file was $SET NOCONTROLY. I once took advantage of this feature of
VMS to break into the machine and create myself an account which could do
various interesting things. The account that I created had no privileges,
but its UIC was [1,4]; it therefore owned all of the system files including
SYSUAF.DAT (the user authorization file).

This explains why VMS now has a flag in the UAF that can be used to 
disable ^Ys at login before executing the login command file.

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Roger Ivie

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