Re: Tagged memory (was Re: Memory Upgrade)

["Ed Fishel" <edfishel@xxxxxxxxxx>]

Ken,

>>If an untrusted *person* has the system authorities necessary to change
programs in this way, then you have a lot worse things to worry about than
programs being modified to bypass tag checking, and should delete the
untrusted person!<<

I agree with you, but please do not forget to think about patched programs
that come from other sources. They could be in products you have purchased
or evaluated. They could come from something someone asked your operator to
restore onto the system. I believe that the most common form of a patched
program is one to make it run in system state. Can we be sure that these
patched programs have not also been patched to manufacture pointers. The
safest thing to do with something that you think may have been patched is
to retranslate or delete it. (Retranslating it will change it to user
state.) On the other hand, if you know and trust the source of the patched
programs on your system, then go ahead and use them.

Ed Fishel,
edfishel@US.IBM.COM