25 Dec
2024
25 Dec
'24
9:58 a.m.
On 12/24/24 21:36, jim stephens via cctalk wrote:
One thing I found and fiddled with for instance was a
utility exit in the tape subsystem library called SPIE.
Turned out I could submit a SPIE handler which could get
control when a tape fault occurred in supervisor mode.
Wasn't hard to generate a fault on the tape and get the
exit triggered.
The system programmers added code to block that after I
reported it to them.
Yup, the original OS 360 had so many security and
reliability holes you could drive 5 Queen Mary ocean liners
abreast through them. The SPIE code gave you the PSW where
the exception occurred, let you do anything you wanted, and
then let you alter the PSW as desired with no checks. This
would allow you to clear the "P" bit and return to your
program in supervisor mode. That was surely one of the
biggest security holes. You could trigger the exception
with a simple divide by zero. (SPIE stands for Specify
Program Interruption Exit.)
Jon