A flaw in the protection system of many operating systems is argument passing. Often, a common shared stack is used by all nested routines for arguments as well as for the remainder of the context of each calling process. (a) Explain what vulnerabilities this flaw presents. (b) Explain how the flaw can be controlled. The shared stack is still to be used for passing arguments and storing context

What will be an ideal response?

One
difficulty
is
that
any
routine
can
be
faulty:
routine
A
puts
an
incorrect
value
on
the
stack
and
B
retrieves
it,
not
knowing
it
is
faulty.
Routine
B
can
be
self-­?defensive,
checking
the
reasonableness
of
the
value.
Obviously,
without
duplicating
the
work
of
A,
B
cannot
determine
whether
the
value
is
exactly
right.
A
second
difficulty
is
stack
depth:
any
routine
can
use
the
entire
stack.
A
third
difficulty
is
that
any
routine
can
modify
results
of
any
other
routine:
routine
A
puts
a
value
on
the
stack,
and
routine
B
subsequently
changes
that
value
to
anything.