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Subject: Re: StackGuard with ... Re: [Paper] Format bugs.
From: Gerardo Richarte (core.lists.bugtraqCORE-SDI.COM)
Date: Mon Jul 24 2000 - 12:51:43 CDT

"Greg A. Woods" wrote:
> It's not possible to do bounds checking without: a) changing the
> function calling interface so that the number of parameters, as
> well as the type of each parameter, can be passed to the function;

        You don't need the number of arguments nor their types, you
only need how much space they take from the stack (the same number
that is subtracted from stack pointer after returning from a call).
        It's true that something must be changed, but I don't think
it to be too deep, isn't there already a special treatment for
<stdarg.h>'s functions? All that needs to be added is pushing the
number of bytes args are taking from stack as first argument, and the
add some [C] code in <stdarg.h>'s functions. Am I wrong?

        In short: you don't need to know anything about types, and I'm
pretty sure that, if you are not trying to do strange things, it'll
not break any functionality.

        richie 

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