Hi Jean-Marc,
----- Original Message -----
From: "Jean-Marc Desperrier" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, 02 March, 2001 16:39
Subject: Re: What to do when there is no /dev/random ??
[...]
> I suggest the content of the stack on any architecture where there are
> asynchronous interrupts that will store content in your local stack.
> Easiest portable way to access it is to read the content of uninitialised
> variables.
Good idea. Didn't think of that one. Thanks!
> Easy to implement and not so bad if properly done (do not read a value
that is
> set by the preceeding function call, do not read a value that is too far
to be
> overwritten by asynchronous interrupts).
Hm, have to think about 'properly doing' this, though.
I guess something like this should be a reasonable start:
static void RAND_collect_from_stack(void)
{
char buffer_to_catch_interrupt_data[256+1];
/* OK, prevent compiler from nagging about 'uninitialized variable' */
interrupt_data[sizeof(buf)-1] = 0;
/*
We don't know exactly what went on before function-call-wise,
so we just take in the whole load.
*/
/*
Embedded OpenSSL: no more floating point operations!
Use fixed point instead: dot is between bit 7&8: 1.0 == (1 << 8)
*/
RAND_add(buffer_to_catch_interrupt_data, sizeof(buf)-1, 1 /* 0.0039
*/ );
}
Groetjes/Greetinx,
Ger
----------------------------------------------------------------------------
--
Ger Hobbelt a.k.a. Insh_Allah mailto:[EMAIL PROTECTED]
----------------------------------------------------------------------------
--
Peter Pan can fly when he thinks his Happy Thought.
I want to fly too.
My Happy Thought is... one part Prozac and one part LSD...
Wow! Awesome, dude!
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