Re: 2.6.12-rc3 mmap lack of consistency among runs

From: Hubert Tonneau
Date: Fri Apr 29 2005 - 08:17:16 EST

Andrew Morton wrote:
> Maybe you're being bitten by the address space randomisation.
> Try
> echo 0 > /proc/sys/kernel/randomize_va_space

Ok, it solves my issue, but:

. desabling it through 'echo 0 > /proc/sys/kernel/randomize_va_space' is not
a solution because only the application knows that it wants it to be desabled,
and the application is not root so cannot write to /proc; morever the
application can only speak for itself so desabling should be on a per process

I can hardly imagine to publish a warning in the README such as:
This software only works if your Linux kernel is configured so that
/proc/sys/kernel/randomize_va_space = 0

. second, my process restart succeeding roughly in 50% cases means that the
randomisation performed is just a toy. A virus assuming fixed memory layout
will still succeed 50% of times to install.

All in all, I'm not concerned about Linux kernel to randomise or not,
but I need to have a reliable way to request a memory region and be granted
that I can request the same one in a futur run.
What is the proper way to get such a memory area ?
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