[erlang-questions] Erlang VM: how clean is our memory?

[Angel Alvarez]

El Jueves, 28 de Abril de 2011 10:46:59 Alex Arnon escribió:
> Hi All,
> 
> We've recently been discussing the security of OS and VM stacks here, and
> several questions came up with regards to the Erlang VM. Specifically, the
> values of "new" and "old" memory.
> As an example, take the OpenBSD Unix-like OS. These guys are fanatics for
> security, and take various steps to ensure that the system is as unbreakable
> as possible, and in the event of breakage - to make life hard (if not
> impossible) for the intruder.
> This includes:
> - Randomization of integer handles, e.g. accepted socket ports.
> - Randomization of memory mapping location, e.g. DLLs (SO) will be loaded in
> random locations in memory.

I thougth that the famous kdeinit trick make kde apps inherit all kde libs at the same memory mapping to save pages

How does this stuff behave on OpenBSD?

> - Newly mapped memory pages are always zeroed before attachment to a
> process's virtual space.
> - Swap can be encrypted, or zeroed, on the fly.
> - The memory allocator also zeroes out freed space.
> 
> In the context of the Erlang BEAM VM, we're interested in the contents of
> memory. What happens, for instance, when:
> - A process is garbage collected.
> - A process is terminated.
> Are the memory locations that have been "cleaned", zeroed out? Is it is, is
> it possible to control it?
> 
> 
> Regards,
> Alex.
> 



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