Re: DRAM data persistence

On Jul 5, 4:37 am, krw <k...@xxxxxxxxxx> wrote:
In article <slrnf8pfm2.5eds.dha...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
dha...@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx says...

Nico Coesel wrote:

Any modern OS clears the memory before freeing it for use
by other tasks.

This is not correct.

This is very correct otherwise there would be a huge security hole.

Name ONE operating system that does this. Besides, if I were to write a
program for which leftover RAM (or swap) content was a security hole, I'd
clear that memory myself before releasing it, rather than relying on your
imaginary OS feature.

MVS, and I believe any other OS that is B2 rated.

Yes, I think you are right. IBM's MVT didn't and this was the source
of many security problems. This was because they assumed that
anything in memory that had a key of zero was theirs but didn't
enforce it. You could make a look alike for an OS data structure and
free it then quickly use it. This way you could fool the OS into
jumping to your code. I can imagine IBM nailing that door shut and
bricking it up.


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  • Re: DRAM data persistence
    ... program for which leftover RAM content was a security hole, ... clear that memory myself before releasing it, rather than relying on your ...
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  • Re: DRAM data persistence
    ... program for which leftover RAM (or swap) content was a security hole, ... clear that memory myself before releasing it, ...
    (sci.electronics.design)