Re: Shared system resources

Sure David. For simplicity of modeling here, let's assume raw database data
was encrypted and the only possibility for attacker to get something from
raw data is to go and dig into sessions leftovers. Now, with that has been
said, do you happen to know what information actually gets stored during
the session into memory, reserved by session process? I'm trying to
determine, basically, does it even worth a talk - maybe there is nothing at
all valuable.

Thanks,

Oleg

On Wed, Dec 23, 2015 at 7:41 AM, David Wilson <dw+pg(at)hmmz(dot)org> wrote:

> On Wed, Dec 23, 2015 at 07:07:31AM -0600, oleg yusim wrote:
>
> > May we run into situation, when attacker dumps memory and analyses it
> > for valuable content, instead of reserving it for own process, where
> > it would be zeroed? My understanding, it is a possibility. Does kernel
> > have any safeguard against it?
>
> Sure it might be possible, but they would not have much useful
> information about which old processes the pages belonged to, and
> besides, they could most likely simply dump memory of a connected client
> in this case, or indeed just examine the filesystem or cache to get at
> the raw PG database files.
>
> Once someone has this level of access to the system it's not really
> useful to model threats much further.
>
> One minor correction from my first mail: MAP_UNINITIALIZED is indeed
> accessible to non-root, but as George mentions only when a non-default
> kernel parameter has been enabled.
>
>
> David
>