[RFC/PATCH 0/3] Add devicetree scanning for randomness

Jason Gunthorpe
2014-02-12T18:20:00Z

On Wed, Feb 12, 2014 at 12:45:54PM -0500, Jason Cooper wrote:

> The bootloader would then load this file into ram, and pass the
> address/size to the kernel either via dt, or commandline. kaslr (run in
> the decompressor) would consume some of this randomness, and then
> random.c would consume the rest in a non-crediting initialization.

Sure is a neat idea, but I think in general it would probably be smart
to include the entire FDT blob in the early random pool, that way you
get MACs and other machine unique data too.

>From there it is a small step to encourage bootloaders to include
boot-time-variable data in the DT like like 'boot time of day', 'cycle
counter', 'random blob', etc.

Then you just need the bootloader to dump the random-seed file into a
DT property.

Or have the bootloader fetch randomness from any HWRNG it has a driver
for. (eg a TPM)

Jason