On Mon, Nov 9, 2015 at 1:07 PM, Laura Abbott <laura@labbott.name> wrote:

I took a look at something closely related sometime ago[1] for
ARM DT based targets. The stack canary was always the same because
it was early enough no entropy was being added and there's no standard
RNG. This series proposed allowing entropy to be read out of the DT.
This still relied on reliable entropy being added to the DT somehow.
Ultimately, I never followed up and this still seems to be an issue.

Yeah this is something that has been bothering me for at least a year or two.

I've brought it up with Grant Likely, hoping that maybe this was something

Linaro could perhaps focus on, but both he and I have just not had the time

to follow up.

We really really need a standard way to pass entropy from the bootloader

into the random driver, for each architecture, and then each boot loader

needs to fetch whatever entropy it can, which may be SoC or architecture

specific. Or someone needs to beat up on the ARM consortium to guarantee

HWRNG with a standard interface.

It could be via the device tree, or via a fixed memory segment, such as how the

boot command line is passed from the bootloader to the kernel. I can help

provide a design and consultation/advice. But I have zero time to do the

implementation, especially on the ARM architecture (where I lack expertise and

sample hardware).

-- Ted