Hi,

On Tue Feb 04, 2025 at 21:59:24 +0200, Flavio Erlich wrote:
> Hi,
>
> According to Linux documentation, if I want to use kASLR I should add on my
> device tree, on the chosen node a kaslr-seed entry (
> https://www.kernel.org/doc/Documentation/devicetree/bindings/chosen.txt).
> I'm running uvmm and I want to use the dt-modify argument to change the
> value on dtb to a value that comes from an HW random generator at runtime.
> I have written an application which reads a random sequence from the HW.
> How can I pass the random value from that application and pass the u64
> value to the ned script which I can use as a seed?
> I can use the application exit code to read 32-bit and run it twice, but
> seems to be overkill to do that.
> I was thinking of sending a newer allocatted Dataspace to the application,
> it will fill it with random data, but I have no idea if it is possible to
> read this Dataspace and concatenate the result to the arguments to uvmm.
> Do you have any other suggestions?

Just give uvmm a 'rng' capability talking L4Re::Random protocol and it
will update the kaslr-seed value in the DT itself. For that your program
will need to implement a L4Re::Random server.



Adam