Re: [PATCH v4 2/3] fdt: add support for rng-seed

Hsin-Yi Wang
2019-05-21T04:10:19Z

On Mon, May 20, 2019 at 7:54 AM Nicolas Boichat <drinkcat@chromium.org> wrote:

> Alphabetical order.
Original headers are not sorted, should I sort them here?
>

>
> I'm a little bit concerned about this, as we really want the rng-seed
> value to be wiped, and not kept in memory (even if it's hard to
> access).
>
> IIUC, fdt_delprop splices the device tree, so it'll override
> "rng-seed" property with whatever device tree entries follow it.
> However, if rng-seed is the last property (or if the entries that
> follow are smaller than rng-seed), the seed will stay in memory (or
> part of it).
>
> fdt_nop_property in v2 would erase it for sure. I don't know if there
> is a way to make sure that rng-seed is removed for good while still
> deleting the property (maybe modify fdt_splice_ to do a memset(.., 0)
> of the moved chunk?).
>
So maybe we can use fdt_nop_property() back?