[PATCH 0/1] ubifs: support authentication without hmac

[Alexander Dahl]

Hello Richard,

thanks for asking back.

Am Dienstag, 30. Juni 2020, 15:36:28 CEST schrieb Richard Weinberger:
> On Mon, Jun 29, 2020 at 9:11 AM Richard Weinberger <richard at nod.at> wrote:
> > U-Boot choose the UBIFS way AFAICT.
> > 
> > But if you have your own minimal loader you can read from an UBI static
> > volume with a few lines of C (~200 LoC). This is what I see/use most of
> > the time. Using static volumes in U-Boot is also possible, IIRC just use
> > "ubi read".
> > 
> > From http://www.linux-mtd.infradead.org/doc/ubi.html#L_overview:
> > """
> > There are 2 types of UBI volumes: dynamic volumes and static volumes.
> > Static volumes are read-only and their contents are protected by CRC-32
> > checksums, while dynamic volumes are read-write and the upper layers
> > (e.g., a file-system) are responsible for ensuring data integrity.
> > 
> > Static volumes are typically used for the kernel, initramfs, and dtb.
> > Larger static volumes may incur a significant penalty when opening, as
> > the CRC-32 needs to be calculated at this time. If you are looking to use
> > static volumes for anything besides the kernel, initramfs, or dtb you are
> > likely doing something wrong and would be better off using a dynamic
> > volume instead. """
> 
> Did this and Wolfgang's input help?

Yes, it did.  I see the benefits of static UBI volumes, and I wish we had 
known this for our projects like 10 years ago.  However I also appreciated 
Wolfgang's input, it's basically what we do with more recent projects.  The 
possibility to easily upgrade kernel image and/or dts speeds up development a 
lot and causes less headaches on system upgrade.

Greets
Alex