Hi Daniel,

On Tue, 28 Jul 2026 at 12:53, Daniel Golle <[email protected]> wrote:
>
> On Tue, Jul 28, 2026 at 12:45:38PM -0600, Simon Glass wrote:
> > Hi Daniel,
> >
> > On 2026-07-21T02:34:47, Daniel Golle <[email protected]> wrote:
> >
> > > v3: address comments by Simon Glass
> >
> > Thanks for the rework - the doc additions in signature.rst and
> > dm-verity.rst read well, and the test fix is a good catch.
> >
> > I still think we should state the compatibility break explicitly
> > somehow: because U-Boot rebuilds the node list rather than trusting
> > hashed-nodes, an image signed by an older mkimage that carries a
> > dm-verity subnode stops verifying under this fix, and an image signed
> > by the new mkimage does not verify on an older U-Boot.
> >
> > The new language in dm-verity.rst documents the security property (the
> > roothash can no longer be swapped out), but it doesn't warn that
> > deployed images must be re-signed after upgrading and that mixed
> > old/new fleets need care.
> >
> > The break is unavoidable I think and I may be overthinking all this,
> > but it would be nice to avoid people getting confused.
>
> Technically you are right, there could be, but I strongly believe
> there aren't any "deployments" of this right now.
>
> The whole mechanism is built in order to be deployed as part of the
> **upcoming** OpenWrt bootstd method. As of today, there aren't
> currently any deployments using dm-verity on OpenWrt with this
> mechanism (apart from some boards on my desk at least, and people
> who have tried the PoC[1] -- which is/was a PoC and obviously subject
> to changes as part of upstream review and standartization)

OK I see...and you would know :-) So that's fine, thanks.

Regards,
Simon

>
> [1]: https://github.com/openwrt/openwrt/pull/22177

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