Hi Jan, On Wed, 10 Nov 2021 at 13:49, Jan Kiszka <jan.kis...@siemens.com> wrote: > > On 10.11.21 08:20, Jan Kiszka wrote: > > On 10.11.21 07:55, Jan Kiszka wrote: > >> On 10.11.21 01:58, Simon Glass wrote: > >>> Hi, > >>> > >>> On Tue, 9 Nov 2021 at 02:17, Jan Kiszka <jan.kis...@siemens.com> wrote: > >>>> > >>>> On 08.11.21 16:28, Roman Kopytin wrote: > >>>>> In order to reduce the coupling between building the kernel and > >>>>> U-Boot, I'd like a tool that can add a public key to U-Boot's dtb > >>>>> without simultaneously signing a FIT image. That tool doesn't seem to > >>>>> exist, so I stole the necessary pieces from mkimage et al and put it > >>>>> in a single .c file. > >>>>> > >>>>> I'm still working on the details of my proposed "require just k out > >>>>> these n required keys" and how it should be implemented, but it will > >>>>> probably involve teaching this tool a bunch of new options. These > >>>>> patches are not necessarily ready for inclusion (unless someone else > >>>>> finds fdt_add_pubkey useful as is), but I thought I might as well send > >>>>> it out for early comments. > >>>> > >>>> I'd also like to see the usage of this hooked into the build process. > >>>> > >>>> And to my understanding of [1], that approach will provide a feature > >>>> that permits hooking with the build but would expect the key as dtsi > >>>> fragment. Can we consolidate the approaches? > >>>> > >>>> My current vision of a user interface would be a Kconfig option that > >>>> takes a list of key files to be injected. Maybe make that three lists, > >>>> one for "required=image", one for "required=conf", and one for optional > >>>> keys (if that has a use case in practice, no idea). > >>> > >>> Also please take a look at binman which is designed to handle create > >>> (or later updating from Yocto) the devicetree or firmware image. > >>> > >> > >> Yes, binman is another problem area, but not for the public key > >> injection, rather for permitting to sign fit images that are described > >> for binman (rather than for mkimage). I'm currently back to dd for > >> signing the U-Boot container in > >> arch/arm/dts/k3-am65-iot2050-boot-image.dtsi, or I would have to split > >> that FIT image description from that file - both not optimal. > > > > OK, this can already be optimized with "binman replace" - once I > > understood where fdtmap can go and where not. Why no support for using > > map files? > > > > Well, too quick: "binman replace" writes everything into a temporary > directory, including the updated image - and then deletes this directory > on exit. So the original image will not be updated, and the update is lost. > > I tried to quickly fix it by adding a rename before FinaliseOutputDir, > but it feels like I'm working against the design of the internal > interfaces here.
If you want to see how things work, check out ftest.py which has all the tests. If there is a test for it, it probably works. If not, it might not. Regards, SImon