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? Jan > > And another area: Trust centers that perform the signing (and only that) > usually do not support random formats and workflows but just few common > ones, e.g. x509. It would be nice to have a way to route out the payload > (hashes etc.) that mkimage would sign, ideally into a standard signing > request, and permit to inject the resulting signature at the right > places into the FIT image. > > But one after the other. > > Jan > -- Siemens AG, T RDA IOT Corporate Competence Center Embedded Linux
