This is a fascinating idea, although I think conceptually it is similar to DRM where in the end it is impossible to avoid giving the user the keys needed to decrypt content. In your scenario, I cannot see a way to avoid a rogue admin gaining access to the runtime-secret (but that certainly does not mean such a way does not exist).
Rather than a technical solution, you might try and find a solution in the process you use to release? You could have multiple (at least three? Two might be enough if requiring consensus) admins sign off on a release. That way, a single rogue admin cannot approve a release. Still it is a very interesting idea and I’d love to read more thoughts on this! Cheers, Joris > On 22 Feb 2017, at 10:05, Bastian Bittorf <b...@npl.de> wrote: > > dear devs, > > I'm polishing up our work-in-progress regarding automated > firmware-upgrades in our community network and I have a concept problem: > > our images/the sha256-sum's are signed: > http://intercity-vpn.de/networks/liszt28/firmware/models/Buffalo%20WZR-HP-AG300H/testing/Standard,DSLR,fotobox,kalua/info.json > > The downloader checks against a list of signatures, where > e.g. 3 signatures must match the sha256 sum. > > There are "automated" signatures (e.g. from builbot) and manual ones, > from humans. For protecting ourselfes from bad admins, there > should be a "secret thing" which is baked into the firmware and > only seeable during runtime: this way we can prevent, that a lazy > admin "signs" a sha256 sum, without really has flashed the image > and can make sure that it really runs. > > Now the question: a secret can be e.g. > # ls -la /etc | md5sum > > This is naive, and a dumb admin can e.g. unsquashfs the > image for getting the data. are there better methods? any ideas? > > bye, bastian > > _______________________________________________ > Lede-dev mailing list > Lede-dev@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/lede-dev _______________________________________________ Lede-dev mailing list Lede-dev@lists.infradead.org http://lists.infradead.org/mailman/listinfo/lede-dev
