We ensure that a `rad/root` ref is included in the signed refs file
under `rad/sigrefs` for all remotes. This prevents a certain kind of
"grafting" attack where signed refs can be copied between repositories,
by having the peer sign over the identity root together with the data refs.
When verifying signed refs, we ensure that the ref is present and points
to an identity branch root that matches the repository identity containing
the signed refs.
Alternatives: lots of alternatives were considered, but this one doesn't
introduce any changes to the signing. The `rad/id/root` name was
considered but is invalid due to `rad/id`.
If a peer had created any references but was also missing the
canonical branch, the `rad id update` command will fail when adding
that peer as a delegate.
Instead, missing delegates and missing default branches are tracked
during verification. If the number of missing delegates means the
`threshold` cannot be met, then the errors are returned.
Signed-off-by: Fintan Halpenny <fintan.halpenny@gmail.com>
X-Clacks-Overhead: GNU Terry Pratchett
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Fintan Halpenny