Fix CDDL inconsistencies in attStmtType and compound format #2216
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I don't think the expression `attStmtTemplate .within $$attStmtType` successfully encodes the intent "Every attestation statement format must have the above fields", for two reasons: it does not define a CDDL rule since it contains no = sign, and even if it did, the `.within` control operator would apply only to the new type defined by that rule, but not to the `attObj` type. CDDL generally makes a distinction between types and groups, and only mentions control operators applying to types, so I don't think we can apply `.within` to `$$attStmtType` directly. This is why we need to duplicate the `authData` field in `attStmtTemplate`.
This is required by the new "compound" attestation statement format.
[CDDL][1] defines that:
>A map matches a specification given as a group when the group matches
>a sequence of name/value pairs such that all of these name/value
>pairs are present in the map and the map has no name/value pair that
>is not covered by the group.
Therefore the control `.within { fmt: text .ne "compound" }` forbids any maps
that contain additional fields besides `fmt`, which is clearly not what was
intended.
[1]: https://datatracker.ietf.org/doc/html/rfc8610#section-2.1
emlun
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MasterKale,
timcappalli,
selfissued and
akshayku
emlun
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Closes #2210. Also fixes a couple of other issues I noticed while working on this:
$attStmtFormatthat (no longer?) exists, it should be$$attStmtType..within { fmt: text .ne "compound" }control onnonCompoundAttStmtinadvertently makesnonCompoundAttStmtunable to match anything, because maps are matched exhaustively (see CDDL, so the right-hand-side of.withinforbids additional fields beyondfmt.Preview | Diff