add a profile flags field

Fix #12

Signed-off-by: Thomas Fossati <[email protected]>

cddl/ex1.diag

@@ -16,5 +16,6 @@
       1ca1ec',
     h'4277bb97ba7b51577a0d38151d3e08b40bdf946753f5b5bdeb814d6ff5
       7a8a5e'
-  ]
+  ],
+  / profile-flags / 4: h'00000101'
 }

cddl/ex2.diag

@@ -0,0 +1,15 @@
+{
+  / id / 1: [
+    / name / "boot loader X",
+    / version / [
+      "1.2.3rc2",
+      16384 / semver /
+    ]
+  ],
+  / measurement / 2: [
+    / alg / "sha-256",
+    / val / h'3996003d486fb91ffb056f7d03f2b2992b215b31dbe7af4b37
+              3431fc7d319da3'
+  ],
+  / profile-flags / 4: h'00000101'
+}

cddl/mc.cddl

@@ -4,4 +4,5 @@ measured-component = {
   &(id: 1) => component-id
   &(measurement: 2) => corim.digest
   ? &(signers: 3) => [ + signer-type ]
+  ? &(flags: 4) => profile-flags
 }

cddl/measured-component.cddlc

@@ -2,6 +2,7 @@ measured-component = {
   &(id: 1) => component-id
   &(measurement: 2) =>  corim.digest
   ? &(signers: 3) => [ + signer-type ]
+  ? &(flags: 4) => profile-flags
 }
 
 signer-type = bytes
@@ -24,3 +25,5 @@ corim.digest = [
   alg: (int / text)
   val: bytes
 ]
+
+profile-flags = bytes .size 4

draft-ietf-rats-eat-measured-component.md

@@ -105,7 +105,7 @@ The information model of a "measured component" is described in {{tab-mc-info-el
 | Signers | One or more unique identifiers of entities signing the measured component. | OPTIONAL |
 {: #tab-mc-info-elems title="Measured Component Information Elements"}
 
-The format should also allow a limited amount of extensibility to accommodate profile-specific semantics.
+The format SHOULD also allow a limited amount of extensibility to accommodate profile-specific semantics.
 
 # Data Model
 
@@ -128,7 +128,7 @@ The data model is inspired by the "PSA software component" claim ({{Section 4.4.
 : One or more signing entities, see {{signer}}.
 
 `profile-flags`
-: a 64-bits field with profile-defined semantics, see {{profile-flags}}.
+: a 64-bit field with profile-defined semantics, see {{profile-flags}}.
 
 ### Component Identifier {#component-id}
 
@@ -161,12 +161,15 @@ If it is used, the profile MUST also specify what each of the entries in the `si
 
 ### Profile Flags {#profile-flags}
 
-TODO(tho) desc
+This field contains at most 64-bit of profile-defined semantics.
 
 ~~~ cddl
 {::include cddl/profile-flags.cddl}
 ~~~
 
+If an EAT profile ({{Section 6 of -rats-eat}}) uses measured components, it MUST specify whether the `profile-flags` field is used.
+If it is used, the profile MUST also specify how to interpret the 64 bits.
+
 ## EAT `measurements-format` Extensions
 
 The CDDL in {{fig-eat-plug}} extends the `$measurements-body-cbor` and `$measurements-body-json` EAT sockets to add support for `measured-component`s to the `Measurements` claim.