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Commit ed74a681 authored by Andrew Scull's avatar Andrew Scull
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Document expectations of DICE mode 

The Open Profile for DICE give possible guidelines on the requirements
for the DICE mode but Android needs those to be strictly specified.

Fix: 263144485
Test: n/a
Change-Id: Ia5fc937654504199cabf4709f1c15484242e0161
parent e0a23885

security/rkp/README.md

+18 −0
Original line number Original line Diff line number Diff line
@@ -291,6 +291,24 @@ available on the device it should appear in the certificate request as the leaf 
of a DKCertChain in AdditionalDKSignatures (see

of a DKCertChain in AdditionalDKSignatures (see

[CertificateRequest](#certificaterequest)).

[CertificateRequest](#certificaterequest)).





#### Mode



The Open Profile for DICE specifies four possible modes with the most important

mode being `normal`. A certificate must only set the mode to `normal` when all

of the following conditions are met when loading and verifying the software

component that is being described by the certificate:



*   verified boot with anti-rollback protection is enabled

*   only the verified boot authorities for production images are enabled

*   debug ports, fuses or other debug facilities are disabled

*   device booted software from the normal primary source e.g. internal flash



If any of these conditions are not met then it is recommended to explicitly

acknowledge this fact by using the `debug` mode. The mode should never be `not

configured`.



#### Configuration descriptor



The Open Profile for DICE allows for an arbitrary configuration descriptor. For

The Open Profile for DICE allows for an arbitrary configuration descriptor. For

BCC entries, this configuration descriptor is a CBOR map with the following

BCC entries, this configuration descriptor is a CBOR map with the following

optional fields. If no fields are relevant, an empty map should be encoded.

optional fields. If no fields are relevant, an empty map should be encoded.