Misc clarifications needed
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Section 2.2.
Primary/Secondary ECUs: Terms used to describe the control units within a ground vehicle. A primary ECU downloads and verifies update images and metadata for itself and for secondary ECUs, and distributes images and metadata to secondaries. Thus, it requires extra storage space and a means to download images and metadata. Secondary ECUs receive their update images and metadata from the primary, and only need to verify and install their own metadata and images.
is the metadata for secondaries doubly verified, once by primary and another time by secondary? Or are those two different types of verifications? (e.g. signature vs. just hash). The standard explains that secondaries must verify the metadata for their images; but the definition is misleading.
Terminology needs a metadata definition for this context.
Section 3.2.1 Use cases.
There is no use case listed for when an ECU is swapped with another at a dealer aftermarket. Presumably the director should know about this change for that particular VIN. The difference with this use case is that it’s not OEM-initiated.
Section 5.2.6
“A single mapping indicating that all images (*) MUST be signed by both the Director and Image repository”
Unclear: Single mapping of what to what? Isn’t this just an indication? And, if this is a general Uptane requirement, why does it have to be in a config file? The next paragraph explains it better. Thus this third bullet seems out of place.
Section 5.3.2.1 “The Director MAY encrypt images for ECUs that require it.”
Is there a secure way for an ECU to come with a requirement that images must be encrypted? E.g. serial number, model/type, and image encryption flag. In the standard there are requirements around image encryption but they seem to have nothing to do with the actual Ecu that may or may not require it. The OEM or Tier-n should decide this. O/w these requirements are of limited value.
@trishankkarthik, @patrickvacek, @plapczyn can one or several of you jump here and review these clarifications?
is the metadata for secondaries doubly verified, once by primary and another time by secondary? Or are those two different types of verifications? (e.g. signature vs. just hash). The standard explains that secondaries must verify the metadata for their images; but the definition is misleading.
Terminology needs a metadata definition for this context.
Yes, doubly verified. In the full verification case, they are essentially the same verification. In the partial verification case, it is different, which may be why there is some ambiguity here. What is your concern? I'm not sure if I've understand what you mean by needing a "metadata definition".
There is no use case listed for when an ECU is swapped with another at a dealer aftermarket. Presumably the director should know about this change for that particular VIN. The difference with this use case is that it’s not OEM-initiated.
Yes, this is a complicated scenario. IIRC this is mentioned in the deployment considerations. (If it isn't, it probably should be.) In any case, if we were to want to put something about this in the standard, that would probably not be something we could do in time for the 1.0 release.
Is there a secure way for an ECU to come with a requirement that images must be encrypted? E.g. serial number, model/type, and image encryption flag. In the standard there are requirements around image encryption but they seem to have nothing to do with the actual Ecu that may or may not require it. The OEM or Tier-n should decide this. O/w these requirements are of limited value.
This seems implementation-dependent to me. It could belong in deployment considerations. It is possible an appropriate sentence or two could be put in the standard, but anything more than that is probably too complex to get into the 1.0 release.
(Sorry, I'm OOO this week... thanks for covering for me!)
Agreed in 6/25 mtg to add definition of metadata from NIST (https://csrc.nist.gov/glossary/term/metadata) but those are either circular or not directly applicable. Suggest this, veterans please correct: "Information associated with a role or an image, containing characteristics or parameters thereof: e.g. cryptographic material parameters, file names and versions."
Also agreed to slightly modify the definition of Primary/Secondary ECU to clarify the verification is done by both (added "also".. .sounds a bit strange though):. e.g. "Secondary ECUs receive their update images and metadata from the primary, and only**/also** need to verify and install their own metadata and images."
I can add this definition as I'm making at capitalization changes.
PR#125 adds the definition of metadata discussed in this issue. I believe we agreed the other issues here would be moved to the pending deployment issues list. @mcvand, if you want to summarize the other concerns touched on here, I will add them to my offline deployment issues list until our deployment materials have a new home.
I'm not sure I can close it. I guess you can try, as the creator, but maybe wait till after tomorrow's meeting. Since I referenced this issue in my PR I'm not sure how that might be affected if you close this now. It probably has no effect, but don't know enough about github to be sure.
This issue can now be closed via PR#125