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project-chip / connectedhomeip

Matter (formerly Project CHIP) creates more connections between more objects, simplifying development for manufacturers and increasing compatibility for consumers, guided by the Connectivity Standards Alliance.
https://buildwithmatter.com
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[Documentation] Source Node Id during comissioning #33518

Closed lava closed 4 days ago

lava commented 5 months ago

Documentation issues

The Matter specification states in 4.13.1.2. Protocol Details that for all PASE messages

The S Flag and DSIZ fields of the Message Flags SHALL be set to 0.

On the other hand, PASE messages are sent unencrypted and thus according to 4.12.1.1. Unsecured Session Context the initiator should "enclose" (?) an ephemeral node id as the source node id:

Ephemeral Initiator Node ID: Randomly selected for each session by the initiator from the Oper­ational Node ID range and enclosed by initiator as Source Node ID and responder as Destination Node ID.

This seems to be a contradiction, since a message cannot include a source node id if the S flag is set to 0.

Empirically, chip-tool ignores the first requirement and just sets the S flag to 1 for the PBKDFParamRequest message.

So, two questions:

  1. Is this the intended behavior?
  2. If yes, is it a bug in the Matter specification or did I miss some other paragraph that reconciles the two?

Platform

No response

Anything else?

No response

Alami-Amine commented 4 days ago

This was Fixed in the Spec for Matter-1.3 that was released in April 2024 The Text says in 4.13.1.2. Protocol Details

• In the PASE messages from the initiator, S Flag SHALL be set to 1 and DSIZ SHALL be set to 0. • In the PASE messages from the responder, S Flag SHALL be set to 0 and DSIZ SHALL be set to 1.

This ticket can be closed.