[lp-wan] Fwd: draft-architecture-02-inputs "better match"

[Ana Minaburo <[e-mail]>]

This too.

---------- Forwarded message ---------
From: Ana Minaburo <[e-mail]>
Date: Tue, May 23, 2023 at 4:39 PM
Subject: draft-architecture-02-inputs "better match"
To: Pascal Thubert (pthubert) <[e-mail]>
Cc: <[e-mail]>, <[e-mail]>


Hello Pascal,
This is the second thread.


   - 2. Section 3. In the Static Context Header Compression, in the first
   paragraph, it is mentioned: "The rule that matches best is used to
   compress."

 *[Ana] *It is very ambiguous because it can be misinterpreted. Does it
refer to the Rule that matches the complete header, i.e., the Rule with the
same FIDs as the header format? Or do you mean the best compression
residue? RFC8724 leaves to the implementation the choice of the Rule to be
used when multiple valid Rules match.



Agreed. This should be discussed on the list since it is an attack vector.
Someone inserting a "better match" can turn a decompressor into a bomber.
Let us start a thread on this.


[Ana] If the best compression residue is what you mean, I agree that it
introduces an attack vector that needs to be solved by a deeper discussion
together with the modification of the Rules during the session.

But In a context, several Rules may match the header and may be used to
compress it. For instance, deciding which one is used is an implementation
problem.