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NIAP Comment on FTP_ITC.1 #63

Open plughy2 opened 2 years ago

plughy2 commented 2 years ago

The iTC received a request from NIAP to address ambiguity found in FTP_ITC.1.2 and FTP_ITC.1.3.

In FTP_ITC.1.2, there is no requirement on which party (the TSF or the authorized IT entity) shall initiate the communication. Yet FTP_ITC.1.3 has the ST author list the services via assignment operation that the TSF shall initiate communication. More specifically, there isn't a way to check what the ST author may put in the assignment operation is correct. In other words, if the ST is being evaluated by itself (or in this case being checked via an automated process), how is the contents of the assignment operation in FTP_ITC.1.3 determined to be correct? Does FTP_ITC.1.3 even provide value when FTP_ITC.1.2 states either party can initiate the communication?

It was suggested that the NDcPP follow the format of the FTP_ITC_EXT.1 requirement as defined in the Protection Profile for General-Purpose Computing Platforms.

Addressing the ambiguity will help NIAP in their effort to automate checking of Security Targets that was being led by Bob Clemons.

dundiddat commented 2 years ago

That proposed change seems fine. The refinement in FTP_ITC.1.2 in NDcPPv2.2e seems entirely unnecessary, so it seems easy and appropriate to remove the refinement "the TSF or the authorized IT entities" and instead directly copy the selection from CC Part 2 "[selection: the TSF, another trusted IT product]".

Note, if the change will include replacing "authorized IT entities" with "trusted IT product" then for consistency there are corresponding wording changes to be made in FTP_ITC.1.1 and application note 39 to replace "authorized IT entities" (plural) and "authorized IT entity" (singular) with "trusted IT product".

BTW, the wording issue seems to be isolated to this SFR. NDcPPv2.2e only contains five occurrences of "authorized IT entity" (or "entities"), all of which are in FTP_ITC.1 or its application note.

plughy2 commented 2 years ago

Adding a link to FTP_ITC_EXT.1 from GPCP: https://commoncriteria.github.io/pp/gpcp/gpcp-release.html#FTP_ITC_EXT.1

Pros: In addition to resolving the NIAP issue stated above, the formatting comments NIAP had with FTP_ITC.1 and FTP_TRP.1 would also be resolved by changing FTP_ITC.1 to the explicitly stated SFR format.

Cons: Requires changing all instances of FTP_ITC.1 to FTP_ITC_EXT.1. Requires a change to FTP_TRP.1.

cfesysco commented 2 years ago

For clarification purposes, could we just revise FTP_ITC.1.3 to "The TSF shall initiate communication communicate via the trusted channel for [assignment: list of services for which the TSF is able to initiate communications]."

Pros: Removes ambiguity between FTP_ITC.1.2 and FTP_ITC.1.3, follows more closely to CC2, minimal changes. Cons: Not the request NIAP asked for.

dundiddat commented 2 years ago

Due to concerns expressed in the comments above, and the potential complexity of addressing this completely/properly, the MINT has decided to postpone resolution of this issue, so for now the status will be changed to "Backlog".