sys/fido2: follow up continued

[Ollrogge]

Contribution description

This PR adds changes to make the FIDO2 API usable without a transport layer as
well as improve the overall usability. With this come changes specific to the native
target, to account for the fact that mtd flash handling is file backed in this case.

This also includes breaking changes to the public API:

• All public methods defined in "sys/include/fido2/ctap.h" now return a
  ctap_status_code_t instead of the size of the response.
• The size of the FIDO2 response is now contained within the response structure
  ctap_resp_t.

Users of the FIDO2 API need to adjust their applications to now expect a status
code as the return value of functions such as fido2_ctap_handle_request and
expect the length of the response in resp->len.

To test the usability of FIDO2 without a transport layer, this PR also adds
another test module which tests the CTAP implementation without transport layer.

With the new test module being added, the old tests are renamed to
sys_fido2_ctap_hid to highlight the fact that they test the CTAP2 implementation
using CTAPHID as transport binding.

Furthermore, this PR removes the dependency of ctap_hid for ztimer64 as
having 64 bit timestamps is not required.

Testing procedure

• tests/sys_fido2_ctap
• tests/sys_fido2_ctap_hid

Issues/PRs references

Depends on PR #18637
Issue regarding file backed flash memory on native: #19559

[chrysn]

I'm splitting review into multiple stages as that's a relatively large number of files for a subsystem with few major contributors. For this round, I'm only looking at changes visible outside the module, including the removed ztimer64 use.

Minor comments inline; one larger here:

There are several incompatible changes to the public fido2 API. Please prepare, ideally in the top post of the PR, a note that can then be placed in the release notes. It should describe to users of the API what they need to change in their applications, with emphasis on changes that might go undetected by the compiler and alter the program's meaning (such as when fido2_ctap_handle_request returns a status code rather than a length, which the compiler may cast implicitly).

[Ollrogge]

With #18637 having been merged a while a go, I would like to get this in as well. Rebased on latest master.

[Ollrogge]

@chrysn Can we get this in ?

[kfessel]

link to #19559 native is using file backed mtd

[kfessel]

✔️ all files are reviewed
✔️ no opposition in 2 weeks

please squash your commits ( to a level of your liking)

[Ollrogge]

✔️ all files are reviewed ✔️ no opposition in 2 weeks

please squash your commits ( to a level of your liking)

Done

[riot-ci]

Murdock results

✔️ PASSED

db95ef6 sys/fido2: Small fix to dependencies && cleanup

Success	Failures	Total	Runtime
10249	0	10249	19m:27s

Artifacts

• Documentation preview

[kfessel]

if fixup chages are related to a previous commit -- please prepare them to be integrated with these commits (aka fixup)

[kfessel]

tests/sys/fido2_ctap/ > BOARD=native64 make failed

https://ci.riot-os.org/results/da5dcdb3166b445dbec7480ea226323c/output/builds/tests/sys/fido2_ctap/native64:gnu.txt

[kfessel]

This is better than before and successfully went through CI

I assume the author tested it.

[Ollrogge]

This is better than before and successfully went through CI

I assume the author tested it.

Done. Ran all tests and everything still works as expected :)

[Ollrogge]

@kfessel thanks for reviewing !