Re: [PATCH v2] lib/crypto: Add SHA3-224, SHA3-256, SHA3-384, SHA-512, SHAKE128, SHAKE256

[Stephan Mueller]

Am Freitag, 19. September 2025, 21:48:00 Mitteleuropäische Sommerzeit 
schrieb David Howells:

Hi David,

> > I see you also have a test in sha3_mod_init(), which doesn't make 
sense.
> > The tests should be in the KUnit test suite(s).  If you intended for 
the
> > sha3_mod_init() test to be a FIPS pre-operational self-test, then (1) 
it
> > would first need to be confirmed with the people doing FIPS
> > certifications that a FIPS pre-operational self-test is actually
> > necessary here, (2) it would need to be fixed to actually fulfill the
> > requirements for that type of test such as panicing the kernel on
> > failure, and (3) it would need to come in its own patch with its own
> > explanation.  But, unless you are sure you actually need the FIPS test,
> > just omit it out for now and focus on the real tests.
> 
> I disagree.  It should have at least a single self-test.  If we fail to 
load
> any modules because the hash is broken on a particular CPU, it would be
> useful to have a note in dmesg.  Loading kunit test modules becomes 
tricky
> in such a case.

Just for clarifications of the FIPS requirements: One test of any of the 
SHA3/SHAKE algorithms during startup is sufficient for *one* Keccak 
implementation. FIPS wants the actual Keccak sponge being tested, it does 
not care for the miniscule differences between the different SHA/SHAKE 
definitions.

Yet, if we have multiple Keccak sponge implementations, then each needs its 
own self test.

Ciao
Stephan