Re: [PATCH] sample/tsm-mr: Use SHA-2 library APIs

[Dan Williams]

Eric Biggers wrote:
> On Wed, Mar 18, 2026 at 08:57:01PM +0100, Arnd Bergmann wrote:
> > On Wed, Mar 18, 2026, at 17:42, Eric Biggers wrote:
> > > Given that tsm_mr_sample has a particular set of algorithms that it
> > > wants, just use the library APIs for those algorithms rather than
> > > crypto_shash.  This is more straightforward and a bit more efficient.
> > >
> > > This fixes an issue where this module failed to build due to the kconfig
> > > options CRYPTO and CRYPTO_HASH not being selected.  Also, even if it
> > > built, crypto_alloc_shash() could fail at runtime due to the needed
> > > algorithms not being available.
> > >
> > > The library functions simply use direct linking.  So if it builds, which
> > > it will due to the kconfig options being enabled, they are available.
> > >
> > > Fixes: f6953f1f9ec4 ("tsm-mr: Add tsm-mr sample code")
> > > Fixes: 44a3873df811 ("coco/guest: Remove unneeded selection of CRYPTO")
> > > Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
> > > ---
> > >
> > > I'd like to take this via libcrypto-next, as that is where
> > > "coco/guest: Remove unneeded selection of CRYPTO" is.
> > 
> > Thanks for fixing this! It is indeed nicer than the fix
> > I sent earlier today.
> > 
> > Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
> 
> Thanks.  Additional acks from the people owning this code (Dan, Cedric?)
> would be appreciated.  But since this fixes a build error and is related
> to the crypto library, I went ahead and applied this to
> https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=libcrypto-next
> 
> I also found that the build error is pre-existing, as CRYPTO_HASH was
> not being selected.  "coco/guest: Remove unneeded selection of CRYPTO"
> just made it a bit easier to encounter, by not selecting CRYPTO either.
> 
> So I updated the second paragraph of the commit message to:
> 
>     This also fixes a bug where this module failed to build if it was
>     enabled without CRYPTO_HASH happening to be set elsewhere in the
>     kconfig.  (With the concurrent change to make TSM_MEASUREMENTS stop
>     selecting CRYPTO, this existing build error would have become easier to
>     encounter, as well.)  Also, even if it built, crypto_alloc_shash() could
>     fail at runtime due to the needed algorithms not being available.
> 
> I also put this commit before "coco/guest: Remove unneeded selection of
> CRYPTO" and dropped the Fixes reference to that.  So now it just has:
> 
>     Fixes: f6953f1f9ec4 ("tsm-mr: Add tsm-mr sample code")


It looks good to me:

Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>

Feel free to take it through your tree since I have nothing immediately
pending for tsm.git.