Re: [Qemu-devel] [PATCH v2 05/17] crypto: add support for anti-forensic split algorithm

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Feb 04, 2016 at 04:26:42PM -0700, Eric Blake wrote:
> On 01/20/2016 10:38 AM, Daniel P. Berrange wrote:
> > The LUKS format specifies an anti-forensic split algorithm which
> > is used to artificially expand the size of the key material on
> > disk. This is an implementation of that algorithm.
> > 
> > Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
> > ---
> >  crypto/Makefile.objs        |   1 +
> >  crypto/afsplit.c            | 162 ++++++++++++++++++++++++++++++++++++++++
> >  include/crypto/afsplit.h    | 135 +++++++++++++++++++++++++++++++++
> >  tests/.gitignore            |   1 +
> >  tests/Makefile              |   2 +
> >  tests/test-crypto-afsplit.c | 176 ++++++++++++++++++++++++++++++++++++++++++++
> >  6 files changed, 477 insertions(+)
> >  create mode 100644 crypto/afsplit.c
> >  create mode 100644 include/crypto/afsplit.h
> >  create mode 100644 tests/test-crypto-afsplit.c
> > 
> > + * @errp: pointer to a NULL-initialized error object
> > + *
> > + * Join the data in @in, which is @blocklen * @stripes
> > + * bytes in size, to form the original small piece o
> > + * data @out, which is @blocklen bytes in size.
> > + *
> > + * Returns: 0 on success, -1 on error;
> > + */
> > +int qcrypto_afsplit_decode(QCryptoHashAlgorithm hash,
> > +                           size_t blocklen,
> > +                           uint32_t stripes,
> > +                           const uint8_t *in,
> > +                           uint8_t *out,
> > +                           Error **errp);
> 
> Markus may have an opinion on whether these functions could return void
> and just use the errp pointer to report errors; but I'm fine with how
> you've done it.

I have a preference to be non-void, as it avoids constantly having to
use a 'Error local_err' and error_propagate to check for failure, so
results in smaller & simpler code.

Regards,
Daniel
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