[fuse-emulator-devel] Re: Problems with fuse 0.6.1 and 0.6.1.1

[Philip K. <pa...@sr...>]

On Sat, Oct 11, 2003 at 02:09:32AM +0200, Humitsec wrote:
> 
> I'm participating at the Speccy Tour 2003, and the first records I sent
> to the tour was recorded using fuse 0.6.1, libspectrum 0.2.0, this last
> compiled against libgcrypt 1.1.10 to get signing support. Every record
> made with that configuration gets a bad signature when checking at
> another system, which uses fuse-utils 0.6.1, libspectrum 0.2.0, and
> libgcrypt 1.1.12.
> 
> Updating the emulator to version 0.6.1.1 (libspectrum 0.2.0.1), and
> keeping libgrcypt 1.1.10 seems to not resolve the problem. Updating to
> libgcrypt 1.1.12 appears to be the solution, at least, to get a good
> signature check *only* when fuse-utils uses a libspectrum compiled in
> another system that uses libgcrypt 1.1.12.

OK, got this one. Quoting from libgcrypt's NEWS file:

"* gcry_pk_sign, gcry_pk_verify and gcry_pk_encrypt can now handle an
   optional pkcs1 flags parameter in the S-expression."

and looking at libspectrum's crypto.c:

static const char *hash_format = "(data (flags raw) (value %m))";

The "(flags raw)" bit is the optional pkcs1 parameter referred to above.
For reasons I haven't really looked into, using the above hash format
with libgcrypt 1.1.10 doesn't produce any warnings or anything like
that, but produces signatures which aren't compatible with anything
else.

There are two ways round this problem that I can see:

* upgrade to libgcrypt 1.1.12. Nice and easy :-)
* if you *really* need to stick with libgcrypt 1.1.10 (or 1.1.11),
  change crypto.c:hash_format to be

static const char *hash_format = "(%m)";

which will then be compatible with 1.1.12 (in both directions --
recordings made with this will verify under a 1.1.12 rzxcheck, and
recordings made with 1.1.12 will verify with this).

Sorry for the confusion, kids... Ivan, I think you'll probably want to
encourage all Tour players to update libgcrypt to 1.1.12.

FWIW, this won't be a problem for any future versions of Fuse as they'll
require a libgcrypt version >= 1.1.42.

Cheers,

Phil

-- 
"I found a 24-hour place for coffee. Remember that bookstore? Well they
became one of those books-and-coffee places and now they're just coffee.
It's like evolution only without the getting-better part."
                                                  Anya: Buffy: After Life