Bug with OpenSSL engine initialization in tls_engine_load_dynamic_generic

[Michael Schaller]

Thank you for the input, David. I'll discuss the issue with my
colleague Mike Gerow and we will probably switch to using p11-kit.
When it comes to WPA Supplicant itself do you think that manually
specifying the pkcs11 engine and module path should be
deprecated/removed?

On Mon, Jun 6, 2016 at 2:34 PM, David Woodhouse <dwmw2 at infradead.org> wrote:
> On Mon, 2016-06-06 at 14:13 +0200, Michael Schaller wrote:
>> David explains correctly what happens. This started happening for us
>> on Debian testing with the release of the libengine-pkcs11-openssl
>> package version 0.2.1-2 in March 2016 and it took us a while to
>> analyze the issue. The package had changed the libpkcs11.so location
>> from /usr/lib/ssl/engines/libpkcs11.so to
>> /usr/lib/x86_64-linux-gnu/openssl-1.0.2/engines/libpkcs11.so. Since
>> this move the autoload of the pkcs11 engine on the ENGINE_by_id call
>> works and we get a pkcs11 engine initialized for the use of p11-kit
>> instead of the expected initialization for the specified opencryptoki
>> module. We initialize the pkcs11 engine and module path via D-Bus via
>> the SetPKCS11EngineAndModulePath method.
>>
>> David, is the general recommendation to switch over to p11-kit?
>
> Yes, definitely.
>
> With p11-kit you get a system-wide configuration for which modules to
> load into which applications, with a per-user override:
> https://p11-glue.freedesktop.org/doc/p11-kit/pkcs11-conf.html
>
> This is honoured directly by GnuTLS applications because GnuTLS uses
> libp11-kit directly. For other crypto libraries (OpenSSL, NSS, etc.) it
> can be achieved just by loading the p11-kit-proxy.so module — which
> loads all the modules specified by the p11-kit configuration, as
> "slots" of its own.
>
> In Fedora it is now considered a bug if any packaged software *doesn't*
> automatically load the tokens specified by the p11-kit configuration,
> and allow you to use a RFC7512 PKCS#11 URI in any place you would have
> been able to use a filename to specify a certificate or key.
>
> So to go back to what you said above...
>
>> we get a pkcs11 engine initialized for the use of p11-kit instead of
>> the expected initialization for the specified opencryptoki> module.
>
> It's not supposed to be "instead of". Your p11-kit configuration is
> supposed to say what modules you want loaded, and then they're visible.
>
> (Yes, it would be nicer if OpenSSL and the engine would use libp11-kit
> directly instead of the trick of loading p11-kit-proxy.so, but we'll
> work on that for OpenSSL 1.3 where we turn PKCS#11 into a proper first-
> class citizen and we'll be able to use it for trust and all kinds of
> other things properly.)
>
>>  We initialize the pkcs11 engine and module path via D-Bus via> the
>> SetPKCS11EngineAndModulePath method.
>
> You shouldn't need to do that. If the 'filename' you pass starts with
> 'pkcs11:' then it gets done automatically. And if you are referencing
> objects in the PKCS#11 token by the horrid old crufty ID string that
> predated RFC7512, then don't :)
>
> --
> dwmw2