Should we automatically generate a module signing key at all?

[David Howells <dhowells@redhat.com>]

Hi Michal, Dave,

Should we automatically generate a module signing key at all since that has
the possibility of accidentally overwriting a key that the builder has placed
in the tree?

Should we instead provide a script:

	./scripts/generate-key

That generates a key if run and make it so that the build fails if you turn on
module signing and there's no key.

The script could then be parameterised, eg:

	./scripts/generate-key -n dhowells@redhat.com -k rsa2048 -d sha256 \
		-o ./my-signing-key.priv -x ./my-signing-key.x509 \
		-p "correct horse battery staple"

Yes, this might throw randconfig into a strop but that can be dealt with by:

 (1) Requiring anyone who runs randconfig to provide a key first just in case.

 (2) Marking the CONFIG_MODULE_SIG_ALL option to be ignored by randconfig - it
     only applies during installation anyway.

 (3) Accept that module *installation* will fail due to a lack of private key
     and just handle a complete lack of X.509 certs in the source and build
     dirs when assembling system_certificates.S.

David