Re: RFC: sign the modules at install time

From: Linus Torvalds
Date: Wed Oct 17 2012 - 19:21:41 EST

On Wed, Oct 17, 2012 at 4:07 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> Hmm. It *should* work for them too, because the debuginfo modules stay
> around in the object tree, and never get stripped there. None of this
> is different from what we used to do before: we stripped the modules
> as we copied them to /lib/modules (where the RPM build obviously would
> have that $RPM_BUILD_ROOT prefix on the module install path).

Ok, I read your description of the odd way fedora builds debuginfo kernels.

I actually think that works fine too. I do agree with adding a "make
sign_modules" target, but it would *re-sign* them after "make
modules_install" has already signed them once.


What you'd do for your debuginfo requirements is:

- do the normal kernel build, and install modules (with *my* patch,
which does signing at install time)

This does the normal (conditionally stripped - you just wouldn't
strip them, but you cannot have done that before either) modules,
installs them, and signs then.

Ta-daa, you have your debuginfo modules installed, and they are
signed. Create the debuginfo rpm.

- now, strip the modules. This obviously destroys the signatures

- do the extra "make sign_modules" that you added, that re-signs the
already installed modules, and now you can create the non-debuginfo

Voila. "make modules_install" does the right thing for everybody -
including normal users. And it does so without the incredible baroque
code. And no normal user is expected to ever use the new "make
sign_modules", but it allows for the Fedora "we'll want to sign them

That said, you could even just do "make sign-modules" on your own
without any makefile targets. After all, it would just be something

find $MODULEDIR --name '*.ko | while read i; do script/sign-file
keyfile x509file $i; done

so it could even be done in that rpm script directly.

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