Re: [PATCH] modsign: provide option to automatically delete the key after modules were installed

From: Alexander Holler
Date: Fri Jan 23 2015 - 07:34:54 EST


Am 23.01.2015 um 12:54 schrieb Alexander Holler:
Am 23.01.2015 um 12:43 schrieb Alexander Holler:
Am 23.01.2015 um 11:55 schrieb Michal Marek:

The .x509 file contains a certificate signed by the private key, but not
the private key. With some scripting, it can be used to verify the
module signatures.


Assuming that doesn't change (hopefully), I'll send v2 in a few minutes
(it just compiles in order to test it). Thanks for assuring me that
.x509 does not and will not contain the private key.

I'm happy I did that. Just deleting the private key currently doesn't
work. A subsequent make fails:

-----------------------------
(...)
INSTALL arch/x86/crypto/aesni-intel.ko
Can't read private key
(...)
-----------------------------

Maybe that's the reason I've always deleted both files, can't remember.

I will see if I find the time and passion to change the Makefile in
order to fix that. So you might either use my existing patch or wait if
I will send a new one.

Having had a look at the Makefile, I don't think I will change that. The reasons are:

1. I have no idea about how distro maintainers do handle their private and public keys used to sign modules.

2. There might be legitimate reasons to build the kernel using only the public key and not regenerating it because the private key doesn't exist.

3. I don't see any real reason not to delete the public key too if this new option is enabled. For me it's enough if the kernel is able to verify the modules with the embedded public key. For other usage scenarios one just should not use the new option.

4. With some scripting it should be possible to extract the public key out of an existing binary kernel. So there is no real need to change the already complicated build process which might make it even more complicated.

That means I'm still happy with the patch. So feel free to ignore or apply it.

Regards,

Alexander Holler
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