On Wed, Jan 27, 2021 at 09:03:59AM -0500, Mimi Zohar wrote:

[Cc'ing linux-integrity]

On Wed, 2021-01-27 at 11:46 +0000, David Howells wrote:

quoted

Jarkko Sakkinen [off-list ref] wrote:

quoted

quoted

I suppose a user space tool could be created. But wouldn’t what is
currently done in the kernel in this area need to be removed?

Right. I don't think this was a great idea in the first place to
do to the kernel but since it exists, I guess the patch does make
sense.

This information needs to be loaded from the UEFI tables before the system
starts loading any kernel modules or running any programs (if we do
verification of such, which I think IMA can do).

There needs to a clear distinction between the pre-boot and post-boot
keys.  UEFI has its own trust model, which should be limited to UEFI. 
The .platform keyring was upstreamed and limited to verifying the kexec
kernel image.   Any other usage of the .platform keyring keys is
abusing its intended purpose.

The cover letter says,   "Anytime the .platform keyring is used, the
keys in the .blacklist keyring are referenced, if a matching key is
found, the key will be rejected."   I don't have a problem with loading
the UEFI X509 dbx entries as long as its usage is limited to verifying
the kexec kernel image.

Mimi

Thanks Mimi, this is a valid argument. I agree.

/Jarkko