On Wed, Jul 31, 2019 at 4:58 PM Sumit Garg [off-list ref] wrote:

quoted

To clarify a bit further - my thought was to support any type of trust
source.

That could be very well accomplished via Trusted Keys abstraction
framework [1]. A trust source just need to implement following APIs:

struct trusted_key_ops ts_trusted_key_ops = {
       .migratable = 0, /* non-migratable */
       .init = init_ts_trusted,
       .seal = ts_key_seal,
       .unseal = ts_key_unseal,
       .get_random = ts_get_random,
       .cleanup = cleanup_ts_trusted,
};

Which is basically the same as implementing a new keytype in the
kernel; abstraction is not raised in any considerable manner this way?

I chose the userspace plugin due to this, you can use userspace aids
to provide any type of service. Use the crypto library you desire to
do the magic you want.

quoted

With the
user mode helper in between anyone can easily add their own thing in
there.

Isn't actual purpose to have trusted keys is to protect user-space
from access to kernel keys in plain format? Doesn't user mode helper
defeat that purpose in one way or another?

Not really. CPU is in the user mode while running the code, but the
code or the secure keydata being is not available to the 'normal'
userspace. It's like microkernel service/driver this way. The usermode
driver is part of the kernel image and it runs on top of a invisible
rootfs.


--
Janne

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