Re: [RFC v2 0/6] Introduce TEE based Trusted Keys support

[Janne Karhunen <janne.karhunen@gmail.com>]

Hi,

To clarify a bit further - my thought was to support any type of trust
source. Remote, local or both. Just having one particular type of
locally bound 'TEE' sounded very limited, especially when nothing from
the TEE execution side is really needed for supporting the kernel
crypto. What you really need is the seal/unseal transaction going
somewhere and where that somewhere is does not matter much. With the
user mode helper in between anyone can easily add their own thing in
there.


--
Janne

On Wed, Jul 31, 2019 at 10:11 AM Janne Karhunen
<janne.karhunen@gmail.com> wrote:
>
> Hi,
>
> Interesting, I wrote something similar and posted it to the lists a while back:
> https://github.com/jkrh/linux/commit/d77ea03afedcb5fd42234cd834da8f8a0809f6a6
>
> Since there are no generic 'TEEs' available, I implemented the same
> thing as a generic protocol translator. The shared memory binding for
> instance already assumes fair amount about the TEE and how that is
> physically present in the system. Besides, the help from usage of shm
> is pretty limited due to the size of the keydata.
>
>
> --
> Janne
>
>
>
>
> On Tue, Jul 30, 2019 at 3:26 PM Sumit Garg <sumit.garg@linaro.org> wrote:
> >
> > Add support for TEE based trusted keys where TEE provides the functionality
> > to seal and unseal trusted keys using hardware unique key. Also, this is
> > an alternative in case platform doesn't possess a TPM device.
> >
> > This series also adds some TEE features like:
> >
> > Patch #1, #2 enables support for registered kernel shared memory with TEE.
> >
> > Patch #3 enables support for private kernel login method required for
> > cases like trusted keys where we don't wan't user-space to directly access
> > TEE service to retrieve trusted key contents.
> >
> > Rest of the patches from #4 to #6 adds support for TEE based trusted keys.
> >
> > This patch-set has been tested with OP-TEE based pseudo TA which can be
> > found here [1].
> >
> > Also, this patch-set is dependent on generic Trusted Keys framework
> > patch-set [2].
> >
> > [1] https://github.com/OP-TEE/optee_os/pull/3082
> > [2] https://lkml.org/lkml/2019/7/18/284
> >
> > Changes in v2:
> > 1. Add reviewed-by tags for patch #1 and #2.
> > 2. Incorporate comments from Jens for patch #3.
> > 3. Switch to use generic trusted keys framework.
> >
> > Sumit Garg (6):
> >   tee: optee: allow kernel pages to register as shm
> >   tee: enable support to register kernel memory
> >   tee: add private login method for kernel clients
> >   KEYS: trusted: Introduce TEE based Trusted Keys
> >   doc: keys: Document usage of TEE based Trusted Keys
> >   MAINTAINERS: Add entry for TEE based Trusted Keys
> >
> >  Documentation/security/keys/index.rst       |   1 +
> >  Documentation/security/keys/tee-trusted.rst |  93 +++++++++
> >  MAINTAINERS                                 |   9 +
> >  drivers/tee/optee/call.c                    |   7 +
> >  drivers/tee/tee_core.c                      |   6 +
> >  drivers/tee/tee_shm.c                       |  16 +-
> >  include/keys/trusted-type.h                 |   3 +
> >  include/keys/trusted_tee.h                  |  66 +++++++
> >  include/linux/tee_drv.h                     |   1 +
> >  include/uapi/linux/tee.h                    |   8 +
> >  security/keys/Kconfig                       |   3 +
> >  security/keys/trusted-keys/Makefile         |   3 +-
> >  security/keys/trusted-keys/trusted-tee.c    | 282 ++++++++++++++++++++++++++++
> >  security/keys/trusted-keys/trusted.c        |   3 +
> >  14 files changed, 498 insertions(+), 3 deletions(-)
> >  create mode 100644 Documentation/security/keys/tee-trusted.rst
> >  create mode 100644 include/keys/trusted_tee.h
> >  create mode 100644 security/keys/trusted-keys/trusted-tee.c
> >
> > --
> > 2.7.4
> >