[PATCH v2 0/7] pseries dynamic secure boot interface using secvar

Russell Currey
2022-12-30T04:21:29Z

Changes in v2:

Remove unnecessary config vars from sysfs and document the others,
thanks to review from Greg. If we end up needing to expose more, we
can add them later and update the docs.

Use sysfs_emit() instead of sprintf() for all sysfs strings

Change the size of the sysfs binary attributes to include the 8-byte
flags header, preventing truncation of large writes.

This series exposes an interface to userspace for reading and writing
secure variables contained within the PowerVM LPAR Platform KeyStore
(PLPKS) for the purpose of configuring dynamic secure boot.

This series builds on past work by Nayna Jain[0] in exposing PLPKS
variables to userspace. Rather than being a generic interface for
interacting with the keystore, however, we use the existing powerpc
secvar infrastructure to only expose objects in the keystore used
for dynamic secure boot. This has the benefit of leveraging an
existing interface and making the implementation relatively minimal.

This series needs to be applied on top of Andrew's recent bugfix
series[1].

There are a few relevant details to note about the implementation:

* New additions to the secvar API, format() and max_size()
* New optional sysfs directory "config/" for arbitrary ASCII variables
* Some OPAL-specific code has been relocated from secvar-sysfs.c to
powernv platform code. Would appreciate any powernv testing!
* Variable names are fixed and only those used for secure boot are
exposed. This is not a generic PLPKS interface, but also
doesn't preclude one being added in future.

With this series, both powernv and pseries platforms support dynamic
secure boot through the same interface.

[0]: https://lore.kernel.org/linuxppc-dev/20221106210744.603240-1-nayna@linux.ibm.com/
[1]: https://lore.kernel.org/linuxppc-dev/20221220071626.1426786-1-ajd@linux.ibm.com/

v1: https://lore.kernel.org/linuxppc-dev/20221228072943.429266-1-ruscur@russell.cc/

Russell Currey (7):
powerpc/pseries: Log hcall return codes for PLPKS debug
powerpc/secvar: WARN_ON_ONCE() if multiple secvar ops are set
powerpc/secvar: Use sysfs_emit() instead of sprintf()
powerpc/secvar: Handle format string in the consumer
powerpc/secvar: Handle max object size in the consumer
powerpc/secvar: Extend sysfs to include config vars
powerpc/pseries: Implement secvars for dynamic secure boot

Documentation/ABI/testing/sysfs-secvar | 67 ++++-
arch/powerpc/include/asm/secvar.h | 5 +
arch/powerpc/kernel/secvar-ops.c | 4 +-
arch/powerpc/kernel/secvar-sysfs.c | 78 +++---
arch/powerpc/platforms/powernv/opal-secvar.c | 44 ++++
arch/powerpc/platforms/pseries/Kconfig | 13 +
arch/powerpc/platforms/pseries/Makefile | 4 +-
arch/powerpc/platforms/pseries/plpks-secvar.c | 245 ++++++++++++++++++
arch/powerpc/platforms/pseries/plpks.c | 2 +
9 files changed, 419 insertions(+), 43 deletions(-)
create mode 100644 arch/powerpc/platforms/pseries/plpks-secvar.c

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2.38.1