[PATCH v4 0/3] powerpc: Enabling IMA arch specific secure boot policies

[Nayna Jain]

This patch set, previously named "powerpc: Enabling secure boot on powernv
systems - Part 1", is part of a series that implements secure boot on
PowerNV systems.

In order to verify the OS kernel on PowerNV, secure boot requires X.509
certificates trusted by the platform, the secure boot modes, and several
other pieces of information. These are stored in secure variables
controlled by OPAL, also known as OPAL secure variables.

The IMA architecture specific policy support on POWER is dependent on OPAL
runtime services to access secure variables. OPAL APIs in skiboot are
modified to define generic interface compatible to any backend. This
patchset is consequently updated to be compatible with new OPAL API
interface. This has cleaned up any EFIsms in the arch specific code.
Further, the ima arch specific policies are updated to be able to support
appended signatures. They also now use per policy template.

Exposing the OPAL secure variables to userspace will be posted as a
separate patch set, allowing the IMA architecture specific policy on POWER
to be upstreamed independently.

This patch set adds the following features:

1. Add support for OPAL Runtime API to access secure variables controlled
by OPAL.
2. Define IMA arch-specific policies based on the secure boot state and
mode of the system. On secure boot enabled PowerNV systems, the OS kernel
signature will be verified by IMA appraisal.

Pre-requisites for this patchset are:
1. OPAL APIs in Skiboot[1]
2. Appended signature support in IMA [2]
3. Per policy template support in IMA [3]

[1] https://patchwork.ozlabs.org/project/skiboot/list/?series=112868 
[2] https://patchwork.ozlabs.org/cover/1087361/. Updated version will be
posted soon
[3] Repo: https://kernel.googlesource.com/pub/scm/linux/kernel/git/zohar/linux-integrity
Branch: next-queued-testing. Commit: f241bb1f42aa95

----------------------------------------------------------------------------------

Original Cover Letter:

This patch set is part of a series that implements secure boot on PowerNV
systems.

In order to verify the OS kernel on PowerNV, secure boot requires X.509
certificates trusted by the platform, the secure boot modes, and several
other pieces of information. These are stored in secure variables
controlled by OPAL, also known as OPAL secure variables.

The IMA architecture specific policy support on Power is dependent on OPAL
runtime services to access secure variables. Instead of directly accessing
the OPAL runtime services, version 3 of this patch set relied upon the
EFI hooks. This version drops that dependency and calls the OPAL runtime
services directly. Skiboot OPAL APIs are due to be posted soon.

Exposing the OPAL secure variables to userspace will be posted as a
separate patch set, allowing the IMA architecture specific policy on Power
to be upstreamed independently.

This patch set adds the following features:

1. Add support for OPAL Runtime API to access secure variables controlled
by OPAL.
2. Define IMA arch-specific policies based on the secure boot state and
mode of the system. On secure boot enabled powernv systems, the OS kernel
signature will be verified by IMA appraisal.

[1] https://patchwork.kernel.org/cover/10882149/

Changelog:

v4:
* Fixed the build issue as reported by Satheesh Rajendran.

v3:
* OPAL APIs in Patch 1 are updated to provide generic interface based on
key/keylen. This patchset updates kernel OPAL APIs to be compatible with
generic interface.
* Patch 2 is cleaned up to use new OPAL APIs. 
* Since OPAL can support different types of backend which can vary in the
variable interpretation, the Patch 2 is updated to add a check for the
backend version
* OPAL API now expects consumer to first check the supported backend version
before calling other secvar OPAL APIs. This check is now added in patch 2.
* IMA policies in Patch 3 is updated to specify appended signature and
per policy template.
* The patches now are free of any EFIisms.

v2:

* Removed Patch 1: powerpc/include: Override unneeded early ioremap
functions
* Updated Subject line and patch description of the Patch 1 of this series
* Removed dependency of OPAL_SECVAR on EFI, CPU_BIG_ENDIAN and UCS2_STRING
* Changed OPAL APIs from static to non-static. Added opal-secvar.h for the
same
* Removed EFI hooks from opal_secvar.c
* Removed opal_secvar_get_next(), opal_secvar_enqueue() and
opal_query_variable_info() function
* get_powerpc_sb_mode() in secboot.c now directly calls OPAL Runtime API
rather than via EFI hooks.
* Fixed log messages in get_powerpc_sb_mode() function.
* Added dependency for PPC_SECURE_BOOT on configs PPC64 and OPAL_SECVAR
* Replaced obj-$(CONFIG_IMA) with obj-$(CONFIG_PPC_SECURE_BOOT) in
arch/powerpc/kernel/Makefile

Claudio Carvalho (1):
  powerpc/powernv: Add OPAL API interface to get secureboot state

Nayna Jain (2):
  powerpc/powernv: detect the secure boot mode of the system
  powerpc: Add support to initialize ima policy rules

 arch/powerpc/Kconfig                         | 14 ++++
 arch/powerpc/include/asm/opal-api.h          |  4 +-
 arch/powerpc/include/asm/opal-secvar.h       | 23 ++++++
 arch/powerpc/include/asm/opal.h              |  6 ++
 arch/powerpc/include/asm/secboot.h           | 21 +++++
 arch/powerpc/kernel/Makefile                 |  1 +
 arch/powerpc/kernel/ima_arch.c               | 54 +++++++++++++
 arch/powerpc/platforms/powernv/Kconfig       |  6 ++
 arch/powerpc/platforms/powernv/Makefile      |  1 +
 arch/powerpc/platforms/powernv/opal-call.c   |  2 +
 arch/powerpc/platforms/powernv/opal-secvar.c | 85 ++++++++++++++++++++
 arch/powerpc/platforms/powernv/secboot.c     | 61 ++++++++++++++
 include/linux/ima.h                          |  3 +-
 13 files changed, 279 insertions(+), 2 deletions(-)
 create mode 100644 arch/powerpc/include/asm/opal-secvar.h
 create mode 100644 arch/powerpc/include/asm/secboot.h
 create mode 100644 arch/powerpc/kernel/ima_arch.c
 create mode 100644 arch/powerpc/platforms/powernv/opal-secvar.c
 create mode 100644 arch/powerpc/platforms/powernv/secboot.c

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2.20.1