[v5,0/2] powerpc: Enabling IMA arch specific secure boot policies

Message

Nayna Jain Aug. 19, 2019, 12:35 p.m. UTC

IMA subsystem supports custom, built-in, arch-specific policies to define
the files to be measured and appraised. These policies are honored based
on the priority where arch-specific policies is the highest and custom
is the lowest.

OpenPOWER systems rely on IMA for signature verification of the kernel.
This patchset adds support for powerpc specific arch policies that are
defined based on system's OS secureboot state. The OS secureboot state
of the system is determined via device-tree entry.

Changelog:
v5:
* secureboot state is now read via device tree entry rather than OPAL
secure variables
* ima arch policies are updated to use policy based template for
measurement rules

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

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

 arch/powerpc/Kconfig               | 13 ++++++
 arch/powerpc/include/asm/secboot.h | 27 ++++++++++++
 arch/powerpc/kernel/Makefile       |  2 +
 arch/powerpc/kernel/ima_arch.c     | 50 +++++++++++++++++++++
 arch/powerpc/kernel/secboot.c      | 71 ++++++++++++++++++++++++++++++
 include/linux/ima.h                |  3 +-
 6 files changed, 165 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/include/asm/secboot.h
 create mode 100644 arch/powerpc/kernel/ima_arch.c
 create mode 100644 arch/powerpc/kernel/secboot.c