Re: [PATCH 1/3] integrity: Make arch_ima_get_secureboot integrity-wide

Ard Biesheuvel
2026-01-16T13:19:05Z

On Fri, 16 Jan 2026 at 14:11, Mimi Zohar <zohar@linux.ibm.com> wrote:
>
> On Fri, 2026-01-16 at 10:41 +0100, Ard Biesheuvel wrote:
> > On Thu, 15 Jan 2026 at 01:43, Coiby Xu <coxu@redhat.com> wrote:
> > >
> > > EVM and other LSMs need the ability to query the secure boot status of
> > > the system, without directly calling the IMA arch_ima_get_secureboot
> > > function. Refactor the secure boot status check into a general,
> > > integrity-wide function named arch_integrity_get_secureboot.
> > >
> > > Define a new Kconfig option CONFIG_INTEGRITY_SECURE_BOOT, which is
> > > automatically configured by the supported architectures. The existing
> > > IMA_SECURE_AND_OR_TRUSTED_BOOT Kconfig loads the architecture specific
> > > IMA policy based on the refactored secure boot status code.
> > >
> > > Reported-and-suggested-by: Mimi Zohar <zohar@linux.ibm.com>
> > > Suggested-by: Roberto Sassu <roberto.sassu@huaweicloud.com>
> > > Signed-off-by: Coiby Xu <coxu@redhat.com>
> > > ---
> > > arch/arm64/Kconfig | 1 +
> > > arch/powerpc/Kconfig | 1 +
> > > arch/powerpc/kernel/Makefile | 2 +-
> > > arch/powerpc/kernel/ima_arch.c | 5 --
> > > arch/powerpc/kernel/integrity_sb_arch.c | 13 +++++
> > > arch/s390/Kconfig | 1 +
> > > arch/s390/kernel/Makefile | 1 +
> > > arch/s390/kernel/ima_arch.c | 6 --
> > > arch/s390/kernel/integrity_sb_arch.c | 9 +++
> > > arch/x86/Kconfig | 1 +
> > > arch/x86/include/asm/efi.h | 4 +-
> > > arch/x86/platform/efi/efi.c | 2 +-
> > > include/linux/ima.h | 7 +--
> > > include/linux/integrity.h | 8 +++
> > > security/integrity/Kconfig | 6 ++
> > > security/integrity/Makefile | 3 +
> > > security/integrity/efi_secureboot.c | 56 +++++++++++++++++++
> > > security/integrity/ima/ima_appraise.c | 2 +-
> > > security/integrity/ima/ima_efi.c | 47 +---------------
> > > security/integrity/ima/ima_main.c | 4 +-
> > > security/integrity/platform_certs/load_uefi.c | 2 +-
> > > 21 files changed, 111 insertions(+), 70 deletions(-)
> > > create mode 100644 arch/powerpc/kernel/integrity_sb_arch.c
> > > create mode 100644 arch/s390/kernel/integrity_sb_arch.c
> > > create mode 100644 security/integrity/efi_secureboot.c
> > >
> > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > > index 93173f0a09c7..4c265b7386bb 100644
> > > --- a/arch/arm64/Kconfig
> > > +++ b/arch/arm64/Kconfig
> > > @@ -2427,6 +2427,7 @@ config EFI
> > > select EFI_STUB
> > > select EFI_GENERIC_STUB
> > > imply IMA_SECURE_AND_OR_TRUSTED_BOOT
> > > + imply INTEGRITY_SECURE_BOOT
> >
> > This allows both to be en/disabled individually, which I don't think
> > is what we want. It also results in more churn across the
> > arch-specific Kconfigs than needed.
> >
> > Wouldn't it be better if IMA_SECURE_AND_OR_TRUSTED_BOOT 'select'ed
> > INTEGRITY_SECURE_BOOT in its Kconfig definition?
>
> As much as possible, EVM (and other LSMs) shouldn't be dependent on another LSM,
> in this case IMA, being configured.

Sure, but that is not my point.

This arrangement allows for IMA_SECURE_AND_OR_TRUSTED_BOOT to be
enabled without INTEGRITY_SECURE_BOOT, resulting in the stub
implementation of arch_integrity_get_secureboot() being used, which
always returns false.