[PATCH v3 1/2] lockdown: kexec_file: prevent unsigned kernel image when KEXEC_SIG not enabled

[Mimi Zohar]

Hi Coiby,

On Fri, 2022-12-30 at 14:58 +0800, Coiby Xu wrote:
> A kernel builder may not enable KEXEC_SIG and some architectures like
> ppc64 simply don't have KEXEC_SIG. In these cases, unless both
> IMA_ARCH_POLICY and secure boot also enabled, lockdown doesn't prevent
> unsigned kernel image from being kexec'ed via the kexec_file_load
> syscall whereas it could prevent one via the kexec_load syscall. Mandate
> signature verification for those cases.

The phrase "unless both IMA_ARCH_POLICY and secure boot also enabled"
doesn't reflect the code.  IMA could contain a custom policy rule which
requires the kexec kernel image signature verification as well.  Refer
to the comment now in mandate_signature_verification().

thanks,

Mimi