[PATCH RFC 0/5] liveupdate: validate restored LUO metadata

[Cris Jacob Maamor <crisjacobmaamor@gmail.com>]

LUO restores metadata from KHO/FDT during liveupdate. The restored
metadata contains physical addresses and count fields used to access and
walk preserved session, file-set, and FLB arrays.

This series adds a non-consuming KHO preserved-range check and uses it
before phys_to_virt() on restored metadata addresses. It also rejects
restored counts above LUO_SESSION_MAX, LUO_FILE_MAX, and LUO_FLB_MAX
before traversal.

As far as I can tell, this is root/admin-only; I do not have evidence
that a normal unprivileged user can trigger it directly.

I have not reproduced this in a VM yet, so I may be missing a KHO
invariant or a preferred restore helper pattern. Feedback on the helper
semantics is welcome.

Cris Jacob Maamor (5):
  kexec: handover: add helper to check preserved page ranges
  liveupdate: validate restored LUO FDT before use
  liveupdate: validate restored LUO session metadata
  liveupdate: validate restored LUO file-set metadata
  liveupdate: validate restored LUO FLB metadata

 include/linux/kexec_handover.h     |  6 +++++
 kernel/liveupdate/kexec_handover.c | 35 ++++++++++++++++++++++++++++++
 kernel/liveupdate/luo_core.c       | 10 ++++++++-
 kernel/liveupdate/luo_file.c       | 14 ++++++++++--
 kernel/liveupdate/luo_flb.c        | 23 +++++++++++++++++++-
 kernel/liveupdate/luo_session.c    | 22 +++++++++++++++++--
 6 files changed, 104 insertions(+), 6 deletions(-)

-- 
2.53.0