[PATCH 0/3][SRU][E] Fix panic when parsing tpm event log from firmware

[Seth Forshee]

BugLink: https://bugs.launchpad.net/bugs/1845454

SRU Justification

Impact: Some systems are getting kernel panics during boot while parsing
tpm event logs from the firmware. This happens only when the tpm and
secure boot are both enabled in the firmware.

Fix: 3 patches which are currently applied to the upstream EFI
maintainer tree.

Test Case: On an affected system, booting a 5.3-based kernel will panic
during boot when the tpm and secure boot are enabled. A patched kernel
will boot successfully. The patches have been verified to fix the issue
on a gen 6 Lenovo X1 Carbon.

Regression Potential: If the patches have bugs they could cause
regressions on systems not currently experiencing issues. The patches
are pretty straightforward though and tagged for stable, so I believe
the risk is minimal and (given the severity of the issue on affected
hardware) acceptable.

Thanks,
Seth


Jerry Snitselaar (1):
  efi/tpm: only set efi_tpm_final_log_size after successful event log
    parsing

Peter Jones (2):
  efi/tpm: Don't access event->count when it isn't mapped.
  efi/tpm: don't traverse an event log with no events

 drivers/firmware/efi/tpm.c   | 24 ++++++++++++++++++------
 include/linux/tpm_eventlog.h | 16 ++++++++++++----
 2 files changed, 30 insertions(+), 10 deletions(-)