[PATCH 5.4 042/108] efi/tpm: Differentiate missing and invalid final event log table.

Greg Kroah-Hartman
2021-07-26T16:04:08Z

From: Michal Suchanek <msuchanek@suse.de>

[ Upstream commit 674a9f1f6815849bfb5bf385e7da8fc198aaaba9 ]

Missing TPM final event log table is not a firmware bug.

Clearly if providing event log in the old format makes the final event
log invalid it should not be provided at least in that case.

Fixes: b4f1874c6216 ("tpm: check event log version before reading final events")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/efi/tpm.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
index c1955d320fec..8f665678e9e3 100644
--- a/drivers/firmware/efi/tpm.c
+++ b/drivers/firmware/efi/tpm.c
@@ -62,9 +62,11 @@ int __init efi_tpm_eventlog_init(void)
tbl_size = sizeof(*log_tbl) + log_tbl->size;
memblock_reserve(efi.tpm_log, tbl_size);

- if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR ||
- log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) {
- pr_warn(FW_BUG "TPM Final Events table missing or invalid\n");
+ if (efi.tpm_final_log == EFI_INVALID_TABLE_ADDR) {
+ pr_info("TPM Final Events table not present\n");
+ goto out;
+ } else if (log_tbl->version != EFI_TCG2_EVENT_LOG_FORMAT_TCG_2) {
+ pr_warn(FW_BUG "TPM Final Events table invalid\n");
goto out;
}

--
2.30.2