2021-07-08 09:48:30

by Michal Suchánek

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

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 <[email protected]>
---
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;
}

--
2.26.2

2021-07-09 16:41:12

by Jarkko Sakkinen

Subject: Re: [PATCH] efi/tpm: Differentiate missing and invalid final event log table.

On Thu, Jul 08, 2021 at 11:46:54AM +0200, Michal Suchanek wrote:
> 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 <[email protected]>
> ---
> 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;
> }
>
> --
> 2.26.2
>
>

Reviewed-by: Jarkko Sakkinen <[email protected]>

/Jarkko

2021-07-16 16:07:17

by Ard Biesheuvel

Subject: Re: [PATCH] efi/tpm: Differentiate missing and invalid final event log table.

On Fri, 9 Jul 2021 at 18:38, Jarkko Sakkinen <[email protected]> wrote:
>
> On Thu, Jul 08, 2021 at 11:46:54AM +0200, Michal Suchanek wrote:
> > 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 <[email protected]>
> > ---
> > 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;
> > }
> >
> > --
> > 2.26.2
> >
> >
>
> Reviewed-by: Jarkko Sakkinen <[email protected]>
>

Queued as a fix, thanks