On Mon, 26 Aug 2019 at 18:30, Peter Jones <pjones@xxxxxxxxxx> wrote:
>
> When there are no entries to put into the final event log, some machines
> will return the template they would have populated anyway. In this case
> the nr_events field is 0, but the rest of the log is just garbage.
>
> This patch stops us from trying to iterate the table with
> __calc_tpm2_event_size() when the number of events in the table is 0.
>
> Signed-off-by: Peter Jones <pjones@xxxxxxxxxx>
> Tested-by: Lyude Paul <lyude@xxxxxxxxxx>
> ---
> drivers/firmware/efi/tpm.c | 14 +++++++++-----
> 1 file changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/firmware/efi/tpm.c b/drivers/firmware/efi/tpm.c
> index 1d3f5ca3eaa..be51ed17c6e 100644
> --- a/drivers/firmware/efi/tpm.c
> +++ b/drivers/firmware/efi/tpm.c
> @@ -75,11 +75,15 @@ int __init efi_tpm_eventlog_init(void)
> goto out;
> }
>
> - tbl_size = tpm2_calc_event_log_size((void *)efi.tpm_final_log
> - + sizeof(final_tbl->version)
> - + sizeof(final_tbl->nr_events),
> - final_tbl->nr_events,
> - log_tbl->log);
> + tbl_size = 0;
> + if (final_tbl->nr_events != 0) {
> + void *events = (void *)efi.tpm_final_log
> + + sizeof(final_tbl->version)
> + + sizeof(final_tbl->nr_events);
Please put a newline here
With that fixed,
Acked-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> + tbl_size = tpm2_calc_event_log_size(events,
> + final_tbl->nr_events,
> + log_tbl->log);
> + }
> memblock_reserve((unsigned long)final_tbl,
> tbl_size + sizeof(*final_tbl));
> early_memunmap(final_tbl, sizeof(*final_tbl));
> --
> 2.23.0.rc2
>
