[PATCH] efi_loader: fix FinalEvents table if an EFI uses GetEventLog

[Ruchika Gupta]

Please ignore this patch. Sent by mistake.

On Thu, 18 Nov 2021 at 11:48, Ruchika Gupta <ruchika.gupta at linaro.org>
wrote:

> ---
>  lib/efi_loader/efi_tcg2.c | 90 ++++++++++++++++++++++++++-------------
>  1 file changed, 61 insertions(+), 29 deletions(-)
>
> diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
> index 189e4a5ba5..215f4b2b04 100644
> --- a/lib/efi_loader/efi_tcg2.c
> +++ b/lib/efi_loader/efi_tcg2.c
> @@ -34,6 +34,7 @@ struct event_log_buffer {
>         size_t final_pos; /* final events config table position */
>         size_t last_event_size;
>         bool get_event_called;
> +       bool ebs_called;
>         bool truncated;
>  };
>
> @@ -186,39 +187,29 @@ static efi_status_t tcg2_pcr_extend(struct udevice
> *dev, u32 pcr_index,
>         return EFI_SUCCESS;
>  }
>
> -/* tcg2_agile_log_append - Append an agile event to out eventlog
> +/* put_event - Append an agile event to an eventlog
>   *
>   * @pcr_index:         PCR index
>   * @event_type:                type of event added
>   * @digest_list:       list of digest algorithms to add
>   * @size:              size of event
>   * @event:             event to add
> + * @log:               log buffer to append the event
>   *
> - * @Return: status code
>   */
> -static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type,
> -                                         struct tpml_digest_values
> *digest_list,
> -                                         u32 size, u8 event[])
> +static void put_event(u32 pcr_index, u32 event_type,
> +                     struct tpml_digest_values *digest_list, u32 size,
> +                     u8 event[], void *log)
>  {
> -       void *log = (void *)((uintptr_t)event_log.buffer + event_log.pos);
>         size_t pos;
>         size_t i;
>         u32 event_size;
>
> -       if (event_log.get_event_called)
> -               log = (void *)((uintptr_t)event_log.final_buffer +
> -                              event_log.final_pos);
> -
>         /*
>          * size refers to the length of event[] only, we need to check
> against
>          * the final tcg_pcr_event2 size
>          */
>         event_size = size + tcg_event_final_size(digest_list);
> -       if (event_log.pos + event_size > TPM2_EVENT_LOG_SIZE ||
> -           event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE) {
> -               event_log.truncated = true;
> -               return EFI_VOLUME_FULL;
> -       }
>
>         put_unaligned_le32(pcr_index, log);
>         pos = offsetof(struct tcg_pcr_event2, event_type);
> @@ -242,25 +233,64 @@ static efi_status_t tcg2_agile_log_append(u32
> pcr_index, u32 event_type,
>         memcpy((void *)((uintptr_t)log + pos), event, size);
>         pos += size;
>
> -       /* make sure the calculated buffer is what we checked against */
> +       /*
> +        * make sure the calculated buffer is what we checked against
> +        * This check should never fail.  It checks the code above is
> +        * calculating the right length for the event we are adding
> +        * */
>         if (pos != event_size)
> -               return EFI_INVALID_PARAMETER;
> +               log_err("Appending to the EventLog failed\n");
>
> -       /* if GetEventLog hasn't been called update the normal log */
> -       if (!event_log.get_event_called) {
> -               event_log.pos += pos;
> -               event_log.last_event_size = pos;
> -       } else {
> -       /* if GetEventLog has been called update config table log */
> -               struct efi_tcg2_final_events_table *final_event;
> +}
>
> -               final_event =
> -                       (struct efi_tcg2_final_events_table
> *)(event_log.final_buffer);
> -               final_event->number_of_events++;
> -               event_log.final_pos += pos;
> +/* tcg2_agile_log_append - Append an agile event to an eventlog
> + *
> + * @pcr_index:         PCR index
> + * @event_type:                type of event added
> + * @digest_list:       list of digest algorithms to add
> + * @size:              size of event
> + * @event:             event to add
> + * @log:               log buffer to append the event
> + *
> + * @Return: status code
> + */
> +static efi_status_t tcg2_agile_log_append(u32 pcr_index, u32 event_type,
> +                                         struct tpml_digest_values
> *digest_list,
> +                                         u32 size, u8 event[])
> +{
> +       void *log = (void *)((uintptr_t)event_log.buffer + event_log.pos);
> +       u32 event_size = size + tcg_event_final_size(digest_list);
> +       struct efi_tcg2_final_events_table *final_event;
> +       efi_status_t ret = EFI_SUCCESS;
> +
> +       /* if ExitBootServices hasn't been called update the normal log */
> +       if (!event_log.ebs_called) {
> +               if (event_log.truncated ||
> +                   event_log.pos + event_size > TPM2_EVENT_LOG_SIZE) {
> +                       event_log.truncated = true;
> +                       return EFI_VOLUME_FULL;
> +               }
> +               put_event(pcr_index, event_type, digest_list, size, event,
> log);
> +               event_log.pos += event_size;
> +               event_log.last_event_size = event_size;
>         }
>
> -       return EFI_SUCCESS;
> +       if (!event_log.get_event_called)
> +               return ret;
> +
> +       /* if GetEventLog has been called update FinalEventLog as well */
> +       if (event_log.final_pos + event_size > TPM2_EVENT_LOG_SIZE)
> +               return EFI_VOLUME_FULL;
> +
> +       log = (void *)((uintptr_t)event_log.final_buffer +
> event_log.final_pos);
> +       put_event(pcr_index, event_type, digest_list, size, event, log);
> +
> +       final_event =
> +               (struct efi_tcg2_final_events_table
> *)event_log.final_buffer;
> +       final_event->number_of_events++;
> +       event_log.final_pos += event_size;
> +
> +       return ret;
>  }
>
>  /**
> @@ -1303,6 +1333,7 @@ static efi_status_t efi_init_event_log(void)
>         event_log.pos = 0;
>         event_log.last_event_size = 0;
>         event_log.get_event_called = false;
> +       event_log.ebs_called = false;
>         event_log.truncated = false;
>
>         /*
> @@ -1792,6 +1823,7 @@ efi_tcg2_notify_exit_boot_services(struct efi_event
> *event, void *context)
>
>         EFI_ENTRY("%p, %p", event, context);
>
> +       event_log.ebs_called = true;
>         ret = platform_get_tpm2_device(&dev);
>         if (ret != EFI_SUCCESS)
>                 goto out;
> --
> 2.25.1
>
>