[PATCH 2/7] efi_loader: fix the return values on efi_tcg

[Heinrich Schuchardt]

Am 22. Juni 2024 18:09:40 MESZ schrieb Ilias Apalodimas <ilias.apalodimas at linaro.org>:
>Hi Heinrich,
>
>[...]
>
>> >       rc = tpm2_submit_command(dev, input_param_block,
>> >                                output_param_block, &resp_buf_size);
>> > @@ -714,19 +721,20 @@ efi_tcg2_get_active_pcr_banks(struct efi_tcg2_protocol *this,
>> >                             u32 *active_pcr_banks)
>> >   {
>> >       struct udevice *dev;
>> > -     efi_status_t ret;
>> > +     efi_status_t ret = EFI_INVALID_PARAMETER;
>> >
>> >       EFI_ENTRY("%p, %p", this, active_pcr_banks);
>> >
>> > -     if (!this || !active_pcr_banks) {
>> > -             ret = EFI_INVALID_PARAMETER;
>> > +     if (!this || !active_pcr_banks)
>> >               goto out;
>> > -     }
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > +
>> > +     if (tcg2_platform_get_tpm2(&dev))
>>
>> EFI_INVALID_PARAMETER does not convey the problem type.
>> Should we return EFI_DEVICE_ERROR here?
>>
>> The authors of the specification only foresaw one or more of the
>> parameters being incorrect (EFI_INVALID_PARAMETER).
>
>I completely agree that the result is misleading. However, I'd prefer
>sticking to the spec for now and maybe add a comment?
>
>
>>
>> > +             goto out;
>> > +
>> > +     if (tcg2_get_active_pcr_banks(dev, active_pcr_banks))
>>
>> EFI_DEVICE_ERROR?
>
>Same here
>
>Thanks for the qucik review!
>/Ilias


Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>


>>
>> Best regards
>>
>> Heinrich
>>
>> >               goto out;
>> >
>> > -     ret = tcg2_get_active_pcr_banks(dev, active_pcr_banks);
>> > +     ret = EFI_SUCCESS;
>> >
>> >   out:
>> >       return EFI_EXIT(ret);
>> > @@ -852,14 +860,15 @@ static efi_status_t measure_event(struct udevice *dev, u32 pcr_index,
>> >                                 u32 event_type, u32 size, u8 event[])
>> >   {
>> >       struct tpml_digest_values digest_list;
>> > -     efi_status_t ret;
>> > +     efi_status_t ret = EFI_DEVICE_ERROR;
>> > +     int rc;
>> >
>> > -     ret = tcg2_create_digest(dev, event, size, &digest_list);
>> > -     if (ret != EFI_SUCCESS)
>> > +     rc = tcg2_create_digest(dev, event, size, &digest_list);
>> > +     if (rc)
>> >               goto out;
>> >
>> > -     ret = tcg2_pcr_extend(dev, pcr_index, &digest_list);
>> > -     if (ret != EFI_SUCCESS)
>> > +     rc = tcg2_pcr_extend(dev, pcr_index, &digest_list);
>> > +     if (rc)
>> >               goto out;
>> >
>> >       ret = tcg2_agile_log_append(pcr_index, event_type, &digest_list,
>> > @@ -901,10 +910,10 @@ static efi_status_t efi_init_event_log(void)
>> >       struct tcg2_event_log elog;
>> >       struct udevice *dev;
>> >       efi_status_t ret;
>> > +     int rc;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > -             return ret;
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> > +             return EFI_DEVICE_ERROR;
>> >
>> >       ret = efi_allocate_pool(EFI_BOOT_SERVICES_DATA, TPM2_EVENT_LOG_SIZE,
>> >                               (void **)&event_log.buffer);
>> > @@ -933,9 +942,11 @@ static efi_status_t efi_init_event_log(void)
>> >        */
>> >       elog.log = event_log.buffer;
>> >       elog.log_size = TPM2_EVENT_LOG_SIZE;
>> > -     ret = tcg2_log_prepare_buffer(dev, &elog, false);
>> > -     if (ret != EFI_SUCCESS)
>> > +     rc = tcg2_log_prepare_buffer(dev, &elog, false);
>> > +     if (rc) {
>> > +             ret = (rc == -ENOBUFS) ? EFI_BUFFER_TOO_SMALL : EFI_DEVICE_ERROR;
>> >               goto free_pool;
>> > +     }
>> >
>> >       event_log.pos = elog.log_position;
>> >
>> > @@ -1306,8 +1317,7 @@ efi_status_t efi_tcg2_measure_dtb(void *dtb)
>> >       if (!is_tcg2_protocol_installed())
>> >               return EFI_SUCCESS;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> >               return EFI_SECURITY_VIOLATION;
>> >
>> >       rsvmap_size = size_of_rsvmap(dtb);
>> > @@ -1356,8 +1366,7 @@ efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *ha
>> >       if (tcg2_efi_app_invoked)
>> >               return EFI_SUCCESS;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> >               return EFI_SECURITY_VIOLATION;
>> >
>> >       ret = tcg2_measure_boot_variable(dev);
>> > @@ -1406,9 +1415,8 @@ efi_status_t efi_tcg2_measure_efi_app_exit(void)
>> >       if (!is_tcg2_protocol_installed())
>> >               return EFI_SUCCESS;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > -             return ret;
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> > +             return EFI_SECURITY_VIOLATION;
>> >
>> >       ret = measure_event(dev, 4, EV_EFI_ACTION,
>> >                           strlen(EFI_RETURNING_FROM_EFI_APPLICATION),
>> > @@ -1437,9 +1445,10 @@ efi_tcg2_notify_exit_boot_services(struct efi_event *event, void *context)
>> >               goto out;
>> >       }
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > +     if (tcg2_platform_get_tpm2(&dev)) {
>> > +             ret = EFI_SECURITY_VIOLATION;
>> >               goto out;
>> > +     }
>> >
>> >       ret = measure_event(dev, 5, EV_EFI_ACTION,
>> >                           strlen(EFI_EXIT_BOOT_SERVICES_INVOCATION),
>> > @@ -1469,9 +1478,8 @@ efi_status_t efi_tcg2_notify_exit_boot_services_failed(void)
>> >       if (!is_tcg2_protocol_installed())
>> >               return EFI_SUCCESS;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > -             goto out;
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> > +             return EFI_SECURITY_VIOLATION;
>> >
>> >       ret = measure_event(dev, 5, EV_EFI_ACTION,
>> >                           strlen(EFI_EXIT_BOOT_SERVICES_INVOCATION),
>> > @@ -1551,8 +1559,7 @@ efi_status_t efi_tcg2_do_initial_measurement(void)
>> >       if (!is_tcg2_protocol_installed())
>> >               return EFI_SUCCESS;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS)
>> > +     if (tcg2_platform_get_tpm2(&dev))
>> >               return EFI_SECURITY_VIOLATION;
>> >
>> >       ret = tcg2_measure_secure_boot_variable(dev);
>> > @@ -1577,8 +1584,7 @@ efi_status_t efi_tcg2_register(void)
>> >       struct efi_event *event;
>> >       u32 err;
>> >
>> > -     ret = tcg2_platform_get_tpm2(&dev);
>> > -     if (ret != EFI_SUCCESS) {
>> > +     if (tcg2_platform_get_tpm2(&dev)) {
>> >               log_warning("Missing TPMv2 device for EFI_TCG_PROTOCOL\n");
>> >               return EFI_SUCCESS;
>> >       }
>> > @@ -1586,6 +1592,7 @@ efi_status_t efi_tcg2_register(void)
>> >       /* initialize the TPM as early as possible. */
>> >       err = tpm_auto_start(dev);
>> >       if (err) {
>> > +             ret = EFI_DEVICE_ERROR;
>> >               log_err("TPM startup failed\n");
>> >               goto fail;
>> >       }
>>