efi_loader: efi_tcg2_register returns appropriate error

This commit modify efi_tcg2_register() to return the
appropriate error.
With this fix, sandbox will not boot because efi_tcg2_register()
fails due to some missing feature in GetCapabilities.
So disable sandbox if EFI_TCG2_PROTOCOL is enabled.

UEFI secure boot variable measurement is not directly related
to TCG2 protocol installation, tcg2_measure_secure_boot_variable()
is moved to the separate function.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
This commit is contained in:
Masahisa Kojima 2021-12-07 14:15:31 +09:00 committed by Heinrich Schuchardt
parent 446266b024
commit 54bec17f6b
4 changed files with 55 additions and 18 deletions

View file

@ -525,6 +525,8 @@ efi_status_t efi_disk_register(void);
efi_status_t efi_rng_register(void);
/* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
efi_status_t efi_tcg2_register(void);
/* Called by efi_init_obj_list() to do initial measurement */
efi_status_t efi_tcg2_do_initial_measurement(void);
/* measure the pe-coff image, extend PCR and add Event Log */
efi_status_t tcg2_measure_pe_image(void *efi, u64 efi_size,
struct efi_loaded_image_obj *handle,

View file

@ -308,6 +308,8 @@ config EFI_TCG2_PROTOCOL
bool "EFI_TCG2_PROTOCOL support"
default y
depends on TPM_V2
# Sandbox TPM currently fails on GetCapabilities needed for TCG2
depends on !SANDBOX
select SHA1
select SHA256
select SHA384

View file

@ -241,6 +241,10 @@ efi_status_t efi_init_obj_list(void)
ret = efi_tcg2_register();
if (ret != EFI_SUCCESS)
goto out;
ret = efi_tcg2_do_initial_measurement();
if (ret == EFI_SECURITY_VIOLATION)
goto out;
}
/* Secure boot */

View file

@ -153,6 +153,15 @@ static u16 alg_to_len(u16 hash_alg)
return 0;
}
static bool is_tcg2_protocol_installed(void)
{
struct efi_handler *handler;
efi_status_t ret;
ret = efi_search_protocol(efi_root, &efi_guid_tcg2_protocol, &handler);
return ret == EFI_SUCCESS;
}
static u32 tcg_event_final_size(struct tpml_digest_values *digest_list)
{
u32 len;
@ -1664,6 +1673,14 @@ void tcg2_uninit(void)
event_log.buffer = NULL;
efi_free_pool(event_log.final_buffer);
event_log.final_buffer = NULL;
if (!is_tcg2_protocol_installed())
return;
ret = efi_remove_protocol(efi_root, &efi_guid_tcg2_protocol,
(void *)&efi_tcg2_protocol);
if (ret != EFI_SUCCESS)
log_err("Failed to remove EFI TCG2 protocol\n");
}
/**
@ -2345,12 +2362,37 @@ error:
return ret;
}
/**
* efi_tcg2_do_initial_measurement() - do initial measurement
*
* Return: status code
*/
efi_status_t efi_tcg2_do_initial_measurement(void)
{
efi_status_t ret;
struct udevice *dev;
if (!is_tcg2_protocol_installed())
return EFI_SUCCESS;
ret = platform_get_tpm2_device(&dev);
if (ret != EFI_SUCCESS)
return EFI_SECURITY_VIOLATION;
ret = tcg2_measure_secure_boot_variable(dev);
if (ret != EFI_SUCCESS)
goto out;
out:
return ret;
}
/**
* efi_tcg2_register() - register EFI_TCG2_PROTOCOL
*
* If a TPM2 device is available, the TPM TCG2 Protocol is registered
*
* Return: An error status is only returned if adding the protocol fails.
* Return: status code
*/
efi_status_t efi_tcg2_register(void)
{
@ -2373,8 +2415,10 @@ efi_status_t efi_tcg2_register(void)
}
ret = efi_init_event_log();
if (ret != EFI_SUCCESS)
if (ret != EFI_SUCCESS) {
tcg2_uninit();
goto fail;
}
ret = efi_add_protocol(efi_root, &efi_guid_tcg2_protocol,
(void *)&efi_tcg2_protocol);
@ -2391,24 +2435,9 @@ efi_status_t efi_tcg2_register(void)
goto fail;
}
ret = tcg2_measure_secure_boot_variable(dev);
if (ret != EFI_SUCCESS) {
tcg2_uninit();
goto fail;
}
return ret;
fail:
log_err("Cannot install EFI_TCG2_PROTOCOL\n");
/*
* Return EFI_SUCCESS and don't stop the EFI subsystem.
* That's done for 2 reasons
* - If the protocol is not installed the PCRs won't be extended. So
* someone later in the boot flow will notice that and take the
* necessary actions.
* - The TPM sandbox is limited and we won't be able to run any efi
* related tests with TCG2 enabled
*/
return EFI_SUCCESS;
return ret;
}