efi_loader: add boot variable measurement

TCG PC Client PFP spec requires to measure "Boot####"
and "BootOrder" variables, EV_SEPARATOR event prior
to the Ready to Boot invocation.
Since u-boot does not implement Ready to Boot event,
these measurements are performed when efi_start_image() is called.

TCG spec also requires to measure "Calling EFI Application from
Boot Option" for each boot attempt, and "Returning from EFI
Application from Boot Option" if a boot device returns control
back to the Boot Manager.

Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>

include/efi_loader.h

@@ -499,6 +499,10 @@ efi_status_t efi_run_image(void *source_buffer, efi_uintn_t source_size);
 efi_status_t efi_init_variables(void);
 /* Notify ExitBootServices() is called */
 void efi_variables_boot_exit_notify(void);
+/* Measure efi application invocation */
+efi_status_t efi_tcg2_measure_efi_app_invocation(void);
+/* Measure efi application exit */
+efi_status_t efi_tcg2_measure_efi_app_exit(void);
 /* Called by bootefi to initialize root node */
 efi_status_t efi_root_node_register(void);
 /* Called by bootefi to initialize runtime */

include/tpm-v2.h

@@ -75,7 +75,7 @@ struct udevice;
 /*
  * event types, cf.
  * "TCG PC Client Platform Firmware Profile Specification", Family "2.0"
- * rev 1.04, June 3, 2019
+ * Level 00 Version 1.05 Revision 23, May 7, 2021
  */
 #define EV_EFI_EVENT_BASE			((u32)0x80000000)
 #define EV_EFI_VARIABLE_DRIVER_CONFIG		((u32)0x80000001)
@@ -87,8 +87,24 @@ struct udevice;
 #define EV_EFI_ACTION				((u32)0x80000007)
 #define EV_EFI_PLATFORM_FIRMWARE_BLOB		((u32)0x80000008)
 #define EV_EFI_HANDOFF_TABLES			((u32)0x80000009)
+#define EV_EFI_PLATFORM_FIRMWARE_BLOB2		((u32)0x8000000A)
+#define EV_EFI_HANDOFF_TABLES2			((u32)0x8000000B)
+#define EV_EFI_VARIABLE_BOOT2			((u32)0x8000000C)
 #define EV_EFI_HCRTM_EVENT			((u32)0x80000010)
 #define EV_EFI_VARIABLE_AUTHORITY		((u32)0x800000E0)
+#define EV_EFI_SPDM_FIRMWARE_BLOB		((u32)0x800000E1)
+#define EV_EFI_SPDM_FIRMWARE_CONFIG		((u32)0x800000E2)
+
+#define EFI_CALLING_EFI_APPLICATION         \
+	"Calling EFI Application from Boot Option"
+#define EFI_RETURNING_FROM_EFI_APPLICATION  \
+	"Returning from EFI Application from Boot Option"
+#define EFI_EXIT_BOOT_SERVICES_INVOCATION   \
+	"Exit Boot Services Invocation"
+#define EFI_EXIT_BOOT_SERVICES_FAILED       \
+	"Exit Boot Services Returned with Failure"
+#define EFI_EXIT_BOOT_SERVICES_SUCCEEDED    \
+	"Exit Boot Services Returned with Success"
 
 /* TPMS_TAGGED_PROPERTY Structure */
 struct tpms_tagged_property {

lib/efi_loader/efi_boottime.c

@@ -2994,6 +2994,16 @@ efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,
 	image_obj->exit_status = &exit_status;
 	image_obj->exit_jmp = &exit_jmp;
 
+	if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) {
+		if (image_obj->image_type == IMAGE_SUBSYSTEM_EFI_APPLICATION) {
+			ret = efi_tcg2_measure_efi_app_invocation();
+			if (ret != EFI_SUCCESS) {
+				log_warning("tcg2 measurement fails(0x%lx)\n",
+					    ret);
+			}
+		}
+	}
+
 	/* call the image! */
 	if (setjmp(&exit_jmp)) {
 		/*
@@ -3252,6 +3262,16 @@ static efi_status_t EFIAPI efi_exit(efi_handle_t image_handle,
 	    exit_status != EFI_SUCCESS)
 		efi_delete_image(image_obj, loaded_image_protocol);
 
+	if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) {
+		if (image_obj->image_type == IMAGE_SUBSYSTEM_EFI_APPLICATION) {
+			ret = efi_tcg2_measure_efi_app_exit();
+			if (ret != EFI_SUCCESS) {
+				log_warning("tcg2 measurement fails(0x%lx)\n",
+					    ret);
+			}
+		}
+	}
+
 	/* Make sure entry/exit counts for EFI world cross-overs match */
 	EFI_EXIT(exit_status);
 

lib/efi_loader/efi_tcg2.c

@@ -35,6 +35,7 @@ struct event_log_buffer {
 };
 
 static struct event_log_buffer event_log;
+static bool tcg2_efi_app_invoked;
 /*
  * When requesting TPM2_CAP_TPM_PROPERTIES the value is on a standard offset.
  * Since the current tpm2_get_capability() response buffers starts at
@@ -1385,6 +1386,126 @@ static efi_status_t tcg2_measure_variable(struct udevice *dev, u32 pcr_index,
 	return ret;
 }
 
+/**
+ * tcg2_measure_boot_variable() - measure boot variables
+ *
+ * @dev:	TPM device
+ *
+ * Return:	status code
+ */
+static efi_status_t tcg2_measure_boot_variable(struct udevice *dev)
+{
+	u16 *boot_order;
+	u16 *boot_index;
+	u16 var_name[] = L"BootOrder";
+	u16 boot_name[] = L"Boot####";
+	u8 *bootvar;
+	efi_uintn_t var_data_size;
+	u32 count, i;
+	efi_status_t ret;
+
+	boot_order = efi_get_var(var_name, &efi_global_variable_guid,
+				 &var_data_size);
+	if (!boot_order) {
+		ret = EFI_NOT_FOUND;
+		goto error;
+	}
+
+	ret = tcg2_measure_variable(dev, 1, EV_EFI_VARIABLE_BOOT2, var_name,
+				    &efi_global_variable_guid, var_data_size,
+				    (u8 *)boot_order);
+	if (ret != EFI_SUCCESS)
+		goto error;
+
+	count = var_data_size / sizeof(*boot_order);
+	boot_index = boot_order;
+	for (i = 0; i < count; i++) {
+		efi_create_indexed_name(boot_name, sizeof(boot_name),
+					"Boot", *boot_index++);
+
+		bootvar = efi_get_var(boot_name, &efi_global_variable_guid,
+				      &var_data_size);
+
+		if (!bootvar) {
+			log_info("%ls not found\n", boot_name);
+			continue;
+		}
+
+		ret = tcg2_measure_variable(dev, 1, EV_EFI_VARIABLE_BOOT2,
+					    boot_name,
+					    &efi_global_variable_guid,
+					    var_data_size, bootvar);
+		free(bootvar);
+		if (ret != EFI_SUCCESS)
+			goto error;
+	}
+
+error:
+	free(boot_order);
+	return ret;
+}
+
+/**
+ * efi_tcg2_measure_efi_app_invocation() - measure efi app invocation
+ *
+ * Return:	status code
+ */
+efi_status_t efi_tcg2_measure_efi_app_invocation(void)
+{
+	efi_status_t ret;
+	u32 pcr_index;
+	struct udevice *dev;
+	u32 event = 0;
+
+	if (tcg2_efi_app_invoked)
+		return EFI_SUCCESS;
+
+	ret = platform_get_tpm2_device(&dev);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	ret = tcg2_measure_boot_variable(dev);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	ret = tcg2_measure_event(dev, 4, EV_EFI_ACTION,
+				 strlen(EFI_CALLING_EFI_APPLICATION),
+				 (u8 *)EFI_CALLING_EFI_APPLICATION);
+	if (ret != EFI_SUCCESS)
+		goto out;
+
+	for (pcr_index = 0; pcr_index <= 7; pcr_index++) {
+		ret = tcg2_measure_event(dev, pcr_index, EV_SEPARATOR,
+					 sizeof(event), (u8 *)&event);
+		if (ret != EFI_SUCCESS)
+			goto out;
+	}
+
+	tcg2_efi_app_invoked = true;
+out:
+	return ret;
+}
+
+/**
+ * efi_tcg2_measure_efi_app_exit() - measure efi app exit
+ *
+ * Return:	status code
+ */
+efi_status_t efi_tcg2_measure_efi_app_exit(void)
+{
+	efi_status_t ret;
+	struct udevice *dev;
+
+	ret = platform_get_tpm2_device(&dev);
+	if (ret != EFI_SUCCESS)
+		return ret;
+
+	ret = tcg2_measure_event(dev, 4, EV_EFI_ACTION,
+				 strlen(EFI_RETURNING_FROM_EFI_APPLICATION),
+				 (u8 *)EFI_RETURNING_FROM_EFI_APPLICATION);
+	return ret;
+}
+
 /**
  * tcg2_measure_secure_boot_variable() - measure secure boot variables
  *