[PATCH 3/5] efi_loader: add boot variable measurement
Masahisa Kojima
masahisa.kojima at linaro.org
Wed Jul 7 15:36:36 CEST 2021
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 at linaro.org>
---
include/efi_loader.h | 4 ++
include/tpm-v2.h | 18 ++++-
lib/efi_loader/efi_boottime.c | 20 ++++++
lib/efi_loader/efi_tcg2.c | 123 ++++++++++++++++++++++++++++++++++
4 files changed, 164 insertions(+), 1 deletion(-)
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 0a9c82a257..281ffff30f 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -407,6 +407,10 @@ 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 EFIAPI efi_tcg2_measure_efi_app_invocation(void);
+/* Measure efi application exit */
+efi_status_t EFIAPI 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 */
diff --git a/include/tpm-v2.h b/include/tpm-v2.h
index 3e48e35861..8a7b7f1874 100644
--- a/include/tpm-v2.h
+++ b/include/tpm-v2.h
@@ -73,7 +73,7 @@ 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)
@@ -85,8 +85,24 @@ 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 {
diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
index f6d5ba05e3..2914800c56 100644
--- a/lib/efi_loader/efi_boottime.c
+++ b/lib/efi_loader/efi_boottime.c
@@ -2993,6 +2993,16 @@ 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) {
+ EFI_PRINT("tcg2 measurement fails(0x%lx)\n",
+ ret);
+ }
+ }
+ }
+
/* call the image! */
if (setjmp(&exit_jmp)) {
/*
@@ -3251,6 +3261,16 @@ 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) {
+ EFI_PRINT("tcg2 measurement fails(0x%lx)\n",
+ ret);
+ }
+ }
+ }
+
/* Make sure entry/exit counts for EFI world cross-overs match */
EFI_EXIT(exit_status);
diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c
index 2a248bd62a..6e903e3cb3 100644
--- a/lib/efi_loader/efi_tcg2.c
+++ b/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
@@ -1383,6 +1384,128 @@ 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 var_name[] = L"BootOrder";
+ u16 boot_name[] = L"Boot0000";
+ u16 hexmap[] = L"0123456789ABCDEF";
+ 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) {
+ log_info("BootOrder not defined\n");
+ 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);
+ for (i = 0; i < count; i++) {
+ boot_name[4] = hexmap[(boot_order[i] & 0xf000) >> 12];
+ boot_name[5] = hexmap[(boot_order[i] & 0x0f00) >> 8];
+ boot_name[6] = hexmap[(boot_order[i] & 0x00f0) >> 4];
+ boot_name[7] = hexmap[(boot_order[i] & 0x000f)];
+
+ 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 EFIAPI 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 EFIAPI 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
*
--
2.17.1
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