Re: [PATCH 2/3] efi_loader: add UEFI GPT measurement

On 9/15/21 7:15 AM, Masahisa Kojima wrote:

This commit adds the UEFI GPT disk partition topology measurement required in TCG PC Client PFP Spec.

Thanks for looking into the missing parts of TCG measurement in U-Boot.

The requirements in the TCG PC Client PFP Spec are strange. It does not explicitly say how to handle multiple block devices. Did the authors never enjoy the pleasure of a second disk drive?

With your implementation you would measure the GPT table of the SD-card from which you load Shim or GRUB but would not care about the GPT of the NVMe drive with your OS.

A clarification by the TCG standards committee would be helpful.

After this series "10.2.7 DEVICE_SECURITY_EVENT_DATA Structure" still needs to be covered.

Best regards

Heinrich

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

include/blk.h | 3 + include/efi_loader.h | 2 +- include/efi_tcg2.h | 12 +++ lib/efi_loader/efi_boottime.c | 2 +- lib/efi_loader/efi_tcg2.c | 175 +++++++++++++++++++++++++++++++++- 5 files changed, 191 insertions(+), 3 deletions(-)

diff --git a/include/blk.h b/include/blk.h index 19bab081c2..f0cc7ca1a2 100644 --- a/include/blk.h +++ b/include/blk.h @@ -45,6 +45,9 @@ enum if_type { #define BLK_PRD_SIZE 20 #define BLK_REV_SIZE 8

+#define PART_FORMAT_PCAT 0x1 +#define PART_FORMAT_GPT 0x2

• /*
  • Identifies the partition table type (ie. MBR vs GPT GUID) signature
  */

diff --git a/include/efi_loader.h b/include/efi_loader.h index 13f0c24058..dbcc296e01 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -503,7 +503,7 @@ efi_status_t efi_init_variables(void); void efi_variables_boot_exit_notify(void); efi_status_t efi_tcg2_notify_exit_boot_services_failed(void); /* Measure efi application invocation */ -efi_status_t efi_tcg2_measure_efi_app_invocation(void); +efi_status_t efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *handle); /* Measure efi application exit */ efi_status_t efi_tcg2_measure_efi_app_exit(void); /* Called by bootefi to initialize root node */ diff --git a/include/efi_tcg2.h b/include/efi_tcg2.h index da33f8a1d0..33257fa96b 100644 --- a/include/efi_tcg2.h +++ b/include/efi_tcg2.h @@ -230,6 +230,18 @@ struct smbios_handoff_table_pointers2 { struct efi_configuration_table table_entry[1]; } __packed;

+/**

• • struct tdUEFI_GPT_DATA - event log structure of industry standard tables
• • @uefi_partition_header: gpt partition header
• • @number_of_partitions: the number of partition
• • @partitions: partition entries
• */

+struct efi_gpt_data {

• gpt_header uefi_partition_header;
• u64 number_of_partitions;
• gpt_entry partitions[];

+} __packed;

• struct efi_tcg2_protocol { efi_status_t (EFIAPI * get_capability)(struct efi_tcg2_protocol *this, struct efi_tcg2_boot_service_capability *capability);

diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index 701e2212c8..bf5661e1ee 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -3003,7 +3003,7 @@ efi_status_t EFIAPI efi_start_image(efi_handle_t image_handle,

if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) { if (image_obj->image_type == IMAGE_SUBSYSTEM_EFI_APPLICATION) {

• 	ret = efi_tcg2_measure_efi_app_invocation();
  

• 	ret = efi_tcg2_measure_efi_app_invocation(image_obj);
  if (ret != EFI_SUCCESS) {
  	log_warning("tcg2 measurement fails(0x%lx)\n",
  		    ret);
  

diff --git a/lib/efi_loader/efi_tcg2.c b/lib/efi_loader/efi_tcg2.c index 7f47998a55..35810615ed 100644 --- a/lib/efi_loader/efi_tcg2.c +++ b/lib/efi_loader/efi_tcg2.c @@ -1525,12 +1525,181 @@ static void *search_smbios_table(void) return NULL; }

+/**

• • search_gpt_dp_node() - search gpt device path node
• • @device_path: device path
• • Return: pointer to the gpt device path node
• */

+static struct +efi_device_path *search_gpt_dp_node(struct efi_device_path *device_path) +{

• struct efi_device_path *dp = device_path;
• while (dp) {

• if (dp->type == DEVICE_PATH_TYPE_MEDIA_DEVICE &&
  

•     dp->sub_type == DEVICE_PATH_SUB_TYPE_HARD_DRIVE_PATH) {
  

• 	struct efi_device_path_hard_drive_path *hd_dp =
  

• 		(struct efi_device_path_hard_drive_path *)dp;
  

• 	if (hd_dp->partmap_type == PART_FORMAT_GPT &&
  

• 	    hd_dp->signature_type == SIG_TYPE_GUID)
  

• 		return dp;
  

• }
  

• dp = efi_dp_next(dp);
  

• }
• return NULL;

+}

+/**

• • tcg2_measure_gpt_table() - measure gpt table
• • @dev: TPM device
• • @loaded_image: handle to the loaded image
• • Return: status code
• */

+static efi_status_t +tcg2_measure_gpt_data(struct udevice *dev,

•       struct efi_loaded_image_obj *loaded_image)
  

+{

• efi_status_t ret;
• efi_handle_t handle;
• struct efi_handler *dp_handler;
• struct efi_device_path *orig_device_path;
• struct efi_device_path *device_path;
• struct efi_device_path *dp;
• struct efi_block_io *block_io;
• struct efi_gpt_data *event = NULL;
• efi_guid_t null_guid = NULL_GUID;
• gpt_header *orig_gpt_h = NULL;
• gpt_entry *orig_gpt_e = NULL;
• gpt_header *gpt_h = NULL;
• gpt_entry *entry = NULL;
• gpt_entry *gpt_e;
• u32 num_of_valid_entry = 0;
• u32 event_size;
• u32 i;
• u32 total_gpt_entry_size;
• ret = efi_search_protocol(&loaded_image->header,

• 		  &efi_guid_loaded_image_device_path,
  

• 		  &dp_handler);
  

• if (ret != EFI_SUCCESS)

• return ret;
  

• orig_device_path = dp_handler->protocol_interface;
• device_path = efi_dp_dup(orig_device_path);
• if (!device_path)

• return EFI_OUT_OF_RESOURCES;
  

• dp = search_gpt_dp_node(device_path);
• if (!dp) {

• /* no GPT device path node found, skip GPT measurement */
  

• ret = EFI_SUCCESS;
  

• goto out1;
  

• }
• /* read GPT header */
• dp->type = DEVICE_PATH_TYPE_END;
• dp->sub_type = DEVICE_PATH_SUB_TYPE_END;
• dp = device_path;
• ret = EFI_CALL(systab.boottime->locate_device_path(&efi_block_io_guid,

• 					   &dp, &handle));
  

• if (ret != EFI_SUCCESS)

• goto out1;
  

• ret = EFI_CALL(efi_handle_protocol(handle,

• 			   &efi_block_io_guid, (void **)&block_io));
  

• if (ret != EFI_SUCCESS)

• goto out1;
  

• orig_gpt_h = calloc(1, (block_io->media->block_size + block_io->media->io_align));
• if (!orig_gpt_h) {

• ret = EFI_OUT_OF_RESOURCES;
  

• goto out2;
  

• }
• gpt_h = (gpt_header *)ALIGN((uintptr_t)orig_gpt_h, block_io->media->io_align);
• ret = block_io->read_blocks(block_io, block_io->media->media_id, 1,

• 		    block_io->media->block_size, gpt_h);
  

• if (ret != EFI_SUCCESS)

• goto out2;
  

• /* read GPT entry */
• total_gpt_entry_size = gpt_h->num_partition_entries *

• 	       gpt_h->sizeof_partition_entry;
  

• orig_gpt_e = calloc(1, total_gpt_entry_size + block_io->media->io_align);
• entry = (void *)ALIGN((uintptr_t)orig_gpt_e, block_io->media->io_align);
• if (!entry) {

• ret = EFI_OUT_OF_RESOURCES;
  

• goto out2;
  

• }
• ret = block_io->read_blocks(block_io, block_io->media->media_id,

• 		    gpt_h->partition_entry_lba,
  

• 		    total_gpt_entry_size, entry);
  

• if (ret != EFI_SUCCESS)

• goto out2;
  

• /* count valid GPT entry */
• gpt_e = entry;
• for (i = 0; i < gpt_h->num_partition_entries; i++) {

• if (guidcmp(&null_guid, &gpt_e->partition_type_guid))
  

• 	num_of_valid_entry++;
  

• gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
  

• }
• /* prepare event data for measurement */
• event_size = sizeof(struct efi_gpt_data) +

• (num_of_valid_entry * gpt_h->sizeof_partition_entry);
  

• event = calloc(1, event_size);
• if (!event) {

• ret = EFI_OUT_OF_RESOURCES;
  

• goto out2;
  

• }
• memcpy(event, gpt_h, sizeof(gpt_header));
• put_unaligned_le64(num_of_valid_entry, &event->number_of_partitions);
• /* copy valid GPT entry */
• gpt_e = entry;
• num_of_valid_entry = 0;
• for (i = 0; i < gpt_h->num_partition_entries; i++) {

• if (guidcmp(&null_guid, &gpt_e->partition_type_guid)) {
  

• 	memcpy((u8 *)event->partitions +
  

• 	       (num_of_valid_entry * gpt_h->sizeof_partition_entry),
  

• 	       gpt_e, gpt_h->sizeof_partition_entry);
  

• 	num_of_valid_entry++;
  

• }
  

• gpt_e = (gpt_entry *)((u8 *)gpt_e + gpt_h->sizeof_partition_entry);
  

• }
• ret = tcg2_measure_event(dev, 5, EV_EFI_GPT_EVENT, event_size, (u8 *)event);
• if (ret != EFI_SUCCESS)

• goto out2;
  

+out2:

• EFI_CALL(efi_close_protocol((efi_handle_t)block_io, &efi_block_io_guid,

• 		    NULL, NULL));
  

• free(orig_gpt_h);
• free(orig_gpt_e);
• free(event);

+out1:

• efi_free_pool(device_path);
• 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 efi_tcg2_measure_efi_app_invocation(struct efi_loaded_image_obj *handle) { efi_status_t ret; u32 pcr_index; @@ -1569,6 +1738,10 @@ efi_status_t efi_tcg2_measure_efi_app_invocation(void) goto out; }

• ret = tcg2_measure_gpt_data(dev, handle);
• if (ret != EFI_SUCCESS)

• goto out;
  

• tcg2_efi_app_invoked = true; out: return ret;