Re: [PATCH v2 2/3] efi_loader: add UEFI GPT measurement

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

On Tue, Sep 21, 2021 at 04:19:30PM +0900, Masahisa Kojima wrote:
> This commit adds the UEFI GPT disk partition topology
> measurement required in TCG PC Client PFP Spec.
> 
> Signed-off-by: Masahisa Kojima <masahisa.kojima@linaro.org>
> ---
> 
> (no changes since v1)
> 
>  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

This isn't used anywhere

> +#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 85a032dbbd..0ecc7f99d7 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[];
>  } __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 4f68f6dfd5..ea2c1ead03 100644
> --- a/lib/efi_loader/efi_tcg2.c
> +++ b/lib/efi_loader/efi_tcg2.c
> @@ -1525,12 +1525,181 @@ static void *find_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 &&

On dp_part_node() partmap_type is set to 2 for EFI partition types.  Why do
we interpret it as 'GPT' here?

> +			    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;
> +

Can't you use efi_bl_read() here, instead of searching for the protocol? 
If you can, moving that out of a static function would make more sense. 

> +	/* 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;
> -- 
> 2.17.1
> 

Cheers
/Ilias