Re: [RFC PATCH v3 2/9] FWU: Add FWU metadata access functions for GPT partitioned block devices

On 1/19/22 19:55, Sughosh Ganu wrote:

In the FWU Multi Bank Update feature, the information about the updatable images is stored as part of the metadata, on a separate partition. Add functions for reading from and writing to the metadata when the updatable images and the metadata are stored on a block device which is formated with GPT based partition scheme.

Signed-off-by: Sughosh Ganu sughosh.ganu@linaro.org

Will a GPT partition remain the only place to store that information? Should this be implemented according to the dirver model?

---

Changes since V2:

• Move the function definition of fwu_verify_mdata to fwu_mdata.c to facilitate reuse

• Remove the block device specific desc->devnum parameter for the fwu_plat_get_alt_num function call

  include/fwu.h | 1 + include/fwu_mdata.h | 2 + lib/fwu_updates/fwu_mdata.c | 29 ++ lib/fwu_updates/fwu_mdata_gpt_blk.c | 520 ++++++++++++++++++++++++++++ 4 files changed, 552 insertions(+) create mode 100644 lib/fwu_updates/fwu_mdata_gpt_blk.c

diff --git a/include/fwu.h b/include/fwu.h index acba725bc8..12f7eecdb0 100644 --- a/include/fwu.h +++ b/include/fwu.h @@ -53,6 +53,7 @@ int fwu_get_active_index(u32 *active_idx); int fwu_update_active_index(u32 active_idx); int fwu_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank, int *alt_num); +int fwu_verify_mdata(struct fwu_mdata *mdata, bool pri_part); int fwu_mdata_check(void); int fwu_revert_boot_index(void); int fwu_accept_image(efi_guid_t *img_type_id, u32 bank); diff --git a/include/fwu_mdata.h b/include/fwu_mdata.h index d788eb69e7..53e39f9af6 100644 --- a/include/fwu_mdata.h +++ b/include/fwu_mdata.h @@ -64,4 +64,6 @@ struct fwu_mdata { struct fwu_image_entry img_entry[CONFIG_FWU_NUM_IMAGES_PER_BANK]; } __attribute__((__packed__));

+extern struct fwu_mdata_ops fwu_gpt_blk_ops;

• #endif /* _FWU_MDATA_H_ */

diff --git a/lib/fwu_updates/fwu_mdata.c b/lib/fwu_updates/fwu_mdata.c index 58e838fe28..252fcf50f6 100644 --- a/lib/fwu_updates/fwu_mdata.c +++ b/lib/fwu_updates/fwu_mdata.c @@ -25,6 +25,35 @@ static struct fwu_mdata_ops *get_fwu_mdata_ops(void) return ops; }

+/**

• • fwu_verify_mdata() - Verify the FWU metadata
• • @mdata: FWU metadata structure
• • @pri_part: FWU metadata partition is primary or secondary
• • Verify the FWU metadata by computing the CRC32 for the metadata
• • structure and comparing it against the CRC32 value stored as part
• • of the structure.
• • Return: 0 if OK, -ve on error
• */

+int fwu_verify_mdata(struct fwu_mdata *mdata, bool pri_part) +{

• u32 calc_crc32;
• void *buf;
• buf = &mdata->version;
• calc_crc32 = crc32(0, buf, sizeof(*mdata) - sizeof(u32));

CRC32 does not offer any security against manipulation. What are the security implications?

Best regards

Heinrich

• if (calc_crc32 != mdata->crc32) {

• log_err("crc32 check failed for %s FWU metadata partition\n",
  

• 	pri_part ? "primary" : "secondary");
  

• return -1;
  

• }
• return 0;

+}

• /**
  • fwu_get_active_index() - Get active_index from the FWU metadata
  • @active_idx: active_index value to be read

diff --git a/lib/fwu_updates/fwu_mdata_gpt_blk.c b/lib/fwu_updates/fwu_mdata_gpt_blk.c new file mode 100644 index 0000000000..cb47ddf4a7 --- /dev/null +++ b/lib/fwu_updates/fwu_mdata_gpt_blk.c @@ -0,0 +1,520 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*

• • Copyright (c) 2021, Linaro Limited
• */

+#include <blk.h> +#include <efi_loader.h> +#include <fwu.h> +#include <fwu_mdata.h> +#include <log.h> +#include <malloc.h> +#include <memalign.h> +#include <part.h> +#include <part_efi.h>

+#include <linux/errno.h> +#include <linux/types.h> +#include <u-boot/crc.h>

+#define PRIMARY_PART BIT(0) +#define SECONDARY_PART BIT(1) +#define BOTH_PARTS (PRIMARY_PART | SECONDARY_PART)

+#define MDATA_READ BIT(0) +#define MDATA_WRITE BIT(1)

+#define IMAGE_ACCEPT_SET BIT(0) +#define IMAGE_ACCEPT_CLEAR BIT(1)

+static int gpt_get_mdata_partitions(struct blk_desc *desc,

• 		    u16 *primary_mpart,
  

• 		    u16 *secondary_mpart)
  

+{

• int i, ret;
• u32 mdata_parts;
• efi_guid_t part_type_guid;
• struct disk_partition info;
• const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
• for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {

• if (part_get_info(desc, i, &info))
  

• 	continue;
  

• uuid_str_to_bin(info.type_guid, part_type_guid.b,
  

• 		UUID_STR_FORMAT_GUID);
  

• if (!guidcmp(&fwu_mdata_guid, &part_type_guid)) {
  

• 	++mdata_parts;
  

• 	if (!*primary_mpart)
  

• 		*primary_mpart = i;
  

• 	else
  

• 		*secondary_mpart = i;
  

• }
  

• }
• if (mdata_parts != 2) {

• log_err("Expect two copies of the FWU metadata instead of %d\n",
  

• 	mdata_parts);
  

• ret = -EINVAL;
  

• } else {

• ret = 0;
  

• }
• return ret;

+}

+static int gpt_get_mdata_disk_part(struct blk_desc *desc,

• 		   struct disk_partition *info,
  

• 		   u32 part_num)
  

+{

• int ret;
• char *mdata_guid_str = "8a7a84a0-8387-40f6-ab41-a8b9a5a60d23";
• ret = part_get_info(desc, part_num, info);
• if (ret < 0) {

• log_err("Unable to get the partition info for the FWU metadata part %d",
  

• 	part_num);
  

• return -1;
  

• }
• /* Check that it is indeed the FWU metadata partition */
• if (!strncmp(info->type_guid, mdata_guid_str, UUID_STR_LEN)) {

• /* Found the FWU metadata partition */
  

• return 0;
  

• }
• return -1;

+}

+static int gpt_read_write_mdata(struct blk_desc *desc,

• 		struct fwu_mdata *mdata,
  

• 		u8 access, u32 part_num)
  

+{

• int ret;
• u32 len, blk_start, blkcnt;
• struct disk_partition info;
• ALLOC_CACHE_ALIGN_BUFFER_PAD(struct fwu_mdata, mdata_aligned, 1,

• 		     desc->blksz);
  

• ret = gpt_get_mdata_disk_part(desc, &info, part_num);
• if (ret < 0) {

• printf("Unable to get the FWU metadata partition\n");
  

• return -ENODEV;
  

• }
• len = sizeof(*mdata);
• blkcnt = BLOCK_CNT(len, desc);
• if (blkcnt > info.size) {

• log_err("Block count exceeds FWU metadata partition size\n");
  

• return -ERANGE;
  

• }
• blk_start = info.start;
• if (access == MDATA_READ) {

• if (blk_dread(desc, blk_start, blkcnt, mdata_aligned) != blkcnt) {
  

• 	log_err("Error reading FWU metadata from the device\n");
  

• 	return -EIO;
  

• }
  

• memcpy(mdata, mdata_aligned, sizeof(struct fwu_mdata));
  

• } else {

• if (blk_dwrite(desc, blk_start, blkcnt, mdata) != blkcnt) {
  

• 	log_err("Error writing FWU metadata to the device\n");
  

• 	return -EIO;
  

• }
  

• }
• return 0;

+}

+static int gpt_read_mdata(struct blk_desc *desc,

• 	  struct fwu_mdata *mdata, u32 part_num)
  

+{

• return gpt_read_write_mdata(desc, mdata, MDATA_READ, part_num);

+}

+static int gpt_write_mdata_partition(struct blk_desc *desc,

• 			struct fwu_mdata *mdata,
  

• 			u32 part_num)
  

+{

• return gpt_read_write_mdata(desc, mdata, MDATA_WRITE, part_num);

+}

+static int fwu_gpt_update_mdata(struct fwu_mdata *mdata) +{

• int ret;
• struct blk_desc *desc;
• u16 primary_mpart = 0, secondary_mpart = 0;
• ret = fwu_plat_get_blk_desc(&desc);
• if (ret < 0) {

• log_err("Block device not found\n");
  

• return -ENODEV;
  

• }
• ret = gpt_get_mdata_partitions(desc, &primary_mpart,

• 			  &secondary_mpart);
  

• if (ret < 0) {

• log_err("Error getting the FWU metadata partitions\n");
  

• return -ENODEV;
  

• }
• /* First write the primary partition*/
• ret = gpt_write_mdata_partition(desc, mdata, primary_mpart);
• if (ret < 0) {

• log_err("Updating primary FWU metadata partition failed\n");
  

• return ret;
  

• }
• /* And now the replica */
• ret = gpt_write_mdata_partition(desc, mdata, secondary_mpart);
• if (ret < 0) {

• log_err("Updating secondary FWU metadata partition failed\n");
  

• return ret;
  

• }
• return 0;

+}

+static int gpt_get_mdata(struct fwu_mdata **mdata) +{

• int ret;
• struct blk_desc *desc;
• u16 primary_mpart = 0, secondary_mpart = 0;
• ret = fwu_plat_get_blk_desc(&desc);
• if (ret < 0) {

• log_err("Block device not found\n");
  

• return -ENODEV;
  

• }
• ret = gpt_get_mdata_partitions(desc, &primary_mpart,

• 		       &secondary_mpart);
  

• if (ret < 0) {

• log_err("Error getting the FWU metadata partitions\n");
  

• return -ENODEV;
  

• }
• *mdata = malloc(sizeof(struct fwu_mdata));
• if (!*mdata) {

• log_err("Unable to allocate memory for reading FWU metadata\n");
  

• return -ENOMEM;
  

• }
• ret = gpt_read_mdata(desc, *mdata, primary_mpart);
• if (ret < 0) {

• log_err("Failed to read the FWU metadata from the device\n");
  

• return -EIO;
  

• }
• ret = fwu_verify_mdata(*mdata, 1);
• if (!ret)

• return 0;
  

• /*

• * Verification of the primary FWU metadata copy failed.
  

• * Try to read the replica.
  

• */
  

• memset(*mdata, 0, sizeof(struct fwu_mdata));
• ret = gpt_read_mdata(desc, *mdata, secondary_mpart);
• if (ret < 0) {

• log_err("Failed to read the FWU metadata from the device\n");
  

• return -EIO;
  

• }
• ret = fwu_verify_mdata(*mdata, 0);
• if (!ret)

• return 0;
  

• /* Both the FWU metadata copies are corrupted. */
• return -1;

+}

+static int gpt_check_mdata_validity(void) +{

• int ret;
• struct blk_desc *desc;
• struct fwu_mdata pri_mdata;
• struct fwu_mdata secondary_mdata;
• u16 primary_mpart = 0, secondary_mpart = 0;
• u16 valid_partitions, invalid_partitions;
• ret = fwu_plat_get_blk_desc(&desc);
• if (ret < 0) {

• log_err("Block device not found\n");
  

• return -ENODEV;
  

• }
• /*

• * Two FWU metadata partitions are expected.
  

• * If we don't have two, user needs to create
  

• * them first
  

• */
  

• valid_partitions = 0;
• ret = gpt_get_mdata_partitions(desc, &primary_mpart,

• 		       &secondary_mpart);
  

• if (ret < 0) {

• log_err("Error getting the FWU metadata partitions\n");
  

• return -ENODEV;
  

• }
• ret = gpt_read_mdata(desc, &pri_mdata, primary_mpart);
• if (ret < 0) {

• log_err("Failed to read the FWU metadata from the device\n");
  

• goto secondary_read;
  

• }
• ret = fwu_verify_mdata(&pri_mdata, 1);
• if (!ret)

• valid_partitions |= PRIMARY_PART;
  

+secondary_read:

• /* Now check the secondary partition */
• ret = gpt_read_mdata(desc, &secondary_mdata, secondary_mpart);
• if (ret < 0) {

• log_err("Failed to read the FWU metadata from the device\n");
  

• goto mdata_restore;
  

• }
• ret = fwu_verify_mdata(&secondary_mdata, 0);
• if (!ret)

• valid_partitions |= SECONDARY_PART;
  

+mdata_restore:

• if (valid_partitions == (PRIMARY_PART | SECONDARY_PART)) {

• ret = -1;
  

• /*
  

•  * Before returning, check that both the
  

•  * FWU metadata copies are the same. If not,
  

•  * the FWU metadata copies need to be
  

•  * re-populated.
  

•  */
  

• if (!memcmp(&pri_mdata, &secondary_mdata,
  

• 	    sizeof(struct fwu_mdata))) {
  

• 	ret = 0;
  

• } else {
  

• 	log_err("Both FWU metadata copies are valid but do not match. Please check!\n");
  

• }
  

• goto out;
  

• }
• ret = -1;
• if (!(valid_partitions & BOTH_PARTS))

• goto out;
  

• invalid_partitions = valid_partitions ^ BOTH_PARTS;
• ret = gpt_write_mdata_partition(desc,

• 			(invalid_partitions == PRIMARY_PART) ?
  

• 			&secondary_mdata : &pri_mdata,
  

• 			(invalid_partitions == PRIMARY_PART) ?
  

• 			primary_mpart : secondary_mpart);
  

• if (ret < 0)

• log_err("Restoring %s FWU metadata partition failed\n",
  

• 	(invalid_partitions == PRIMARY_PART) ?
  

• 	"primary" : "secondary");
  

+out:

• return ret;

+}

+int fwu_gpt_get_active_index(u32 *active_idx) +{

• int ret;
• struct fwu_mdata *mdata;
• ret = gpt_get_mdata(&mdata);
• if (ret < 0) {

• log_err("Unable to get valid FWU metadata\n");
  

• goto out;
  

• }
• /*

• * Found the FWU metadata partition, now read the active_index
  

• * value
  

• */
  

• *active_idx = mdata->active_index;
• if (*active_idx > CONFIG_FWU_NUM_BANKS - 1) {

• printf("Active index value read is incorrect\n");
  

• ret = -EINVAL;
  

• goto out;
  

• }

+out:

• free(mdata);
• return ret;

+}

+static int gpt_get_image_alt_num(struct blk_desc *desc,

• 		 efi_guid_t image_type_id,
  

• 		 u32 update_bank, int *alt_no)
  

+{

• int ret, i;
• u32 part;
• struct fwu_mdata *mdata;
• struct fwu_image_entry *img_entry;
• struct fwu_image_bank_info *img_bank_info;
• struct disk_partition info;
• efi_guid_t unique_part_guid;
• efi_guid_t image_guid = NULL_GUID;
• ret = gpt_get_mdata(&mdata);
• if (ret < 0) {

• log_err("Unable to read valid FWU metadata\n");
  

• goto out;
  

• }
• /*

• * The FWU metadata has been read. Now get the image_uuid for the
  

• * image with the update_bank.
  

• */
  

• for (i = 0; i < CONFIG_FWU_NUM_IMAGES_PER_BANK; i++) {

• if (!guidcmp(&image_type_id,
  

• 	     &mdata->img_entry[i].image_type_uuid)) {
  

• 	img_entry = &mdata->img_entry[i];
  

• 	img_bank_info = &img_entry->img_bank_info[update_bank];
  

• 	guidcpy(&image_guid, &img_bank_info->image_uuid);
  

• 	break;
  

• }
  

• }
• /*

• * Now read the GPT Partition Table Entries to find a matching
  

• * partition with UniquePartitionGuid value. We need to iterate
  

• * through all the GPT partitions since they might be in any
  

• * order
  

• */
  

• for (i = 1; i < MAX_SEARCH_PARTITIONS; i++) {

• if (part_get_info(desc, i, &info))
  

• 	continue;
  

• uuid_str_to_bin(info.uuid, unique_part_guid.b,
  

• 		UUID_STR_FORMAT_GUID);
  

• if (!guidcmp(&unique_part_guid, &image_guid)) {
  

• 	/* Found the partition */
  

• 	part = i;
  

• 	*alt_no = fwu_plat_get_alt_num(&part);
  

• 	if (*alt_no != -1)
  

• 		log_info("alt_num %d for partition %pUl\n",
  

• 			  *alt_no, &image_guid);
  

• 	ret = 0;
  

• 	break;
  

• }
  

• }
• if (*alt_no == -1) {

• log_err("alt_num not found for partition with GUID %pUl\n",
  

• 	&image_guid);
  

• ret = -EINVAL;
  

• }
• if (i == MAX_SEARCH_PARTITIONS) {

• log_err("Partition with the image guid not found\n");
  

• ret = -EINVAL;
  

• }

+out:

• free(mdata);
• return ret;

+}

+int fwu_gpt_get_image_alt_num(efi_guid_t image_type_id, u32 update_bank,

• 	      int *alt_no)
  

+{

• int ret;
• struct blk_desc *desc;
• ret = fwu_plat_get_blk_desc(&desc);
• if (ret < 0) {

• log_err("Block device not found\n");
  

• return -ENODEV;
  

• }
• return gpt_get_image_alt_num(desc, image_type_id, update_bank, alt_no);

+}

+int fwu_gpt_mdata_check(void) +{

• /*

• * Check if both the copies of the FWU metadata are
  

• * valid. If one has gone bad, restore it from the
  

• * other good copy.
  

• */
  

• return gpt_check_mdata_validity();

+}

+int fwu_gpt_get_mdata(struct fwu_mdata **mdata) +{

• return gpt_get_mdata(mdata);

+}

+static int fwu_gpt_set_clear_image_accept(efi_guid_t *img_type_id,

• 			  u32 bank, u8 action)
  

+{

• void *buf;
• int ret, i;
• u32 nimages;
• struct fwu_mdata *mdata;
• struct fwu_image_entry *img_entry;
• struct fwu_image_bank_info *img_bank_info;
• ret = gpt_get_mdata(&mdata);
• if (ret < 0) {

• log_err("Unable to get valid FWU metadata\n");
  

• goto out;
  

• }
• nimages = CONFIG_FWU_NUM_IMAGES_PER_BANK;
• img_entry = &mdata->img_entry[0];
• for (i = 0; i < nimages; i++) {

• if (!guidcmp(&img_entry[i].image_type_uuid, img_type_id)) {
  

• 	img_bank_info = &img_entry[i].img_bank_info[bank];
  

• 	if (action == IMAGE_ACCEPT_SET)
  

• 		img_bank_info->accepted |= FWU_IMAGE_ACCEPTED;
  

• 	else
  

• 		img_bank_info->accepted = 0;
  

• 	buf = &mdata->version;
  

• 	mdata->crc32 = crc32(0, buf, sizeof(*mdata) -
  

• 			     sizeof(u32));
  

• 	ret = fwu_gpt_update_mdata(mdata);
  

• 	goto out;
  

• }
  

• }
• /* Image not found */
• ret = -EINVAL;

+out:

• free(mdata);
• return ret;

+}

+static int fwu_gpt_accept_image(efi_guid_t *img_type_id, u32 bank) +{

• return fwu_gpt_set_clear_image_accept(img_type_id, bank,

• 			      IMAGE_ACCEPT_SET);
  

+}

+static int fwu_gpt_clear_accept_image(efi_guid_t *img_type_id, u32 bank) +{

• return fwu_gpt_set_clear_image_accept(img_type_id, bank,

• 			      IMAGE_ACCEPT_CLEAR);
  

+}

+struct fwu_mdata_ops fwu_gpt_blk_ops = {

• .get_active_index = fwu_gpt_get_active_index,
• .get_image_alt_num = fwu_gpt_get_image_alt_num,
• .mdata_check = fwu_gpt_mdata_check,
• .set_accept_image = fwu_gpt_accept_image,
• .clear_accept_image = fwu_gpt_clear_accept_image,
• .get_mdata = fwu_gpt_get_mdata,
• .update_mdata = fwu_gpt_update_mdata,

+};