Re: [PATCH v14 03/15] FWU: Add FWU metadata access driver for GPT partitioned block devices

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

Hi Sughosh, 

[...]

> +};
> +
> +static int gpt_get_mdata_partitions(struct blk_desc *desc,
> +				    uint mdata_parts[2])
> +{
> +	int i, ret;
> +	u32 nparts;
> +	efi_guid_t part_type_guid;
> +	struct disk_partition info;
> +	const efi_guid_t fwu_mdata_guid = FWU_MDATA_GUID;
> +
> +	nparts = 0;
> +	for (i = 1; i < MAX_SEARCH_PARTITIONS && nparts < 2; i++) {

The 'nparts < 2' might hide an actual problem.  Can we get rid of it and
only rely on the test at the end?

> +		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[nparts] = i;
> +			++nparts;
> +		}
> +	}
> +
> +	if (nparts != 2) {
> +		log_debug("Expect two copies of the FWU metadata instead of %d\n",
> +			  nparts);
> +		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_debug("Unable to get the partition info for the FWU metadata part %d\n",
> +			  part_num);
> +		return -ENOENT;
> +	}
> +
> +	/* 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;
> +	}

Drop the comment and {}

> +
> +	return -ENOENT;
> +}
> +
> +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 -ENOENT;
> +	}
> +
> +	len = sizeof(*mdata);
> +	blkcnt = BLOCK_CNT(len, desc);
> +	if (blkcnt > info.size) {
> +		log_debug("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_debug("Error reading FWU metadata from the device\n");
> +			return -EIO;
> +		}
> +		memcpy(mdata, mdata_aligned, sizeof(struct fwu_mdata));

I know we are using mdata in a 'controlled' way but I think it's better if
we have a check against NULL in the top of the function

> +	} else {
> +		if (blk_dwrite(desc, blk_start, blkcnt, mdata) != blkcnt) {
> +			log_debug("Error writing FWU metadata to the device\n");
> +			return -EIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int fwu_gpt_update_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> +	int ret;
> +	struct blk_desc *desc;
> +	uint mdata_parts[2];
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	desc = dev_get_uclass_plat(priv->blk_dev);
> +
> +	ret = gpt_get_mdata_partitions(desc, mdata_parts);
> +	if (ret < 0) {
> +		log_debug("Error getting the FWU metadata partitions\n");
> +		return -ENOENT;
> +	}
> +
> +	/* First write the primary partition */
> +	ret = gpt_read_write_mdata(desc, mdata, MDATA_WRITE, mdata_parts[0]);
> +	if (ret < 0) {
> +		log_debug("Updating primary FWU metadata partition failed\n");
> +		return ret;
> +	}
> +
> +	/* And now the replica */
> +	ret = gpt_read_write_mdata(desc, mdata, MDATA_WRITE, mdata_parts[1]);
> +	if (ret < 0) {
> +		log_debug("Updating secondary FWU metadata partition failed\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static int gpt_get_mdata(struct blk_desc *desc, struct fwu_mdata *mdata)
> +{
> +	int ret;
> +	uint mdata_parts[2];
> +
> +	ret = gpt_get_mdata_partitions(desc, mdata_parts);
> +
> +	if (ret < 0) {
> +		log_debug("Error getting the FWU metadata partitions\n");
> +		return -ENOENT;
> +	}
> +
> +	ret = gpt_read_write_mdata(desc, mdata, MDATA_READ, mdata_parts[0]);
> +	if (ret < 0) {
> +		log_debug("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_write_mdata(desc, mdata, MDATA_READ, mdata_parts[1]);
> +	if (ret < 0) {
> +		log_debug("Failed to read the FWU metadata from the device\n");
> +		return -EIO;
> +	}
> +
> +	ret = fwu_verify_mdata(mdata, 0);
> +	if (!ret)
> +		return 0;

Can we move this before writing potentially bogus data to part 1 and just
fail early?

> +
> +	/* Both the FWU metadata copies are corrupted. */
> +	return -EIO;
> +}
> +
> +static int fwu_gpt_get_mdata(struct udevice *dev, struct fwu_mdata *mdata)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return gpt_get_mdata(dev_get_uclass_plat(priv->blk_dev), mdata);
> +}
> +
> +static int fwu_gpt_get_mdata_partitions(struct udevice *dev, uint *mdata_parts)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return gpt_get_mdata_partitions(dev_get_uclass_plat(priv->blk_dev),
> +					mdata_parts);
> +}
> +
> +static int fwu_gpt_read_mdata_partition(struct udevice *dev,
> +					struct fwu_mdata *mdata, uint part_num)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return gpt_read_write_mdata(dev_get_uclass_plat(priv->blk_dev),
> +				    mdata, MDATA_READ, part_num);
> +}
> +
> +static int fwu_gpt_write_mdata_partition(struct udevice *dev,
> +					struct fwu_mdata *mdata, uint part_num)
> +{
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	return gpt_read_write_mdata(dev_get_uclass_plat(priv->blk_dev),
> +				    mdata, MDATA_WRITE, part_num);
> +}
> +
> +static int fwu_get_mdata_device(struct udevice *dev, struct udevice **mdata_dev)
> +{
> +	u32 phandle;
> +	int ret, size;
> +	struct udevice *parent;
> +	const fdt32_t *phandle_p = NULL;
> +
> +	phandle_p = dev_read_prop(dev, "fwu-mdata-store", &size);
> +	if (!phandle_p) {
> +		log_debug("fwu-mdata-store property not found\n");
> +		return -ENOENT;
> +	}
> +
> +	phandle = fdt32_to_cpu(*phandle_p);
> +
> +	ret = device_get_global_by_ofnode(ofnode_get_by_phandle(phandle),
> +					  &parent);
> +	if (ret)
> +		return ret;
> +
> +	return blk_get_from_parent(parent, mdata_dev);
> +}
> +
> +static int fwu_mdata_gpt_blk_probe(struct udevice *dev)
> +{
> +	int ret;
> +	struct udevice *mdata_dev = NULL;
> +	struct fwu_mdata_gpt_blk_priv *priv = dev_get_priv(dev);
> +
> +	ret = fwu_get_mdata_device(dev, &mdata_dev);
> +	if (ret)
> +		return ret;
> +
> +	priv->blk_dev = mdata_dev;
> +
> +	return 0;
> +}
> +
> +static const struct fwu_mdata_ops fwu_gpt_blk_ops = {
> +	.get_mdata = fwu_gpt_get_mdata,
> +	.update_mdata = fwu_gpt_update_mdata,
> +	.get_mdata_part_num = fwu_gpt_get_mdata_partitions,
> +	.read_mdata_partition = fwu_gpt_read_mdata_partition,
> +	.write_mdata_partition = fwu_gpt_write_mdata_partition,
> +};
> +
> +static const struct udevice_id fwu_mdata_ids[] = {
> +	{ .compatible = "u-boot,fwu-mdata-gpt" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(fwu_mdata_gpt_blk) = {
> +	.name		= "fwu-mdata-gpt-blk",
> +	.id		= UCLASS_FWU_MDATA,
> +	.of_match	= fwu_mdata_ids,
> +	.ops		= &fwu_gpt_blk_ops,
> +	.probe		= fwu_mdata_gpt_blk_probe,
> +	.priv_auto	= sizeof(struct fwu_mdata_gpt_blk_priv),
> +};
> diff --git a/include/fwu.h b/include/fwu.h
> index 84c4ffacee..eb4ce19262 100644
> --- a/include/fwu.h
> +++ b/include/fwu.h
> @@ -14,6 +14,10 @@
>  struct fwu_mdata;
>  struct udevice;
>  
> +struct fwu_mdata_gpt_blk_priv {
> +	struct udevice *blk_dev;
> +};
> +
>  /**
>   * @mdata_check: check the validity of the FWU metadata partitions
>   * @get_mdata() - Get a FWU metadata copy
> -- 
> 2.34.1
> 


Thanks
/Ilias