linux-kernel - Re: [PATCH v3 4/6] tpm: replace TPM algorithms IDs with tpm_pcr_bank_info structs in tpm

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Message-ID: <20170623103259.j7ollu3gvhu7yznb@linux.intel.com>
Date:   Fri, 23 Jun 2017 12:32:59 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Roberto Sassu <roberto.sassu@...wei.com>
Cc:     tpmdd-devel@...ts.sourceforge.net,
        linux-ima-devel@...ts.sourceforge.net,
        linux-security-module@...r.kernel.org, keyrings@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 4/6] tpm: replace TPM algorithms IDs with
 tpm_pcr_bank_info structs in tpm_chip

On Wed, Jun 21, 2017 at 04:29:39PM +0200, Roberto Sassu wrote:
> This patch replaces the array of TPM algorithms ID, stored in the tpm_chip
> structure, with an array of the new structure tpm_pcr_bank_info.
> 
> The array is initialized during the execution of tpm2_get_pcr_allocation(),
> by tpm2_init_pcr_bank_info().
> 
> tpm2_pcr_extend() and tpm_pcr_extend() have been modified to use the
> digest size retrieved from the TPM instead of that from the crypto
> subsystem.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>

How do you deal with the trusted keys code?

> ---
>  drivers/char/tpm/tpm-interface.c |  4 ++--
>  drivers/char/tpm/tpm.h           |  2 +-
>  drivers/char/tpm/tpm2-cmd.c      | 22 +++++++++++-----------
>  3 files changed, 14 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index d2b4df6..a11598a 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -897,8 +897,8 @@ int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
>  		memset(digest_list, 0, sizeof(digest_list));
>  
>  		for (i = 0; i < ARRAY_SIZE(chip->active_banks) &&
> -			    chip->active_banks[i] != TPM2_ALG_ERROR; i++) {
> -			digest_list[i].alg_id = chip->active_banks[i];
> +		     chip->active_banks[i].alg_id != TPM2_ALG_ERROR; i++) {
> +			digest_list[i].alg_id = chip->active_banks[i].alg_id;
>  			memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
>  			count++;
>  		}
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 62c600d..d285bc6 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -208,7 +208,7 @@ struct tpm_chip {
>  	const struct attribute_group *groups[3];
>  	unsigned int groups_cnt;
>  
> -	u16 active_banks[7];
> +	struct tpm_pcr_bank_info active_banks[7];
>  #ifdef CONFIG_ACPI
>  	acpi_handle acpi_dev_handle;
>  	char ppi_version[TPM_PPI_VERSION_LEN + 1];
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index 74a68ea..7bd2cf7 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -301,7 +301,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>  	struct tpm2_null_auth_area auth_area;
>  	int rc;
>  	int i;
> -	int j;
>  
>  	if (count > ARRAY_SIZE(chip->active_banks))
>  		return -EINVAL;
> @@ -323,14 +322,10 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>  	tpm_buf_append_u32(&buf, count);
>  
>  	for (i = 0; i < count; i++) {
> -		for (j = 0; j < ARRAY_SIZE(tpm2_hash_map); j++) {
> -			if (digests[i].alg_id != tpm2_hash_map[j].tpm_id)
> -				continue;
> -			tpm_buf_append_u16(&buf, digests[i].alg_id);
> -			tpm_buf_append(&buf, (const unsigned char
> -					      *)&digests[i].digest,
> -			       hash_digest_size[tpm2_hash_map[j].crypto_id]);
> -		}
> +		/* digests[i].alg_id == chip->active_banks[i].alg_id */
> +		tpm_buf_append_u16(&buf, digests[i].alg_id);
> +		tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
> +			       chip->active_banks[i].digest_size);
>  	}
>  
>  	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
> @@ -1076,7 +1071,12 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
>  		}
>  
>  		memcpy(&pcr_selection, marker, sizeof(pcr_selection));
> -		chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
> +		rc =  tpm2_init_pcr_bank_info(chip,
> +					be16_to_cpu(pcr_selection.hash_alg),
> +					&chip->active_banks[i]);
> +		if (rc)
> +			break;
> +
>  		sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
>  			sizeof(pcr_selection.size_of_select) +
>  			pcr_selection.size_of_select;
> @@ -1085,7 +1085,7 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
>  
>  out:
>  	if (i < ARRAY_SIZE(chip->active_banks))
> -		chip->active_banks[i] = TPM2_ALG_ERROR;
> +		chip->active_banks[i].alg_id = TPM2_ALG_ERROR;
>  
>  	tpm_buf_destroy(&buf);
>  
> -- 
> 2.9.3
> 

Hard to review the actual code change as it really does not live on its
own.

/Jarkko