linux-kernel - Re: [tpmdd-devel] [PATCH v3 2/6] tpm: use tpm2_pcr_read_tpm_buf() in tpm2_do

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Message-ID: <20170623095511.3yxnrzujwnaliozz@linux.intel.com>
Date:   Fri, 23 Jun 2017 11:55:11 +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: [tpmdd-devel] [PATCH v3 2/6] tpm: use tpm2_pcr_read_tpm_buf() in
 tpm2_do_selftest()

On Wed, Jun 21, 2017 at 04:29:37PM +0200, Roberto Sassu wrote:
> tpm2_do_selftest() performs a PCR read during the TPM initialization phase.
> This patch replaces the PCR read code with a call to
> tpm2_pcr_read_tpm_buf(). tpm2_do_selftest() parses the result of the
> TPM command, in order to retrieve the return code.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>

Work this out with a call to tpm2_pcr_read() instead.

/Jarkko

> ---
>  drivers/char/tpm/tpm2-cmd.c | 32 ++++++++++----------------------
>  1 file changed, 10 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
> index afd1b63..6a9fe0d 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -227,16 +227,6 @@ static const u8 tpm2_ordinal_duration[TPM2_CC_LAST - TPM2_CC_FIRST + 1] = {
>  	TPM_UNDEFINED		/* 18f */
>  };
>  
> -#define TPM2_PCR_READ_IN_SIZE \
> -	(sizeof(struct tpm_input_header) + \
> -	 sizeof(struct tpm2_pcr_read_in))
> -
> -static const struct tpm_input_header tpm2_pcrread_header = {
> -	.tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
> -	.length = cpu_to_be32(TPM2_PCR_READ_IN_SIZE),
> -	.ordinal = cpu_to_be32(TPM2_CC_PCR_READ)
> -};
> -
>  static int tpm2_pcr_read_tpm_buf(struct tpm_chip *chip, int pcr_idx,
>  				 enum tpm2_algorithms algo, struct tpm_buf *buf,
>  				 char *msg)
> @@ -938,7 +928,8 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
>  	unsigned int loops;
>  	unsigned int delay_msec = 100;
>  	unsigned long duration;
> -	struct tpm2_cmd cmd;
> +	struct tpm_buf buf;
> +	tpm_cmd_header *header;
>  	int i;
>  
>  	duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST);
> @@ -951,20 +942,17 @@ static int tpm2_do_selftest(struct tpm_chip *chip)
>  
>  	for (i = 0; i < loops; i++) {
>  		/* Attempt to read a PCR value */
> -		cmd.header.in = tpm2_pcrread_header;
> -		cmd.params.pcrread_in.pcr_selects_cnt = cpu_to_be32(1);
> -		cmd.params.pcrread_in.hash_alg = cpu_to_be16(TPM2_ALG_SHA1);
> -		cmd.params.pcrread_in.pcr_select_size = TPM2_PCR_SELECT_MIN;
> -		cmd.params.pcrread_in.pcr_select[0] = 0x01;
> -		cmd.params.pcrread_in.pcr_select[1] = 0x00;
> -		cmd.params.pcrread_in.pcr_select[2] = 0x00;
> -
> -		rc = tpm_transmit_cmd(chip, NULL, &cmd, sizeof(cmd), 0, 0,
> -				      NULL);
> +		rc = tpm2_pcr_read_tpm_buf(chip, 0, TPM2_ALG_SHA1, &buf, NULL);
> +		if (rc >= 0) {
> +			header = (tpm_cmd_header *)buf.data;
> +			rc = be32_to_cpu(header->out.return_code);
> +		}
> +
> +		tpm_buf_destroy(&buf);
> +
>  		if (rc < 0)
>  			break;
>  
> -		rc = be32_to_cpu(cmd.header.out.return_code);
>  		if (rc != TPM2_RC_TESTING)
>  			break;
>  
> -- 
> 2.9.3
> 
> 
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