Re: [tpmdd-devel] [PATCH v3 2/6] tpm: use tpm2_pcr_read_tpm_buf() in tpm2_do_selftest()

[Roberto Sassu]

On 6/23/2017 11:55 AM, Jarkko Sakkinen wrote:
> 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@xxxxxxxxxx>
>
> Work this out with a call to tpm2_pcr_read() instead.

Would it be ok to add tpm_algo, return_code, digest_size and log_msg
as new parameters of tpm2_pcr_read()? If not, please let me know
how I can pass the command return code to tpm2_do_selftest() and
the digest size, for the algorithms supported by the TPM, to
tpm2_get_pcr_allocation().

Thanks

Roberto


> /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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