Re: [PATCH 2/2] tpm: migrate pubek_show to struct tpm_buf

[Jarkko Sakkinen]

On Tue, Jun 20, 2017 at 11:38:03AM +0200, Jarkko Sakkinen wrote:
> Migrated pubek_show to struct tpm_buf and cleaned up its implementation.
> Previously the output parameter structure was declared but left
> completely unused. Now it is used to refer different fields of the
> output. We can move it to tpm-sysfs.c as it does not have any use
> outside of that file.
> 
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>

Can anyone help peer testing this change?

https://patchwork.kernel.org/patch/9799057/

/Jarkko

> ---
>  drivers/char/tpm/tpm-sysfs.c | 87 ++++++++++++++++++++++++--------------------
>  drivers/char/tpm/tpm.h       | 13 -------
>  2 files changed, 48 insertions(+), 52 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
> index eedb8e47bde2..fcb69f1162ab 100644
> --- a/drivers/char/tpm/tpm-sysfs.c
> +++ b/drivers/char/tpm/tpm-sysfs.c
> @@ -20,44 +20,48 @@
>  #include <linux/device.h>
>  #include "tpm.h"
>  
> -#define READ_PUBEK_RESULT_SIZE 314
> +struct tpm_readpubek_out {
> +	u8 algorithm[4];
> +	u8 encscheme[2];
> +	u8 sigscheme[2];
> +	__be32 paramsize;
> +	u8 parameters[12];
> +	__be32 keysize;
> +	u8 modulus[256];
> +	u8 checksum[20];
> +} __packed;
> +
>  #define READ_PUBEK_RESULT_MIN_BODY_SIZE (28 + 256)
>  #define TPM_ORD_READPUBEK 124
> -static const struct tpm_input_header tpm_readpubek_header = {
> -	.tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
> -	.length = cpu_to_be32(30),
> -	.ordinal = cpu_to_be32(TPM_ORD_READPUBEK)
> -};
> +
>  static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
>  			  char *buf)
>  {
> -	u8 *data;
> -	struct tpm_cmd_t tpm_cmd;
> -	ssize_t err;
> -	int i, rc;
> +	struct tpm_buf tpm_buf;
> +	struct tpm_readpubek_out *out;
> +	ssize_t rc;
> +	int i;
>  	char *str = buf;
>  	struct tpm_chip *chip = to_tpm_chip(dev);
> +	char anti_replay[20];
>  
> -	memset(&tpm_cmd, 0, sizeof(tpm_cmd));
> -
> -	tpm_cmd.header.in = tpm_readpubek_header;
> -	err = tpm_transmit_cmd(chip, NULL, &tpm_cmd, READ_PUBEK_RESULT_SIZE,
> -			       READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
> -			       "attempting to read the PUBEK");
> -	if (err)
> -		goto out;
> -
> -	/*
> -	   ignore header 10 bytes
> -	   algorithm 32 bits (1 == RSA )
> -	   encscheme 16 bits
> -	   sigscheme 16 bits
> -	   parameters (RSA 12->bytes: keybit, #primes, expbit)
> -	   keylenbytes 32 bits
> -	   256 byte modulus
> -	   ignore checksum 20 bytes
> -	 */
> -	data = tpm_cmd.params.readpubek_out_buffer;
> +	memset(&anti_replay, 0, sizeof(anti_replay));
> +
> +	rc = tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK);
> +	if (rc)
> +		return rc;
> +
> +	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));
> +
> +	rc = tpm_transmit_cmd(chip, NULL, tpm_buf.data, PAGE_SIZE,
> +			      READ_PUBEK_RESULT_MIN_BODY_SIZE, 0,
> +			      "attempting to read the PUBEK");
> +	if (rc) {
> +		tpm_buf_destroy(&tpm_buf);
> +		return 0;
> +	}
> +
> +	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
>  	str +=
>  	    sprintf(str,
>  		    "Algorithm: %02X %02X %02X %02X\n"
> @@ -68,21 +72,26 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
>  		    "%02X %02X %02X %02X\n"
>  		    "Modulus length: %d\n"
>  		    "Modulus:\n",
> -		    data[0], data[1], data[2], data[3],
> -		    data[4], data[5],
> -		    data[6], data[7],
> -		    data[12], data[13], data[14], data[15],
> -		    data[16], data[17], data[18], data[19],
> -		    data[20], data[21], data[22], data[23],
> -		    be32_to_cpu(*((__be32 *) (data + 24))));
> +		    out->algorithm[0], out->algorithm[1], out->algorithm[2],
> +		    out->algorithm[3],
> +		    out->encscheme[0], out->encscheme[1],
> +		    out->sigscheme[0], out->sigscheme[1],
> +		    out->parameters[0], out->parameters[1],
> +		    out->parameters[2], out->parameters[3],
> +		    out->parameters[4], out->parameters[5],
> +		    out->parameters[6], out->parameters[7],
> +		    out->parameters[8], out->parameters[9],
> +		    out->parameters[10], out->parameters[11],
> +		    be32_to_cpu(out->keysize));
>  
>  	for (i = 0; i < 256; i++) {
> -		str += sprintf(str, "%02X ", data[i + 28]);
> +		str += sprintf(str, "%02X ", out->modulus[i]);
>  		if ((i + 1) % 16 == 0)
>  			str += sprintf(str, "\n");
>  	}
> -out:
> +
>  	rc = str - buf;
> +	tpm_buf_destroy(&tpm_buf);
>  	return rc;
>  }
>  static DEVICE_ATTR_RO(pubek);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index cdd261383dea..d9835b31f652 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -343,17 +343,6 @@ enum tpm_sub_capabilities {
>  	TPM_CAP_PROP_TIS_DURATION = 0x120,
>  };
>  
> -struct	tpm_readpubek_params_out {
> -	u8	algorithm[4];
> -	u8	encscheme[2];
> -	u8	sigscheme[2];
> -	__be32	paramsize;
> -	u8	parameters[12]; /*assuming RSA*/
> -	__be32	keysize;
> -	u8	modulus[256];
> -	u8	checksum[20];
> -} __packed;
> -
>  typedef union {
>  	struct	tpm_input_header in;
>  	struct	tpm_output_header out;
> @@ -387,8 +376,6 @@ struct tpm_startup_in {
>  } __packed;
>  
>  typedef union {
> -	struct	tpm_readpubek_params_out readpubek_out;
> -	u8	readpubek_out_buffer[sizeof(struct tpm_readpubek_params_out)];
>  	struct	tpm_pcrread_in	pcrread_in;
>  	struct	tpm_pcrread_out	pcrread_out;
>  	struct	tpm_getrandom_in getrandom_in;
> -- 
> 2.11.0
>