On Mon, 2006-04-03 at 11:42 -0500, Kylene Jo Hall wrote:
> ssize_t tpm_show_pcrs(struct device *dev, struct device_attribute *attr,
> char *buf)
> {
> - u8 data[READ_PCR_RESULT_SIZE];
> + u8 data[30];
Is this correct? Are you guaranteed that this data read will never,
ever exceed 30 bytes? Any reason it shouldn't be a variable?
> ssize_t len;
> int i, j, num_pcrs;
> __be32 index;
> @@ -150,26 +659,28 @@ ssize_t tpm_show_pcrs(struct device *dev
> if (chip == NULL)
> return -ENODEV;
>
> - memcpy(data, cap_pcr, sizeof(cap_pcr));
> + memcpy(data, tpm_cap, sizeof(tpm_cap));
> + data[TPM_CAP_IDX] = TPM_CAP_PROP;
> + data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_PCR;
> +
> if ((len = tpm_transmit(chip, data, sizeof(data)))
> - < CAP_PCR_RESULT_SIZE) {
> + <= TPM_ERROR_SIZE) {
> dev_dbg(chip->dev, "A TPM error (%d) occurred "
> - "attempting to determine the number of PCRS\n",
> - be32_to_cpu(*((__be32 *) (data + 6))));
> + "attempting to determine the number of PCRS\n",
> + be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX))));
> return 0;
> }
I know this is old code, but I see this little
be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX))));
snippet at least twice. It is also a bit hard to read. Seems likt it
would be a great candidate for a little helper function.
Come to think of it, that entire if() sequence appears to be repeated
quite a few times.
> num_pcrs = be32_to_cpu(*((__be32 *) (data + 14)));
> -
> for (i = 0; i < num_pcrs; i++) {
> memcpy(data, pcrread, sizeof(pcrread));
> index = cpu_to_be32(i);
> memcpy(data + 10, &index, 4);
> if ((len = tpm_transmit(chip, data, sizeof(data)))
> - < READ_PCR_RESULT_SIZE){
> + <= TPM_ERROR_SIZE) {
> dev_dbg(chip->dev, "A TPM error (%d) occurred"
> " attempting to read PCR %d of %d\n",
> - be32_to_cpu(*((__be32 *) (data + 6))),
> + be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX))),
> i, num_pcrs);
> goto out;
> }
> @@ -208,11 +724,11 @@ ssize_t tpm_show_pubek(struct device *de
>
> memcpy(data, readpubek, sizeof(readpubek));
>
> - if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <
> - READ_PUBEK_RESULT_SIZE) {
> + if ((len = tpm_transmit(chip, data, READ_PUBEK_RESULT_SIZE)) <=
> + TPM_ERROR_SIZE) {
> dev_dbg(chip->dev, "A TPM error (%d) occurred "
> - "attempting to read the PUBEK\n",
> - be32_to_cpu(*((__be32 *) (data + 6))));
> + "attempting to read the PUBEK\n",
> + be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX))));
> rc = 0;
> goto out;
> }
> @@ -250,29 +284,20 @@ out:
> }
> EXPORT_SYMBOL_GPL(tpm_show_pubek);
>
> -#define CAP_VER_RESULT_SIZE 18
> +#define CAP_VERSION_1_1 6
> +#define CAP_VERSION_IDX 13
> static const u8 cap_version[] = {
> 0, 193, /* TPM_TAG_RQU_COMMAND */
> 0, 0, 0, 18, /* length */
> 0, 0, 0, 101, /* TPM_ORD_GetCapability */
> - 0, 0, 0, 6,
> + 0, 0, 0, 0,
> 0, 0, 0, 0
> };
>
> -#define CAP_MANUFACTURER_RESULT_SIZE 18
> -static const u8 cap_manufacturer[] = {
> - 0, 193, /* TPM_TAG_RQU_COMMAND */
> - 0, 0, 0, 22, /* length */
> - 0, 0, 0, 101, /* TPM_ORD_GetCapability */
> - 0, 0, 0, 5,
> - 0, 0, 0, 4,
> - 0, 0, 1, 3
> -};
> -
> ssize_t tpm_show_caps(struct device *dev, struct device_attribute *attr,
> char *buf)
> {
> - u8 data[sizeof(cap_manufacturer)];
> + u8 data[30];
> ssize_t len;
> char *str = buf;
>
> @@ -282,26 +793,37 @@ ssize_t tpm_show_caps(struct device *dev
> if (chip == NULL)
> return -ENODEV;
>
> - memcpy(data, cap_manufacturer, sizeof(cap_manufacturer));
> + memcpy(data, tpm_cap, sizeof(tpm_cap));
> + data[TPM_CAP_IDX] = TPM_CAP_PROP;
> + data[TPM_CAP_SUBCAP_IDX] = TPM_CAP_PROP_MANUFACTURER;
>
> - if ((len = tpm_transmit(chip, data, sizeof(data))) <
> - CAP_MANUFACTURER_RESULT_SIZE)
> - return len;
> + if ((len = tpm_transmit(chip, data, sizeof(data))) <=
> + TPM_ERROR_SIZE) {
> + dev_dbg(chip->dev, "A TPM error (%d) occurred "
> + "attempting to determine the manufacturer\n",
> + be32_to_cpu(*((__be32 *) (data + TPM_RET_CODE_IDX))));
> + return 0;
> + }
Since you're going through and modifying these, it might be nice to
change them to the more normal (and readable) style of
len = tpm_transmit(chip, data, sizeof(data));
if (len < CAP_MANUFACTURER_RESULT_SIZE)
return len;
Note that that doesn't even increase the number of lines of code.
-- Dave
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