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authorNayna Jain <nayna@linux.vnet.ibm.com>2017-01-30 04:59:40 -0500
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2017-02-03 22:03:14 +0200
commit1db15344f874f656b267a79467d1e7ee6442ba09 (patch)
treed179dbde779749998c1f62c71a8e9901e6b4c15b /drivers/char/tpm
parent7d761119a914ec0ac05ec2a5378d1f86e680967d (diff)
tpm: implement TPM 2.0 capability to get active PCR banks
This patch implements the TPM 2.0 capability TPM_CAP_PCRS to retrieve the active PCR banks from the TPM. This is needed to enable extending all active banks as recommended by TPM 2.0 TCG Specification. Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Tested-by: Kenneth Goldman <kgold@linux.vnet.ibm.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Diffstat (limited to 'drivers/char/tpm')
-rw-r--r--drivers/char/tpm/tpm.h5
-rw-r--r--drivers/char/tpm/tpm2-cmd.c77
2 files changed, 82 insertions, 0 deletions
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index dbe0c5a72c67..db0398a4e3e5 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -97,6 +97,7 @@ enum tpm2_return_codes {
};
enum tpm2_algorithms {
+ TPM2_ALG_ERROR = 0x0000,
TPM2_ALG_SHA1 = 0x0004,
TPM2_ALG_KEYEDHASH = 0x0008,
TPM2_ALG_SHA256 = 0x000B,
@@ -127,6 +128,7 @@ enum tpm2_permanent_handles {
};
enum tpm2_capabilities {
+ TPM2_CAP_PCRS = 5,
TPM2_CAP_TPM_PROPERTIES = 6,
};
@@ -187,6 +189,8 @@ struct tpm_chip {
const struct attribute_group *groups[3];
unsigned int groups_cnt;
+
+ u16 active_banks[7];
#ifdef CONFIG_ACPI
acpi_handle acpi_dev_handle;
char ppi_version[TPM_PPI_VERSION_LEN + 1];
@@ -540,4 +544,5 @@ int tpm2_auto_startup(struct tpm_chip *chip);
void tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type);
unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
int tpm2_probe(struct tpm_chip *chip);
+ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);
#endif
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 42fe3dde0d8c..6fbd42c2a528 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -1030,3 +1030,80 @@ out:
rc = -ENODEV;
return rc;
}
+
+struct tpm2_pcr_selection {
+ __be16 hash_alg;
+ u8 size_of_select;
+ u8 pcr_select[3];
+} __packed;
+
+/**
+ * tpm2_get_pcr_allocation() - get TPM active PCR banks.
+ *
+ * @chip: TPM chip to use.
+ *
+ * Return: Same as with tpm_transmit_cmd.
+ */
+ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
+{
+ struct tpm2_pcr_selection pcr_selection;
+ struct tpm_buf buf;
+ void *marker;
+ void *end;
+ void *pcr_select_offset;
+ unsigned int count;
+ u32 sizeof_pcr_selection;
+ u32 rsp_len;
+ int rc;
+ int i = 0;
+
+ rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_CAPABILITY);
+ if (rc)
+ return rc;
+
+ tpm_buf_append_u32(&buf, TPM2_CAP_PCRS);
+ tpm_buf_append_u32(&buf, 0);
+ tpm_buf_append_u32(&buf, 1);
+
+ rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0,
+ "get tpm pcr allocation");
+ if (rc)
+ goto out;
+
+ count = be32_to_cpup(
+ (__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
+
+ if (count > ARRAY_SIZE(chip->active_banks)) {
+ rc = -ENODEV;
+ goto out;
+ }
+
+ marker = &buf.data[TPM_HEADER_SIZE + 9];
+
+ rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
+ end = &buf.data[rsp_len];
+
+ for (i = 0; i < count; i++) {
+ pcr_select_offset = marker +
+ offsetof(struct tpm2_pcr_selection, size_of_select);
+ if (pcr_select_offset >= end) {
+ rc = -EFAULT;
+ break;
+ }
+
+ memcpy(&pcr_selection, marker, sizeof(pcr_selection));
+ chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
+ sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
+ sizeof(pcr_selection.size_of_select) +
+ pcr_selection.size_of_select;
+ marker = marker + sizeof_pcr_selection;
+ }
+
+out:
+ if (i < ARRAY_SIZE(chip->active_banks))
+ chip->active_banks[i] = TPM2_ALG_ERROR;
+
+ tpm_buf_destroy(&buf);
+
+ return rc;
+}