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 <na...@linux.vnet.ibm.com>
---
drivers/char/tpm/tpm.h | 5 +++
drivers/char/tpm/tpm2-cmd.c | 79 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 84 insertions(+)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 1ae9768..3d8121e 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -43,6 +43,7 @@ enum tpm_const {
TPM_NUM_DEVICES = 65536,
TPM_RETRY = 50, /* 5 seconds */
TPM_NUM_EVENT_LOG_FILES = 3,
+ TPM2_MAX_PCR_BANKS = 7,
};
enum tpm_timeout {
@@ -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;
+
+ enum tpm2_algorithms active_banks[TPM2_MAX_PCR_BANKS];
#ifdef CONFIG_ACPI
acpi_handle acpi_dev_handle;
char ppi_version[TPM_PPI_VERSION_LEN + 1];
@@ -545,4 +549,5 @@ 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 6eda239..dd03fd8 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -83,6 +83,25 @@ struct tpm2_get_tpm_pt_out {
__be32 value;
} __packed;
+struct tpm2_tpms_pcr_selection {
+ __be16 hash_alg;
+ u8 size_of_select;
+ u8 pcr_select[3];
+} __packed;
+
+struct tpm2_getcap_in {
+ __be32 cap_id;
+ __be32 property_id;
+ __be32 property_cnt;
+} __packed;
+
+struct tpm2_getcap_out {
+ u8 more_data;
+ __be32 subcap_id;
+ __be32 count;
+ char cap_data[0];
+} __packed;
+
struct tpm2_get_random_in {
__be16 size;
} __packed;
@@ -100,6 +119,8 @@ union tpm2_cmd_params {
struct tpm2_pcr_extend_in pcrextend_in;
struct tpm2_get_tpm_pt_in get_tpm_pt_in;
struct tpm2_get_tpm_pt_out get_tpm_pt_out;
+ struct tpm2_getcap_in getcap_in;
+ struct tpm2_getcap_out getcap_out;
struct tpm2_get_random_in getrandom_in;
struct tpm2_get_random_out getrandom_out;
};
@@ -993,8 +1014,66 @@ int tpm2_auto_startup(struct tpm_chip *chip)
}
}
+ rc = tpm2_get_pcr_allocation(chip);
+
out:
if (rc > 0)
rc = -ENODEV;
return rc;
}
+
+#define TPM2_GETCAP_IN_SIZE \
+ (sizeof(struct tpm_input_header) + sizeof(struct tpm2_getcap_in))
+
+static const struct tpm_input_header tpm2_getcap_header = {
+ .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
+ .length = cpu_to_be32(TPM2_GETCAP_IN_SIZE),
+ .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
+};
+
+/**
+ * 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_cmd cmd;
+ struct tpm2_tpms_pcr_selection pcr_selection;
+ void *marker;
+ unsigned int count = 0;
+ int rc;
+ int i;
+
+ cmd.header.in = tpm2_getcap_header;
+ cmd.params.getcap_in.cap_id = cpu_to_be32(TPM2_CAP_PCRS);
+ cmd.params.getcap_in.property_id = cpu_to_be32(0);
+ cmd.params.getcap_in.property_cnt = cpu_to_be32(1);
+
+ rc = tpm_transmit_cmd(chip, &cmd, sizeof(cmd), 0,
+ "get tpm pcr allocation");
+ if (rc < 0)
+ goto out;
+
+ count = be32_to_cpu(cmd.params.getcap_out.count);
+ if (count > TPM2_MAX_PCR_BANKS) {
+ dev_err(&chip->dev,
+ "%s: Error: Invalid active PCR banks count\n",
+ __func__);
+ return -ENODEV;
+ }
+
+ marker = &cmd.params.getcap_out.cap_data;
+ for (i = 0; i < count; i++) {
+ memcpy(&pcr_selection, marker, sizeof(pcr_selection));
+ chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
+ marker = marker + sizeof(struct tpm2_tpms_pcr_selection);
+ }
+
+out:
+ if (count < TPM2_MAX_PCR_BANKS)
+ chip->active_banks[count] = 0;
+ return rc;
+}
--
2.5.0
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