Re: [tpmdd-devel] [PATCH RFC 2/2] tpm: refactor tpm2_get_tpm_pt to tpm2_getcap_cmd
From: Nayna
Date: Thu Nov 17 2016 - 06:51:10 EST
On 11/12/2016 05:32 AM, Jarkko Sakkinen wrote:
On Fri, Nov 11, 2016 at 09:51:45AM +0530, Nayna wrote:
On 10/09/2016 03:44 PM, Jarkko Sakkinen wrote:
Refactored tpm2_get_tpm_pt to tpm2_getcap_cmd, which means that it also
takes capability ID as input. This is required to access
TPM_CAP_HANDLES, which contains metadata needed for swapping transient
data.
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm.h | 6 +++-
drivers/char/tpm/tpm2-cmd.c | 64 ++++++++++++++++++++---------------------
drivers/char/tpm/tpm_tis_core.c | 3 +-
3 files changed, 38 insertions(+), 35 deletions(-)
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 0fab6d5..8176f42 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -85,6 +85,10 @@ enum tpm2_capabilities {
TPM2_CAP_TPM_PROPERTIES = 6,
};
+enum tpm2_properties {
+ TPM2_PT_FAMILY_INDICATOR = 0x100,
+};
+
enum tpm2_startup_types {
TPM2_SU_CLEAR = 0x0000,
TPM2_SU_STATE = 0x0001,
@@ -485,7 +489,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
int tpm2_unseal_trusted(struct tpm_chip *chip,
struct trusted_key_payload *payload,
struct trusted_key_options *options);
-ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
+ssize_t tpm2_getcap_cmd(struct tpm_chip *chip, u32 cap_id, u32 property_id,
u32 *value, const char *desc);
int tpm2_auto_startup(struct tpm_chip *chip);
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 2900e18..fcf3d86 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -111,13 +111,13 @@ struct tpm2_pcr_extend_in {
u8 digest[TPM_DIGEST_SIZE];
} __packed;
-struct tpm2_get_tpm_pt_in {
+struct tpm2_getcap_in {
__be32 cap_id;
__be32 property_id;
__be32 property_cnt;
} __packed;
-struct tpm2_get_tpm_pt_out {
+struct tpm2_getcap_out {
u8 more_data;
__be32 subcap_id;
__be32 property_cnt;
@@ -140,8 +140,8 @@ union tpm2_cmd_params {
struct tpm2_pcr_read_in pcrread_in;
struct tpm2_pcr_read_out pcrread_out;
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;
};
@@ -435,16 +435,6 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
return total ? total : -EIO;
}
-#define TPM2_GET_TPM_PT_IN_SIZE \
- (sizeof(struct tpm_input_header) + \
- sizeof(struct tpm2_get_tpm_pt_in))
-
-static const struct tpm_input_header tpm2_get_tpm_pt_header = {
- .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
- .length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
- .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
-};
-
/**
* Append TPMS_AUTH_COMMAND to the buffer. The buffer must be allocated with
* tpm_buf_alloc().
@@ -750,35 +740,43 @@ out:
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_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
- * @chip: TPM chip to use.
- * @property_id: property ID.
- * @value: output variable.
+ * tpm2_getcap_cmd() - execute a TPM2_GetCapability command
+ * @chip: TPM chip to use
+ * @cap_id: capability ID
+ * @property_id: property ID
+ * @value: value of the property
* @desc: passed to tpm_transmit_cmd()
*
- * 0 is returned when the operation is successful. If a negative number is
- * returned it remarks a POSIX error code. If a positive number is returned
- * it remarks a TPM error.
+ * Return: same as with tpm_transmit_cmd
*/
-ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value,
- const char *desc)
+ssize_t tpm2_getcap_cmd(struct tpm_chip *chip, u32 cap_id, u32 property_id,
+ u32 *value, const char *desc)
This function currently returns single value "u32 *value" as output data.
Some calling function expect list of values from capabilities output.
For eg., get_active_banks() use TPM_CAP_PCRS capability to retrieve list of
active banks. And this capability returns array of pcr selections(which is a
struct representing each active PCR bank)
I was thinking, can we define output parameter as struct of cap_id and union
of expected cap_data ?
Unless you have major concerns about performance, which I think are not
relevant here, calling this in a loop is perfectly adequate and a lot of
simpler than having a generic version (with moreData handling and
everything).
I would rather see uses of struct cap_t to shrink than to expand. The
same goes for other horrific unions that exist today in the driver.
I agree with the idea of not using union.
I tested this for capability TPM2_CAP_PCRS. It seems TPM2_CAP_PCRS
capability always returns full PCR allocation, and more_data as 0, So, I
think the idea of looping over based on more_data may not work for this
capability.
I was thinking in place of having u32 *value returning actual value, can
we have it as void *value, where getcap_cmd will memcpy its out
parameter content after subcap_id to value, and then calling function
typecast to expected type and use it.
Please let me know if I am missing something in using this function.
Thanks & Regards,
- Nayna
/Jarkko