Re: [PATCH v5 13/17] tpm: use tpm_try_get_ops() in tpm-sysfs.c.

From: Stefan Berger
Date: Thu Nov 08 2018 - 10:26:29 EST


On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
Use tpm_try_get_ops() in tpm-sysfs.c so that we can consider moving
other decorations (locking, localities, power management for example)
inside it. This direction can be of course taken only after other call
sites for tpm_transmit() have been treated in the same way.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>

Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>

---
drivers/char/tpm/tpm-sysfs.c | 123 ++++++++++++++++++++++-------------
1 file changed, 78 insertions(+), 45 deletions(-)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 03e704f99ed6..3733491671ca 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -39,7 +39,6 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
{
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);
@@ -47,17 +46,17 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,

memset(&anti_replay, 0, sizeof(anti_replay));

- if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
+ if (tpm_try_get_ops(chip))
return 0;

+ if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
+ goto out_ops;
+
tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));

- rc = tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
- 0, "attempting to read the PUBEK");
- if (rc) {
- tpm_buf_destroy(&tpm_buf);
- return 0;
- }
+ if (tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
+ 0, "attempting to read the PUBEK"))
+ goto out_buf;

out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
str +=
@@ -88,9 +87,11 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
str += sprintf(str, "\n");
}

- rc = str - buf;
+out_buf:
tpm_buf_destroy(&tpm_buf);
- return rc;
+out_ops:
+ tpm_put_ops(chip);
+ return str - buf;
}
static DEVICE_ATTR_RO(pubek);

@@ -103,10 +104,15 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
char *str = buf;
struct tpm_chip *chip = to_tpm_chip(dev);

+ if (tpm_try_get_ops(chip))
+ return 0;
+
if (tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
"attempting to determine the number of PCRS",
- sizeof(cap.num_pcrs)))
+ sizeof(cap.num_pcrs))) {
+ tpm_put_ops(chip);
return 0;
+ }

num_pcrs = be32_to_cpu(cap.num_pcrs);
for (i = 0; i < num_pcrs; i++) {
@@ -119,6 +125,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
str += sprintf(str, "%02X ", digest[j]);
str += sprintf(str, "\n");
}
+ tpm_put_ops(chip);
return str - buf;
}
static DEVICE_ATTR_RO(pcrs);
@@ -126,16 +133,21 @@ static DEVICE_ATTR_RO(pcrs);
static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
+ struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t rc = 0;
cap_t cap;
- ssize_t rc;

- rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
- "attempting to determine the permanent enabled state",
- sizeof(cap.perm_flags));
- if (rc)
+ if (tpm_try_get_ops(chip))
return 0;

+ if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
+ "attempting to determine the permanent enabled state",
+ sizeof(cap.perm_flags)))
+ goto out_ops;
+
rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
+out_ops:
+ tpm_put_ops(chip);
return rc;
}
static DEVICE_ATTR_RO(enabled);
@@ -143,16 +155,21 @@ static DEVICE_ATTR_RO(enabled);
static ssize_t active_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
+ struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t rc = 0;
cap_t cap;
- ssize_t rc;

- rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
- "attempting to determine the permanent active state",
- sizeof(cap.perm_flags));
- if (rc)
+ if (tpm_try_get_ops(chip))
return 0;

+ if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
+ "attempting to determine the permanent active state",
+ sizeof(cap.perm_flags)))
+ goto out_ops;
+
rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
+out_ops:
+ tpm_put_ops(chip);
return rc;
}
static DEVICE_ATTR_RO(active);
@@ -160,16 +177,21 @@ static DEVICE_ATTR_RO(active);
static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
+ struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t rc = 0;
cap_t cap;
- ssize_t rc;

- rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
- "attempting to determine the owner state",
- sizeof(cap.owned));
- if (rc)
+ if (tpm_try_get_ops(chip))
return 0;

+ if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
+ "attempting to determine the owner state",
+ sizeof(cap.owned)))
+ goto out_ops;
+
rc = sprintf(buf, "%d\n", cap.owned);
+out_ops:
+ tpm_put_ops(chip);
return rc;
}
static DEVICE_ATTR_RO(owned);
@@ -177,16 +199,21 @@ static DEVICE_ATTR_RO(owned);
static ssize_t temp_deactivated_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
+ struct tpm_chip *chip = to_tpm_chip(dev);
+ ssize_t rc = 0;
cap_t cap;
- ssize_t rc;

- rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
- "attempting to determine the temporary state",
- sizeof(cap.stclear_flags));
- if (rc)
+ if (tpm_try_get_ops(chip))
return 0;

+ if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
+ "attempting to determine the temporary state",
+ sizeof(cap.stclear_flags)))
+ goto out_ops;
+
rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
+out_ops:
+ tpm_put_ops(chip);
return rc;
}
static DEVICE_ATTR_RO(temp_deactivated);
@@ -195,15 +222,18 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct tpm_chip *chip = to_tpm_chip(dev);
- cap_t cap;
- ssize_t rc;
+ ssize_t rc = 0;
char *str = buf;
+ cap_t cap;

- rc = tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
- "attempting to determine the manufacturer",
- sizeof(cap.manufacturer_id));
- if (rc)
+ if (tpm_try_get_ops(chip))
return 0;
+
+ if (tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
+ "attempting to determine the manufacturer",
+ sizeof(cap.manufacturer_id)))
+ goto out_ops;
+
str += sprintf(str, "Manufacturer: 0x%x\n",
be32_to_cpu(cap.manufacturer_id));

@@ -220,11 +250,10 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
cap.tpm_version_1_2.revMinor);
} else {
/* Otherwise just use TPM_STRUCT_VER */
- rc = tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
- "attempting to determine the 1.1 version",
- sizeof(cap.tpm_version));
- if (rc)
- return 0;
+ if (tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
+ "attempting to determine the 1.1 version",
+ sizeof(cap.tpm_version)))
+ goto out_ops;
str += sprintf(str,
"TCG version: %d.%d\nFirmware version: %d.%d\n",
cap.tpm_version.Major,
@@ -232,8 +261,10 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
cap.tpm_version.revMajor,
cap.tpm_version.revMinor);
}
-
- return str - buf;
+ rc = str - buf;
+out_ops:
+ tpm_put_ops(chip);
+ return rc;
}
static DEVICE_ATTR_RO(caps);

@@ -241,10 +272,12 @@ static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct tpm_chip *chip = to_tpm_chip(dev);
- if (chip == NULL)
+
+ if (tpm_try_get_ops(chip))
return 0;

chip->ops->cancel(chip);
+ tpm_put_ops(chip);
return count;
}
static DEVICE_ATTR_WO(cancel);