[PATCH] tpm: fixes uninitialized allocated banks for IBM vtpm driver

Nayna Jain
2019-07-04T03:32:27Z

The nr_allocated_banks and allocated banks are initialized as part of
tpm_chip_register. Currently, this is done as part of auto startup
function. However, some drivers, like the ibm vtpm driver, do not run
auto startup during initialization. This results in uninitialized memory
issue and causes a kernel panic during boot.

This patch moves the pcr allocation outside the auto startup function
into tpm_chip_register. This ensures that allocated banks are initialized
in any case.

Fixes: 879b589210a9 ("tpm: retrieve digest size of unknown algorithms with
PCR read")
Signed-off-by: Nayna Jain <nayna@linux.ibm.com>
---
drivers/char/tpm/tpm-chip.c | 37 +++++++++++++++++++++++++++++++++++++
drivers/char/tpm/tpm.h | 1 +
drivers/char/tpm/tpm1-cmd.c | 12 ------------
drivers/char/tpm/tpm2-cmd.c | 6 +-----
4 files changed, 39 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 8804c9e916fd..958508bb8379 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -550,6 +550,39 @@ static int tpm_add_hwrng(struct tpm_chip *chip)
return hwrng_register(&chip->hwrng);
}

+/*
+ * tpm_pcr_allocation() - initializes the chip allocated banks for PCRs
+ */
+static int tpm_pcr_allocation(struct tpm_chip *chip)
+{
+ int rc = 0;
+
+ if (chip->flags & TPM_CHIP_FLAG_TPM2) {
+ rc = tpm2_get_pcr_allocation(chip);
+ if (rc)
+ goto out;
+ }
+
+ /* Initialize TPM 1.2 */
+ chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks),
+ GFP_KERNEL);
+ if (!chip->allocated_banks) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ chip->allocated_banks[0].alg_id = TPM_ALG_SHA1;
+ chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1];
+ chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1;
+ chip->nr_allocated_banks = 1;
+
+ return 0;
+out:
+ if (rc < 0)
+ rc = -ENODEV;
+ return rc;
+}
+
/*
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
@@ -573,6 +606,10 @@ int tpm_chip_register(struct tpm_chip *chip)
if (rc)
return rc;

+ rc = tpm_pcr_allocation(chip);
+ if (rc)
+ return rc;
+
tpm_sysfs_add_device(chip);

rc = tpm_bios_log_setup(chip);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index 2cce072f25b5..eabe6b755fa6 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -454,6 +454,7 @@ int tpm2_unseal_trusted(struct tpm_chip *chip,
ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
u32 *value, const char *desc);

+ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);
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);
diff --git a/drivers/char/tpm/tpm1-cmd.c b/drivers/char/tpm/tpm1-cmd.c
index 85dcf2654d11..ec5f3693c096 100644
--- a/drivers/char/tpm/tpm1-cmd.c
+++ b/drivers/char/tpm/tpm1-cmd.c
@@ -696,18 +696,6 @@ int tpm1_auto_startup(struct tpm_chip *chip)
goto out;
}

- chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks),
- GFP_KERNEL);
- if (!chip->allocated_banks) {
- rc = -ENOMEM;
- goto out;
- }
-
- chip->allocated_banks[0].alg_id = TPM_ALG_SHA1;
- chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1];
- chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1;
- chip->nr_allocated_banks = 1;
-
return rc;
out:
if (rc > 0)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index e74c5b7b64bf..b4384d0e3741 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -841,7 +841,7 @@ struct tpm2_pcr_selection {
u8 pcr_select[3];
} __packed;

-static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
+ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
{
struct tpm2_pcr_selection pcr_selection;
struct tpm_buf buf;
@@ -1041,10 +1041,6 @@ int tpm2_auto_startup(struct tpm_chip *chip)
goto out;
}

- rc = tpm2_get_pcr_allocation(chip);
- if (rc)
- goto out;
-
rc = tpm2_get_cc_attrs_tbl(chip);

out:
--
2.20.1