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Subject[PATCH v4 1/6] tpm: dynamically allocate active_banks array
Date
This patch removes the hard-coded limit of the active_banks array size.
It stores in the tpm_chip structure the number of active PCR banks,
determined in tpm2_get_pcr_allocation(), and replaces the static array
with a pointer to a dynamically allocated array.

As a consequence of the introduction of nr_active_banks, tpm_pcr_extend()
does not check anymore if the algorithm stored in tpm_chip is equal to
zero. The active_banks array always contains valid algorithms.

Fixes: 1db15344f874 ("tpm: implement TPM 2.0 capability to get active
PCR banks")

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
drivers/char/tpm/tpm-chip.c | 1 +
drivers/char/tpm/tpm-interface.c | 19 ++++++++++++-------
drivers/char/tpm/tpm.h | 3 ++-
drivers/char/tpm/tpm2-cmd.c | 17 ++++++++---------
4 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 46caadca916a..2a9e8b744436 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -160,6 +160,7 @@ static void tpm_dev_release(struct device *dev)
kfree(chip->log.bios_event_log);
kfree(chip->work_space.context_buf);
kfree(chip->work_space.session_buf);
+ kfree(chip->active_banks);
kfree(chip);
}

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1a803b0cf980..ba7ca6b3e664 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1039,8 +1039,7 @@ static int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
{
int rc;
- struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
- u32 count = 0;
+ struct tpm2_digest *digest_list;
int i;

chip = tpm_find_get_ops(chip);
@@ -1048,16 +1047,22 @@ int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
return -ENODEV;

if (chip->flags & TPM_CHIP_FLAG_TPM2) {
- memset(digest_list, 0, sizeof(digest_list));
+ digest_list = kmalloc_array(chip->nr_active_banks,
+ sizeof(*digest_list), GFP_KERNEL);
+ if (!digest_list)
+ return -ENOMEM;

- for (i = 0; i < ARRAY_SIZE(chip->active_banks) &&
- chip->active_banks[i] != TPM2_ALG_ERROR; i++) {
+ memset(digest_list, 0,
+ chip->nr_active_banks * sizeof(*digest_list));
+
+ for (i = 0; i < chip->nr_active_banks; i++) {
digest_list[i].alg_id = chip->active_banks[i];
memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
- count++;
}

- rc = tpm2_pcr_extend(chip, pcr_idx, count, digest_list);
+ rc = tpm2_pcr_extend(chip, pcr_idx, chip->nr_active_banks,
+ digest_list);
+ kfree(digest_list);
tpm_put_ops(chip);
return rc;
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index f3501d05264f..98368c3a6ff7 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -248,7 +248,8 @@ struct tpm_chip {
const struct attribute_group *groups[3];
unsigned int groups_cnt;

- u16 active_banks[7];
+ u32 nr_active_banks;
+ u16 *active_banks;
#ifdef CONFIG_ACPI
acpi_handle acpi_dev_handle;
char ppi_version[TPM_PPI_VERSION_LEN + 1];
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index c31b490bd41d..533089cede07 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -242,7 +242,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
int i;
int j;

- if (count > ARRAY_SIZE(chip->active_banks))
+ if (count > chip->nr_active_banks)
return -EINVAL;

rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
@@ -859,7 +859,6 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
void *marker;
void *end;
void *pcr_select_offset;
- unsigned int count;
u32 sizeof_pcr_selection;
u32 rsp_len;
int rc;
@@ -878,11 +877,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
if (rc)
goto out;

- count = be32_to_cpup(
+ chip->nr_active_banks = be32_to_cpup(
(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);

- if (count > ARRAY_SIZE(chip->active_banks)) {
- rc = -ENODEV;
+ chip->active_banks = kmalloc_array(chip->nr_active_banks,
+ sizeof(*chip->active_banks),
+ GFP_KERNEL);
+ if (!chip->active_banks) {
+ rc = -ENOMEM;
goto out;
}

@@ -891,7 +893,7 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
rsp_len = be32_to_cpup((__be32 *)&buf.data[2]);
end = &buf.data[rsp_len];

- for (i = 0; i < count; i++) {
+ for (i = 0; i < chip->nr_active_banks; i++) {
pcr_select_offset = marker +
offsetof(struct tpm2_pcr_selection, size_of_select);
if (pcr_select_offset >= end) {
@@ -908,9 +910,6 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
}

out:
- if (i < ARRAY_SIZE(chip->active_banks))
- chip->active_banks[i] = TPM2_ALG_ERROR;
-
tpm_buf_destroy(&buf);

return rc;
--
2.17.1
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