tpm: dynamically allocate the allocated_banks array
This patch renames active_banks (member of tpm_chip) to allocated_banks,
stores the number of allocated PCR banks in nr_allocated_banks (new member
of tpm_chip), and replaces the static array with a pointer to a dynamically
allocated array.
tpm2_get_pcr_allocation() determines if a PCR bank is allocated by checking
the mask in the TPML_PCR_SELECTION structure returned by the TPM for
TPM2_Get_Capability(). If a bank is not allocated, the TPM returns that
bank in TPML_PCR_SELECTION, with all bits in the mask set to zero. In this
case, the bank is not included in chip->allocated_banks, to avoid that TPM
driver users unnecessarily calculate a digest for that bank.
One PCR bank with algorithm set to SHA1 is always allocated for TPM 1.x.
As a consequence of the introduction of nr_allocated_banks,
tpm_pcr_extend() does not check anymore if the algorithm stored in tpm_chip
is equal to zero.
Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 971d46e..bd20b9a 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c
@@ -234,7 +234,7 @@ int tpm2_pcr_extend(struct tpm_chip *chip, u32 pcr_idx, u32 count,
int i;
int j;
- if (count > ARRAY_SIZE(chip->active_banks))
+ if (count > chip->nr_allocated_banks)
return -EINVAL;
rc = tpm_buf_init(&buf, TPM2_ST_SESSIONS, TPM2_CC_PCR_EXTEND);
@@ -808,8 +808,10 @@ 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 nr_possible_banks;
+ u32 nr_alloc_banks = 0;
+ u16 hash_alg;
u32 rsp_len;
int rc;
int i = 0;
@@ -826,11 +828,14 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
if (rc)
goto out;
- count = be32_to_cpup(
+ nr_possible_banks = be32_to_cpup(
(__be32 *)&buf.data[TPM_HEADER_SIZE + 5]);
- if (count > ARRAY_SIZE(chip->active_banks)) {
- rc = -ENODEV;
+ chip->allocated_banks = kcalloc(nr_possible_banks,
+ sizeof(*chip->allocated_banks),
+ GFP_KERNEL);
+ if (!chip->allocated_banks) {
+ rc = -ENOMEM;
goto out;
}
@@ -839,7 +844,7 @@ 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 < nr_possible_banks; i++) {
pcr_select_offset = marker +
offsetof(struct tpm2_pcr_selection, size_of_select);
if (pcr_select_offset >= end) {
@@ -848,17 +853,23 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip)
}
memcpy(&pcr_selection, marker, sizeof(pcr_selection));
- chip->active_banks[i] = be16_to_cpu(pcr_selection.hash_alg);
+ hash_alg = be16_to_cpu(pcr_selection.hash_alg);
+
+ pcr_select_offset = memchr_inv(pcr_selection.pcr_select, 0,
+ pcr_selection.size_of_select);
+ if (pcr_select_offset) {
+ chip->allocated_banks[nr_alloc_banks] = hash_alg;
+ nr_alloc_banks++;
+ }
+
sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
sizeof(pcr_selection.size_of_select) +
pcr_selection.size_of_select;
marker = marker + sizeof_pcr_selection;
}
+ chip->nr_allocated_banks = nr_alloc_banks;
out:
- if (i < ARRAY_SIZE(chip->active_banks))
- chip->active_banks[i] = TPM2_ALG_ERROR;
-
tpm_buf_destroy(&buf);
return rc;