Messages in this thread | | | Subject | Re: [PATCH v4 1/6] tpm: dynamically allocate active_banks array | From | Roberto Sassu <> | Date | Wed, 7 Nov 2018 10:41:57 +0100 |
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On 11/7/2018 7:14 AM, Nayna Jain wrote: > > > On 11/06/2018 08:31 PM, Roberto Sassu wrote: >> This patch removes the hard-coded limit of the active_banks array size. > > > The hard-coded limit in static array active_banks[] represents the > maximum possible banks. > A TPM might have three banks, but only one bank may be active. > > To confirm my understanding, is the idea for this patch is to > dynamically identify the number of possible banks or the number of > active banks ?
The idea is to dynamically identify the number of active banks.
In the TPM Commands specification (section 30.2.1), I found:
TPM_CAP_PCRS – Returns the current allocation of PCR in a TPML_PCR_SELECTION.
You mentioned:
#TPM_RC_SIZE response code when count is greater than the possible number of banks
but TPML_PCR_SELECTION is provided by the TPM.
Roberto
>> 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]); > > > As per my understanding, the count in the TPML_PCR_SELECTION represent > the number of possible banks and not the number of active banks. > TCG Structures Spec for TPM 2.0 - Table 102 mentions this as explanation > of #TPM_RC_SIZE. > > Thanks & Regards, > - Nayna > > >> >> - 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; >
-- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Bo PENG, Jian LI, Yanli SHI
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