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Message-ID: <38bdee38-503b-0bac-efba-99f285018934@huawei.com>
Date: Tue, 13 Nov 2018 14:34:39 +0100
From: Roberto Sassu <roberto.sassu@...wei.com>
To: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
CC: <zohar@...ux.ibm.com>, <linux-integrity@...r.kernel.org>,
<linux-security-module@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <silviu.vlasceanu@...wei.com>
Subject: Re: [PATCH v4 1/6] tpm: dynamically allocate active_banks array
On 11/8/2018 2:46 PM, Jarkko Sakkinen wrote:
> Orrayn Tue, Nov 06, 2018 at 04:01:54PM +0100, Roberto Sassu wrote:
>> 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@...wei.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;
>
> Should take digest_list as input. Probably callers could re-use the
> same digest_list array multiple times?
>
> Move struct tpm_chip to include/linux/tpm.h so that the caller can query
> nr_active_banks and active_banks and can create the digest array by
> itself. Lets do this right at once now that this is being restructured.
I have to move also other structures and #define. Wouldn't be better to
introduce a new function to pass to the caller active_banks and
nr_active_banks?
Roberto
>>
>> 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));
>
> You should use kcalloc() to allocate 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
>>
>
> /Jarkko
>
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