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Message-ID: <3034c896-788b-50f9-23cb-f4b2cd6363e6@huawei.com>
Date: Mon, 5 Nov 2018 10:47:19 +0100
From: Roberto Sassu <roberto.sassu@...wei.com>
To: Mimi Zohar <zohar@...ux.ibm.com>, <jarkko.sakkinen@...ux.intel.com>
CC: <linux-integrity@...r.kernel.org>,
<linux-security-module@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <silviu.vlasceanu@...wei.com>
Subject: Re: [PATCH v3 4/5] tpm: retrieve digest size of unknown algorithms
with PCR read
On 11/1/2018 5:02 PM, Mimi Zohar wrote:
> On Tue, 2018-10-30 at 16:47 +0100, Roberto Sassu wrote:
[...]
>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>> index 633e16f42107..8662e8587dce 100644
>> --- a/drivers/char/tpm/tpm.h
>> +++ b/drivers/char/tpm/tpm.h
>> @@ -237,7 +237,7 @@ struct tpm_chip {
>> const struct attribute_group *groups[3];
>> unsigned int groups_cnt;
>>
>> - u16 active_banks[7];
>> + struct tpm_bank_info active_banks[7];
>
> Commit 1db15344f874 ("tpm: implement TPM 2.0 capability to get active
> PCR banks") defined active_banks[7]. Subsequently, commit
> 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware event
> log") defined TPM2_PCR_ACTIVE_BANKS as 3. I'm not sure which is the
> correct value, but the number of active_banks should not be hard coded
> here.
Jarkko, should I change the value of TPM2_PCR_ACTIVE_BANKS, or set the
size of the active_banks array to TPM2_PCR_ACTIVE_BANKS?
>> #ifdef CONFIG_ACPI
>> acpi_handle acpi_dev_handle;
>> char ppi_version[TPM_PPI_VERSION_LEN + 1];
>> @@ -565,7 +565,7 @@ static inline u32 tpm2_rc_value(u32 rc)
>> }
>>
>> int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx,
>> - struct tpm_digest *digest_struct);
>> + struct tpm_digest *digest_struct, u16 *digest_size_ptr);
>> int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>> struct tpm_digest *digests);
>> int tpm2_get_random(struct tpm_chip *chip, u8 *dest, size_t max);
>> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
>> index 8babd826ad27..8e821e7b4674 100644
>> --- a/drivers/char/tpm/tpm2-cmd.c
>> +++ b/drivers/char/tpm/tpm2-cmd.c
>> @@ -180,11 +180,12 @@ struct tpm2_pcr_read_out {
>> * @chip: TPM chip to use.
>> * @pcr_idx: index of the PCR to read.
>> * @digest_struct: pcr bank and buffer current PCR value is written to.
>> + * @digest_size_ptr: pointer to variable that stores the digest size.
>> *
>> * Return: Same as with tpm_transmit_cmd.
>> */
>> int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx,
>> - struct tpm_digest *digest_struct)
>> + struct tpm_digest *digest_struct, u16 *digest_size_ptr)
>> {
>> int rc;
>> struct tpm_buf buf;
>> @@ -219,6 +220,9 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx,
>> goto out;
>> }
>>
>> + if (digest_size_ptr)
>> + *digest_size_ptr = digest_size;
>> +
>> memcpy(digest_struct->digest, out->digest, digest_size);
>> out:
>> tpm_buf_destroy(&buf);
>> @@ -249,7 +253,6 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>> struct tpm2_null_auth_area auth_area;
>> int rc;
>> int i;
>> - int j;
>>
>> if (count > ARRAY_SIZE(chip->active_banks))
>> return -EINVAL;
>> @@ -271,14 +274,9 @@ int tpm2_pcr_extend(struct tpm_chip *chip, int pcr_idx, u32 count,
>> tpm_buf_append_u32(&buf, count);
>>
>> for (i = 0; i < count; i++) {
>> - for (j = 0; j < ARRAY_SIZE(tpm2_hash_map); j++) {
>> - if (digests[i].alg_id != tpm2_hash_map[j].tpm_id)
>> - continue;
>> - tpm_buf_append_u16(&buf, digests[i].alg_id);
>> - tpm_buf_append(&buf, (const unsigned char
>> - *)&digests[i].digest,
>> - hash_digest_size[tpm2_hash_map[j].crypto_id]);
>> - }
>> + tpm_buf_append_u16(&buf, digests[i].alg_id);
>> + tpm_buf_append(&buf, (const unsigned char *)&digests[i].digest,
>> + chip->active_banks[i].digest_size);
>> }
>>
>
> These tpm2_pcr_extend changes don't belong here in this patch. Please
> move them to 1/5.
Also in this case, alg_id and digest_size are defined in patch 4/5.
>> rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
>> @@ -855,6 +853,26 @@ int tpm2_probe(struct tpm_chip *chip)
>> }
>> EXPORT_SYMBOL_GPL(tpm2_probe);
>>
>> +static int tpm2_init_bank_info(struct tpm_chip *chip,
>> + struct tpm_bank_info *bank)
>> +{
>> + struct tpm_digest digest = {.alg_id = bank->alg_id};
>> + int i;
>> +
>> + for (i = 0; i < ARRAY_SIZE(tpm2_hash_map); i++) {
>> + enum hash_algo crypto_algo = tpm2_hash_map[i].crypto_id;
>> +
>> + if (bank->alg_id != tpm2_hash_map[i].tpm_id)
>> + continue;
>> +
>> + bank->digest_size = hash_digest_size[crypto_algo];
>> + bank->crypto_id = crypto_algo;
>> + return 0;
>> + }
>> +
>> + return tpm2_pcr_read(chip, 0, &digest, &bank->digest_size);
>> +}
>> +
>> struct tpm2_pcr_selection {
>> __be16 hash_alg;
>> u8 size_of_select;
>> @@ -909,7 +927,12 @@ 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);
>> + chip->active_banks[i].alg_id =
>> + be16_to_cpu(pcr_selection.hash_alg);
>> + rc = tpm2_init_bank_info(chip, &chip->active_banks[i]);
>
> Please fix the formatting in the above 2 lines.
>
> There's been discussion in the past on removing scripts/Lindent from
> the coding-style documentation, but that hasn't happened quite yet. I
> do think section 3 "New drivers" in Documentation/hwmon/submitting-
> patches has a good balance.
>
> * Running your patch or driver file(s) through checkpatch does not mean its
> formatting is clean. If unsure about formatting in your new driver, run it
> through Lindent. Lindent is not perfect, and you may have to do some minor
> cleanup, but it is a good start.
Ok.
Thanks
Roberto
> thanks!
>
> Mimi
>
>> + if (rc)
>> + break;
>> +
>> sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
>> sizeof(pcr_selection.size_of_select) +
>> pcr_selection.size_of_select;
>> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
>> index 4f00daf44dd2..3f91124837cf 100644
>> --- a/include/linux/tpm.h
>> +++ b/include/linux/tpm.h
>> @@ -46,6 +46,12 @@ struct tpm_digest {
>> u8 digest[SHA512_DIGEST_SIZE];
>> } __packed;
>>
>> +struct tpm_bank_info {
>> + u16 alg_id;
>> + u16 digest_size;
>> + u16 crypto_id;
>> +};
>> +
>> enum TPM_OPS_FLAGS {
>> TPM_OPS_AUTO_STARTUP = BIT(0),
>> };
>
--
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