Re: [PATCH v2, RESEND 2/3] tpm: modify tpm_pcr_read() definition to pass TPM hash algorithms

Re: [PATCH v2, RESEND 2/3] tpm: modify tpm_pcr_read() definition to pass TPM hash algorithms

[Mimi Zohar]

On Fri, 2018-09-21 at 12:24 +0200, Roberto Sassu wrote:
> On 9/17/2018 11:38 AM, Roberto Sassu wrote:
> > Currently the TPM driver allows other kernel subsystems to read only the
> > SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> > tpm2_pcr_read() to pass an array of tpm_digest structures, which contains
> > the desired hash algorithms. Initially, the array size is limited to 1.
> 
> Jarkko, is this patch ok?
> 
> Mimi, I wait for your review of the IMA part.

Yes, I know.  I've been on vacation and am hoping to review your, Eric
Bigger's and Nayna's patches soon.  Sorry for the delay!

Mimi

Re: [PATCH v2, RESEND 2/3] tpm: modify tpm_pcr_read() definition to pass TPM hash algorithms

[Jarkko Sakkinen]

On Fri, Sep 21, 2018 at 12:24:15PM +0200, Roberto Sassu wrote:
> On 9/17/2018 11:38 AM, Roberto Sassu wrote:
> > Currently the TPM driver allows other kernel subsystems to read only the
> > SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> > tpm2_pcr_read() to pass an array of tpm_digest structures, which contains
> > the desired hash algorithms. Initially, the array size is limited to 1.
> 
> Jarkko, is this patch ok?
> 
> Mimi, I wait for your review of the IMA part.
> 
> Roberto

Oops, just bumped into these. Have to check next week. Please add me to
either to- or cc-field in the future.

/Jarkko

Re: [PATCH v2, RESEND 2/3] tpm: modify tpm_pcr_read() definition to pass TPM hash algorithms

[Jarkko Sakkinen]

On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> Currently the TPM driver allows other kernel subsystems to read only the
> SHA1 PCR bank. This patch modifies the parameters of tpm_pcr_read() and
> tpm2_pcr_read() to pass an array of tpm_digest structures, which contains
> the desired hash algorithms. Initially, the array size is limited to 1.
> 
> Due to the API change, IMA functions have been modified.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  drivers/char/tpm/tpm-interface.c    | 13 +++++++++----
>  drivers/char/tpm/tpm.h              |  3 ++-
>  drivers/char/tpm/tpm2-cmd.c         | 17 +++++++++++------
>  include/linux/tpm.h                 |  6 ++++--
>  security/integrity/ima/ima_crypto.c | 10 +++++-----
>  5 files changed, 31 insertions(+), 18 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-
> interface.c
> index 645c9aa7677a..81872880b5f1 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -976,21 +976,26 @@ EXPORT_SYMBOL_GPL(tpm_is_tpm2);
>   * tpm_pcr_read - read a PCR value from SHA1 bank
>   * @chip:	a &struct tpm_chip instance, %NULL for the default chip
>   * @pcr_idx:	the PCR to be retrieved
> - * @res_buf:	the value of the PCR
> + * @count:	number of digests passed
> + * @digests:	list of pcr banks and buffers current PCR values are
> written to
>   *
>   * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> +int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> +		 struct tpm_digest *digests)
>  {
>  	int rc;
>  
> +	if (count != 1)
> +		return -EINVAL;
> +
>  	chip = tpm_find_get_ops(chip);
>  	if (!chip)
>  		return -ENODEV;
>  	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> -		rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
> +		rc = tpm2_pcr_read(chip, pcr_idx, count, digests);
>  	else
> -		rc = tpm_pcr_read_dev(chip, pcr_idx, res_buf);
> +		rc = tpm_pcr_read_dev(chip, pcr_idx, digests[0].digest);
>  	tpm_put_ops(chip);
>  	return rc;
>  }
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index b928ba44d864..9479e1ae1b4c 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -564,7 +564,8 @@ static inline u32 tpm2_rc_value(u32 rc)
>  	return (rc & BIT(7)) ? rc & 0xff : rc;
>  }
>  
> -int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
> +int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> +		  struct tpm_digest *digests);
>  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 2d7397b8a0d1..601d67c76c1e 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -179,11 +179,13 @@ struct tpm2_pcr_read_out {
>   * tpm2_pcr_read() - read a PCR value
>   * @chip:	TPM chip to use.
>   * @pcr_idx:	index of the PCR to read.
> - * @res_buf:	buffer to store the resulting hash.
> + * @count:	number of digests passed.
> + * @digests:	list of pcr banks and buffers current PCR values are
> written to.
>   *
>   * Return: Same as with tpm_transmit_cmd.
>   */
> -int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> +int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> +		  struct tpm_digest *digests)
>  {
>  	int rc;
>  	struct tpm_buf buf;
> @@ -192,6 +194,8 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8
> *res_buf)
>  
>  	if (pcr_idx >= TPM2_PLATFORM_PCR)
>  		return -EINVAL;
> +	if (count > 1)
> +		return -EINVAL;
>  
>  	rc = tpm_buf_init(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_READ);
>  	if (rc)
> @@ -200,16 +204,17 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u8
> *res_buf)
>  	pcr_select[pcr_idx >> 3] = 1 << (pcr_idx & 0x7);
>  
>  	tpm_buf_append_u32(&buf, 1);
> -	tpm_buf_append_u16(&buf, TPM_ALG_SHA1);
> +	tpm_buf_append_u16(&buf, count ? digests[0].alg_id : TPM_ALG_SHA1);
>  	tpm_buf_append_u8(&buf, TPM2_PCR_SELECT_MIN);
>  	tpm_buf_append(&buf, (const unsigned char *)pcr_select,
>  		       sizeof(pcr_select));
>  
>  	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
> -			res_buf ? "attempting to read a pcr value" : NULL);
> -	if (rc == 0 && res_buf) {
> +			      count ? "attempting to read a pcr value" :
> NULL);
> +	if (rc == 0 && count) {
>  		out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
> -		memcpy(res_buf, out->digest, SHA1_DIGEST_SIZE);
> +		memcpy(digests[0].digest, out->digest,
> +		       be16_to_cpu(out->digest_size));
>  	}
>  
>  	tpm_buf_destroy(&buf);
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 71d7bbf5f690..ac9fc47f4494 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -71,7 +71,8 @@ struct tpm_class_ops {
>  #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
>  
>  extern int tpm_is_tpm2(struct tpm_chip *chip);
> -extern int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf);
> +extern int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> +			struct tpm_digest *digests);
>  extern int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8
> *hash);
>  extern int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen);
>  extern int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max);
> @@ -87,7 +88,8 @@ static inline int tpm_is_tpm2(struct tpm_chip *chip)
>  {
>  	return -ENODEV;
>  }
> -static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8
> *res_buf)
> +static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> +			       struct tpm_digest *digests)
>  {
>  	return -ENODEV;
>  }
> diff --git a/security/integrity/ima/ima_crypto.c
> b/security/integrity/ima/ima_crypto.c
> index 7e7e7e7c250a..4c94cf810d15 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -629,12 +629,12 @@ int ima_calc_buffer_hash(const void *buf, loff_t len,
>  	return calc_buffer_shash(buf, len, hash);
>  }
>  
> -static void __init ima_pcrread(int idx, u8 *pcr)
> +static void __init ima_pcrread(int idx, struct tpm_digest *d)
>  {
>  	if (!ima_tpm_chip)
>  		return;
>  
> -	if (tpm_pcr_read(ima_tpm_chip, idx, pcr) != 0)
> +	if (tpm_pcr_read(ima_tpm_chip, idx, 1, d) != 0)
>  		pr_err("Error Communicating to TPM chip\n");
>  }
>  
> @@ -644,7 +644,7 @@ static void __init ima_pcrread(int idx, u8 *pcr)
>  static int __init ima_calc_boot_aggregate_tfm(char *digest,
>  					      struct crypto_shash *tfm)
>  {
> -	u8 pcr_i[TPM_DIGEST_SIZE];
> +	struct tpm_digest d = {.alg_id = TPM_ALG_SHA1};
>  	int rc, i;
>  	SHASH_DESC_ON_STACK(shash, tfm);
>  
> @@ -657,9 +657,9 @@ static int __init ima_calc_boot_aggregate_tfm(char
> *digest,
>  
>  	/* cumulative sha1 over tpm registers 0-7 */
>  	for (i = TPM_PCR0; i < TPM_PCR8; i++) {
> -		ima_pcrread(i, pcr_i);
> +		ima_pcrread(i, &d);
>  		/* now accumulate with current aggregate */
> -		rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE);
> +		rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE);
>  	}
>  	if (!rc)
>  		crypto_shash_final(shash, digest);

The change would be good if there was a patch in the series that would
use arrays larger than one. The principle is that something added only
at the point when it is taken use of. You should remove @count for now.

/Jarkko

Re: [PATCH v2, RESEND 3/3] tpm: retrieve digest size of unknown algorithms with PCR read

[Jarkko Sakkinen]

On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> Currently, the TPM driver retrieves the digest size from a table mapping
> TPM algorithms identifiers to identifiers defined by the crypto subsystem.
> If the algorithm is not defined by the latter, the digest size can be
> retrieved from the output of the PCR read command.
> 
> The patch retrieves at TPM startup the digest sizes for each PCR bank and
> stores them in the new structure tpm_active_bank_info, member of tpm_chip,
> so that the information can be passed to other kernel subsystems.
> 
> tpm_active_bank_info contains: the TPM algorithm identifier, necessary to
> generate the event log as defined by Trusted Computing Group (TCG); the
> digest size, to pad/truncate a digest calculated with a different
> algorithm; the crypto subsystem identifier, to calculate the digest of
> event data.
> 
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  drivers/char/tpm/tpm-interface.c | 11 +++++++---
>  drivers/char/tpm/tpm.h           |  4 ++--
>  drivers/char/tpm/tpm2-cmd.c      | 47 ++++++++++++++++++++++++++++++---------
> -
>  include/linux/tpm.h              |  6 +++++
>  4 files changed, 51 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-
> interface.c
> index 81872880b5f1..02dcdcda5a3c 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -993,7 +993,7 @@ int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u32
> count,
>  	if (!chip)
>  		return -ENODEV;
>  	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> -		rc = tpm2_pcr_read(chip, pcr_idx, count, digests);
> +		rc = tpm2_pcr_read(chip, pcr_idx, count, digests, NULL);
>  	else
>  		rc = tpm_pcr_read_dev(chip, pcr_idx, digests[0].digest);
>  	tpm_put_ops(chip);
> @@ -1056,8 +1056,8 @@ int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx,
> const u8 *hash)
>  		memset(digest_list, 0, sizeof(digest_list));
>  
>  		for (i = 0; i < ARRAY_SIZE(chip->active_banks) &&
> -			    chip->active_banks[i] != TPM_ALG_ERROR; i++) {
> -			digest_list[i].alg_id = chip->active_banks[i];
> +		     chip->active_banks[i].alg_id != TPM_ALG_ERROR; i++) {
> +			digest_list[i].alg_id = chip->active_banks[i].alg_id;
>  			memcpy(digest_list[i].digest, hash, TPM_DIGEST_SIZE);
>  			count++;
>  		}
> @@ -1158,6 +1158,11 @@ int tpm1_auto_startup(struct tpm_chip *chip)
>  		goto out;
>  	}
>  
> +	chip->active_banks[0].alg_id = TPM_ALG_SHA1;
> +	chip->active_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1];
> +	chip->active_banks[0].crypto_id = HASH_ALGO_SHA1;
> +	chip->active_banks[1].alg_id = TPM_ALG_ERROR;
> +
>  	return rc;
>  out:
>  	if (rc > 0)
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 9479e1ae1b4c..385843b49c17 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_active_bank_info active_banks[7];
>  #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, u32 count,
> -		  struct tpm_digest *digests);
> +		  struct tpm_digest *digests, u16 *sizes);
>  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 601d67c76c1e..51d2454c5329 100644
> --- a/drivers/char/tpm/tpm2-cmd.c
> +++ b/drivers/char/tpm/tpm2-cmd.c
> @@ -181,11 +181,12 @@ struct tpm2_pcr_read_out {
>   * @pcr_idx:	index of the PCR to read.
>   * @count:	number of digests passed.
>   * @digests:	list of pcr banks and buffers current PCR values are
> written to.
> + * @sizes:	list of digest sizes.
>   *
>   * Return: Same as with tpm_transmit_cmd.
>   */
>  int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u32 count,
> -		  struct tpm_digest *digests)
> +		  struct tpm_digest *digests, u16 *sizes)
>  {
>  	int rc;
>  	struct tpm_buf buf;
> @@ -215,6 +216,9 @@ int tpm2_pcr_read(struct tpm_chip *chip, int pcr_idx, u32
> count,
>  		out = (struct tpm2_pcr_read_out *)&buf.data[TPM_HEADER_SIZE];
>  		memcpy(digests[0].digest, out->digest,
>  		       be16_to_cpu(out->digest_size));
> +
> +		if (sizes)
> +			sizes[0] = be16_to_cpu(out->digest_size);
>  	}
>  
>  	tpm_buf_destroy(&buf);
> @@ -245,7 +249,6 @@ 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;
> @@ -267,14 +270,9 @@ 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);
>  	}
>  
>  	rc = tpm_transmit_cmd(chip, NULL, buf.data, PAGE_SIZE, 0, 0,
> @@ -851,6 +849,26 @@ int tpm2_probe(struct tpm_chip *chip)
>  }
>  EXPORT_SYMBOL_GPL(tpm2_probe);
>  
> +static int tpm2_init_active_bank_info(struct tpm_chip *chip,
> +				      struct tpm_active_bank_info
> *active_bank)
> +{
> +	struct tpm_digest digest = {.alg_id = active_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 (active_bank->alg_id != tpm2_hash_map[i].tpm_id)
> +			continue;
> +
> +		active_bank->digest_size = hash_digest_size[crypto_algo];
> +		active_bank->crypto_id = crypto_algo;
> +		return 0;
> +	}
> +
> +	return tpm2_pcr_read(chip, 0, 1, &digest, &active_bank->digest_size);
> +}
> +
>  struct tpm2_pcr_selection {
>  	__be16  hash_alg;
>  	u8  size_of_select;
> @@ -905,7 +923,12 @@ 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_active_bank_info(chip, &chip-
> >active_banks[i]);
> +		if (rc)
> +			break;
> +
>  		sizeof_pcr_selection = sizeof(pcr_selection.hash_alg) +
>  			sizeof(pcr_selection.size_of_select) +
>  			pcr_selection.size_of_select;
> @@ -914,7 +937,7 @@ static ssize_t tpm2_get_pcr_allocation(struct tpm_chip
> *chip)
>  
>  out:
>  	if (i < ARRAY_SIZE(chip->active_banks))
> -		chip->active_banks[i] = TPM_ALG_ERROR;
> +		chip->active_banks[i].alg_id = TPM_ALG_ERROR;
>  
>  	tpm_buf_destroy(&buf);
>  
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index ac9fc47f4494..c8372ff582c3 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_active_bank_info {
> +	u16 alg_id;
> +	u16 digest_size;
> +	u16 crypto_id;
> +};
> +
>  enum TPM_OPS_FLAGS {
>  	TPM_OPS_AUTO_STARTUP = BIT(0),
>  };

Still think that we should use zero as marker for the end and not use
TPM_ALG_ERROR as zero is the defacto way to terminate an array. It
should be a separate commit. I can accept this and send such a patch
after this has been merged or alternatively you can include such patch
to a new version of the series.

Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM

[Mimi Zohar]

On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> Resending to maintainer with correct mailing lists in CC.
> 
> The TPM driver currently relies on the crypto subsystem to determine the
> digest size of supported TPM algorithms. In the future, TPM vendors might
> implement new algorithms in their chips, and those algorithms might not
> be supported by the crypto subsystem.
> 
> Usually, vendors provide patches for the new hardware, and likely
> the crypto subsystem will be updated before the new algorithm is
> introduced. However, old kernels might be updated later, after patches
> are included in the mainline kernel. This would leave the opportunity
> for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> are not extended.
> 
> This patch set provides a long term solution for this issue. If a TPM
> algorithm is not known by the crypto subsystem, the TPM driver retrieves
> the digest size from the TPM with a PCR read. All the PCR banks are
> extended, even if the algorithm is not yet supported by the crypto
> subsystem.

Other than checking the digest size before copying the pcrread buffer,
the patches look good.  Please add my Ack on all 3 patches.

(New address) Acked-by: Mimi Zohar <zohar@linux.ibm.com>

Thanks!

Mimi

Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM

[Mimi Zohar]

On Wed, 2018-09-26 at 10:40 -0400, Mimi Zohar wrote:
> On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> > Resending to maintainer with correct mailing lists in CC.
> > 
> > The TPM driver currently relies on the crypto subsystem to determine the
> > digest size of supported TPM algorithms. In the future, TPM vendors might
> > implement new algorithms in their chips, and those algorithms might not
> > be supported by the crypto subsystem.
> > 
> > Usually, vendors provide patches for the new hardware, and likely
> > the crypto subsystem will be updated before the new algorithm is
> > introduced. However, old kernels might be updated later, after patches
> > are included in the mainline kernel. This would leave the opportunity
> > for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> > are not extended.
> > 
> > This patch set provides a long term solution for this issue. If a TPM
> > algorithm is not known by the crypto subsystem, the TPM driver retrieves
> > the digest size from the TPM with a PCR read. All the PCR banks are
> > extended, even if the algorithm is not yet supported by the crypto
> > subsystem.
> 
> Other than checking the digest size before copying the pcrread buffer,
> the patches look good.  Please add my Ack on all 3 patches.
> 
> (New address) Acked-by: Mimi Zohar <zohar@linux.ibm.com>

I've reviewed, and am currently running with these patches.

Even if the IMA changes were in a separate patch, we wouldn't be able
to break up the patch set anyway.  Jarkko, I'd appreciate your
carrying the entire patch set.

Roberto, a similar change needs to be made for tpm_pcr_extend.  Are
you planning on posting those changes as well?

Mimi

Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM

[Roberto Sassu]

On 9/26/2018 8:03 PM, Mimi Zohar wrote:
> On Wed, 2018-09-26 at 10:40 -0400, Mimi Zohar wrote:
>> On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
>>> Resending to maintainer with correct mailing lists in CC.
>>>
>>> The TPM driver currently relies on the crypto subsystem to determine the
>>> digest size of supported TPM algorithms. In the future, TPM vendors might
>>> implement new algorithms in their chips, and those algorithms might not
>>> be supported by the crypto subsystem.
>>>
>>> Usually, vendors provide patches for the new hardware, and likely
>>> the crypto subsystem will be updated before the new algorithm is
>>> introduced. However, old kernels might be updated later, after patches
>>> are included in the mainline kernel. This would leave the opportunity
>>> for attackers to misuse PCRs, as PCR banks with an unknown algorithm
>>> are not extended.
>>>
>>> This patch set provides a long term solution for this issue. If a TPM
>>> algorithm is not known by the crypto subsystem, the TPM driver retrieves
>>> the digest size from the TPM with a PCR read. All the PCR banks are
>>> extended, even if the algorithm is not yet supported by the crypto
>>> subsystem.
>>
>> Other than checking the digest size before copying the pcrread buffer,
>> the patches look good.  Please add my Ack on all 3 patches.
>>
>> (New address) Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> 
> I've reviewed, and am currently running with these patches.
> 
> Even if the IMA changes were in a separate patch, we wouldn't be able
> to break up the patch set anyway.  Jarkko, I'd appreciate your
> carrying the entire patch set.
> 
> Roberto, a similar change needs to be made for tpm_pcr_extend.  Are
> you planning on posting those changes as well?

Yes, I was planning to send the patch after this patch set is accepted.

Roberto

Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM

[Mimi Zohar]

On Thu, 2018-09-27 at 08:50 +0200, Roberto Sassu wrote:
> On 9/26/2018 8:03 PM, Mimi Zohar wrote:

> > Roberto, a similar change needs to be made for tpm_pcr_extend.  Are
> > you planning on posting those changes as well?
> 
> Yes, I was planning to send the patch after this patch set is accepted.

Great!

Mimi

Re: [PATCH v2, RESEND 0/3] tpm: retrieve digest size of unknown algorithms from TPM

[Jarkko Sakkinen]

On Thu, Sep 27, 2018 at 08:50:14AM +0200, Roberto Sassu wrote:
> On 9/26/2018 8:03 PM, Mimi Zohar wrote:
> > On Wed, 2018-09-26 at 10:40 -0400, Mimi Zohar wrote:
> > > On Mon, 2018-09-17 at 11:38 +0200, Roberto Sassu wrote:
> > > > Resending to maintainer with correct mailing lists in CC.
> > > > 
> > > > The TPM driver currently relies on the crypto subsystem to determine the
> > > > digest size of supported TPM algorithms. In the future, TPM vendors might
> > > > implement new algorithms in their chips, and those algorithms might not
> > > > be supported by the crypto subsystem.
> > > > 
> > > > Usually, vendors provide patches for the new hardware, and likely
> > > > the crypto subsystem will be updated before the new algorithm is
> > > > introduced. However, old kernels might be updated later, after patches
> > > > are included in the mainline kernel. This would leave the opportunity
> > > > for attackers to misuse PCRs, as PCR banks with an unknown algorithm
> > > > are not extended.
> > > > 
> > > > This patch set provides a long term solution for this issue. If a TPM
> > > > algorithm is not known by the crypto subsystem, the TPM driver retrieves
> > > > the digest size from the TPM with a PCR read. All the PCR banks are
> > > > extended, even if the algorithm is not yet supported by the crypto
> > > > subsystem.
> > > 
> > > Other than checking the digest size before copying the pcrread buffer,
> > > the patches look good.  Please add my Ack on all 3 patches.
> > > 
> > > (New address) Acked-by: Mimi Zohar <zohar@linux.ibm.com>
> > 
> > I've reviewed, and am currently running with these patches.
> > 
> > Even if the IMA changes were in a separate patch, we wouldn't be able
> > to break up the patch set anyway.  Jarkko, I'd appreciate your
> > carrying the entire patch set.
> > 
> > Roberto, a similar change needs to be made for tpm_pcr_extend.  Are
> > you planning on posting those changes as well?
> 
> Yes, I was planning to send the patch after this patch set is accepted.
> 
> Roberto

Mimi, I can carry it yes.

/Jarkko