Patchwork [v2] tpm: use struct tpm_chip for tpm_chip_find_get()

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Submitter Jarkko Sakkinen
Date Oct. 25, 2017, 11:55 a.m.
Message ID <20171025115508.5682-1-jarkko.sakkinen@linux.intel.com>
Download mbox | patch
Permalink /patch/371239/
State New
Headers show

Comments

Jarkko Sakkinen - Oct. 25, 2017, 11:55 a.m.
Device number (the character device index) is not a stable identifier
for a TPM chip. That is the reason why every call site passes
TPM_ANY_NUM to tpm_chip_find_get().

This commit changes the API in a way that instead a struct tpm_chip
instance is given and NULL means the default chip. In addition, this
commit refines the documentation to be up to date with the
implementation.

Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> (@chip_num -> @chip)
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
---
v2:
* Further defined function documentation.
* Changed @chip_num to @chip instead of removing the parameter as suggested by
  Jason Gunthorpe.
 drivers/char/hw_random/tpm-rng.c    |   2 +-
 drivers/char/tpm/tpm-chip.c         |  21 +++---
 drivers/char/tpm/tpm-interface.c    | 135 +++++++++++++++++++-----------------
 drivers/char/tpm/tpm.h              |   2 +-
 include/linux/tpm.h                 |  38 +++++-----
 security/integrity/ima/ima_crypto.c |   2 +-
 security/integrity/ima/ima_init.c   |   2 +-
 security/integrity/ima/ima_queue.c  |   2 +-
 security/keys/trusted.c             |  35 +++++-----
 9 files changed, 125 insertions(+), 114 deletions(-)
PrasannaKumar Muralidharan - Oct. 25, 2017, 3:10 p.m.
Hi Jarkko,

On 25 October 2017 at 17:25, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
> Device number (the character device index) is not a stable identifier
> for a TPM chip. That is the reason why every call site passes
> TPM_ANY_NUM to tpm_chip_find_get().
>
> This commit changes the API in a way that instead a struct tpm_chip
> instance is given and NULL means the default chip. In addition, this
> commit refines the documentation to be up to date with the
> implementation.
>
> Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> (@chip_num -> @chip)
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> v2:
> * Further defined function documentation.
> * Changed @chip_num to @chip instead of removing the parameter as suggested by
>   Jason Gunthorpe.
>  drivers/char/hw_random/tpm-rng.c    |   2 +-
>  drivers/char/tpm/tpm-chip.c         |  21 +++---
>  drivers/char/tpm/tpm-interface.c    | 135 +++++++++++++++++++-----------------
>  drivers/char/tpm/tpm.h              |   2 +-
>  include/linux/tpm.h                 |  38 +++++-----
>  security/integrity/ima/ima_crypto.c |   2 +-
>  security/integrity/ima/ima_init.c   |   2 +-
>  security/integrity/ima/ima_queue.c  |   2 +-
>  security/keys/trusted.c             |  35 +++++-----
>  9 files changed, 125 insertions(+), 114 deletions(-)
>
> diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
> index d6d448266f07..c5e363825af0 100644
> --- a/drivers/char/hw_random/tpm-rng.c
> +++ b/drivers/char/hw_random/tpm-rng.c
> @@ -25,7 +25,7 @@
>
>  static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
>  {
> -       return tpm_get_random(TPM_ANY_NUM, data, max);
> +       return tpm_get_random(NULL, data, max);
>  }
>
>  static struct hwrng tpm_rng = {
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index a114e8f7fb90..c7a4e7fb424d 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -81,21 +81,26 @@ void tpm_put_ops(struct tpm_chip *chip)
>  EXPORT_SYMBOL_GPL(tpm_put_ops);
>
>  /**
> - * tpm_chip_find_get() - return tpm_chip for a given chip number
> - * @chip_num: id to find
> + * tpm_chip_find_get() - find and reserve a TPM chip
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
>   *
> - * The return'd chip has been tpm_try_get_ops'd and must be released via
> - * tpm_put_ops
> + * Finds a TPM chip and reserves its class device and operations. The chip must
> + * be released with tpm_chip_put_ops() after use.
> + *
> + * Return:
> + * A reserved &struct tpm_chip instance.
> + * %NULL if a chip is not found.
> + * %NULL if the chip is not available.
>   */
> -struct tpm_chip *tpm_chip_find_get(int chip_num)
> +struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
>  {
> -       struct tpm_chip *chip, *res = NULL;
> +       struct tpm_chip *res = NULL;
> +       int chip_num = 0;
>         int chip_prev;
>
>         mutex_lock(&idr_lock);
>
> -       if (chip_num == TPM_ANY_NUM) {
> -               chip_num = 0;
> +       if (!chip) {
>                 do {
>                         chip_prev = chip_num;
>                         chip = idr_get_next(&dev_nums_idr, &chip_num);

When chip is not NULL just do tpm_try_get_ops(chip). Current code does
more things which are not required.

> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index ebe0a1d36d8c..19f820f775b5 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -809,19 +809,20 @@ int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
>  }
>
>  /**
> - * tpm_is_tpm2 - is the chip a TPM2 chip?
> - * @chip_num:  tpm idx # or ANY
> + * tpm_is_tpm2 - do we a have a TPM2 chip?
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
>   *
> - * Returns < 0 on error, and 1 or 0 on success depending whether the chip
> - * is a TPM2 chip.
> + * Return:
> + * 1 if we have a TPM2 chip.
> + * 0 if we don't have a TPM2 chip.
> + * A negative number for system errors (errno).
>   */
> -int tpm_is_tpm2(u32 chip_num)
> +int tpm_is_tpm2(struct tpm_chip *chip)
>  {
> -       struct tpm_chip *chip;
>         int rc;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL)
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip)
>                 return -ENODEV;
>
>         rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
> @@ -833,23 +834,19 @@ int tpm_is_tpm2(u32 chip_num)
>  EXPORT_SYMBOL_GPL(tpm_is_tpm2);
>
>  /**
> - * tpm_pcr_read - read a pcr value
> - * @chip_num:  tpm idx # or ANY
> - * @pcr_idx:   pcr idx to retrieve
> - * @res_buf:   TPM_PCR value
> - *             size of res_buf is 20 bytes (or NULL if you don't care)
> + * 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
>   *
> - * The TPM driver should be built-in, but for whatever reason it
> - * isn't, protect against the chip disappearing, by incrementing
> - * the module usage count.
> + * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
> +int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
>  {
> -       struct tpm_chip *chip;
>         int rc;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL)
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip)
>                 return -ENODEV;
>         if (chip->flags & TPM_CHIP_FLAG_TPM2)
>                 rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
> @@ -889,25 +886,26 @@ static int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
>  }
>
>  /**
> - * tpm_pcr_extend - extend pcr value with hash
> - * @chip_num:  tpm idx # or AN&
> - * @pcr_idx:   pcr idx to extend
> - * @hash:      hash value used to extend pcr value
> + * tpm_pcr_extend - extend a PCR value in SHA1 bank.
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
> + * @pcr_idx:   the PCR to be retrieved
> + * @hash:      the hash value used to extend the PCR value
>   *
> - * The TPM driver should be built-in, but for whatever reason it
> - * isn't, protect against the chip disappearing, by incrementing
> - * the module usage count.
> + * Note: with TPM 2.0 extends also those banks with a known digest size to the
> + * cryto subsystem in order to prevent malicious use of those PCR banks. In the
> + * future we should dynamically determine digest sizes.
> + *
> + * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
> +int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
>  {
>         int rc;
> -       struct tpm_chip *chip;
>         struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
>         u32 count = 0;
>         int i;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL)
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip)
>                 return -ENODEV;
>
>         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> @@ -1019,17 +1017,24 @@ int tpm1_auto_startup(struct tpm_chip *chip)
>         return rc;
>  }
>
> -int tpm_send(u32 chip_num, void *cmd, size_t buflen)
> +/**
> + * tpm_send - send a TPM command
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
> + * @cmd:       a TPM command buffer
> + * @buflen:    the length of the TPM command buffer
> + *
> + * Return: same as with tpm_transmit_cmd()
> + */
> +int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
>  {
> -       struct tpm_chip *chip;
>         int rc;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL)
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip)
>                 return -ENODEV;
>
>         rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0,
> -                             "attempting tpm_cmd");
> +                             "attempting to a send a command");
>         tpm_put_ops(chip);
>         return rc;
>  }
> @@ -1127,16 +1132,15 @@ static const struct tpm_input_header tpm_getrandom_header = {
>  };
>
>  /**
> - * tpm_get_random() - Get random bytes from the tpm's RNG
> - * @chip_num: A specific chip number for the request or TPM_ANY_NUM
> - * @out: destination buffer for the random bytes
> - * @max: the max number of bytes to write to @out
> + * tpm_get_random() - get random bytes from the TPM's RNG
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
> + * @out:       destination buffer for the random bytes
> + * @max:       the max number of bytes to write to @out
>   *
> - * Returns < 0 on error and the number of bytes read on success
> + * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_get_random(u32 chip_num, u8 *out, size_t max)
> +int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
>  {
> -       struct tpm_chip *chip;
>         struct tpm_cmd_t tpm_cmd;
>         u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
>         int err, total = 0, retries = 5;
> @@ -1145,8 +1149,8 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>         if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
>                 return -EINVAL;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL)
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip)
>                 return -ENODEV;
>
>         if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> @@ -1188,22 +1192,23 @@ int tpm_get_random(u32 chip_num, u8 *out, size_t max)
>  EXPORT_SYMBOL_GPL(tpm_get_random);
>
>  /**
> - * tpm_seal_trusted() - seal a trusted key
> - * @chip_num: A specific chip number for the request or TPM_ANY_NUM
> - * @options: authentication values and other options
> - * @payload: the key data in clear and encrypted form
> + * tpm_seal_trusted() - seal a trusted key payload
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
> + * @options:   authentication values and other options
> + * @payload:   the key data in clear and encrypted form
> + *
> + * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
> + * the keyring subsystem.
>   *
> - * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
> - * are supported.
> + * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_seal_trusted(u32 chip_num, struct trusted_key_payload *payload,
> +int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload,
>                      struct trusted_key_options *options)
>  {
> -       struct tpm_chip *chip;
>         int rc;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
>                 return -ENODEV;
>
>         rc = tpm2_seal_trusted(chip, payload, options);
> @@ -1215,21 +1220,23 @@ EXPORT_SYMBOL_GPL(tpm_seal_trusted);
>
>  /**
>   * tpm_unseal_trusted() - unseal a trusted key
> - * @chip_num: A specific chip number for the request or TPM_ANY_NUM
> - * @options: authentication values and other options
> - * @payload: the key data in clear and encrypted form
> + * @chip:      a &struct tpm_chip instance, %NULL for the default chip
> + * @options:   authentication values and other options
> + * @payload:   the key data in clear and encrypted form
> + *
> + * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
> + * the keyring subsystem.
>   *
> - * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
> - * are supported.
> + * Return: same as with tpm_transmit_cmd()
>   */
> -int tpm_unseal_trusted(u32 chip_num, struct trusted_key_payload *payload,
> +int tpm_unseal_trusted(struct tpm_chip *chip,
> +                      struct trusted_key_payload *payload,
>                        struct trusted_key_options *options)
>  {
> -       struct tpm_chip *chip;
>         int rc;
>
> -       chip = tpm_chip_find_get(chip_num);
> -       if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
> +       chip = tpm_chip_find_get(chip);
> +       if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
>                 return -ENODEV;
>
>         rc = tpm2_unseal_trusted(chip, payload, options);
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index c1866cc02e30..6c189174c0d3 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -516,7 +516,7 @@ static inline void tpm_msleep(unsigned int delay_msec)
>                      delay_msec * 1000);
>  };
>
> -struct tpm_chip *tpm_chip_find_get(int chip_num);
> +struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip);
>  __must_check int tpm_try_get_ops(struct tpm_chip *chip);
>  void tpm_put_ops(struct tpm_chip *chip);
>
> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> index 5a090f5ab335..ddc9b88ff6d3 100644
> --- a/include/linux/tpm.h
> +++ b/include/linux/tpm.h
> @@ -24,11 +24,6 @@
>
>  #define TPM_DIGEST_SIZE 20     /* Max TPM v1.2 PCR size */
>
> -/*
> - * Chip num is this value or a valid tpm idx
> - */
> -#define        TPM_ANY_NUM 0xFFFF
> -
>  struct tpm_chip;
>  struct trusted_key_payload;
>  struct trusted_key_options;
> @@ -54,42 +49,47 @@ struct tpm_class_ops {
>
>  #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
>
> -extern int tpm_is_tpm2(u32 chip_num);
> -extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf);
> -extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash);
> -extern int tpm_send(u32 chip_num, void *cmd, size_t buflen);
> -extern int tpm_get_random(u32 chip_num, u8 *data, size_t max);
> -extern int tpm_seal_trusted(u32 chip_num,
> +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_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);
> +extern int tpm_seal_trusted(struct tpm_chip *chip,
>                             struct trusted_key_payload *payload,
>                             struct trusted_key_options *options);
> -extern int tpm_unseal_trusted(u32 chip_num,
> +extern int tpm_unseal_trusted(struct tpm_chip *chip,
>                               struct trusted_key_payload *payload,
>                               struct trusted_key_options *options);
>  #else
> -static inline int tpm_is_tpm2(u32 chip_num)
> +static inline int tpm_is_tpm2(struct tpm_chip *chip)
>  {
>         return -ENODEV;
>  }
> -static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) {
> +static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
> +{
>         return -ENODEV;
>  }
> -static inline int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) {
> +static inline int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx,
> +                                const u8 *hash)
> +{
>         return -ENODEV;
>  }
> -static inline int tpm_send(u32 chip_num, void *cmd, size_t buflen) {
> +static inline int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
> +{
>         return -ENODEV;
>  }
> -static inline int tpm_get_random(u32 chip_num, u8 *data, size_t max) {
> +static inline int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max)
> +{
>         return -ENODEV;
>  }
>
> -static inline int tpm_seal_trusted(u32 chip_num,
> +static inline int tpm_seal_trusted(struct tpm_chip *chip,
>                                    struct trusted_key_payload *payload,
>                                    struct trusted_key_options *options)
>  {
>         return -ENODEV;
>  }
> -static inline int tpm_unseal_trusted(u32 chip_num,
> +static inline int tpm_unseal_trusted(struct tpm_chip *chip,
>                                      struct trusted_key_payload *payload,
>                                      struct trusted_key_options *options)
>  {
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index 802d5d20f36f..3371d134ee62 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -644,7 +644,7 @@ static void __init ima_pcrread(int idx, u8 *pcr)
>         if (!ima_used_chip)
>                 return;
>
> -       if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
> +       if (tpm_pcr_read(NULL, idx, pcr) != 0)
>                 pr_err("Error Communicating to TPM chip\n");
>  }
>
> diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
> index 2967d497a665..29b72cd2502e 100644
> --- a/security/integrity/ima/ima_init.c
> +++ b/security/integrity/ima/ima_init.c
> @@ -110,7 +110,7 @@ int __init ima_init(void)
>         int rc;
>
>         ima_used_chip = 0;
> -       rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
> +       rc = tpm_pcr_read(NULL, 0, pcr_i);
>         if (rc == 0)
>                 ima_used_chip = 1;
>
> diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
> index a02a86d51102..418f35e38015 100644
> --- a/security/integrity/ima/ima_queue.c
> +++ b/security/integrity/ima/ima_queue.c
> @@ -145,7 +145,7 @@ static int ima_pcr_extend(const u8 *hash, int pcr)
>         if (!ima_used_chip)
>                 return result;
>
> -       result = tpm_pcr_extend(TPM_ANY_NUM, pcr, hash);
> +       result = tpm_pcr_extend(NULL, pcr, hash);
>         if (result != 0)
>                 pr_err("Error Communicating to TPM chip, result: %d\n", result);
>         return result;
> diff --git a/security/keys/trusted.c b/security/keys/trusted.c
> index ddfaebf60fc8..d2b20b1cc2f1 100644
> --- a/security/keys/trusted.c
> +++ b/security/keys/trusted.c
> @@ -355,13 +355,12 @@ static int TSS_checkhmac2(unsigned char *buffer,
>   * For key specific tpm requests, we will generate and send our
>   * own TPM command packets using the drivers send function.
>   */
> -static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
> -                           size_t buflen)
> +static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
>  {
>         int rc;
>
>         dump_tpm_buf(cmd);
> -       rc = tpm_send(chip_num, cmd, buflen);
> +       rc = tpm_send(NULL, cmd, buflen);
>         dump_tpm_buf(cmd);
>         if (rc > 0)
>                 /* Can't return positive return codes values to keyctl */
> @@ -382,10 +381,10 @@ static int pcrlock(const int pcrnum)
>
>         if (!capable(CAP_SYS_ADMIN))
>                 return -EPERM;
> -       ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE);
> +       ret = tpm_get_random(NULL, hash, SHA1_DIGEST_SIZE);
>         if (ret != SHA1_DIGEST_SIZE)
>                 return ret;
> -       return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
> +       return tpm_pcr_extend(NULL, pcrnum, hash) ? -EINVAL : 0;
>  }
>
>  /*
> @@ -398,7 +397,7 @@ static int osap(struct tpm_buf *tb, struct osapsess *s,
>         unsigned char ononce[TPM_NONCE_SIZE];
>         int ret;
>
> -       ret = tpm_get_random(TPM_ANY_NUM, ononce, TPM_NONCE_SIZE);
> +       ret = tpm_get_random(NULL, ononce, TPM_NONCE_SIZE);
>         if (ret != TPM_NONCE_SIZE)
>                 return ret;
>
> @@ -410,7 +409,7 @@ static int osap(struct tpm_buf *tb, struct osapsess *s,
>         store32(tb, handle);
>         storebytes(tb, ononce, TPM_NONCE_SIZE);
>
> -       ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
> +       ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
>         if (ret < 0)
>                 return ret;
>
> @@ -434,7 +433,7 @@ static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
>         store16(tb, TPM_TAG_RQU_COMMAND);
>         store32(tb, TPM_OIAP_SIZE);
>         store32(tb, TPM_ORD_OIAP);
> -       ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
> +       ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
>         if (ret < 0)
>                 return ret;
>
> @@ -493,7 +492,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
>         if (ret < 0)
>                 goto out;
>
> -       ret = tpm_get_random(TPM_ANY_NUM, td->nonceodd, TPM_NONCE_SIZE);
> +       ret = tpm_get_random(NULL, td->nonceodd, TPM_NONCE_SIZE);
>         if (ret != TPM_NONCE_SIZE)
>                 goto out;
>         ordinal = htonl(TPM_ORD_SEAL);
> @@ -542,7 +541,7 @@ static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
>         store8(tb, cont);
>         storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
>
> -       ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
> +       ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
>         if (ret < 0)
>                 goto out;
>
> @@ -603,7 +602,7 @@ static int tpm_unseal(struct tpm_buf *tb,
>
>         ordinal = htonl(TPM_ORD_UNSEAL);
>         keyhndl = htonl(SRKHANDLE);
> -       ret = tpm_get_random(TPM_ANY_NUM, nonceodd, TPM_NONCE_SIZE);
> +       ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
>         if (ret != TPM_NONCE_SIZE) {
>                 pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
>                 return ret;
> @@ -635,7 +634,7 @@ static int tpm_unseal(struct tpm_buf *tb,
>         store8(tb, cont);
>         storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
>
> -       ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
> +       ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
>         if (ret < 0) {
>                 pr_info("trusted_key: authhmac failed (%d)\n", ret);
>                 return ret;
> @@ -748,7 +747,7 @@ static int getoptions(char *c, struct trusted_key_payload *pay,
>         int i;
>         int tpm2;
>
> -       tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
> +       tpm2 = tpm_is_tpm2(NULL);
>         if (tpm2 < 0)
>                 return tpm2;
>
> @@ -917,7 +916,7 @@ static struct trusted_key_options *trusted_options_alloc(void)
>         struct trusted_key_options *options;
>         int tpm2;
>
> -       tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
> +       tpm2 = tpm_is_tpm2(NULL);
>         if (tpm2 < 0)
>                 return NULL;
>
> @@ -967,7 +966,7 @@ static int trusted_instantiate(struct key *key,
>         size_t key_len;
>         int tpm2;
>
> -       tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
> +       tpm2 = tpm_is_tpm2(NULL);
>         if (tpm2 < 0)
>                 return tpm2;
>
> @@ -1008,7 +1007,7 @@ static int trusted_instantiate(struct key *key,
>         switch (key_cmd) {
>         case Opt_load:
>                 if (tpm2)
> -                       ret = tpm_unseal_trusted(TPM_ANY_NUM, payload, options);
> +                       ret = tpm_unseal_trusted(NULL, payload, options);
>                 else
>                         ret = key_unseal(payload, options);
>                 dump_payload(payload);
> @@ -1018,13 +1017,13 @@ static int trusted_instantiate(struct key *key,
>                 break;
>         case Opt_new:
>                 key_len = payload->key_len;
> -               ret = tpm_get_random(TPM_ANY_NUM, payload->key, key_len);
> +               ret = tpm_get_random(NULL, payload->key, key_len);
>                 if (ret != key_len) {
>                         pr_info("trusted_key: key_create failed (%d)\n", ret);
>                         goto out;
>                 }
>                 if (tpm2)
> -                       ret = tpm_seal_trusted(TPM_ANY_NUM, payload, options);
> +                       ret = tpm_seal_trusted(NULL, payload, options);
>                 else
>                         ret = key_seal(payload, options);
>                 if (ret < 0)
> --
> 2.14.1
>

Regards,
PrasannaKumar

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Jason Gunthorpe - Oct. 25, 2017, 3:22 p.m.
On Wed, Oct 25, 2017 at 01:55:04PM +0200, Jarkko Sakkinen wrote:
> Device number (the character device index) is not a stable identifier
> for a TPM chip. That is the reason why every call site passes
> TPM_ANY_NUM to tpm_chip_find_get().
> 
> This commit changes the API in a way that instead a struct tpm_chip
> instance is given and NULL means the default chip. In addition, this
> commit refines the documentation to be up to date with the
> implementation.
> 
> Suggested-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> (@chip_num -> @chip)
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> v2:
> * Further defined function documentation.
> * Changed @chip_num to @chip instead of removing the parameter as suggested by
>   Jason Gunthorpe.

Reviewed-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>

Jason

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Jarkko Sakkinen - Oct. 25, 2017, 7:34 p.m.
On Wed, Oct 25, 2017 at 08:40:26PM +0530, PrasannaKumar Muralidharan wrote:
> > -struct tpm_chip *tpm_chip_find_get(int chip_num)
> > +struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
> >  {
> > -       struct tpm_chip *chip, *res = NULL;
> > +       struct tpm_chip *res = NULL;
> > +       int chip_num = 0;
> >         int chip_prev;
> >
> >         mutex_lock(&idr_lock);
> >
> > -       if (chip_num == TPM_ANY_NUM) {
> > -               chip_num = 0;
> > +       if (!chip) {
> >                 do {
> >                         chip_prev = chip_num;
> >                         chip = idr_get_next(&dev_nums_idr, &chip_num);
> 
> When chip is not NULL just do tpm_try_get_ops(chip). Current code does
> more things which are not required.

Your observation is right that there is something wrong but conclusions
are incorrect.

It's actually a regression.

If @chip has a value, the code does one iteration of what it is doing in
the first branch of the condition. That is completely bogus semantics to
say the least.

To sort that out I'll introduce a new field to struct tpm_chip:

  u64 id;

This gets a value from a global count every time a chip is created.

The function will become then:

struct tpm_chip *tpm_chip_find_get(u64 id)
{
	struct tpm_chup *chip;
	struct tpm_chip *res = NULL;
	int chip_num = 0;
	int chip_prev;

	mutex_lock(&idr_lock);

	do {
		chip_prev = chip_num;

		chip = idr_get_next(&dev_nums_idr, &chip_num);

		if (chip && (!id || id == chip->id) && !tpm_try_get_ops(chip)) {
			res = chip;
			break;
		}
	} while (chip_prev != chip_num);

	mutex_unlock(&idr_lock);

	return res;
}

Thanks for spotting this out. I'll refine the patch.

/Jarkko

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Jason Gunthorpe - Oct. 25, 2017, 7:46 p.m.
> struct tpm_chip *tpm_chip_find_get(u64 id)
> {
> 	struct tpm_chup *chip;
> 	struct tpm_chip *res = NULL;
> 	int chip_num = 0;
> 	int chip_prev;
> 
> 	mutex_lock(&idr_lock);
> 
> 	do {
> 		chip_prev = chip_num;
> 
> 		chip = idr_get_next(&dev_nums_idr, &chip_num);
> 
> 		if (chip && (!id || id == chip->id) && !tpm_try_get_ops(chip)) {
> 			res = chip;
> 			break;
> 		}
> 	} while (chip_prev != chip_num);
> 
> 	mutex_unlock(&idr_lock);
> 
> 	return res;
> }

?? The old version was correct, idr_find_slowpath is better than an
idr_get_next serach if you already know id.

PrasannaKumar's solution seems right, if we already have chip, then we
just need to lock it again:

struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
{
	struct tpm_chip *res = NULL;

	mutex_lock(&idr_lock);

	if (!chip) {
		int chip_num = 0;
		int chip_prev;

		do {
			chip_prev = chip_num;
			chip = idr_get_next(&dev_nums_idr, &chip_num);
			if (chip && !tpm_try_get_ops(chip)) {
				res = chip;
				break;
			}
		} while (chip_prev != chip_num);
	} else {
		if (!tpm_try_get_ops(chip))
			res = chip;
	}

	mutex_unlock(&idr_lock);

	return res;
}

Jason

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Jarkko Sakkinen - Oct. 25, 2017, 8:07 p.m.
On Wed, Oct 25, 2017 at 01:46:33PM -0600, Jason Gunthorpe wrote:
> > struct tpm_chip *tpm_chip_find_get(u64 id)
> > {
> > 	struct tpm_chup *chip;
> > 	struct tpm_chip *res = NULL;
> > 	int chip_num = 0;
> > 	int chip_prev;
> > 
> > 	mutex_lock(&idr_lock);
> > 
> > 	do {
> > 		chip_prev = chip_num;
> > 
> > 		chip = idr_get_next(&dev_nums_idr, &chip_num);
> > 
> > 		if (chip && (!id || id == chip->id) && !tpm_try_get_ops(chip)) {
> > 			res = chip;
> > 			break;
> > 		}
> > 	} while (chip_prev != chip_num);
> > 
> > 	mutex_unlock(&idr_lock);
> > 
> > 	return res;
> > }
> 
> ?? The old version was correct, idr_find_slowpath is better than an
> idr_get_next serach if you already know id.
> 
> PrasannaKumar's solution seems right, if we already have chip, then we
> just need to lock it again:
> 
> struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
> {
> 	struct tpm_chip *res = NULL;
> 
> 	mutex_lock(&idr_lock);
> 
> 	if (!chip) {
> 		int chip_num = 0;
> 		int chip_prev;
> 
> 		do {
> 			chip_prev = chip_num;
> 			chip = idr_get_next(&dev_nums_idr, &chip_num);
> 			if (chip && !tpm_try_get_ops(chip)) {
> 				res = chip;
> 				break;
> 			}
> 		} while (chip_prev != chip_num);
> 	} else {
> 		if (!tpm_try_get_ops(chip))
> 			res = chip;
> 	}
> 
> 	mutex_unlock(&idr_lock);
> 
> 	return res;
> }
> 
> Jason

The id has a nice feature that it is unique for one boot cycle you can
even try to get a chip that has been deleted. It has the most stable
properties in the long run.

Address is a reusable identifier in one boot cycle.

/Jarkko

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Jason Gunthorpe - Oct. 25, 2017, 8:17 p.m.
On Wed, Oct 25, 2017 at 10:07:46PM +0200, Jarkko Sakkinen wrote:

> The id has a nice feature that it is unique for one boot cycle you can
> even try to get a chip that has been deleted. It has the most stable
> properties in the long run.

It isn't unique, we can re-use ids them via idr_alloc(). We should
never use index inside the kernel.

> Address is a reusable identifier in one boot cycle.

It is invalid to pass in a chip for which the caller does not hold a
kref, so address is the safest argument.

Jason

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Jarkko Sakkinen - Oct. 26, 2017, 10:54 a.m.
On Wed, Oct 25, 2017 at 02:17:44PM -0600, Jason Gunthorpe wrote:
> On Wed, Oct 25, 2017 at 10:07:46PM +0200, Jarkko Sakkinen wrote:
> 
> > The id has a nice feature that it is unique for one boot cycle you can
> > even try to get a chip that has been deleted. It has the most stable
> > properties in the long run.
> 
> It isn't unique, we can re-use ids them via idr_alloc(). We should
> never use index inside the kernel.
> 
> > Address is a reusable identifier in one boot cycle.
> 
> It is invalid to pass in a chip for which the caller does not hold a
> kref, so address is the safest argument.
> 
> Jason

I'll buy this too (sending update today).

/Jarkko

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Patch

diff --git a/drivers/char/hw_random/tpm-rng.c b/drivers/char/hw_random/tpm-rng.c
index d6d448266f07..c5e363825af0 100644
--- a/drivers/char/hw_random/tpm-rng.c
+++ b/drivers/char/hw_random/tpm-rng.c
@@ -25,7 +25,7 @@ 
 
 static int tpm_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
 {
-	return tpm_get_random(TPM_ANY_NUM, data, max);
+	return tpm_get_random(NULL, data, max);
 }
 
 static struct hwrng tpm_rng = {
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index a114e8f7fb90..c7a4e7fb424d 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -81,21 +81,26 @@  void tpm_put_ops(struct tpm_chip *chip)
 EXPORT_SYMBOL_GPL(tpm_put_ops);
 
 /**
- * tpm_chip_find_get() - return tpm_chip for a given chip number
- * @chip_num: id to find
+ * tpm_chip_find_get() - find and reserve a TPM chip
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
  *
- * The return'd chip has been tpm_try_get_ops'd and must be released via
- * tpm_put_ops
+ * Finds a TPM chip and reserves its class device and operations. The chip must
+ * be released with tpm_chip_put_ops() after use.
+ *
+ * Return:
+ * A reserved &struct tpm_chip instance.
+ * %NULL if a chip is not found.
+ * %NULL if the chip is not available.
  */
-struct tpm_chip *tpm_chip_find_get(int chip_num)
+struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip)
 {
-	struct tpm_chip *chip, *res = NULL;
+	struct tpm_chip *res = NULL;
+	int chip_num = 0;
 	int chip_prev;
 
 	mutex_lock(&idr_lock);
 
-	if (chip_num == TPM_ANY_NUM) {
-		chip_num = 0;
+	if (!chip) {
 		do {
 			chip_prev = chip_num;
 			chip = idr_get_next(&dev_nums_idr, &chip_num);
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index ebe0a1d36d8c..19f820f775b5 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -809,19 +809,20 @@  int tpm_pcr_read_dev(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 }
 
 /**
- * tpm_is_tpm2 - is the chip a TPM2 chip?
- * @chip_num:	tpm idx # or ANY
+ * tpm_is_tpm2 - do we a have a TPM2 chip?
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
  *
- * Returns < 0 on error, and 1 or 0 on success depending whether the chip
- * is a TPM2 chip.
+ * Return:
+ * 1 if we have a TPM2 chip.
+ * 0 if we don't have a TPM2 chip.
+ * A negative number for system errors (errno).
  */
-int tpm_is_tpm2(u32 chip_num)
+int tpm_is_tpm2(struct tpm_chip *chip)
 {
-	struct tpm_chip *chip;
 	int rc;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL)
+	chip = tpm_chip_find_get(chip);
+	if (!chip)
 		return -ENODEV;
 
 	rc = (chip->flags & TPM_CHIP_FLAG_TPM2) != 0;
@@ -833,23 +834,19 @@  int tpm_is_tpm2(u32 chip_num)
 EXPORT_SYMBOL_GPL(tpm_is_tpm2);
 
 /**
- * tpm_pcr_read - read a pcr value
- * @chip_num:	tpm idx # or ANY
- * @pcr_idx:	pcr idx to retrieve
- * @res_buf:	TPM_PCR value
- *		size of res_buf is 20 bytes (or NULL if you don't care)
+ * 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
  *
- * The TPM driver should be built-in, but for whatever reason it
- * isn't, protect against the chip disappearing, by incrementing
- * the module usage count.
+ * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf)
+int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
 {
-	struct tpm_chip *chip;
 	int rc;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL)
+	chip = tpm_chip_find_get(chip);
+	if (!chip)
 		return -ENODEV;
 	if (chip->flags & TPM_CHIP_FLAG_TPM2)
 		rc = tpm2_pcr_read(chip, pcr_idx, res_buf);
@@ -889,25 +886,26 @@  static int tpm1_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash,
 }
 
 /**
- * tpm_pcr_extend - extend pcr value with hash
- * @chip_num:	tpm idx # or AN&
- * @pcr_idx:	pcr idx to extend
- * @hash:	hash value used to extend pcr value
+ * tpm_pcr_extend - extend a PCR value in SHA1 bank.
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @pcr_idx:	the PCR to be retrieved
+ * @hash:	the hash value used to extend the PCR value
  *
- * The TPM driver should be built-in, but for whatever reason it
- * isn't, protect against the chip disappearing, by incrementing
- * the module usage count.
+ * Note: with TPM 2.0 extends also those banks with a known digest size to the
+ * cryto subsystem in order to prevent malicious use of those PCR banks. In the
+ * future we should dynamically determine digest sizes.
+ *
+ * Return: same as with tpm_transmit_cmd()
  */
-int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash)
+int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx, const u8 *hash)
 {
 	int rc;
-	struct tpm_chip *chip;
 	struct tpm2_digest digest_list[ARRAY_SIZE(chip->active_banks)];
 	u32 count = 0;
 	int i;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL)
+	chip = tpm_chip_find_get(chip);
+	if (!chip)
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
@@ -1019,17 +1017,24 @@  int tpm1_auto_startup(struct tpm_chip *chip)
 	return rc;
 }
 
-int tpm_send(u32 chip_num, void *cmd, size_t buflen)
+/**
+ * tpm_send - send a TPM command
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @cmd:	a TPM command buffer
+ * @buflen:	the length of the TPM command buffer
+ *
+ * Return: same as with tpm_transmit_cmd()
+ */
+int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
 {
-	struct tpm_chip *chip;
 	int rc;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL)
+	chip = tpm_chip_find_get(chip);
+	if (!chip)
 		return -ENODEV;
 
 	rc = tpm_transmit_cmd(chip, NULL, cmd, buflen, 0, 0,
-			      "attempting tpm_cmd");
+			      "attempting to a send a command");
 	tpm_put_ops(chip);
 	return rc;
 }
@@ -1127,16 +1132,15 @@  static const struct tpm_input_header tpm_getrandom_header = {
 };
 
 /**
- * tpm_get_random() - Get random bytes from the tpm's RNG
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @out: destination buffer for the random bytes
- * @max: the max number of bytes to write to @out
+ * tpm_get_random() - get random bytes from the TPM's RNG
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @out:	destination buffer for the random bytes
+ * @max:	the max number of bytes to write to @out
  *
- * Returns < 0 on error and the number of bytes read on success
+ * Return: same as with tpm_transmit_cmd()
  */
-int tpm_get_random(u32 chip_num, u8 *out, size_t max)
+int tpm_get_random(struct tpm_chip *chip, u8 *out, size_t max)
 {
-	struct tpm_chip *chip;
 	struct tpm_cmd_t tpm_cmd;
 	u32 recd, num_bytes = min_t(u32, max, TPM_MAX_RNG_DATA), rlength;
 	int err, total = 0, retries = 5;
@@ -1145,8 +1149,8 @@  int tpm_get_random(u32 chip_num, u8 *out, size_t max)
 	if (!out || !num_bytes || max > TPM_MAX_RNG_DATA)
 		return -EINVAL;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL)
+	chip = tpm_chip_find_get(chip);
+	if (!chip)
 		return -ENODEV;
 
 	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
@@ -1188,22 +1192,23 @@  int tpm_get_random(u32 chip_num, u8 *out, size_t max)
 EXPORT_SYMBOL_GPL(tpm_get_random);
 
 /**
- * tpm_seal_trusted() - seal a trusted key
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @options: authentication values and other options
- * @payload: the key data in clear and encrypted form
+ * tpm_seal_trusted() - seal a trusted key payload
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @options:	authentication values and other options
+ * @payload:	the key data in clear and encrypted form
+ *
+ * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
+ * the keyring subsystem.
  *
- * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
- * are supported.
+ * Return: same as with tpm_transmit_cmd()
  */
-int tpm_seal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+int tpm_seal_trusted(struct tpm_chip *chip, struct trusted_key_payload *payload,
 		     struct trusted_key_options *options)
 {
-	struct tpm_chip *chip;
 	int rc;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+	chip = tpm_chip_find_get(chip);
+	if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
 		return -ENODEV;
 
 	rc = tpm2_seal_trusted(chip, payload, options);
@@ -1215,21 +1220,23 @@  EXPORT_SYMBOL_GPL(tpm_seal_trusted);
 
 /**
  * tpm_unseal_trusted() - unseal a trusted key
- * @chip_num: A specific chip number for the request or TPM_ANY_NUM
- * @options: authentication values and other options
- * @payload: the key data in clear and encrypted form
+ * @chip:	a &struct tpm_chip instance, %NULL for the default chip
+ * @options:	authentication values and other options
+ * @payload:	the key data in clear and encrypted form
+ *
+ * Note: only TPM 2.0 chip are supported. TPM 1.x implementation is located in
+ * the keyring subsystem.
  *
- * Returns < 0 on error and 0 on success. At the moment, only TPM 2.0 chips
- * are supported.
+ * Return: same as with tpm_transmit_cmd()
  */
-int tpm_unseal_trusted(u32 chip_num, struct trusted_key_payload *payload,
+int tpm_unseal_trusted(struct tpm_chip *chip,
+		       struct trusted_key_payload *payload,
 		       struct trusted_key_options *options)
 {
-	struct tpm_chip *chip;
 	int rc;
 
-	chip = tpm_chip_find_get(chip_num);
-	if (chip == NULL || !(chip->flags & TPM_CHIP_FLAG_TPM2))
+	chip = tpm_chip_find_get(chip);
+	if (!chip || !(chip->flags & TPM_CHIP_FLAG_TPM2))
 		return -ENODEV;
 
 	rc = tpm2_unseal_trusted(chip, payload, options);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index c1866cc02e30..6c189174c0d3 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -516,7 +516,7 @@  static inline void tpm_msleep(unsigned int delay_msec)
 		     delay_msec * 1000);
 };
 
-struct tpm_chip *tpm_chip_find_get(int chip_num);
+struct tpm_chip *tpm_chip_find_get(struct tpm_chip *chip);
 __must_check int tpm_try_get_ops(struct tpm_chip *chip);
 void tpm_put_ops(struct tpm_chip *chip);
 
diff --git a/include/linux/tpm.h b/include/linux/tpm.h
index 5a090f5ab335..ddc9b88ff6d3 100644
--- a/include/linux/tpm.h
+++ b/include/linux/tpm.h
@@ -24,11 +24,6 @@ 
 
 #define TPM_DIGEST_SIZE 20	/* Max TPM v1.2 PCR size */
 
-/*
- * Chip num is this value or a valid tpm idx
- */
-#define	TPM_ANY_NUM 0xFFFF
-
 struct tpm_chip;
 struct trusted_key_payload;
 struct trusted_key_options;
@@ -54,42 +49,47 @@  struct tpm_class_ops {
 
 #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
 
-extern int tpm_is_tpm2(u32 chip_num);
-extern int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf);
-extern int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash);
-extern int tpm_send(u32 chip_num, void *cmd, size_t buflen);
-extern int tpm_get_random(u32 chip_num, u8 *data, size_t max);
-extern int tpm_seal_trusted(u32 chip_num,
+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_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);
+extern int tpm_seal_trusted(struct tpm_chip *chip,
 			    struct trusted_key_payload *payload,
 			    struct trusted_key_options *options);
-extern int tpm_unseal_trusted(u32 chip_num,
+extern int tpm_unseal_trusted(struct tpm_chip *chip,
 			      struct trusted_key_payload *payload,
 			      struct trusted_key_options *options);
 #else
-static inline int tpm_is_tpm2(u32 chip_num)
+static inline int tpm_is_tpm2(struct tpm_chip *chip)
 {
 	return -ENODEV;
 }
-static inline int tpm_pcr_read(u32 chip_num, int pcr_idx, u8 *res_buf) {
+static inline int tpm_pcr_read(struct tpm_chip *chip, int pcr_idx, u8 *res_buf)
+{
 	return -ENODEV;
 }
-static inline int tpm_pcr_extend(u32 chip_num, int pcr_idx, const u8 *hash) {
+static inline int tpm_pcr_extend(struct tpm_chip *chip, int pcr_idx,
+				 const u8 *hash)
+{
 	return -ENODEV;
 }
-static inline int tpm_send(u32 chip_num, void *cmd, size_t buflen) {
+static inline int tpm_send(struct tpm_chip *chip, void *cmd, size_t buflen)
+{
 	return -ENODEV;
 }
-static inline int tpm_get_random(u32 chip_num, u8 *data, size_t max) {
+static inline int tpm_get_random(struct tpm_chip *chip, u8 *data, size_t max)
+{
 	return -ENODEV;
 }
 
-static inline int tpm_seal_trusted(u32 chip_num,
+static inline int tpm_seal_trusted(struct tpm_chip *chip,
 				   struct trusted_key_payload *payload,
 				   struct trusted_key_options *options)
 {
 	return -ENODEV;
 }
-static inline int tpm_unseal_trusted(u32 chip_num,
+static inline int tpm_unseal_trusted(struct tpm_chip *chip,
 				     struct trusted_key_payload *payload,
 				     struct trusted_key_options *options)
 {
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 802d5d20f36f..3371d134ee62 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -644,7 +644,7 @@  static void __init ima_pcrread(int idx, u8 *pcr)
 	if (!ima_used_chip)
 		return;
 
-	if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0)
+	if (tpm_pcr_read(NULL, idx, pcr) != 0)
 		pr_err("Error Communicating to TPM chip\n");
 }
 
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 2967d497a665..29b72cd2502e 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -110,7 +110,7 @@  int __init ima_init(void)
 	int rc;
 
 	ima_used_chip = 0;
-	rc = tpm_pcr_read(TPM_ANY_NUM, 0, pcr_i);
+	rc = tpm_pcr_read(NULL, 0, pcr_i);
 	if (rc == 0)
 		ima_used_chip = 1;
 
diff --git a/security/integrity/ima/ima_queue.c b/security/integrity/ima/ima_queue.c
index a02a86d51102..418f35e38015 100644
--- a/security/integrity/ima/ima_queue.c
+++ b/security/integrity/ima/ima_queue.c
@@ -145,7 +145,7 @@  static int ima_pcr_extend(const u8 *hash, int pcr)
 	if (!ima_used_chip)
 		return result;
 
-	result = tpm_pcr_extend(TPM_ANY_NUM, pcr, hash);
+	result = tpm_pcr_extend(NULL, pcr, hash);
 	if (result != 0)
 		pr_err("Error Communicating to TPM chip, result: %d\n", result);
 	return result;
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ddfaebf60fc8..d2b20b1cc2f1 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -355,13 +355,12 @@  static int TSS_checkhmac2(unsigned char *buffer,
  * For key specific tpm requests, we will generate and send our
  * own TPM command packets using the drivers send function.
  */
-static int trusted_tpm_send(const u32 chip_num, unsigned char *cmd,
-			    size_t buflen)
+static int trusted_tpm_send(unsigned char *cmd, size_t buflen)
 {
 	int rc;
 
 	dump_tpm_buf(cmd);
-	rc = tpm_send(chip_num, cmd, buflen);
+	rc = tpm_send(NULL, cmd, buflen);
 	dump_tpm_buf(cmd);
 	if (rc > 0)
 		/* Can't return positive return codes values to keyctl */
@@ -382,10 +381,10 @@  static int pcrlock(const int pcrnum)
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
-	ret = tpm_get_random(TPM_ANY_NUM, hash, SHA1_DIGEST_SIZE);
+	ret = tpm_get_random(NULL, hash, SHA1_DIGEST_SIZE);
 	if (ret != SHA1_DIGEST_SIZE)
 		return ret;
-	return tpm_pcr_extend(TPM_ANY_NUM, pcrnum, hash) ? -EINVAL : 0;
+	return tpm_pcr_extend(NULL, pcrnum, hash) ? -EINVAL : 0;
 }
 
 /*
@@ -398,7 +397,7 @@  static int osap(struct tpm_buf *tb, struct osapsess *s,
 	unsigned char ononce[TPM_NONCE_SIZE];
 	int ret;
 
-	ret = tpm_get_random(TPM_ANY_NUM, ononce, TPM_NONCE_SIZE);
+	ret = tpm_get_random(NULL, ononce, TPM_NONCE_SIZE);
 	if (ret != TPM_NONCE_SIZE)
 		return ret;
 
@@ -410,7 +409,7 @@  static int osap(struct tpm_buf *tb, struct osapsess *s,
 	store32(tb, handle);
 	storebytes(tb, ononce, TPM_NONCE_SIZE);
 
-	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
 	if (ret < 0)
 		return ret;
 
@@ -434,7 +433,7 @@  static int oiap(struct tpm_buf *tb, uint32_t *handle, unsigned char *nonce)
 	store16(tb, TPM_TAG_RQU_COMMAND);
 	store32(tb, TPM_OIAP_SIZE);
 	store32(tb, TPM_ORD_OIAP);
-	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
 	if (ret < 0)
 		return ret;
 
@@ -493,7 +492,7 @@  static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 	if (ret < 0)
 		goto out;
 
-	ret = tpm_get_random(TPM_ANY_NUM, td->nonceodd, TPM_NONCE_SIZE);
+	ret = tpm_get_random(NULL, td->nonceodd, TPM_NONCE_SIZE);
 	if (ret != TPM_NONCE_SIZE)
 		goto out;
 	ordinal = htonl(TPM_ORD_SEAL);
@@ -542,7 +541,7 @@  static int tpm_seal(struct tpm_buf *tb, uint16_t keytype,
 	store8(tb, cont);
 	storebytes(tb, td->pubauth, SHA1_DIGEST_SIZE);
 
-	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
 	if (ret < 0)
 		goto out;
 
@@ -603,7 +602,7 @@  static int tpm_unseal(struct tpm_buf *tb,
 
 	ordinal = htonl(TPM_ORD_UNSEAL);
 	keyhndl = htonl(SRKHANDLE);
-	ret = tpm_get_random(TPM_ANY_NUM, nonceodd, TPM_NONCE_SIZE);
+	ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE);
 	if (ret != TPM_NONCE_SIZE) {
 		pr_info("trusted_key: tpm_get_random failed (%d)\n", ret);
 		return ret;
@@ -635,7 +634,7 @@  static int tpm_unseal(struct tpm_buf *tb,
 	store8(tb, cont);
 	storebytes(tb, authdata2, SHA1_DIGEST_SIZE);
 
-	ret = trusted_tpm_send(TPM_ANY_NUM, tb->data, MAX_BUF_SIZE);
+	ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE);
 	if (ret < 0) {
 		pr_info("trusted_key: authhmac failed (%d)\n", ret);
 		return ret;
@@ -748,7 +747,7 @@  static int getoptions(char *c, struct trusted_key_payload *pay,
 	int i;
 	int tpm2;
 
-	tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
+	tpm2 = tpm_is_tpm2(NULL);
 	if (tpm2 < 0)
 		return tpm2;
 
@@ -917,7 +916,7 @@  static struct trusted_key_options *trusted_options_alloc(void)
 	struct trusted_key_options *options;
 	int tpm2;
 
-	tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
+	tpm2 = tpm_is_tpm2(NULL);
 	if (tpm2 < 0)
 		return NULL;
 
@@ -967,7 +966,7 @@  static int trusted_instantiate(struct key *key,
 	size_t key_len;
 	int tpm2;
 
-	tpm2 = tpm_is_tpm2(TPM_ANY_NUM);
+	tpm2 = tpm_is_tpm2(NULL);
 	if (tpm2 < 0)
 		return tpm2;
 
@@ -1008,7 +1007,7 @@  static int trusted_instantiate(struct key *key,
 	switch (key_cmd) {
 	case Opt_load:
 		if (tpm2)
-			ret = tpm_unseal_trusted(TPM_ANY_NUM, payload, options);
+			ret = tpm_unseal_trusted(NULL, payload, options);
 		else
 			ret = key_unseal(payload, options);
 		dump_payload(payload);
@@ -1018,13 +1017,13 @@  static int trusted_instantiate(struct key *key,
 		break;
 	case Opt_new:
 		key_len = payload->key_len;
-		ret = tpm_get_random(TPM_ANY_NUM, payload->key, key_len);
+		ret = tpm_get_random(NULL, payload->key, key_len);
 		if (ret != key_len) {
 			pr_info("trusted_key: key_create failed (%d)\n", ret);
 			goto out;
 		}
 		if (tpm2)
-			ret = tpm_seal_trusted(TPM_ANY_NUM, payload, options);
+			ret = tpm_seal_trusted(NULL, payload, options);
 		else
 			ret = key_seal(payload, options);
 		if (ret < 0)