Re: [PATCH v2] tpm: use a map for tpm2_calc_ordinal_duration()

[Jarkko Sakkinen <jarkko@kernel.org>]

On Mon, Jun 08, 2026 at 02:46:28PM +0000, Benoit HOUYERE wrote:
> Hello Serge and Jarkko,
> 
> 
> We have detected a regression with this fix. Indeed, it miss one zero on TPM_LONG_LONG. Initial value was 300000 and not 30000.
> 
> > +	{TPM2_CC_CREATE_PRIMARY, 30000},
> > +	{TPM2_CC_CREATE, 30000},
> > +	{TPM2_CC_CREATE_LOADED, 30000},
> 
> > +enum tpm2_durations {
> >  	TPM2_DURATION_SHORT     =     20,
> > -	TPM2_DURATION_MEDIUM    =    750,
> >  	TPM2_DURATION_LONG      =   2000,
> > -	TPM2_DURATION_LONG_LONG = 300000,
> >  	TPM2_DURATION_DEFAULT   = 120000,
> >  };
> 
> Best Regards,  Cordialement, Cordialmente, Hälsningar, 最好的问候, Mit besten Grüßen, 真心を込めて, 진심으로
> 
> 
> Benoit HOUYERE | Tel: +33 6 14 22 81 30
> TPM specialist

This has been fixed in 478a3f949a43822dc6ce089345ae80e8dcde3300.

> 
> -----Original Message-----
> From: Serge E. Hallyn <serge@hallyn.com> 
> Sent: Friday, September 19, 2025 5:49 AM
> To: Jarkko Sakkinen <jarkko@kernel.org>
> Cc: linux-integrity@vger.kernel.org; Frédéric Jouen <fjouen@sealsq.com>; Peter Huewe <peterhuewe@gmx.de>; Jason Gunthorpe <jgg@ziepe.ca>; James Bottomley <James.Bottomley@hansenpartnership.com>; Mimi Zohar <zohar@linux.ibm.com>; David Howells <dhowells@redhat.com>; Paul Moore <paul@paul-moore.com>; James Morris <jmorris@namei.org>; Serge E. Hallyn <serge@hallyn.com>; open list <linux-kernel@vger.kernel.org>; open list:KEYS-TRUSTED <keyrings@vger.kernel.org>; open list:SECURITY SUBSYSTEM <linux-security-module@vger.kernel.org>
> Subject: Re: [PATCH v2] tpm: use a map for tpm2_calc_ordinal_duration()
> 
> On Thu, Sep 18, 2025 at 10:30:18PM +0300, Jarkko Sakkinen wrote:
> > The current shenanigans for duration calculation introduce too much 
> > complexity for a trivial problem, and further the code is hard to 
> > patch and maintain.
> > 
> > Address these issues with a flat look-up table, which is easy to 
> > understand and patch. If leaf driver specific patching is required in 
> > future, it is easy enough to make a copy of this table during driver 
> > initialization and add the chip parameter back.
> > 
> > 'chip->duration' is retained for TPM 1.x.
> > 
> > As the first entry for this new behavior address TCG spec update 
> > mentioned in this issue:
> > 
> > https://github.com/raspberrypi/linux/issues/7054
> > 
> > Therefore, for TPM_SelfTest the duration is set to 3000 ms.
> > 
> > This does not categorize a as bug, given that this is introduced to 
> > the spec after the feature was originally made.
> > 
> > Cc: Frédéric Jouen <fjouen@sealsq.com>
> > Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
> 
> fwiw (which shouldn't be much) looks good to me, but two questions, one here and one below.
> 
> First, it looks like in the existing code it is possible for a tpm2 chip to set its own timeouts and then set the TPM_CHIP_FLAG_HAVE_TIMEOUTS flag to avoid using the defaults, but I don't see anything using that in-tree.  Is it possible that there are out of tree drivers that will be sabotaged here?  Or am I misunderstanding that completely?
> 
> > ---
> > v2:
> > - Add the missing msec_to_jiffies() calls.
> > - Drop redundant stuff.
> > ---
> >  drivers/char/tpm/tpm-interface.c |   2 +-
> >  drivers/char/tpm/tpm.h           |   2 +-
> >  drivers/char/tpm/tpm2-cmd.c      | 127 ++++++++-----------------------
> >  include/linux/tpm.h              |   5 +-
> >  4 files changed, 37 insertions(+), 99 deletions(-)
> > 
> > diff --git a/drivers/char/tpm/tpm-interface.c 
> > b/drivers/char/tpm/tpm-interface.c
> > index b71725827743..c9f173001d0e 100644
> > --- a/drivers/char/tpm/tpm-interface.c
> > +++ b/drivers/char/tpm/tpm-interface.c
> > @@ -52,7 +52,7 @@ MODULE_PARM_DESC(suspend_pcr,  unsigned long 
> > tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)  {
> >  	if (chip->flags & TPM_CHIP_FLAG_TPM2)
> > -		return tpm2_calc_ordinal_duration(chip, ordinal);
> > +		return tpm2_calc_ordinal_duration(ordinal);
> >  	else
> >  		return tpm1_calc_ordinal_duration(chip, ordinal);  } diff --git 
> > a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h index 
> > 7bb87fa5f7a1..2726bd38e5ac 100644
> > --- a/drivers/char/tpm/tpm.h
> > +++ b/drivers/char/tpm/tpm.h
> > @@ -299,7 +299,7 @@ ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 
> > property_id,  ssize_t tpm2_get_pcr_allocation(struct tpm_chip *chip);  
> > int tpm2_auto_startup(struct tpm_chip *chip);  void 
> > tpm2_shutdown(struct tpm_chip *chip, u16 shutdown_type); -unsigned 
> > long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
> > +unsigned long tpm2_calc_ordinal_duration(u32 ordinal);
> >  int tpm2_probe(struct tpm_chip *chip);  int 
> > tpm2_get_cc_attrs_tbl(struct tpm_chip *chip);  int tpm2_find_cc(struct 
> > tpm_chip *chip, u32 cc); diff --git a/drivers/char/tpm/tpm2-cmd.c 
> > b/drivers/char/tpm/tpm2-cmd.c index 524d802ede26..7d77f6fbc152 100644
> > --- a/drivers/char/tpm/tpm2-cmd.c
> > +++ b/drivers/char/tpm/tpm2-cmd.c
> > @@ -28,120 +28,57 @@ static struct tpm2_hash tpm2_hash_map[] = {
> >  
> >  int tpm2_get_timeouts(struct tpm_chip *chip)  {
> > -	/* Fixed timeouts for TPM2 */
> >  	chip->timeout_a = msecs_to_jiffies(TPM2_TIMEOUT_A);
> >  	chip->timeout_b = msecs_to_jiffies(TPM2_TIMEOUT_B);
> >  	chip->timeout_c = msecs_to_jiffies(TPM2_TIMEOUT_C);
> >  	chip->timeout_d = msecs_to_jiffies(TPM2_TIMEOUT_D);
> > -
> > -	/* PTP spec timeouts */
> > -	chip->duration[TPM_SHORT] = msecs_to_jiffies(TPM2_DURATION_SHORT);
> > -	chip->duration[TPM_MEDIUM] = msecs_to_jiffies(TPM2_DURATION_MEDIUM);
> > -	chip->duration[TPM_LONG] = msecs_to_jiffies(TPM2_DURATION_LONG);
> > -
> > -	/* Key creation commands long timeouts */
> > -	chip->duration[TPM_LONG_LONG] =
> > -		msecs_to_jiffies(TPM2_DURATION_LONG_LONG);
> > -
> >  	chip->flags |= TPM_CHIP_FLAG_HAVE_TIMEOUTS;
> > -
> >  	return 0;
> >  }
> >  
> > -/**
> > - * tpm2_ordinal_duration_index() - returns an index to the chip 
> > duration table
> > - * @ordinal: TPM command ordinal.
> > - *
> > - * The function returns an index to the chip duration table
> > - * (enum tpm_duration), that describes the maximum amount of
> > - * time the chip could take to return the result for a  particular ordinal.
> > - *
> > - * The values of the MEDIUM, and LONG durations are taken
> > - * from the PC Client Profile (PTP) specification (750, 2000 msec)
> > - *
> > - * LONG_LONG is for commands that generates keys which empirically 
> > takes
> > - * a longer time on some systems.
> > - *
> > - * Return:
> > - * * TPM_MEDIUM
> > - * * TPM_LONG
> > - * * TPM_LONG_LONG
> > - * * TPM_UNDEFINED
> > +/*
> > + * Contains the maximum durations in milliseconds for TPM2 commands.
> >   */
> > -static u8 tpm2_ordinal_duration_index(u32 ordinal) -{
> > -	switch (ordinal) {
> > -	/* Startup */
> > -	case TPM2_CC_STARTUP:                 /* 144 */
> > -		return TPM_MEDIUM;
> > -
> > -	case TPM2_CC_SELF_TEST:               /* 143 */
> > -		return TPM_LONG;
> > -
> > -	case TPM2_CC_GET_RANDOM:              /* 17B */
> > -		return TPM_LONG;
> > -
> > -	case TPM2_CC_SEQUENCE_UPDATE:         /* 15C */
> > -		return TPM_MEDIUM;
> > -	case TPM2_CC_SEQUENCE_COMPLETE:       /* 13E */
> > -		return TPM_MEDIUM;
> > -	case TPM2_CC_EVENT_SEQUENCE_COMPLETE: /* 185 */
> > -		return TPM_MEDIUM;
> > -	case TPM2_CC_HASH_SEQUENCE_START:     /* 186 */
> > -		return TPM_MEDIUM;
> > -
> > -	case TPM2_CC_VERIFY_SIGNATURE:        /* 177 */
> > -		return TPM_LONG_LONG;
> > -
> > -	case TPM2_CC_PCR_EXTEND:              /* 182 */
> > -		return TPM_MEDIUM;
> > -
> > -	case TPM2_CC_HIERARCHY_CONTROL:       /* 121 */
> > -		return TPM_LONG;
> > -	case TPM2_CC_HIERARCHY_CHANGE_AUTH:   /* 129 */
> > -		return TPM_LONG;
> > -
> > -	case TPM2_CC_GET_CAPABILITY:          /* 17A */
> > -		return TPM_MEDIUM;
> > -
> > -	case TPM2_CC_NV_READ:                 /* 14E */
> > -		return TPM_LONG;
> > -
> > -	case TPM2_CC_CREATE_PRIMARY:          /* 131 */
> > -		return TPM_LONG_LONG;
> > -	case TPM2_CC_CREATE:                  /* 153 */
> > -		return TPM_LONG_LONG;
> > -	case TPM2_CC_CREATE_LOADED:           /* 191 */
> > -		return TPM_LONG_LONG;
> > -
> > -	default:
> > -		return TPM_UNDEFINED;
> > -	}
> > -}
> > +static const struct {
> > +	unsigned long ordinal;
> > +	unsigned long duration;
> > +} tpm2_ordinal_duration_map[] = {
> > +	{TPM2_CC_STARTUP, 750},
> > +	{TPM2_CC_SELF_TEST, 3000},
> 
> I assume you intended to increase TPM2_CC_SELF_TEST from 2000 to 3000 here?  But it's not mentioned in the commit, so making sure...
> 
> > +	{TPM2_CC_GET_RANDOM, 2000},
> > +	{TPM2_CC_SEQUENCE_UPDATE, 750},
> > +	{TPM2_CC_SEQUENCE_COMPLETE, 750},
> > +	{TPM2_CC_EVENT_SEQUENCE_COMPLETE, 750},
> > +	{TPM2_CC_HASH_SEQUENCE_START, 750},
> > +	{TPM2_CC_VERIFY_SIGNATURE, 30000},
> > +	{TPM2_CC_PCR_EXTEND, 750},
> > +	{TPM2_CC_HIERARCHY_CONTROL, 2000},
> > +	{TPM2_CC_HIERARCHY_CHANGE_AUTH, 2000},
> > +	{TPM2_CC_GET_CAPABILITY, 750},
> > +	{TPM2_CC_NV_READ, 2000},
> > +	{TPM2_CC_CREATE_PRIMARY, 30000},
> > +	{TPM2_CC_CREATE, 30000},
> > +	{TPM2_CC_CREATE_LOADED, 30000},
> > +};
> >  
> >  /**
> > - * tpm2_calc_ordinal_duration() - calculate the maximum command duration
> > - * @chip:    TPM chip to use.
> > + * tpm2_calc_ordinal_duration() - Calculate the maximum command 
> > + duration
> >   * @ordinal: TPM command ordinal.
> >   *
> > - * The function returns the maximum amount of time the chip could 
> > take
> > - * to return the result for a particular ordinal in jiffies.
> > - *
> > - * Return: A maximal duration time for an ordinal in jiffies.
> > + * Returns the maximum amount of time the chip is expected by kernel 
> > + to
> > + * take in jiffies.
> >   */
> > -unsigned long tpm2_calc_ordinal_duration(struct tpm_chip *chip, u32 
> > ordinal)
> > +unsigned long tpm2_calc_ordinal_duration(u32 ordinal)
> >  {
> > -	unsigned int index;
> > +	int i;
> >  
> > -	index = tpm2_ordinal_duration_index(ordinal);
> > +	for (i = 0; i < ARRAY_SIZE(tpm2_ordinal_duration_map); i++)
> > +		if (ordinal == tpm2_ordinal_duration_map[i].ordinal)
> > +			return msecs_to_jiffies(tpm2_ordinal_duration_map[i].duration);
> >  
> > -	if (index != TPM_UNDEFINED)
> > -		return chip->duration[index];
> > -	else
> > -		return msecs_to_jiffies(TPM2_DURATION_DEFAULT);
> > +	return msecs_to_jiffies(TPM2_DURATION_DEFAULT);
> >  }
> >  
> > -
> >  struct tpm2_pcr_read_out {
> >  	__be32	update_cnt;
> >  	__be32	pcr_selects_cnt;
> > diff --git a/include/linux/tpm.h b/include/linux/tpm.h index 
> > b0e9eb5ef022..dc0338a783f3 100644
> > --- a/include/linux/tpm.h
> > +++ b/include/linux/tpm.h
> > @@ -228,10 +228,11 @@ enum tpm2_timeouts {
> >  	TPM2_TIMEOUT_B          =   4000,
> >  	TPM2_TIMEOUT_C          =    200,
> >  	TPM2_TIMEOUT_D          =     30,
> > +};
> > +
> > +enum tpm2_durations {
> >  	TPM2_DURATION_SHORT     =     20,
> > -	TPM2_DURATION_MEDIUM    =    750,
> >  	TPM2_DURATION_LONG      =   2000,
> > -	TPM2_DURATION_LONG_LONG = 300000,
> >  	TPM2_DURATION_DEFAULT   = 120000,
> >  };
> >  
> > --
> > 2.39.5
> 

BR, Jarkko