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From:   Dirk Gouders <dirk@gouders.net>
To:     Lukasz Majczak <lma@semihalf.com>,
        Jarkko Sakkinen <jarkko@kernel.org>
Cc:     Guenter Roeck <linux@roeck-us.net>,
        James Bottomley <James.Bottomley@hansenpartnership.com>,
        Tj <ml.linux@elloe.vision>, Peter Huewe <peterhuewe@gmx.de>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org,
        Radoslaw Biernacki <rad@semihalf.com>,
        Marcin Wojtas <mw@semihalf.com>,
        Alex Levin <levinale@google.com>
Subject: Re: [PATCH v3] tpm_tis: Add missing tpm_request/relinquish_locality
 calls
In-Reply-To: <ghh7mu1f3p.fsf@gouders.net> (Dirk Gouders's message of "Tue, 02
        Feb 2021 19:47:38 +0100")
References: <20210128130753.1283534-1-lma@semihalf.com>
        <20210202155139.521421-1-lma@semihalf.com>
        <ghh7mu1f3p.fsf@gouders.net>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
Date:   Wed, 03 Feb 2021 12:46:25 +0100
Message-ID: <gh5z39ml0u.fsf@gouders.net>
MIME-Version: 1.0
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Dirk Gouders <dirk@gouders.net> writes:

> Lukasz Majczak <lma@semihalf.com> writes:
>
>> There are missing calls to tpm_request_locality before the calls to
>> the tpm_get_timeouts() and tpm_tis_probe_irq_single() - both functions
>> internally send commands to the tpm. As the current
>> approach might work for tpm2, it fails for tpm1.x - in that case
>> call to tpm_get_timeouts() or tpm_tis_probe_irq_single()
>> without acquired locality fails and in turn causes tpm_tis_core_init()
>> to fail, it can be observed in the log with the following warning
>> trace:
>>
>> [    4.324298] TPM returned invalid status
>> [    4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f
>> [    4.325888] Modules linked in:
>> [    4.326287] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G        W         5.11.0-rc6-next-20210201-00003-g214461adb2e8 #43
>> [    4.327406] Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.430.0 07/20/2018
>> [    4.327918] RIP: 0010:tpm_tis_status+0x86/0x8f
>> [    4.328323] Code: 28 00 00 00 48 3b 45 f0 75 24 89 d8 48 83 c4 10 5b 5d c3 c6 05 58 d9 28 01 01 31 db 48 c7 c7 73 52 98 9c 31 c0 e8 c2 17 b0 ff <0f> 0b eb cd e8 cf 4f 55 00 0f 1f 44 00 00 55 48 89 e56
>> [    4.330592] RSP: 0000:ffff88810092f7a0 EFLAGS: 00010246
>> [    4.331223] RAX: 691ee151166db100 RBX: 0000000000000000 RCX: 0000000000000001
>> [    4.331860] RDX: 0000000000000006 RSI: ffffffff9c96d302 RDI: 00000000ffffffff
>> [    4.332272] RBP: ffff88810092f7b8 R08: dffffc0000000000 R09: fffffbfff39c96ce
>> [    4.332683] R10: fffffbfff39c96ce R11: 0000000000000001 R12: ffff8881053e2000
>> [    4.333109] R13: 0000000065000000 R14: ffff888105d71000 R15: ffff888105cd2628
>> [    4.333738] FS:  0000000000000000(0000) GS:ffff88842f200000(0000) knlGS:0000000000000000
>> [    4.334432] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [    4.334783] CR2: 0000000000000000 CR3: 0000000037828001 CR4: 00000000003706e0
>> [    4.335196] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> [    4.335886] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> [    4.336793] Call Trace:
>> [    4.337107]  tpm_tis_send_data+0x3d/0x22f
>> [    4.337506]  tpm_tis_send_main+0x30/0xf5
>> [    4.337746]  tpm_transmit+0xbf/0x327
>> [    4.338042]  ? __alloc_pages_nodemask+0x261/0x36d
>> [    4.338615]  tpm_transmit_cmd+0x2c/0x93
>> [    4.339109]  tpm1_getcap+0x232/0x285
>> [    4.339578]  tpm1_get_timeouts+0x48/0x47d
>> [    4.339964]  ? lockdep_init_map_type+0x71/0x257
>> [    4.340256]  ? lockdep_init_map_type+0x71/0x257
>> [    4.340719]  ? __raw_spin_lock_init+0x40/0x69
>> [    4.341208]  tpm_tis_core_init+0x402/0x5ee
>> [    4.341629]  tpm_tis_init+0x11d/0x1a2
>> [    4.341867]  tpm_tis_pnp_init+0x91/0xb5
>> [    4.342101]  ? tis_int_handler+0x15f/0x15f
>> [    4.342466]  pnp_device_probe+0x79/0x9f
>> [    4.342941]  really_probe+0x149/0x4a8
>> [    4.343412]  driver_probe_device+0xd6/0x144
>> [    4.343968]  device_driver_attach+0x42/0x5b
>> [    4.344382]  __driver_attach+0xca/0x139
>> [    4.344617]  ? driver_attach+0x1f/0x1f
>> [    4.344860]  bus_for_each_dev+0x85/0xb7
>> [    4.345096]  bus_add_driver+0x12b/0x228
>> [    4.345330]  driver_register+0x64/0xed
>> [    4.345560]  init_tis+0xa5/0xeb
>> [    4.345784]  ? lock_is_held_type+0x100/0x141
>> [    4.346044]  ? tpm_init+0x106/0x106
>> [    4.346259]  ? rcu_read_lock_sched_held+0x41/0x7e
>> [    4.346542]  ? tpm_init+0x106/0x106
>> [    4.346678] battery: ACPI: Battery Slot [BAT0] (battery present)
>> [    4.346754]  do_one_initcall+0x1b9/0x43d
>> [    4.346776]  ? asm_sysvec_apic_timer_interrupt+0x12/0x20
>> [    4.347659]  ? lockdep_hardirqs_on+0x8e/0x12e
>> [    4.347937]  ? lock_is_held_type+0x100/0x141
>> [    4.348196]  ? rcu_read_lock_sched_held+0x41/0x7e
>> [    4.348477]  do_initcall_level+0x99/0xa9
>> [    4.348717]  ? kernel_init+0xe/0x10a
>> [    4.348954]  do_initcalls+0x4e/0x79
>> [    4.349170]  kernel_init_freeable+0x15a/0x1ae
>> [    4.349434]  ? rest_init+0x1d6/0x1d6
>> [    4.349655]  kernel_init+0xe/0x10a
>> [    4.349882]  ret_from_fork+0x22/0x30
>> [    4.350103] irq event stamp: 700039
>> [    4.350318] hardirqs last  enabled at (700047): [<ffffffff9b735265>] console_unlock+0x4be/0x538
>> [    4.350836] hardirqs last disabled at (700056): [<ffffffff9b734e84>] console_unlock+0xdd/0x538
>> [    4.351331] softirqs last  enabled at (699522): [<ffffffff9c4004ec>] __do_softirq+0x4ec/0x539
>> [    4.351835] softirqs last disabled at (699517): [<ffffffff9c200f62>] asm_call_irq_on_stack+0x12/0x20
>>
>> Following the trace one can also notice a comment in the tpm_tis_status():
>>
>> 		/*
>> 		 * If this trips, the chances are the read is
>> 		 * returning 0xff because the locality hasn't been
>> 		 * acquired.  Usually because tpm_try_get_ops() hasn't
>> 		 * been called before doing a TPM operation.
>> 		 */
>> In this case we don't have to call tpm_try_get_ops()
>> as both calls (tpm_get_timeouts() and tpm_tis_probe_irq_single()) are
>> in the tpm_tis_core_init function and don't require any locking or clock 
>> enablement. Similar usage is in the probe_itpm() function also called
>> inside tpm_tis_core_init().
>> Tested on Samsung Chromebook Pro (Caroline).
>>
>> Signed-off-by: Lukasz Majczak <lma@semihalf.com>
>> ---
>> Hi Jarkko
>>
>> I have checked the linux-next with James patches, also followed Dirk
>> suggestion applying remaining ones, although without any luck -
>> a warning trace was still present. As Guneter mentioned earlier, this
>> patch[1] doesn't address a lack of acquired locality in the
>> tpm_get_timeouts() and does it only for tpm_tis_probe_irq_single() but
>> also without a call to tpm_relinquish_locality().
>>
>> Here are my logs from the clean linux-next master branch [2]
>> (with two James' patches present) and with my
>> patch applied[3]
>>
>> Best regards,
>> Lukasz
>>
>> [1] https://lore.kernel.org/linux-integrity/20201001180925.13808-5-James.Bottomley@HansenPartnership.com/
>> [2] https://gist.github.com/semihalf-majczak-lukasz/f588c0684a6cc7d983bb9c4eb4bda586
>> [3] https://gist.github.com/semihalf-majczak-lukasz/88ede933bc7d28d806e3532850a04054
>>
>> v2 -> v3:
>>  - Added braces around if part of if/else statements
>>  - Rebased to linux-next
>>  - Updated commit message
>>  
>>  drivers/char/tpm/tpm-chip.c      |  4 ++--
>>  drivers/char/tpm/tpm-interface.c | 13 ++++++++++---
>>  drivers/char/tpm/tpm.h           |  2 ++
>>  drivers/char/tpm/tpm_tis_core.c  | 14 +++++++++++---
>>  4 files changed, 25 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
>> index ddaeceb7e109..5351963a4b19 100644
>> --- a/drivers/char/tpm/tpm-chip.c
>> +++ b/drivers/char/tpm/tpm-chip.c
>> @@ -32,7 +32,7 @@ struct class *tpm_class;
>>  struct class *tpmrm_class;
>>  dev_t tpm_devt;
>>  
>> -static int tpm_request_locality(struct tpm_chip *chip)
>> +int tpm_request_locality(struct tpm_chip *chip)
>>  {
>>  	int rc;
>> @@ -47,7 +47,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
>>  	return 0;
>>  }
>>  
>> -static void tpm_relinquish_locality(struct tpm_chip *chip)
>> +void tpm_relinquish_locality(struct tpm_chip *chip)
>>  {
>>  	int rc;
>>  
>
> Here, it seems
>
> +EXPORT_SYMBOL_GPL(tpm_request_locality);
>
> and
>
> +EXPORT_SYMBOL_GPL(tpm_relinquish_locality);
>
> are needed.  Otherwise building tpm* modules fails:
>
> ERROR: modpost: "tpm_request_locality" [drivers/char/tpm/tpm_tis_core.ko] undefined!
> ERROR: modpost: "tpm_relinquish_locality" [drivers/char/tpm/tpm_tis_core.ko] undefined!
> make[1]: *** [scripts/Makefile.modpost:132: Module.symvers] Error 1
> make[1]: *** Deleting file 'Module.symvers'
> make: *** [Makefile:1405: modules] Error 2
>
> Otherwise, testing this patch results in no more warning
>
> TPM returned invalid status: 0xff
>
> and also no more warnings:
>
> tpm tpm0: tpm_try_transmit: send(): error -5
> tpm tpm0: [Firmware Bug]: TPM interrupt not working, polling instead
>
> Dirk
>
>> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>> index 1621ce818705..2a9001d329f2 100644
>> --- a/drivers/char/tpm/tpm-interface.c
>> +++ b/drivers/char/tpm/tpm-interface.c
>> @@ -241,10 +241,17 @@ int tpm_get_timeouts(struct tpm_chip *chip)
>>  	if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
>>  		return 0;
>>  
>> -	if (chip->flags & TPM_CHIP_FLAG_TPM2)
>> +	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
>>  		return tpm2_get_timeouts(chip);
>> -	else
>> -		return tpm1_get_timeouts(chip);
>> +	} else {
>> +		ssize_t ret = tpm_request_locality(chip);
>> +
>> +		if (ret)
>> +			return ret;
>> +		ret = tpm1_get_timeouts(chip);
>> +		tpm_relinquish_locality(chip);
>> +		return ret;
>> +	}
>>  }
>>  EXPORT_SYMBOL_GPL(tpm_get_timeouts);
>>  
>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>> index 947d1db0a5cc..8c13008437dd 100644
>> --- a/drivers/char/tpm/tpm.h
>> +++ b/drivers/char/tpm/tpm.h
>> @@ -193,6 +193,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
>>  
>>  int tpm_chip_start(struct tpm_chip *chip);
>>  void tpm_chip_stop(struct tpm_chip *chip);
>> +int tpm_request_locality(struct tpm_chip *chip);
>> +void tpm_relinquish_locality(struct tpm_chip *chip);
>>  struct tpm_chip *tpm_find_get_ops(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/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
>> index 431919d5f48a..d4f381d6356e 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -708,11 +708,19 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
>>  	u32 cap2;
>>  	cap_t cap;
>>  
>> -	if (chip->flags & TPM_CHIP_FLAG_TPM2)
>> +	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
>>  		return tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
>> -	else
>> -		return tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc,
>> +	} else {
>> +		ssize_t ret = tpm_request_locality(chip);
>> +
>> +		if (ret)
>> +			return ret;
>> +		ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc,
>>  				  0);
>> +		tpm_relinquish_locality(chip);
>> +		return ret;
>> +	}
>> +
>>  }
>>  
>>  /* Register the IRQ and issue a command that will cause an interrupt. If an

My apologies for just more noise from here.

But I think it could be important that I withdraw my above statement
concerning positive test results on my hardware.

I was now trying to understand Lukasz' fix and started wondering how
changes in the case of !(chip->flags & TPM_CHIP_FLAG_TPM2) could affect
my environment: tpm_tis STM0125:00: 2.0 TPM (device-id 0x0, rev-id 78).

So, I became very nervous and re-did several tests and it
(understandably) turned out that Lukasz' patch does not affect my machine
at all -- nearly: the only effect I noticed is that tpm_tis doesn't get
loaded automatically with his patch applied.  I have to load it manually
but then get the familiar log messages.

But the tests I based my wrong statement on were done with static
tpm_tis, because of symbols not having been exported (V3).
I now noticed that tpm_tis behaves different depending on if it is built
static or as a module (latest tests done with
5.11.0-rc6-next-20210202-x86_64+).

In the static case, all I see in the logs is:

[    2.673818] tpm_tis STM0125:00: 2.0 TPM (device-id 0x0, rev-id 78)

Perhaps there are better ways to access and test TPM but I tested it
using getrandom: no further messages in the kernel log were generated.

If tpm_tis it is built as a module the behavior is the one with warnings
and falling back to polling.

Dirk