linux.git/drivers/char/tpm, branch v6.3

tpm: disable hwrng for fTPM on some AMD designs

2023-03-12T21:28:10+00:00

AMD has issued an advisory indicating that having fTPM enabled in
BIOS can cause "stuttering" in the OS.  This issue has been fixed
in newer versions of the fTPM firmware, but it's up to system
designers to decide whether to distribute it.

This issue has existed for a while, but is more prevalent starting
with kernel 6.1 because commit b006c439d58db ("hwrng: core - start
hwrng kthread also for untrusted sources") started to use the fTPM
for hwrng by default. However, all uses of /dev/hwrng result in
unacceptable stuttering.

So, simply disable registration of the defective hwrng when detecting
these faulty fTPM versions.  As this is caused by faulty firmware, it
is plausible that such a problem could also be reproduced by other TPM
interactions, but this hasn't been shown by any user's testing or reports.

It is hypothesized to be triggered more frequently by the use of the RNG
because userspace software will fetch random numbers regularly.

Intentionally continue to register other TPM functionality so that users
that rely upon PCR measurements or any storage of data will still have
access to it.  If it's found later that another TPM functionality is
exacerbating this problem a module parameter it can be turned off entirely
and a module parameter can be introduced to allow users who rely upon
fTPM functionality to turn it on even though this problem is present.

Link: https://www.amd.com/en/support/kb/faq/pa-410
Link: https://bugzilla.kernel.org/show_bug.cgi?id=216989
Link: https://lore.kernel.org/all/20230209153120.261904-1-Jason@zx2c4.com/
Fixes: b006c439d58d ("hwrng: core - start hwrng kthread also for untrusted sources")
Cc: stable@vger.kernel.org
Cc: Jarkko Sakkinen 
Cc: Thorsten Leemhuis 
Cc: James Bottomley 
Tested-by: reach622@mailcuk.com
Tested-by: Bell <1138267643@qq.com>
Co-developed-by: Jason A. Donenfeld 
Signed-off-by: Jason A. Donenfeld 
Signed-off-by: Mario Limonciello 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm/eventlog: Don't abort tpm_read_log on faulty ACPI address

2023-03-12T21:28:10+00:00

tpm_read_log_acpi() should return -ENODEV when no eventlog from the ACPI
table is found. If the firmware vendor includes an invalid log address
we are unable to map from the ACPI memory and tpm_read_log() returns -EIO
which would abort discovery of the eventlog.

Change the return value from -EIO to -ENODEV when acpi_os_map_iomem()
fails to map the event log.

The following hardware was used to test this issue:
    Framework Laptop (Pre-production)
    BIOS: INSYDE Corp, Revision: 3.2
    TPM Device: NTC, Firmware Revision: 7.2

Dump of the faulty ACPI TPM2 table:
    [000h 0000   4]                    Signature : "TPM2"    [Trusted Platform Module hardware interface Table]
    [004h 0004   4]                 Table Length : 0000004C
    [008h 0008   1]                     Revision : 04
    [009h 0009   1]                     Checksum : 2B
    [00Ah 0010   6]                       Oem ID : "INSYDE"
    [010h 0016   8]                 Oem Table ID : "TGL-ULT"
    [018h 0024   4]                 Oem Revision : 00000002
    [01Ch 0028   4]              Asl Compiler ID : "ACPI"
    [020h 0032   4]        Asl Compiler Revision : 00040000

    [024h 0036   2]               Platform Class : 0000
    [026h 0038   2]                     Reserved : 0000
    [028h 0040   8]              Control Address : 0000000000000000
    [030h 0048   4]                 Start Method : 06 [Memory Mapped I/O]

    [034h 0052  12]            Method Parameters : 00 00 00 00 00 00 00 00 00 00 00 00
    [040h 0064   4]           Minimum Log Length : 00010000
    [044h 0068   8]                  Log Address : 000000004053D000

Fixes: 0cf577a03f21 ("tpm: Fix handling of missing event log")
Tested-by: Erkki Eilonen 
Signed-off-by: Morten Linderud 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: add vendor flag to command code validation

2023-02-13T08:11:20+00:00

Some TPM 2.0 devices have support for additional commands which are not
part of the TPM 2.0 specifications.
These commands are identified with bit 29 of the 32 bits command codes.
Contrarily to other fields of the TPMA_CC spec structure used to list
available commands, the Vendor flag also has to be present in the
command code itself (TPM_CC) when called.

Add this flag to tpm_find_cc() mask to prevent blocking vendor command
codes that can actually be supported by the underlying TPM device.

Signed-off-by: Julien Gomes 
Tested-by: Jarkko Sakkinen 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: Add reserved memory event log

2023-02-13T08:11:20+00:00

Some platforms may desire to pass the event log up to Linux in the
form of a reserved memory region. In particular, this is desirable
for embedded systems or baseboard management controllers (BMCs)
booting with U-Boot. IBM OpenBMC BMCs will be the first user.
Add support for the reserved memory in the TPM core to find the
region and map it.

Signed-off-by: Eddie James 
[jarkko: removed spurious dev_info()'s from tpm_read_log_memory_region()]
Reviewed-by: Jarkko Sakkinen 
[yang: return -ENOMEM when devm_memremap() fails]
Signed-off-by: Yang Yingliang 
Signed-off-by: Jarkko Sakkinen

tpm: Use managed allocation for bios event log

2023-02-13T08:11:20+00:00

Since the bios event log is freed in the device release function,
let devres handle the deallocation. This will allow other memory
allocation/mapping functions to be used for the bios event log.

Signed-off-by: Eddie James 
Tested-by: Jarkko Sakkinen 
Reviewed-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: tis_i2c: Convert to i2c's .probe_new()

2023-02-13T08:11:20+00:00

The probe function doesn't make use of the i2c_device_id * parameter so it
can be trivially converted.

Signed-off-by: Uwe Kleine-König 
Acked-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: tpm_i2c_nuvoton: Convert to i2c's .probe_new()

2023-02-13T08:11:20+00:00

.probe_new() doesn't get the i2c_device_id * parameter, so determine
that explicitly in the probe function.

Signed-off-by: Uwe Kleine-König 
Acked-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: tpm_i2c_infineon: Convert to i2c's .probe_new()

2023-02-13T08:11:20+00:00

The probe function doesn't make use of the i2c_device_id * parameter so it
can be trivially converted.

Signed-off-by: Uwe Kleine-König 
Acked-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: tpm_i2c_atmel: Convert to i2c's .probe_new()

2023-02-13T08:11:20+00:00

The probe function doesn't make use of the i2c_device_id * parameter so it
can be trivially converted.

Signed-off-by: Uwe Kleine-König 
Acked-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen

tpm: st33zp24: Convert to i2c's .probe_new()

2023-02-13T08:11:20+00:00

The probe function doesn't make use of the i2c_device_id * parameter so it
can be trivially converted.

Signed-off-by: Uwe Kleine-König 
Acked-by: Jarkko Sakkinen 
Signed-off-by: Jarkko Sakkinen