Messages in this thread Patch in this message | | | Subject | Re: [PATCH] tpm: fixes uninitialized allocated banks for IBM vtpm driver | From | Stefan Berger <> | Date | Fri, 5 Jul 2019 10:13:56 -0400 |
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On 7/3/19 11:32 PM, Nayna Jain wrote: > The nr_allocated_banks and allocated banks are initialized as part of > tpm_chip_register. Currently, this is done as part of auto startup > function. However, some drivers, like the ibm vtpm driver, do not run > auto startup during initialization. This results in uninitialized memory > issue and causes a kernel panic during boot. > > This patch moves the pcr allocation outside the auto startup function > into tpm_chip_register. This ensures that allocated banks are initialized > in any case. > > Fixes: 879b589210a9 ("tpm: retrieve digest size of unknown algorithms with > PCR read") > Signed-off-by: Nayna Jain <nayna@linux.ibm.com> > --- > drivers/char/tpm/tpm-chip.c | 37 +++++++++++++++++++++++++++++++++++++ > drivers/char/tpm/tpm.h | 1 + > drivers/char/tpm/tpm1-cmd.c | 12 ------------ > drivers/char/tpm/tpm2-cmd.c | 6 +----- > 4 files changed, 39 insertions(+), 17 deletions(-) > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > index 8804c9e916fd..958508bb8379 100644 > --- a/drivers/char/tpm/tpm-chip.c > +++ b/drivers/char/tpm/tpm-chip.c > @@ -550,6 +550,39 @@ static int tpm_add_hwrng(struct tpm_chip *chip) > return hwrng_register(&chip->hwrng); > } > > +/* > + * tpm_pcr_allocation() - initializes the chip allocated banks for PCRs > + */ > +static int tpm_pcr_allocation(struct tpm_chip *chip) > +{ > + int rc = 0; > + > + if (chip->flags & TPM_CHIP_FLAG_TPM2) { > + rc = tpm2_get_pcr_allocation(chip); > + if (rc) > + goto out; > + } > + > + /* Initialize TPM 1.2 */ > + chip->allocated_banks = kcalloc(1, sizeof(*chip->allocated_banks), > + GFP_KERNEL); > + if (!chip->allocated_banks) { > + rc = -ENOMEM; > + goto out; > + } > + > + chip->allocated_banks[0].alg_id = TPM_ALG_SHA1; > + chip->allocated_banks[0].digest_size = hash_digest_size[HASH_ALGO_SHA1]; > + chip->allocated_banks[0].crypto_id = HASH_ALGO_SHA1; > + chip->nr_allocated_banks = 1; > + > + return 0; > +out: > + if (rc < 0) > + rc = -ENODEV;
The old code where you lifted this from said:
out: if (rc > 0) rc = -ENODEV; return rc;
It would not overwrite -ENOMEM with -ENODEV but yours does.
I think the correct fix would be to use:
if (rc > 0)
rc = -ENODEV;
> + return rc; > +} > + > /* > * tpm_chip_register() - create a character device for the TPM chip > * @chip: TPM chip to use. > @@ -573,6 +606,10 @@ int tpm_chip_register(struct tpm_chip *chip) > if (rc) > return rc;
Above this is tpm_chip_stop(chip) because (afaik) none of the following function calls in tpm_chip_register() needed the TPM, but now with tpm_pcr_allocation() you will need to send a command to the TPM. So I would say you should move the tpm_chip_stop() into the error branch visible above and also after the tpm_pcr_allocation().
> + rc = tpm_pcr_allocation(chip); tpm_chip_stop(chip); > + if (rc) > + return rc; > + > tpm_sysfs_add_device(chip); > > rc = tpm_bios_log_setup(chip);
Stefan
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