Yes. Can you ping me once it is in? I can merge this after that. /Jarkko
On Thu, May 18, 2017 at 08:21:32AM -0700, Josh Zimmerman wrote: > Are there any other changes I should make to this patch, or is it good > to go once the patch it depends on is in? > > Thanks! > Josh > > > On Mon, May 15, 2017 at 5:08 PM, Josh Zimmerman <jo...@google.com> wrote: > > If a TPM2 loses power without a TPM2_Shutdown command being issued (a > > "disorderly reboot"), it may lose some state that has yet to be > > persisted to NVRam, and will increment the DA counter (eventually, this > > will cause the TPM to lock the user out.) > > > > NOTE: This only changes behavior on TPM2 devices. Since TPM1 uses sysfs, > > and sysfs relies on implicit locking on chip->ops, it is not safe to > > allow this code to run in TPM1, or to add sysfs support to TPM2, until > > that locking is made explicit. > > > > This patch is dependent on '[PATCH] Add "shutdown" to "struct class".' > > http://marc.info/?l=linux-kernel&m=149463235025420&w=2 > > > > Signed-off-by: Josh Zimmerman <jo...@google.com> > > > > ---- > > v2: > > - Properly split changes between this and another commit > > - Use proper locking primitive. > > - Fix commenting style > > v3: > > - Re-fix commenting style > > --- > > drivers/char/tpm/tpm-chip.c | 20 ++++++++++++++++++++ > > drivers/char/tpm/tpm-sysfs.c | 3 +++ > > 2 files changed, 23 insertions(+) > > > > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c > > index 9dec9f551b83..272a42e77574 100644 > > --- a/drivers/char/tpm/tpm-chip.c > > +++ b/drivers/char/tpm/tpm-chip.c > > @@ -142,6 +142,25 @@ static void tpm_devs_release(struct device *dev) > > put_device(&chip->dev); > > } > > > > +static void tpm_shutdown(struct device *dev) > > +{ > > + struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev); > > + /* TPM 2.0 requires that the TPM2_Shutdown() command be issued > > prior to > > + * loss of power. If it is not, the DA counter will be incremented > > and, > > + * eventually, the user will be locked out of their TPM. > > + * XXX: This codepath relies on the fact that sysfs is not enabled > > for > > + * TPM2: sysfs uses an implicit lock on chip->ops, so this use could > > + * race if TPM2 has sysfs support enabled before TPM sysfs's > > implicit > > + * locking is fixed. > > + */ > > + if (chip->flags & TPM_CHIP_FLAG_TPM2) { > > + down_write(&chip->ops_sem); > > + tpm2_shutdown(chip, TPM_SU_CLEAR); > > + chip->ops = NULL; > > + up_write(&chip->ops_sem); > > + } > > +} > > + > > /** > > * tpm_chip_alloc() - allocate a new struct tpm_chip instance > > * @pdev: device to which the chip is associated > > @@ -181,6 +200,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, > > device_initialize(&chip->devs); > > > > chip->dev.class = tpm_class; > > + chip->dev.class.shutdown = tpm_shutdown; > > chip->dev.release = tpm_dev_release; > > chip->dev.parent = pdev; > > chip->dev.groups = chip->groups; > > diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c > > index 55405dbe43fa..5e5ff7eb6f7e 100644 > > --- a/drivers/char/tpm/tpm-sysfs.c > > +++ b/drivers/char/tpm/tpm-sysfs.c > > @@ -294,6 +294,9 @@ static const struct attribute_group tpm_dev_group = { > > > > void tpm_sysfs_add_device(struct tpm_chip *chip) > > { > > + /* XXX: Before this restriction is removed, tpm_sysfs must be > > updated > > + * to explicitly lock chip->ops. > > + */ > > if (chip->flags & TPM_CHIP_FLAG_TPM2) > > return; > > > > -- > > 2.13.0.303.g4ebf302169-goog > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ tpmdd-devel mailing list tpmdd-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/tpmdd-devel
