From mboxrd@z Thu Jan 1 00:00:00 1970 From: jsnitsel@redhat.com (Jerry Snitselaar) Date: Sat, 25 Mar 2017 05:21:30 -0700 Subject: [PATCH v4] tpm_crb: request and relinquish locality 0 In-Reply-To: <20170324101922.mw7vzgesckp26wro@intel.com> References: <20170324101032.13496-1-jarkko.sakkinen@iki.fi> <20170324101922.mw7vzgesckp26wro@intel.com> Message-ID: <87fui17dit.fsf@redhat.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org Jarkko Sakkinen @ 2017-03-24 10:19 GMT: > On Fri, Mar 24, 2017 at 12:10:30PM +0200, Jarkko Sakkinen wrote: >> This commit adds support for requesting and relinquishing locality 0 in >> tpm_crb for the course of command transmission. >> >> In order to achieve this, two new callbacks are added to struct >> tpm_class_ops: >> >> - request_locality >> - relinquish_locality >> >> With CRB interface you first set either requestAccess or relinquish bit >> from TPM_LOC_CTRL_x register and then wait for locAssigned and >> tpmRegValidSts bits to be set in the TPM_LOC_STATE_x register. >> >> The reason why were are doing this is to make sure that the driver >> will work properly with Intel TXT that uses locality 2. There's no >> explicit guarantee that it would relinquish this locality. In more >> general sense this commit enables tpm_crb to be a well behaving >> citizen in a multi locality environment. >> >> Signed-off-by: Jarkko Sakkinen >> --- >> v2: >> - TPM driver level calllbacks >> v3: >> - Call ops->relinquish_locality only if ops->request_locality has been >> successful. >> - Do not reserve locality in nested tpm_transmit calls. >> - Check for tpmRegValidSts to make sure that the value in TPM_LOC_STATE_x is >> stable. >> v4: >> - Removed tpm_tis_core changes. It needs to be done separately. It will be >> postponed to 4.13. >> - Store locality to struct tpm_chip while active. >> drivers/char/tpm/tpm-chip.c | 1 + >> drivers/char/tpm/tpm-interface.c | 13 +++++++++++++ >> drivers/char/tpm/tpm.h | 3 +++ >> drivers/char/tpm/tpm_crb.c | 41 ++++++++++++++++++++++++++++++++++++++++ >> include/linux/tpm.h | 3 ++- >> 5 files changed, 60 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c >> index aade699..a321bd5 100644 >> --- a/drivers/char/tpm/tpm-chip.c >> +++ b/drivers/char/tpm/tpm-chip.c >> @@ -231,6 +231,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev, >> goto out; >> } >> >> + chip->locality = -1; >> return chip; >> >> out: >> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c >> index 95c6f98..1815666 100644 >> --- a/drivers/char/tpm/tpm-interface.c >> +++ b/drivers/char/tpm/tpm-interface.c >> @@ -384,6 +384,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space, >> ssize_t len = 0; >> u32 count, ordinal; >> unsigned long stop; >> + bool need_locality = chip->locality == -1; > > This must be set *after* taking the mutex. Otherwise, I think this > should be fine now. > > /Jarkko Sorry, I missed this email earlier. Yeah, I ran into this while trying to get the tpm_tis code working with this change tonight. Are you just going to move the assignment to right before the if block for request_locality? I've tested with the assignment moved inside the mutex on a kabylake system. I also tested with a patch for adding support to tpm_tis on a tpm_tis system, but that is a work in progress. -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html