From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751784AbcFKBys (ORCPT ); Fri, 10 Jun 2016 21:54:48 -0400 Received: from mail-vk0-f50.google.com ([209.85.213.50]:35335 "EHLO mail-vk0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034AbcFKByq (ORCPT ); Fri, 10 Jun 2016 21:54:46 -0400 MIME-Version: 1.0 In-Reply-To: <20160610194248.GA7011@intel.com> References: <1465346740-60120-1-git-send-email-eswierk@skyportsystems.com> <1465426818-89356-1-git-send-email-eswierk@skyportsystems.com> <1465426818-89356-4-git-send-email-eswierk@skyportsystems.com> <20160610121957.GA6229@intel.com> <20160610194248.GA7011@intel.com> From: Ed Swierk Date: Fri, 10 Jun 2016 18:54:05 -0700 Message-ID: Subject: Re: [PATCH v5 3/4] tpm: Allow TPM chip drivers to override reported command durations To: Jarkko Sakkinen Cc: tpmdd-devel@lists.sourceforge.net, Stefan Berger , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, Jason Gunthorpe Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 10, 2016 at 12:42 PM, Jarkko Sakkinen wrote: > On Fri, Jun 10, 2016 at 10:34:15AM -0700, Ed Swierk wrote: >> On Fri, Jun 10, 2016 at 5:19 AM, Jarkko Sakkinen >> wrote: >> > On Wed, Jun 08, 2016 at 04:00:17PM -0700, Ed Swierk wrote: >> >> Some TPM chips report bogus command durations in their capabilities, >> >> just as others report incorrect timeouts. Rework tpm_get_timeouts() >> >> to allow chip drivers to override either via a single callback. >> >> Also clean up handling of TPMs that report milliseconds instead of >> >> microseconds. >> >> >> >> Signed-off-by: Ed Swierk >> >> --- >> >> drivers/char/tpm/tpm-interface.c | 177 +++++++++++++++++++++------------------ >> >> drivers/char/tpm/tpm_tis.c | 35 ++------ >> >> include/linux/tpm.h | 3 +- >> >> 3 files changed, 106 insertions(+), 109 deletions(-) >> >> >> >> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c >> >> index cc1e5bc..b8a08bb 100644 >> >> --- a/drivers/char/tpm/tpm-interface.c >> >> +++ b/drivers/char/tpm/tpm-interface.c >> >> @@ -502,123 +502,138 @@ static int tpm_startup(struct tpm_chip *chip, __be16 startup_type) >> >> "attempting to start the TPM"); >> >> } >> >> >> >> -int tpm_get_timeouts(struct tpm_chip *chip) >> >> +static int tpm_get_cap_prop(struct tpm_chip *chip, __be32 type, int size, >> >> + cap_t *cap, char *desc) >> >> { >> >> struct tpm_cmd_t tpm_cmd; >> >> - unsigned long new_timeout[4]; >> >> - unsigned long old_timeout[4]; >> >> - struct duration_t *duration_cap; >> >> ssize_t rc; >> >> >> >> tpm_cmd.header.in = tpm_getcap_header; >> >> tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; >> >> tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); >> >> - tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT; >> >> + tpm_cmd.params.getcap_in.subcap = type; >> >> rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, NULL); >> >> >> >> if (rc == TPM_ERR_INVALID_POSTINIT) { >> >> /* The TPM is not started, we are the first to talk to it. >> >> Execute a startup command. */ >> >> - dev_info(chip->pdev, "Issuing TPM_STARTUP"); >> >> + dev_info(chip->pdev, "Issuing TPM_STARTUP\n"); >> >> if (tpm_startup(chip, TPM_ST_CLEAR)) >> >> return rc; >> >> >> >> tpm_cmd.header.in = tpm_getcap_header; >> >> tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; >> >> tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); >> >> - tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_TIMEOUT; >> >> + tpm_cmd.params.getcap_in.subcap = type; >> >> rc = tpm_transmit_cmd(chip, &tpm_cmd, TPM_INTERNAL_RESULT_SIZE, >> >> NULL); >> >> } >> >> + >> >> if (rc) { >> >> dev_err(chip->pdev, >> >> - "A TPM error (%zd) occurred attempting to determine the timeouts\n", >> >> - rc); >> >> - goto duration; >> >> + "Error %zd reading %s\n", rc, desc); >> >> + return -EINVAL; >> >> } >> >> >> >> if (be32_to_cpu(tpm_cmd.header.out.return_code) != 0 || >> >> be32_to_cpu(tpm_cmd.header.out.length) >> >> - != sizeof(tpm_cmd.header.out) + sizeof(u32) + 4 * sizeof(u32)) >> >> + != sizeof(tpm_cmd.header.out) + sizeof(u32) + size * sizeof(u32)) { >> >> + dev_err(chip->pdev, >> >> + "Bad return code or length reading %s\n", desc); >> >> return -EINVAL; >> >> - >> >> - old_timeout[0] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.a); >> >> - old_timeout[1] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.b); >> >> - old_timeout[2] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.c); >> >> - old_timeout[3] = be32_to_cpu(tpm_cmd.params.getcap_out.cap.timeout.d); >> >> - memcpy(new_timeout, old_timeout, sizeof(new_timeout)); >> >> - >> >> - /* >> >> - * Provide ability for vendor overrides of timeout values in case >> >> - * of misreporting. >> >> - */ >> >> - if (chip->ops->update_timeouts != NULL) >> >> - chip->vendor.timeout_adjusted = >> >> - chip->ops->update_timeouts(chip, new_timeout); >> >> - >> >> - if (!chip->vendor.timeout_adjusted) { >> >> - /* Don't overwrite default if value is 0 */ >> >> - if (new_timeout[0] != 0 && new_timeout[0] < 1000) { >> >> - int i; >> >> - >> >> - /* timeouts in msec rather usec */ >> >> - for (i = 0; i != ARRAY_SIZE(new_timeout); i++) >> >> - new_timeout[i] *= 1000; >> >> - chip->vendor.timeout_adjusted = true; >> >> - } >> >> } >> >> >> >> - /* Report adjusted timeouts */ >> >> - if (chip->vendor.timeout_adjusted) { >> >> - dev_info(chip->pdev, >> >> - HW_ERR "Adjusting reported timeouts: A %lu->%luus B %lu->%luus C %lu->%luus D %lu->%luus\n", >> >> - old_timeout[0], new_timeout[0], >> >> - old_timeout[1], new_timeout[1], >> >> - old_timeout[2], new_timeout[2], >> >> - old_timeout[3], new_timeout[3]); >> >> - } >> >> + memcpy(cap, &tpm_cmd.params.getcap_out.cap, sizeof(cap_t)); >> >> >> >> - chip->vendor.timeout_a = usecs_to_jiffies(new_timeout[0]); >> >> - chip->vendor.timeout_b = usecs_to_jiffies(new_timeout[1]); >> >> - chip->vendor.timeout_c = usecs_to_jiffies(new_timeout[2]); >> >> - chip->vendor.timeout_d = usecs_to_jiffies(new_timeout[3]); >> >> + return 0; >> >> +} >> >> >> >> -duration: >> >> - tpm_cmd.header.in = tpm_getcap_header; >> >> - tpm_cmd.params.getcap_in.cap = TPM_CAP_PROP; >> >> - tpm_cmd.params.getcap_in.subcap_size = cpu_to_be32(4); >> >> - tpm_cmd.params.getcap_in.subcap = TPM_CAP_PROP_TIS_DURATION; >> >> +int tpm_get_timeouts(struct tpm_chip *chip) >> >> +{ >> >> + cap_t cap1, cap2; >> >> + int rc1, rc2; >> >> + struct tpm_vendor_specific orig_vendor; >> >> + >> >> + rc1 = tpm_get_cap_prop(chip, TPM_CAP_PROP_TIS_TIMEOUT, 4, &cap1, >> >> + "timeouts"); >> >> + if (rc1 == 0) { >> >> + be32_to_cpus(&cap1.timeout.a); >> >> + be32_to_cpus(&cap1.timeout.b); >> >> + be32_to_cpus(&cap1.timeout.c); >> >> + be32_to_cpus(&cap1.timeout.d); >> >> + chip->vendor.timeout_a = usecs_to_jiffies(cap1.timeout.a); >> >> + chip->vendor.timeout_b = usecs_to_jiffies(cap1.timeout.b); >> >> + chip->vendor.timeout_c = usecs_to_jiffies(cap1.timeout.c); >> >> + chip->vendor.timeout_d = usecs_to_jiffies(cap1.timeout.d); >> >> + } >> >> + rc2 = tpm_get_cap_prop(chip, TPM_CAP_PROP_TIS_DURATION, 3, &cap2, >> >> + "durations"); >> >> + if (rc2 == 0) { >> >> + be32_to_cpus(&cap2.duration.tpm_short); >> >> + be32_to_cpus(&cap2.duration.tpm_medium); >> >> + be32_to_cpus(&cap2.duration.tpm_long); >> >> + chip->vendor.duration[TPM_SHORT] = >> >> + usecs_to_jiffies(cap2.duration.tpm_short); >> >> + chip->vendor.duration[TPM_MEDIUM] = >> >> + usecs_to_jiffies(cap2.duration.tpm_medium); >> >> + chip->vendor.duration[TPM_LONG] = >> >> + usecs_to_jiffies(cap2.duration.tpm_long); >> >> + } >> > >> > This is major change to the semantics. Before -EINVAL would have been >> > return on error condition. >> > >> > PS If you want to encapsulate tpm_get_cap_prop(), that step should be >> > a separate commit (prepend this one). >> >> Good points. >> >> I'm confused about the error semantics in the first (timeouts) part of >> tpm_get_timeouts(). If tpm_transmit_cmd() returns zero and a header >> check fails, it returns -EINVAL. But if tpm_transmit_cmd() returns >> nonzero, it swallows the error. >> >> In contrast, in the second (durations) part, an error is returned in >> either case. >> >> Is this difference intentional, or should tpm_get_timeouts() return >> errors immediately in all cases? > > Sometimes these kinds of things are just "evolutional" :) > > There are also couple of other things that don't look right: > > * tpm_transmit_cmd() already prints the TPM error > * If you use dev_err(), you must fail. If we ought to continue, it > should be at most dev_warn(). > > In my opinion it is just plain wrong to continue to the durations part > in the case of TPM error. I would like to hear a second opinion, though. > >> --Ed > > /Jarkko I'll split tpm_get_cap_prop() out from tpm_get_timeouts() in a separate commit, and adjust the error handling on the assumption that TPM errors should always be propagated. --Ed