From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3FD9CC54FCC for ; Mon, 20 Apr 2020 22:28:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 11DFD206DD for ; Mon, 20 Apr 2020 22:28:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="fGatc6hX"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="qd2xvTqY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726991AbgDTW2J (ORCPT ); Mon, 20 Apr 2020 18:28:09 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:59676 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726262AbgDTW2J (ORCPT ); Mon, 20 Apr 2020 18:28:09 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id F22998EE17B; Mon, 20 Apr 2020 15:28:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1587421689; bh=SwjsJe4PvxQ16YGtb7jybezJ0G6d0YoVjLD7KzTwv6U=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=fGatc6hXHI1HovdfP0O7oVunYhOEywq4HeAjbdMkybgGeZ4BW+VRjA+xZ6Lx0gnfc 5CQUpZQ8HocHR/wto4h/YZKV/5vPIxphxleZbs8os8ajGub8EGeoV5S5yql2AlUSzc u2idUYaTDzyjXaxLyYSaxBIZ5tA6ULHtUtg5bA3U= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RSosx6i5XlqN; Mon, 20 Apr 2020 15:28:08 -0700 (PDT) Received: from [153.66.254.194] (unknown [50.35.76.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id 6392A8EE0B9; Mon, 20 Apr 2020 15:28:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1587421688; bh=SwjsJe4PvxQ16YGtb7jybezJ0G6d0YoVjLD7KzTwv6U=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=qd2xvTqYeGnCE3b7xCxa2uvdml11EvH7UAjyVIDenvGcXytxVziVmJDW750kEEEPB qLXjBY04DA+Yd/+rN5oCwVwm6jJT5ZOfBfojEmnWpuEbxy7QR2llfypLx6KscdO06M 2IaQKOCrg4wQFPh6Nkkh7hYza4o8wDgxaKIpWvqs= Message-ID: <1587421686.3493.2.camel@HansenPartnership.com> Subject: Re: [PATCH] tpm_tis: work around status register bug in STMicroelectronics TPM From: James Bottomley To: Jarkko Sakkinen , zohar@linux.ibm.com Cc: Omar Sandoval , Peter Huewe , Jason Gunthorpe , linux-integrity@vger.kernel.org Date: Mon, 20 Apr 2020 15:28:06 -0700 In-Reply-To: <20200420204641.GA14637@linux.intel.com> References: <6c55d7c1fb84e5bf2ace9f05ec816ef67bd873e1.1586990595.git.osandov@fb.com> <1586994699.3931.18.camel@HansenPartnership.com> <20200416001605.GA673482@vader> <20200416002442.GB673482@vader> <1587060171.15329.7.camel@HansenPartnership.com> <20200417235527.GB85230@linux.intel.com> <1587168748.5867.2.camel@HansenPartnership.com> <20200420204641.GA14637@linux.intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org On Mon, 2020-04-20 at 23:46 +0300, Jarkko Sakkinen wrote: > On Fri, Apr 17, 2020 at 05:12:28PM -0700, James Bottomley wrote: > > On Sat, 2020-04-18 at 02:55 +0300, Jarkko Sakkinen wrote: > > > On Thu, Apr 16, 2020 at 11:02:51AM -0700, James Bottomley wrote: > > > > On Wed, 2020-04-15 at 17:24 -0700, Omar Sandoval wrote: > > > > > On Wed, Apr 15, 2020 at 05:16:05PM -0700, Omar Sandoval > > > > > wrote: > > > > > > On Wed, Apr 15, 2020 at 04:51:39PM -0700, James Bottomley > > > > > > wrote: > > > > > > > On Wed, 2020-04-15 at 15:45 -0700, Omar Sandoval wrote: > > > > > > > > From: Omar Sandoval > > > > > > > > > > > > > > > > We've encountered a particular model of > > > > > > > > STMicroelectronics > > > > > > > > TPM > > > > > > > > that transiently returns a bad value in the status > > > > > > > > register. > > > > > > > > This causes the kernel to believe that the TPM is ready > > > > > > > > to > > > > > > > > receive a command when it actually isn't, which in turn > > > > > > > > causes > > > > > > > > the send to time out in get_burstcount(). In testing, > > > > > > > > reading > > > > > > > > the status register one extra time convinces the TPM to > > > > > > > > return > > > > > > > > a valid value. > > > > > > > > > > > > > > Interesting, I've got a very early upgradeable nuvoton > > > > > > > that seems to be behaving like this. > > > > > > > > > > > > I'll attach the userspace reproducer I used to figure this > > > > > > out. I'd be interested to see if it times out on your TPM, > > > > > > too. Note that it bangs on /dev/mem and assumes that the > > > > > > MMIO address is 0xfed40000. That seems to be the hard- > > > > > > coded > > > > > > address for x86 in the kernel, but just to be safe you > > > > > > might want to check `grep MSFT0101 /proc/iomem`. > > > > > > > > > > Forgot to attach it, of course... > > > > > > > > > > > > Thanks! You facebook guys run with interesting kernel options > > > > ... I eventually had to disable CONFIG_STRICT_DEVMEM and > > > > rebuild my kernel to get it to run. > > > > > > > > However, the bad news is that this isn't my problem, it seems > > > > to be more timeout related I get the same symptoms: logs full > > > > of > > > > > > > > [14570.626594] tpm tpm0: tpm_try_transmit: tpm_send: error -62 > > > > > > > > and the TPM won't recover until the box is reset. To get my > > > > TPM to be usable, I have to fiddle our default timeouts like > > > > this: > > > > > > > > --- a/drivers/char/tpm/tpm.h > > > > +++ b/drivers/char/tpm/tpm.h > > > > @@ -41,8 +41,8 @@ enum tpm_timeout { > > > > TPM_TIMEOUT_RETRY = 100, /* msecs */ > > > > TPM_TIMEOUT_RANGE_US = 300, /* usecs */ > > > > TPM_TIMEOUT_POLL = 1, /* msecs */ > > > > - TPM_TIMEOUT_USECS_MIN = 100, /* usecs */ > > > > - TPM_TIMEOUT_USECS_MAX = 500 /* usecs */ > > > > + TPM_TIMEOUT_USECS_MIN = 750, /* usecs */ > > > > + TPM_TIMEOUT_USECS_MAX = 1000, /* usecs */ > > > > }; > > > > > > > > But I think the problem is unique to my nuvoton because there > > > > haven't been any other reports of problems like this ... and > > > > with these timeouts my system functions normally in spite of me > > > > being a heavy TPM user. > > > > > > What downsides there would be to increase these a bit? > > > > PCR writes would take longer meaning IMA initialization would > > become slower. > > Does it matter? Not if you're the one telling Mimi ... and I'm at least 1 mile from the blast radius. But more seriously: Nayna Jain did a series of patches improving the time it takes to poll the TPM for operations precisely because the TPM PCR extend was going so slowly: https://lore.kernel.org/linux-integrity/20180516055125.5685-1-nayna@linux.vnet.ibm.com/ I also reported the issue shortly after that patch was integrated, but everyone seemed to think it was just a problem with my TPM chip (it's an early Nuvoton field upgraded to 2.0): https://lore.kernel.org/linux-integrity/1531328689.3260.8.camel@HansenPartnership.com/ James