linux-kernel - Re: [PATCH v7 2/2] tpm: add securityfs support for TPM 2.0 firmware event log

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170103133309.lt5k4c37rjq5vcbq@intel.com>
Date:   Tue, 3 Jan 2017 15:33:09 +0200
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Nayna <nayna@...ux.vnet.ibm.com>
Cc:     tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
        tpmdd@...horst.net, jgunthorpe@...idianresearch.com,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 2/2] tpm: add securityfs support for TPM 2.0 firmware
 event log

On Tue, Jan 03, 2017 at 01:09:18PM +0530, Nayna wrote:
> 
> 
> On 01/03/2017 03:42 AM, Jarkko Sakkinen wrote:
> > On Sun, Dec 11, 2016 at 12:35:33AM -0500, Nayna Jain wrote:
> > > Unlike the device driver support for TPM 1.2, the TPM 2.0 does
> > > not support the securityfs pseudo files for displaying the
> > > firmware event log.
> > > 
> > > This patch enables support for providing the TPM 2.0 event log in
> > > binary form. TPM 2.0 event log supports a crypto agile format that
> > > records multiple digests, which is different from TPM 1.2. This
> > > patch enables the tpm_bios_log_setup for TPM 2.0  and adds the
> > > event log parser which understand the TPM 2.0 crypto agile format.
> > > 
> > > Signed-off-by: Nayna Jain <nayna@...ux.vnet.ibm.com>
> > 
> > There is something fundamentally wrong in this commit.
> > 
> > You must not allow this feature unless CONFIG_OF is set. It is the only
> > interface where the supply path of the event log is well defined on
> > platforms that include a TPM 2.0 chip.
> 
> As per current implementation, if ACPI with TPM 2.0 doesn't support event
> log, tpm_read_log_acpi() is expected to return rc and tpm_bios_log_setup
> will not create securityfs. This is inline with our design for TPM 1.2 event
> log.

At minimum you must have a check for TPM_CHIP_FLAG_TPM2 in the beginning
of tpm_read_log_acpi. It is wrong to even try to open TCPA in this case.

/Jarkko