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SubjectRe: [PATCH 1/7] ima: on soft reboot, restore the measurement list
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On Tue, 2016-08-09 at 09:55 -0400, Mimi Zohar wrote:
> On Tue, 2016-08-09 at 10:19 -0300, Thiago Jung Bauermann wrote:
> > Am Dienstag, 09 August 2016, 09:01:13 schrieb Mimi Zohar:
> > > On Tue, 2016-08-09 at 20:59 +1000, Michael Ellerman wrote:
> > > > Mimi Zohar <zohar@linux.vnet.ibm.com> writes:
> > > > > diff --git a/security/integrity/ima/ima.h
> > > > > b/security/integrity/ima/ima.h
> > > > > index b5728da..84e8d36 100644
> > > > > --- a/security/integrity/ima/ima.h
> > > > > +++ b/security/integrity/ima/ima.h
> > > > > @@ -102,6 +102,13 @@ struct ima_queue_entry {
> > > > >
> > > > > };
> > > > > extern struct list_head ima_measurements; /* list of all
> > measurements
> > > > > */
> > > > >
> > > > > +/* Some details preceding the binary serialized measurement list */
> > > > > +struct ima_kexec_hdr {
> > > > > + unsigned short version;
> > > > > + unsigned long buffer_size;
> > > > > + unsigned long count;
> > > > > +} __packed;
> > > > > +
> > > >
> > > > Am I understanding it correctly that this structure is passed between
> > > > kernels?
> > > Yes, the header prefixes the measurement list, which is being passed on
> > > the same computer to the next kernel. Could the architecture (eg.
> > > LE/BE) change between soft re-boots?
> >
> > Yes. I am able to boot a BE kernel from an LE kernel with my patches.
> > Whether we want to support that or not is another question...
>
> The <securityfs/ima/binary_runtime_measurements is system architecture
> dependent. It looks like the khdr->version check in
> ima_restore_measurement_list() would fail if the architecture changes.
>
> If/when we update the binary measurement list format to support multiple
> TPM PCRs, we should address the endianness as well.

That should have been "TPM PCR banks". TPM 2.0 allows for multiple TPM
PCR banks.

Mimi

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