xen-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 02/28/2008 03:42:07 AM:
> Hi
>
> I have looked through some source code and have the following questions:
>
> 1)
> in tools/vtpm/vtpm/tpm/tpm_storage.c
>
> TPM_RESULT TPM_LoadKey2(TPM_KEY_HANDLE parentHandle, TPM_KEY *inKey,
> TPM_AUTH *auth1, TPM_KEY_HANDLE *inkeyHandle)
> {
> info("TPM_LoadKey2() is currently emulated by TPM_LoadKey()");
> return TPM_LoadKey(parentHandle, inKey, auth1, inkeyHandle);
> }
>
> So TPM_LoadKey2 is actually a wrapper around TPM_LoadKey() with exactly
> same parameters. My question is if they are using same parameters why
> one fails while the other succeeds?
It's (for example) the return path that's different. TPM_LoadKey2()
does NOT calculate the HMAC over the key's handle. And that's actually
the source of the bug.
>
> And why is it necessary to wrap the TPM_LoadKey function with exactly
> same call? Any pointers would be highly appreciated.
Here's a link to a fairly recent version of the specification.
https://www.trustedcomputinggroup.org/specs/TPM/mainP3Commandsrev103.zip
>
> 2)
> in tools/vtpm/vtpm/tpm/tpm_commands.h
>
> * Description: ([TPM_Part3], Section 10.5)
>
> What is this TPM_Part3 document mentioned here and where can I locate
> it? Is this the document named "TPM Main Part3 IBM Commands" written by
> Ken Goldman and you? If that is correct, I have Revision 10 of this
> document dated 25 April 2005 and that document does not have Section
> 10.5. Is there a more recent version that I am not aware of?
No, this is not referring to that document. It's referring to the one
link above.
>
> 3) Is this problem specific to TPM hardware (ie only infinion tpm) or
> xen version?
It's a bug in the TPM emulator.
This patch here does the trick. When I have some time I'll try to
prepare a patch for the patch that the Xen build process applies on
top of the tpm emulator code. I'll also send it to the maintainer(s)
of the tpm emualtor.
--- ./tpm_emulator/tpm/tpm_cmd_handler.c 2008-02-27
16:35:41.000000000 -0500
+++ vtpm/tpm/tpm_cmd_handler.c 2008-02-28 14:43:28.000000000 -0500
@@ -94,12 +94,18 @@ void tpm_compute_out_param_digest(TPM_CO
sha1_ctx_t sha1;
UINT32 res = CPU_TO_BE32(rsp->result);
UINT32 ord = CPU_TO_BE32(ordinal);
+ UINT32 offset = 0;
/* compute SHA1 hash */
sha1_init(&sha1);
sha1_update(&sha1, (BYTE*)&res, 4);
sha1_update(&sha1, (BYTE*)&ord, 4);
- sha1_update(&sha1, rsp->param, rsp->paramSize);
+ if (ordinal == TPM_ORD_LoadKey2) {
+ offset = 4;
+ }
+ if (rsp->paramSize - offset > 0) {
+ sha1_update(&sha1, rsp->param + offset, rsp->paramSize - offset);
+ }
sha1_final(&sha1, rsp->auth1->digest);
if (rsp->auth2 != NULL) memcpy(rsp->auth2->digest,
rsp->auth1->digest, sizeof(rsp->auth1->digest));
Please try it.
>
> 4) You said you used some tools to trace and alter tss behaviour. What
> is this tool and how can I obtain it?
It's not a publicly available tool. It's basically forming the TPM
commands directly and writes them to /dev/tpm0 and so circumvents the
TSS stack.
Stefan
>
> Thanks for your time
> Erdem Bayer
>
> Stefan Berger wrote On 28-02-2008 04:47:
> >
> > xense-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 02/27/2008
04:02:41 PM:
> >
> > > Hi
> > >
> > > I have checked out the 0.3.2cvs version of trousers and finally
get the
> > > tsstest working with very few differences from when it is run under
> > > non-xen host. My previous attempts was on 0.3.1 (stable).
> > >
> > > However when run tpm_sealdata, I still get
> > >
> > > Tspi_Key_LoadKey failed: 0x00003113 - layer=tsp, code=0113 (275),
> > > Authorization failed.
> >
> > So, I just tried this and I ran into the same problem. I then used
> > some tools that let me control whether to use TPM_LoadKey() or
> > TPM_LoadKey2(). Loading a key with TPM_LoadKey2() failed due to HMAC
> > authorization failing, TPM_LoadKey() worked. From what I saw is that
> > the TSS is using TPM_LoadKey2() and the TPM implementation then
states
> > that TPM_LoadKey2() is emulated using TPM_LoadKey(). Well, it
seems to
> > be a bug in the TPM_LoadKey2() implementation.
> >
> > >
> > > This reminds me that maybe I am using vtpm wrong way. Is there a
> > > document about how to use vtpm?
> > >
> > No, you are using it correctly.
> >
> > Stefan
> >
> >
> >
> > > Here is what I do from sratch:
> > >
> > > 1. Clear and reactivate TPM from bios.
> > > 2. Run vtpm_managerd in dom0 and let it continue running on console.
> > > 3. Boot domU with vif statement in config file.
> > > 4. Run tcsd -f on domU and let it continue running on console.
> > >
> > > From now on every tpm operation I run on domU returns an error.
> > >
> > > Operations tried on domU
> > >
> > > 1. I tried tpm_takeownership with success (although I see an
error on
> > > tcsd -f output, I assume it is normal because I see exact same error
> > > when I run takeownership from non-xen host and actually prove
ownership
> > > taken by using sealdata successfully) but when I try
tpm_sealdata I get
> > > above error.
> > >
> > > 2. After starting from scratch, I tried tpm_sealdata without
first try
> > > to take ownership. This time there is a different output:
> > >
> > > Enter SRK password:
> > > Tspi_Key_CreateKey failed: 0x00000003 - layer=tpm, code=0003
(3), Bad
> > > Parameter
> > >
> > > I think I am not able to use vtpm because probably I am not
doing the
> > > right sequence of actions on domU. So if there is a document
about vtpm
> > > usage, please point me to it.
> > >
> > > And here is another question:
> > >
> > > I never run tpm_takeownership on dom0. Whenever I start from
scratch I
> > > let the vtpm_managerd to take ownership of tpm. However, I do
not know
> > > the owner or srk password it uses. When I use vtpm on domU and
asked
> > for
> > > the srk pasword, which password should I enter? Also, should I take
> > > ownership of vtpm on domU every time I booted it? How do I save
> > state of
> > > the vtpm for a domain across boots?
> > >
> > > Thanks for time.
> > > Erdem Bayer
> > >
> > >
> > > Stefan Berger wrote On 27-02-2008 05:59:
> > > >
> > > > xense-devel-bounces@xxxxxxxxxxxxxxxxxxx wrote on 02/26/2008
> > 06:28:01 PM:
> > > >
> > > > > Hi
> > > > >
> > > > > I have successfully applied the patch mentioned here
> > > > >
> > > >
> >
(http://lists.xensource.com/archives/html/xense-devel/2007-04/msg00005.html
> > > )
> > > >
> > > > > to the xen v. 3.1.3 on an HP nx8325 with Infineon TPM.
> > > > >
> > > > > I cleared the tpm, deleted /var/vtpm/VTPM file and rebooted.
> > > > >
> > > > > After reboot, vtpm_managerd runs ok. (output is attched to the
> > mail.)
> > > > >
> > > > > I created a pv vm with the option vtpm = ['instance=1,
> > backend=0'] The
> > > > > vm boots fine.
> > > > >
> > > > > I installed trousers-0.3.1 and tpm-tools-1.3.1 from sources on
> > the vm.
> > > > >
> > > > > I run tcsd -f on the vm. (output is attched to the mail.)
> > > > >
> > > > > I checkout and run the trousers test suite. 10 tests passed
with 230
> > > > > failed. (Is this expected?)
> > > >
> > > >
> > > > It is likely that this (v)TPM implementation has quite a few
bugs,
> > but
> > > > I would not expect that many errors.
> > > >
> > > > >
> > > > > When I try tpm_takeownership on the vm, the command runs fine.
> > > > (Although
> > > > > a strange warning appers on tcsd output which is attched).
> > > >
> > > > This error may be related to older versions of the TPM device
driver
> > > > having used an ioctl interface for sending/receiving commands
to/from
> > > > the TPM and the TSS still tries this interface first. This
should not
> > > > be a reason for the errors you are seeing.
> > > >
> > > > >
> > > > > But when I try tpm_sealdata < foo on the vm I get the following
> > error.
> > > > >
> > > > > Tspi_Key_LoadKey failed: 0x00003113 - layer=tsp, code=0113
(275),
> > > > > Authorization failed
> > > > >
> > > > > But other tpm_version runs fine on vm.
> > > > >
> > > > > tpm-test:~# tpm_version
> > > > > TPM 1.2 Version Info:
> > > > > Chip Version: 1.2.0.4
> > > > > Spec Level: 2
> > > > > Errata Revision: 94
> > > > > TPM Vendor ID:
> > > > > TPM Version: 01010000
> > > > > Manufacturer Info: 4554485a
> > > > >
> > > > > Also this quote is from Xen User's Guide:
> > > > >
> > > > > "Similarly, the TPM frontend driver must be compiled for the
kernel
> > > > > trying to use TPM functionality. Its driver can be selected
in the
> > > > > kernel configuration section Device Driver / Character
Devices / TPM
> > > > > Devices. Along with that the TPM driver for the built-in TPM
must be
> > > > > selected."
> > > > >
> > > > > According to my understanding driver for the built-in TPM
must be
> > > > > selected on the kernel where TPM frontend driver is used. Am I
> > correct
> > > > > about this assumption? (The problem is tpm_infineon driver can
> > not be
> > > >
> > > > The driver for the built-in Infineon TPM must be built into
Domain-0,
> > > > the TPM frontend driver in the guest domain and the backend driver
> > > > also into Domain-0. This has probably been done correctly since
> > > > otherwise the vTPM would not work at all.
> > > >
> > > >
> > > > > selected on an unpriviledged kernel, it can only be selected
on a
> > > > > priviledged kernel)
> > > > >
> > > > > Am I missing something here? Why do I get auth errors?
> > > >
> > > >
> > > > Did you try to run the same sequence of comands (tpm commands,
test
> > > > suite etc.) on a plain Linux kernel with the TSS stack against the
> > > > built-in Infineone TPM? From what I remember, the test suite
for the
> > > > TSS stack either tries to set a specific TPM owner password or it
> > must
> > > > previously have been set to it by the user, otherwise many
> > > > authentication errors will occur.
> > > >
> > > > Stefan
> > > >
> > > > >
> > > > > Thanks in advance.
> > > > >
> > > > > Erdem Bayer
> > > > > [attachment "vtpm_managerd.out" deleted by Stefan
Berger/Watson/IBM]
> > > > > [attachment "tcsd.out" deleted by Stefan Berger/Watson/IBM]
> > > > > _______________________________________________
> > > > > Xense-devel mailing list
> > > > > Xense-devel@xxxxxxxxxxxxxxxxxxx
> > > > > http://lists.xensource.com/xense-devel
> > >
> > > _______________________________________________
> > > Xense-devel mailing list
> > > Xense-devel@xxxxxxxxxxxxxxxxxxx
> > > http://lists.xensource.com/xense-devel
>
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