Re: [tpm2] tpm2_nvwrite failing

* Re: [tpm2] tpm2_nvwrite failing
@ 2018-03-15 22:03 Roberts, William C
  0 siblings, 0 replies; 2+ messages in thread
From: Roberts, William C @ 2018-03-15 22:03 UTC (permalink / raw)
  To: tpm2

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You're using the owner hierarchy for authorization, where
as you want to use the nv index for authorization.
So when you write and read, your -a needs to match your -x value.

This worked for me:
#!/bin/sh

echo "my nv daat" > /tmp/idfile

NVRAM=0x1800005
HIERACHY=0x40000001
PCRS=sha256:0,1,2,3
PCRVALUE=/tmp/pcrvalue
POLICY=/tmp/policy

echo "Releasing NVRAM - this might fail, but this is OK"
tpm2_nvrelease -x $NVRAM -a $HIERACHY

echo "Constructing policy"
tpm2_pcrlist -Q -L $PCRS -o $PCRVALUE
tpm2_createpolicy -P -L $PCRS -F $PCRVALUE -f $POLICY

echo "Defining area"
tpm2_nvdefine -x $NVRAM -a $HIERACHY -s 64  -L $POLICY -t "policywrite|policyread"
#tpm2_nvdefine -x $NVRAM -a $HIERACHY -s 64 -t "policyread|policywrite"

echo "Writing ID"
cat /tmp/idfile | tpm2_nvwrite -x $NVRAM -a $NVRAM -L $PCRS -F $PCRVALUE
#cat /tmp/idfile | tpm2_nvwrite -x $NVRAM -a $HIERACHY

echo "Reading ID - first attempt should fail if the policy works"
tpm2_nvread -x $NVRAM -a $NVRAM

echo "Reading ID - second attempt should work"
tpm2_nvread -x $NVRAM -a $NVRAM -L $PCRS -F $PCRVALUE

--- EOF ----

As far as nv.sh failures, I don't see them on the simulator. So I would need more information
to understand what the issue you might be.

From: tpm2 [mailto:tpm2-bounces(a)lists.01.org] On Behalf Of Ian Oliver
Sent: Tuesday, March 13, 2018 6:06 AM
To: tpm2(a)lists.01.org
Subject: [tpm2] tpm2_nvwrite failing

Hi

Using 1.3-rc2 of tpm2_tools
We're seeing tpm2_nvwrite fail with policies, both in the nv.sh test file and when run manually
Here's the script which basically follows nv.sh.  NB: the file /tmp/idfile exists and contains data!

#!/bin/sh

NVRAM=0x1800005
HIERACHY=0x40000001
PCRS=sha256:0,1,2,3
PCRVALUE=/tmp/pcrvalue
POLICY=/tmp/policy

echo "Releasing NVRAM - this might fail, but this is OK"
tpm2_nvrelease -x $NVRAM -a $HIERACHY

echo "Constructing policy"
tpm2_pcrlist -Q -L $PCRS -o $PCRVALUE
tpm2_createpolicy -P -L $PCRS -F $PCRVALUE -f $POLICY

echo "Defining area"
tpm2_nvdefine -x $NVRAM -a $HIERACHY -s 64  -L $POLICY -t "policyread|policywrite"
#tpm2_nvdefine -x $NVRAM -a $HIERACHY -s 64 -t "policyread|policywrite"

echo "Writing ID"
cat /tmp/idfile | tpm2_nvwrite -x $NVRAM -a $HIERACHY -L $PCRS -F $PCRVALUE
#cat /tmp/idfile | tpm2_nvwrite -x $NVRAM -a $HIERACHY

echo "Reading ID - first attempt should fail if the policy works"
tpm2_nvread -x $NVRAM -a $HIERACHY
tpm2_nvread -x $NVRAM -a $HIERACHY -L $PCRS -F $PCRVALUE

Specifically:

15$tpm2_nvrelease -x 0x1800005 -a 0x40000001
16$tpm2_pcrlist -Q -L sha256:0,1,2,3 -o /tmp/pcrvalue
17$tpm2_createpolicy -P -L sha256:0,1,2,3 -F /tmp/pcrvalue -f /tmp/policy
18$tpm2_nvdefine -x 0x1800005 -a 0x40000001 -s 64 -L /tmp/policy -t "policyread|policywrite"
19$tpm2_nvlist

0x1800005:
  hash algorithm:
    friendly: sha256
    value: 0xB
  attributes:
    friendly: policywrite|policyread
    value: 0x8000800
  size: 64
  authorization policy: 60DF98CF0931EE42B5372DBC49E7B1966559A62A159B12C90556240D37E2D938

20$echo -n "test" | tpm2_nvwrite -x 0x1800005 -a 0x40000001 -L sha256:0,1,2,3 -F /tmp/pcrvalue
ERROR: Failed to write NV area at index 0x1800005 (25165829) offset 0x0. Error:0x12f
21$cat /tmp/idfile | tpm2_nvwrite -x 0x1800005 -a 0x40000001 -L sha256:0,1,2,3 -F /tmp/pcrvalue
ERROR: Failed to write NV area at index 0x1800005 (25165829) offset 0x0. Error:0x12f
22$tpm2_rc_decode 0x12f
error layer
  hex: 0x0
  identifier: TSS2_TPM_ERROR_LEVEL
  description: Error produced by the TPM
format 0 error code
  hex: 0x2f
  name: TPM_RC_AUTH_UNAVAILABLE
  description: authValue or authPolicy is not available for selected entity.
t.
Ian

-- 
Dr. Ian Oliver
===============================
Privacy Engineering:  via Amazon
Twitter: @i_j_oliver

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