trustedjava-support

[Trustedjava-support] Correct behaviour of TcTpm.quote() with respect to used PCR values

[Artem D. <ar...@cc...>]

I seem to be stuck at a conflict between the TrustedJava documentation
and the implementation.

Is the quote method of TcTpm supposed to update the pcrComposite
parameter with the actual PCR values?

According to documentation on:
http://trustedjava.sourceforge.net/jtss/javadoc_all/iaik/tc/tss/api/tspi/TcITpm.html

the updating is the correct behaviour, as stated by:

"The required information about which PCRs should be quoted must be
set in the PcrComposite object before calling this method. On return
each element of the collection has its pcrValue set."

However, in the code for TcTpm.java in jTSS 0.2, the actual PCR values
used for hashing are never placed in the PcrComposite object nor
returned to the caller in any way.

Is the correct behaviour of the quote operation to set the values in
the pcrComposite parameter, or to not set the values?

Artem

Re: [Trustedjava-support] Correct behaviour of TcTpm.quote() with respect to used PCR values

[<ron...@ia...>]

Hello Artem,

Artem Dinaburg wrote:
 > I seem to be stuck at a conflict between the TrustedJava documentation
 > and the implementation.

 > Is the correct behaviour of the quote operation to set the values in
 > the pcrComposite parameter, or to not set the values?

Thank you for pointing out this problem with the documentation.

The correct behavior in accordance the 1.2 Errata A specs is the following:

The pcrComposite object is only used as input parameter. Thus no actual 
PCR values will be set in it or returned with it.
If you need to know the single PCR values, you have to extract them with 
  getPcrValue() of class TcPcrCompositeBase.

The current software implementation is in line with the specification, 
so I will update the documentation with the next release.

Regards, Ronald

-- 
IAIK, TU Graz