Move nvram_read functions to the XTT library

[kathrynfejer]

This will move the nvram.[h,c] code from xaptum-tpm into xtt, and remove read_nvram from the tool's client in favor of xtt_read_object. This will allow us to read out data of variable length from the TPM.

It also creates 'read_in_from_TPMandread_in_from_files` which read in DAA specific information (TPM or software defined), in an attempt to separate the two different ways to run DAA a bit more.

Fixes #78

[zanebeckwith]

Few minor requests, but otherwise looking good!

One bigger request: could we add an nvram command to the tool? So that we can use the xtt tool to dump things from the TPMs nvram? So we could do something like:

xtt nvram -t gpk -o gpk.bin

to get the gpk into the file gpk.bin.

The xaptum-tpm project already has this code, in the util directory. Again, we can just move this over.

[zanebeckwith]

I just force-pushed, to rebase onto the new master (after my changes to remove server ID, which collided a little with some of your changes to the TPM handles).

Could you refactor the TCTI/SAPI stuff from tool/client.c into its own file, and use that in tool/nvraam.c (I know I said don't worry about it in person, but I take that back!). Also, can tool/nvram.c use util/file_io rather than defining its own file writing?

[zanebeckwith]

I made a couple more requests, things I hadn't noticed earlier.

I've now tested this with the new xaptum-tpm release and with our current issuing architecture, and it looks good!

[kathrynfejer]

One other thing, I noticed that we still have all the client and server data, but may not need anything but the gid.bin and daa_secretkey.bin anymore. I don't know if anyone depends on the other files being there, or won't want to use the tool to generate them each time. At the least, we can probably remove the server_id.bin from both client and server.

[zanebeckwith]

In the example data, we need everything except server id, right? (That was an oversight on my part; you're right, that server id file should be remove)

Until we mainstream the ecdaa tool, all the DAA-specific stuff will still have to be there, right?

[kathrynfejer]

Oops, sorry, yes we will need that. We can now read in the DAA specific data, but only if we are using a TPM.

[zanebeckwith]

Ah, I see! Yea, using a TPM, the DAA stuff required is minimal. But, yea, to support software-DAA, we still example DAA files.

Is this ready to go?

[kathrynfejer]

Yep! Should be good to go!

[zanebeckwith]

Looks great! Thanks!