TSS.MSR / TSS.NET - How can I list persistent handles on a TPM2 device via C#?

Question

If I am on Linux, with the tpm2-tools installed, I can run a tpm2_getcap handles-persistent command and get a list of persistent handles, like:

• 0x81000001
• 0x81010001

I want to do the same thing on Windows with an enabled TPM2. Ideally, I'd like to do this programmatically in C#, likely using TSS.NET (I guess). However, I can't find a decent sample that gives this information (at least in a way I can understand it). I tried the GetCapabilities sample, but that doesn't cover Cap.Handles.

Anyone have a suggestion on how I might do this, or another way to approach the issue?

Answer 1

Ah, found something in a subsequent search that sorted out my issue:

ICapabilitiesUnion caps;
tpm.GetCapability(Cap.Handles, 0x81000000, 32, out caps);
var handles = (HandleArray)caps;
var tpmHandles = handles.handle;

Console.WriteLine($"Found the following handles:");
int index = 0;
foreach (var handle in tpmHandles)
{
    var handleValue = handle.handle.ToString("X");
    var handleType = handle.GetType().ToString();
    Console.WriteLine($"{index++}: {handleValue} type:{handleType}");
}

That creates the following output, which is what I was looking for:

Checking for TPM2 Persistent Handles
Found the following handles:
0: 81000001 type:Persistent
1: 81000002 type:Persistent
2: 81000009 type:Persistent
3: 81010001 type:Persistent
4: 81800001 type:Persistent
5: 81800002 type:Persistent

Answer 2

Ah, found something in a subsequent search that sorted out my issue:

ICapabilitiesUnion caps;
tpm.GetCapability(Cap.Handles, 0x81000000, 32, out caps);
var handles = (HandleArray)caps;
var tpmHandles = handles.handle;
Console.WriteLine($"Found the following handles:");
int index = 0;
foreach (var handle in tpmHandles)
{
    var handleValue = handle.handle.ToString("X");
    var handleType = handle.GetType().ToString();
    Console.WriteLine($"{index++}: {handleValue} type:{handleType}");
}

That creates the following output, which is what I was looking for:

Checking for TPM2 Persistent Handles

Found the following handles:

0: 81000001 type:Persistent

1: 81000002 type:Persistent

2: 81000009 type:Persistent

3: 81010001 type:Persistent

4: 81800001 type:Persistent

5: 81800002 type:Persistent