/// <summary>
/// This TBS returns a random handle value in the desired handle range (ugh).
/// </summary>
/// <param name="owner"></param>
/// <param name="tpmHandle"></param>
/// <returns></returns>
private uint GetFreeHandle(Tbs.TbsContext owner, TpmHandle tpmHandle)
{
Tbs.SlotType neededType = Tbs.SlotTypeFromHandle(tpmHandle);
if (neededType == Tbs.SlotType.NoSlot)
{
return(tpmHandle.handle);
}
int numTries = 0;
while (true)
{
Ht handleType = tpmHandle.GetType();
var randomPos = (uint)Globs.GetRandomInt((int)TpmHandle.GetRangeLength(tpmHandle.GetType()));
uint candidateHandle = ((uint)handleType << 24) + randomPos;
if (!OwnerHandleInUse(owner, candidateHandle))
{
return(candidateHandle);
}
numTries++;
if (numTries >= 1000)
{
break;
}
}
throw new Exception("Too many TBS contexts");
}
internal ObjectContext GetContext(Tbs.TbsContext caller, TpmHandle callerHandle)
{
if (Tbs.SlotTypeFromHandle(callerHandle) == Tbs.SlotType.NoSlot)
{
// Indicates that this is a TPM resident object (NV-slot, primary-handle, PWAP-handle, etc.)
var temp = new ObjectContext {
TheTpmHandle = callerHandle
};
return(temp);
}
ObjectContext x = ObjectContexts.Find(item => (item.Owner == caller) && item.OwnerHandle.handle == callerHandle.handle);
// Note that x may be null
return(x);
}
internal ObjectContext CreateObjectContext(Tbs.TbsContext owner, TpmHandle tpmHandle)
{
Tbs.SlotType newSlotType = Tbs.SlotTypeFromHandle(tpmHandle);
if (newSlotType == Tbs.SlotType.NoSlot)
{
throw new Exception("should not be here");
}
// Make a new slot context of the requisite type
uint tbsHandle = GetFreeHandle(owner, tpmHandle);
var newContext = new ObjectContext {
OwnerHandle = new TpmHandle(tbsHandle),
TheTpmHandle = tpmHandle,
TheSlotType = newSlotType,
LastUseCount = GetUseCount(),
Loaded = true,
Owner = owner
};
ObjectContexts.Add(newContext);
return(newContext);
}
/// <summary>
/// Remove all contexts associated with a client (to support client disconnect).
/// </summary>
/// <param name="owner"></param>
public void RemoveAll(Tbs.TbsContext owner)
{
ObjectContexts.RemoveAll(item => item.Owner == owner);
}
private bool OwnerHandleInUse(Tbs.TbsContext owner, uint ownerHandle)
{
return(ObjectContexts.Find(item => (item.Owner == owner && item.OwnerHandle.handle == ownerHandle)) != null);
}