public PolicyAce AddNextAce(PolicyAce nextAce)
{
if (this is TpmPolicyOr)
{
Globs.Throw<ArgumentException>("AddNextAce: Do not call AddNextAce for an OR node: Use AddPolicyBranch instead.");
}
if (NextAce != null)
{
Globs.Throw<ArgumentException>("AddNextAce: Policy ACE already has a child");
}
if (!String.IsNullOrEmpty(BranchIdentifier))
{
if (String.IsNullOrEmpty(nextAce.BranchIdentifier))
{
nextAce.BranchIdentifier = BranchIdentifier;
}
else if (nextAce.BranchIdentifier != BranchIdentifier)
{
Globs.Throw<ArgumentException>("AddNextAce: Policy ACE with non-empty BranchName can only have a child with the same or no branch name");
}
BranchIdentifier = "";
}
NextAce = nextAce;
NextAce.PreviousAce = this;
return nextAce;
}
private PolicyAce GetNodeIdInternal(PolicyAce n, string nodeId)
{
if (n.NodeId == nodeId)
{
return(n);
}
// ReSharper disable once CanBeReplacedWithTryCastAndCheckForNull
if (n is TpmPolicyOr)
{
foreach (PolicyAce a in ((TpmPolicyOr)n).PolicyBranches)
{
PolicyAce ace = GetNodeIdInternal(a, nodeId);
if (ace != null)
{
return(ace);
}
}
}
if (n.NextAce != null)
{
return(GetNodeIdInternal(n.NextAce, nodeId));
}
return(null);
}
/// <summary>
/// Create a simple policy chain (no ORs).
/// </summary>
public void Create(PolicyAce[] singlePolicyChain)
{
// ReSharper disable once RedundantExplicitArraySize
var arr = new PolicyAce[1][] { singlePolicyChain };
CreateNormalizedPolicy(arr);
}
// Returns the linked list as an array
internal static PolicyAce[] GetArrayRepresentation(PolicyAce head)
{
int numElems = 0;
PolicyAce next = head;
do
{
if (next == null)
{
break;
}
next = next.NextAce;
numElems++;
} while (true);
var arr = new PolicyAce[numElems];
int count = 0;
next = head;
do
{
if (next == null)
{
break;
}
arr[count] = next;
next = next.NextAce;
count++;
} while (true);
return(arr);
}
/// <summary>
/// Load a policy from a stream (MemoryStream, FileStream) in the specified format
/// </summary>
/// <param name="format"></param>
/// <param name="sourceStream"></param>
public void Deserialize(PolicySerializationFormat format, Stream sourceStream)
{
TpmPolicy pol = null;
switch (format)
{
case PolicySerializationFormat.Xml:
{
var ser = new DataContractSerializer(typeof(TpmPolicy));
pol = (TpmPolicy)ser.ReadObject(sourceStream);
break;
}
case PolicySerializationFormat.Json:
{
var ser = new DataContractJsonSerializer(typeof(TpmPolicy));
pol = (TpmPolicy)ser.ReadObject(sourceStream);
break;
}
default:
Globs.Throw <ArgumentException>("PolicyTree.Deserialize: Unknown format " + format);
return;
}
pol.AssociatedPolicy = this;
PolicyRoot = pol.PolicyRoot;
}
internal static PolicyAce FromArrayRepresentation(PolicyAce[] arr, PolicyTree policy)
{
PolicyAce root = null;
PolicyAce current = null;
PolicyAce previous = null;
// Makes a doubly linked list from an array
foreach (PolicyAce a in arr)
{
// All ACEs have an associated policy tree
a.AssociatedPolicy = policy;
// we need a link to previous
if (previous != null)
{
a.PreviousAce = previous;
}
// previous needs a link to us
if (current != null)
{
current.NextAce = a;
}
current = a;
if (root == null)
{
root = current;
}
previous = a;
}
return(root);
}
public PolicyAce AddNextAce(PolicyAce nextAce)
{
if (this is TpmPolicyOr)
{
Globs.Throw <ArgumentException>("AddNextAce: Do not call AddNextAce for " +
"an OR node. Use AddPolicyBranch instead.");
}
if (NextAce != null)
{
Globs.Throw <ArgumentException>("AddNextAce: Policy ACE already has a child");
}
if (!String.IsNullOrEmpty(BranchID))
{
if (String.IsNullOrEmpty(nextAce.BranchID))
{
nextAce.BranchID = BranchID;
}
else if (nextAce.BranchID != BranchID)
{
Globs.Throw <ArgumentException>(
"AddNextAce: Policy ACE with non-empty BranchName " +
"can only have a child with the same or no branch name");
}
BranchID = "";
}
NextAce = nextAce;
NextAce.PreviousAce = this;
return(nextAce);
}
public PolicyTree InsertPolicyRoot(PolicyAce newRoot)
{
if (PolicyRoot != null)
newRoot.AddNextAce(PolicyRoot);
PolicyRoot = newRoot;
return this;
}
public PolicyTree InsertPolicyRoot(PolicyAce newRoot)
{
if (PolicyRoot != null)
{
newRoot.AddNextAce(PolicyRoot);
}
SetPolicyRoot(newRoot);
return(this);
}
public TpmHash GetPolicyDigest()
{
PolicyAce dummyAce = null;
if (null == PolicyRoot)
{
return(new TpmHash(PolicyHash.HashAlg));
}
// First, check that the tree is OK. An exception is thrown if checks fail.
CheckPolicy("", ref dummyAce);
return(PolicyRoot.GetPolicyDigest(PolicyHash.HashAlg));
}
/// <summary>
/// Returns the ticket associated with a prior policy execution (or null).
/// </summary>
/// <param name="nodeIdentifier"></param>
/// <returns></returns>
public TkAuth GetTicket(string nodeIdentifier)
{
MatchingNode = null;
PolicyAce matchingAce = GetNodeIdInternal(PolicyRoot, nodeIdentifier);
if (matchingAce == null)
{
return(null);
}
TkAuth tic = ((TpmPolicySigned)matchingAce).GetPolicyTicket();
return(tic);
}
/// <summary>
/// Run a path on the policy tree. The path is identified by the leaf identifier string. A session is
/// created and returned. If allowErrors is true then errors returned do not cause an exception (but
/// are returned in the response code).
/// </summary>
/// <param name="tpm"></param>
/// <param name="policySession"></param>
/// <param name="branchToEvaluate"></param>
/// <param name="allowErrors"></param>
/// <returns></returns>
public TpmRc RunPolicy(Tpm2 tpm, PolicyTree policyTree, string branchToEvaluate = null, bool allowErrors = false)
{
policyTree.AllowErrorsInPolicyEval = allowErrors;
PolicyAce leafAce = null;
// First, check that the policy is OK.
policyTree.CheckPolicy(branchToEvaluate, ref leafAce);
if (leafAce == null)
{
Globs.Throw("RunPolicy: Branch identifier " + branchToEvaluate + " does not exist");
}
var responseCode = TpmRc.Success;
try
{
if (allowErrors)
{
tpm._DisableExceptions();
}
tpm._InitializeSession(this);
// Walk up the tree from the leaf..
PolicyAce nextAce = leafAce;
while (nextAce != null)
{
responseCode = nextAce.Execute(tpm, this, policyTree);
if (responseCode != TpmRc.Success)
{
break;
}
// ..and continue along the path to the root
nextAce = nextAce.PreviousAce;
}
}
finally
{
if (allowErrors)
{
tpm._EnableExceptions();
}
}
return(responseCode);
}
/// <summary>
/// Sets the current policy tree to a policy branch represented by its leaf ACE.
/// A policy branch can be constructed by means of the following expressions:
/// new TpmAce1().And(new TpmAce2()).And(new TpmAce3());
/// or
/// new TpmAce1().AddNextAce(new TpmAce2()).AddNextAce(new TpmAce3());
/// </summary>
public void Set(PolicyAce leaf)
{
if (leaf == null)
{
PolicyRoot = null;
return;
}
// The construction policyTree.Set()
// evaluates to ace4. We have to go back to the root.
if (String.IsNullOrEmpty(leaf.BranchID))
{
leaf.BranchID = "leaf";
}
do
{
PolicyRoot = leaf;
leaf = leaf.PreviousAce;
} while (leaf != null);
}
protected PolicyAce[] ChainToArray(PolicyAce ace)
{
int count = 0;
PolicyAce curr = ace;
while (curr.NextAce != null)
{
count++;
curr = curr.NextAce;
}
PolicyAce[] arr = new PolicyAce[count];
curr = ace;
for (int i = 0; i < count; i++)
{
arr[i] = curr;
curr = curr.NextAce;
arr[i].PreviousAce = null;
arr[i].NextAce = null;
}
return(arr);
}
private PolicyAce FindNodeId(PolicyAce ace, string nodeId)
{
if (ace.NodeId == nodeId)
{
return(ace);
}
if (ace is TpmPolicyOr)
{
foreach (PolicyAce branchRoot in ((TpmPolicyOr)ace).PolicyBranches)
{
PolicyAce a = FindNodeId(branchRoot, nodeId);
if (a != null)
{
return(a);
}
}
}
return(ace.NextAce == null ? null : FindNodeId(ace.NextAce, nodeId));
}
public void AddPolicyBranches(PolicyAce[] arr)
{
PolicyBranches.Clear();
foreach (PolicyAce a in arr)
{
PolicyBranches.Add(a);
}
}
internal void CheckBranchIDs(PolicyAce ace, string branchIdToFind,
ref PolicyAce matchingAce)
{
if (ace == null)
{
return;
}
ace.AssociatedPolicy = this;
// ReSharper disable once CanBeReplacedWithTryCastAndCheckForNull
if (ace is TpmPolicyOr)
{
// Go down each branch of the OR
PolicyContainsOrs = true;
var orAce = (TpmPolicyOr)ace;
foreach (PolicyAce nextAce in orAce.PolicyBranches)
{
CheckBranchIDs(nextAce, branchIdToFind, ref matchingAce);
}
}
else
{
PolicyAce nextAce = ace.NextAce;
if (nextAce != null)
{
CheckBranchIDs(nextAce, branchIdToFind, ref matchingAce);
return;
}
// We are at the leaf. If there are no ORs in this chain then we are
// done. If there are ORs then check two things (1) that the leaf
// has a non-empty BranchIdentifier, and (2) that the branchIdentifiers
// are unique.
if (!PolicyContainsOrs)
{
matchingAce = ace;
if (String.IsNullOrEmpty(ace.BranchID))
{
ace.BranchID = "leaf";
}
return;
}
if (String.IsNullOrEmpty(ace.BranchID))
{
Globs.Throw("CheckPolicyIdInternal: Branch leaf does not have a BranchID");
}
if (BranchIdCollection.Contains(ace.BranchID))
{
Globs.Throw("CheckPolicyIdInternal: Replicated BranchID " + ace.BranchID);
}
BranchIdCollection.Add(ace.BranchID);
if (ace.BranchID == branchIdToFind)
{
matchingAce = ace;
}
}
}
internal void CheckPolicyIdInternal(PolicyAce ace, string branchIdToFind, ref PolicyAce matchingAce, string nodeIdToFind = "")
{
// we allow null sessions
if (ace == null)
{
return;
}
ace.AssociatedPolicy = this;
// ReSharper disable once CanBeReplacedWithTryCastAndCheckForNull
if (ace is TpmPolicyOr)
{
// Go down each branch of the OR
PolicyContainsOrs = true;
var orAce = (TpmPolicyOr)ace;
foreach (PolicyAce nextAce in orAce.PolicyBranches)
{
CheckPolicyIdInternal(nextAce, branchIdToFind, ref matchingAce, nodeIdToFind);
}
}
else
{
PolicyAce nextAce = ace.NextAce;
if (nextAce != null)
{
CheckPolicyIdInternal(nextAce, branchIdToFind, ref matchingAce, nodeIdToFind);
return;
}
// We are at the leaf. If there are no ORs in this chain then we are done. If there
// are ORs then check two things (1) that the leaf has a non-empty BranchIdentifier,
// and (2) that the branchIdentifiers are unique.
if (!PolicyContainsOrs)
{
matchingAce = ace;
if (String.IsNullOrEmpty(ace.BranchIdentifier))
{
ace.BranchIdentifier = "leaf";
}
return;
}
if (String.IsNullOrEmpty(ace.BranchIdentifier))
{
throw new Exception("Branch leaf does not have a BranchIdentifier");
}
if (BranchIdCollection.Contains(ace.BranchIdentifier))
{
throw new Exception("Replicated branch leaf" + ace.BranchIdentifier);
}
BranchIdCollection.Add(ace.BranchIdentifier);
if (ace.BranchIdentifier == branchIdToFind)
{
matchingAce = ace;
}
if (!String.IsNullOrEmpty(nodeIdToFind))
{
if (nodeIdToFind == ace.NodeId)
{
MatchingNode = ace;
matchingAce = ace;
}
}
}
}
/// <summary>
/// Load a policy from a stream (MemoryStream, FileStream) in the specified format
/// </summary>
/// <param name="policyIdentifier"></param>
/// <param name="fileName"></param>
public void Deserialize(PolicySerializationFormat format, Stream sourceStream)
{
TpmPolicy pol = null;
switch (format)
{
case PolicySerializationFormat.Xml:
{
var ser = new DataContractSerializer(typeof(TpmPolicy));
pol = (TpmPolicy)ser.ReadObject(sourceStream);
break;
}
case PolicySerializationFormat.Json:
{
var ser = new DataContractJsonSerializer(typeof(TpmPolicy));
pol = (TpmPolicy)ser.ReadObject(sourceStream);
break;
}
default:
Globs.Throw<ArgumentException>("PolicyTree.Deserialize: Unknown format " + format);
return;
}
pol.AssociatedPolicy = this;
PolicyRoot = pol.PolicyRoot;
}
protected PolicyAce ArrayToChain(PolicyAce[] arr)
{
for (int j = 0; j < arr.Length - 1; j++)
{
arr[j].NextAce = arr[j + 1];
arr[j + 1].PreviousAce = arr[j];
}
return arr[0];
}
/// <summary>
/// A "normalized" policy is one transformed into disjunctive normal form,
/// in which a collection of policy "AND chains" is combined with PolicyOR
/// before submission to the TPM.
/// Callers must provide an-array-of-arrays of TpmPolicyACEs. The arrays may NOT
/// contain PolicyOr (these will be added automatically), but each array MUST be
/// terminated with a unique string identifier encoded in a TpmPolicyChainId.
/// </summary>
/// <param name="policy"></param>
public void CreateNormalizedPolicy(PolicyAce[][] policy)
{
// To validate that the input does not have any repeated branchIds or ACEs
var branchIdDict = new Dictionary <string, string>();
var aces = new HashSet <object>();
int numBranches = 0;
bool unnamedBranches = false;
// The following code validates and transforms the array-of-arrays into a linked
// list + OR nodes tree. First collect lists of chains in the chains collection.
var chains = new List <PolicyAce>();
foreach (PolicyAce[] chain in policy)
{
numBranches++;
PolicyAce leaf = null;
PolicyAce previousAce = null;
PolicyAce root = null;
// Turn the array into a doubly-linked list
foreach (PolicyAce ace in chain)
{
// Repeats are illegal
if (aces.Contains(ace))
{
Globs.Throw <ArgumentException>("CreateNormalizedPolicy: " +
"Repeated ACE in policy");
}
// Already associated with a session is illegal
if (ace.AssociatedPolicy != null)
{
Globs.Throw <ArgumentException>("CreateNormalizedPolicy: " +
"ACE is already associated with a policy");
}
ace.AssociatedPolicy = this;
aces.Add(ace);
// OR is illegal in normal form (these are added automatically
// at the root to union the arrays that are input to this function).
if (ace is TpmPolicyOr)
{
Globs.Throw <ArgumentException>("CreateNormalizedPolicy: " +
"Normalized form cannot contain TpmPolicyOr");
}
if (previousAce != null)
{
previousAce.NextAce = ace;
}
ace.PreviousAce = previousAce;
previousAce = ace;
// Is the branchId valid?
string branchId = ace.BranchID;
if (!String.IsNullOrEmpty(branchId))
{
if (branchIdDict.ContainsKey(branchId))
{
Globs.Throw <ArgumentException>("CreateNormalizedPolicy: " +
"Repeated branch-identifier " + branchId);
}
branchIdDict.Add(branchId, "");
}
if (root == null)
{
root = ace;
}
leaf = ace;
}
// Does the leaf have a branch ID?
if (leaf != null && String.IsNullOrEmpty(leaf.BranchID))
{
unnamedBranches = true;
}
// Else we have a good chain starting at root
chains.Add(root);
}
if (unnamedBranches && numBranches != 1)
{
throw new ArgumentException("Policy-chain leaf does not have a branch identifier");
}
// We now have a list of chains in chains.
int numChains = chains.Count;
// A single chain (no ORs)
if (numChains == 1)
{
PolicyRoot = chains[0];
return;
}
// Each TPM_or can take up to 8 inputs. We will add OR-aces to the root
// to capture all chains. The algorithm is that we create an OR and keep
// adding chains in the input order until full (if it is the last chain)
// or one-less than full. Then create a new OR, attach it to the last OR
// and keep filling as before.
var theRoot = new TpmPolicyOr();
TpmPolicyOr currentOrAce = theRoot;
for (int j = 0; j < numChains; j++)
{
bool lastChain = (j == numChains - 1);
if ((currentOrAce.PolicyBranches.Count < 7) || lastChain)
{
currentOrAce.AddPolicyBranch(chains[j]);
}
else
{
// We have overflowed the TpmPolicyOr so add a new child-OR
// attached to the previous as the final (8th) branch.
var nextOr = new TpmPolicyOr();
currentOrAce.AddPolicyBranch(nextOr);
currentOrAce = nextOr;
currentOrAce.AddPolicyBranch(chains[j]);
}
}
// All input chains are connected up to one or more ORs at the root so we are done.
PolicyRoot = theRoot;
}
/// <summary>
/// Check to see if all branches have an ID and that the IDs are unique.
/// </summary>
/// <param name="branchIdToFind"></param>
/// <param name="matchingAce"></param>
internal void CheckPolicy(string branchIdToFind, ref PolicyAce matchingAce)
{
PolicyContainsOrs = false;
BranchIdCollection = new HashSet<string>();
CheckPolicyIdInternal(PolicyRoot, branchIdToFind, ref matchingAce);
}
// [Obsolete]
public PolicyAce SetPolicyRoot(PolicyAce root)
{
PolicyRoot = root;
return(PolicyRoot);
}
internal void CheckPolicyIdInternal(PolicyAce ace, string branchIdToFind, ref PolicyAce matchingAce, string nodeIdToFind = "")
{
// we allow null sessions
if (ace == null)
return;
ace.AssociatedPolicy = this;
// ReSharper disable once CanBeReplacedWithTryCastAndCheckForNull
if (ace is TpmPolicyOr)
{
// Go down each branch of the OR
PolicyContainsOrs = true;
var orAce = (TpmPolicyOr)ace;
foreach (PolicyAce nextAce in orAce.PolicyBranches)
{
CheckPolicyIdInternal(nextAce, branchIdToFind, ref matchingAce, nodeIdToFind);
}
}
else
{
PolicyAce nextAce = ace.NextAce;
if (nextAce != null)
{
CheckPolicyIdInternal(nextAce, branchIdToFind, ref matchingAce, nodeIdToFind);
return;
}
// We are at the leaf. If there are no ORs in this chain then we are done. If there
// are ORs then check two things (1) that the leaf has a non-empty BranchIdentifier,
// and (2) that the branchIdentifiers are unique.
if (!PolicyContainsOrs)
{
matchingAce = ace;
if (String.IsNullOrEmpty(ace.BranchIdentifier))
{
ace.BranchIdentifier = "leaf";
}
return;
}
if (String.IsNullOrEmpty(ace.BranchIdentifier))
{
Globs.Throw("CheckPolicyIdInternal: Branch leaf does not have a BranchIdentifier");
}
if (BranchIdCollection.Contains(ace.BranchIdentifier))
{
Globs.Throw("CheckPolicyIdInternal: Replicated branch leaf" + ace.BranchIdentifier);
}
BranchIdCollection.Add(ace.BranchIdentifier);
if (ace.BranchIdentifier == branchIdToFind)
{
matchingAce = ace;
}
if (!String.IsNullOrEmpty(nodeIdToFind))
{
if (nodeIdToFind == ace.NodeId)
{
MatchingNode = ace;
matchingAce = ace;
}
}
}
}
/// <summary>
/// This sample illustrates the use of a TpmPolicyOr.
/// </summary>
static void PolicyOr(Tpm2 tpm)
{
Console.WriteLine("PolicyOr sample:");
//
// Check if policy commands are implemented by TPM. This list
// could include all the other used commands as well.
// This check here makes sense for policy commands, because
// usually a policy has to be executed in full. If a command
// out of the chain of policy commands is not implemented in the
// TPM, the policy cannot be satisfied.
//
var usedCommands = new[] {
TpmCc.PolicyLocality,
TpmCc.PolicyPCR,
TpmCc.PolicyAuthValue
};
foreach (var commandCode in usedCommands)
{
if (!tpm.Helpers.IsImplemented(commandCode))
{
Console.WriteLine("Cancel Policy OR sample, because command {0} is not implemented by TPM.", commandCode);
return;
}
}
var pcrs = new uint[] { 1, 2, 3 };
var sel = new PcrSelection(TpmAlgId.Sha, pcrs);
PcrSelection[] selOut;
Tpm2bDigest[] pcrValues;
//
// First read the PCR values
//
tpm.PcrRead(new[] { sel }, out selOut, out pcrValues);
//
// Save the current PCR values in a convenient data structure
//
var expectedPcrVals = new PcrValueCollection(selOut, pcrValues);
//
// Tpm2Lib encapsulates a set of policy assertions as the PolicyTree class.
//
var policyTree = new PolicyTree(TpmAlgId.Sha256);
//
// First branch of PolicyOr
//
var branch1 = new PolicyAce[]
{
new TpmPolicyLocality(LocalityAttr.TpmLocZero),
new TpmPolicyPcr(expectedPcrVals),
"branch_1"
};
//
// Second branch of PolicyOr
//
var branch2 = new PolicyAce[]
{
new TpmPolicyAuthValue(),
"branch_2"
};
//
// Create the policy. CreateNormalizedPolicy takes an array-of-arrays
// of PolicyACEs that are to be OR'ed together (the branches themselves cannot
// contain TpmPOlicyOrs). The library code constructs a policy tree with
// minimum number of TpmPolicyOrs at the root.
//
policyTree.CreateNormalizedPolicy(new[] {branch1, branch2});
//
// Ask Tpm2Lib for the expected policy-hash for this policy
//
TpmHash expectedPolicyHash = policyTree.GetPolicyDigest();
//
// Create a sealed primary object with the policy-hash we just calculated
//
var dataToSeal = new byte[] { 1, 2, 3, 4, 5, 4, 3, 2, 1 };
var authVal = new byte[] { 1, 2 };
TpmHandle primHandle = CreateSealedPrimaryObject(tpm,
dataToSeal,
authVal,
expectedPolicyHash.HashData);
//
// Create an actual TPM policy session to evaluate the policy
//
AuthSession session = tpm.StartAuthSessionEx(TpmSe.Policy, TpmAlgId.Sha256);
//
// Run the policy on the TPM
//
session.RunPolicy(tpm, policyTree, "branch_1");
//
// And unseal the object
//
byte[] unsealedData = tpm[session].Unseal(primHandle);
Console.WriteLine("Unsealed data for branch_1: " + BitConverter.ToString(unsealedData));
//
// Now run the other branch
//
tpm.PolicyRestart(session.Handle);
session.RunPolicy(tpm, policyTree, "branch_2");
//
// And the session will be unusable
//
unsealedData = tpm[session].Unseal(primHandle);
Console.WriteLine("Unsealed data for branch_2: " + BitConverter.ToString(unsealedData));
//
// Clean up
//
tpm.FlushContext(session.Handle);
tpm.FlushContext(primHandle);
}
/// <summary>
/// A "normalized" policy is one transformed into disjunctive normal form in which a collection
/// of policy "AND chains" is combined with PolicyOR before submission to the TPM.
/// Callers must provide an-array-of-arrays of TpmPolicyACEs. The arrays may NOT
/// contain PolicyOr (these will be added automatically), but each array MUST be terminated
/// with a unique string identifier encoded in a TpmPolicyChainId.
/// </summary>
/// <param name="policy"></param>
public void CreateNormalizedPolicy(PolicyAce[][] policy)
{
// To validate that the input does not have any repeated branchIds or ACEs
var branchIdDict = new Dictionary<string, string>();
var aces = new HashSet<object>();
int numBranches = 0;
bool unnamedBranches = false;
// The following code validates and transforms the array-of-arrays into a linked
// list + OR nodes tree. First collect lists of chains in the chains collection.
var chains = new List<PolicyAce>();
foreach (PolicyAce[] chain in policy)
{
numBranches++;
PolicyAce leaf = null;
PolicyAce previousAce = null;
PolicyAce root = null;
// Turn the array into a doubly-linked list
foreach (PolicyAce ace in chain)
{
// Repeats are illegal
if (aces.Contains(ace))
{
Globs.Throw<ArgumentException>("CreateNormalizedPolicy: Repeated ACE in policy");
}
// Already associated with a session is illegal
if (ace.AssociatedPolicy != null)
{
Globs.Throw<ArgumentException>("CreateNormalizedPolicy: ACE is already associated with a policy");
}
ace.AssociatedPolicy = this;
aces.Add(ace);
// OR is illegal in normal form (these are added automatically
// at the root to union the arrays that are input to this function).
if (ace is TpmPolicyOr)
{
Globs.Throw<ArgumentException>("CreateNormalizedPolicy: Normalized form cannot contain TpmPolicyOr");
}
if (previousAce != null)
{
previousAce.NextAce = ace;
}
ace.PreviousAce = previousAce;
previousAce = ace;
// Is the branchId valid?
string branchId = ace.BranchIdentifier;
if (!String.IsNullOrEmpty(branchId))
{
if (branchIdDict.ContainsKey(branchId))
{
Globs.Throw<ArgumentException>("CreateNormalizedPolicy: Repeated branch-identifier " + branchId);
}
branchIdDict.Add(branchId, "");
}
if (root == null)
{
root = ace;
}
leaf = ace;
}
// Does the leaf have a branch ID?
if (leaf != null && String.IsNullOrEmpty(leaf.BranchIdentifier))
{
unnamedBranches = true;
}
// Else we have a good chain starting at root
chains.Add(root);
}
if (unnamedBranches && numBranches != 1)
{
throw new ArgumentException("Policy-chain leaf does not have a branch identifier");
}
// We now have a list of chains in chains.
int numChains = chains.Count;
// A single chain (no ORs)
if (numChains == 1)
{
PolicyRoot = chains[0];
return;
}
// Each TPM_or can take up to 8 inputs. We will add OR-aces to the root to capture all
// chains. The algorithm is that we create an OR and keep adding chains in the input order
// until full (if it is the last chain) or one-less than full. Then create a new OR, attach it
// to the last OR and keep filling as before.
var theRoot = new TpmPolicyOr();
TpmPolicyOr currentOrAce = theRoot;
for (int j = 0; j < numChains; j++)
{
bool lastChain = (j == numChains - 1);
if ((currentOrAce.PolicyBranches.Count < 7) || lastChain)
{
currentOrAce.AddPolicyBranch(chains[j]);
}
else
{
// We have overflowed the TpmPolicyOr so add a new child-OR
// attached to the previous as the final (8th) branch.
var nextOr = new TpmPolicyOr();
currentOrAce.AddPolicyBranch(nextOr);
currentOrAce = nextOr;
currentOrAce.AddPolicyBranch(chains[j]);
}
}
// All input chains are connected up to one or more ORs at the root so we are done.
PolicyRoot = theRoot;
}
internal static PolicyAce FromArrayRepresentation(PolicyAce[] arr, PolicyTree policy)
{
PolicyAce root = null;
PolicyAce current = null;
PolicyAce previous = null;
// Makes a doubly linked list from an array
foreach (PolicyAce a in arr)
{
// All ACEs have an associated policy tree
a.AssociatedPolicy = policy;
// we need a link to previous
if (previous != null)
{
a.PreviousAce = previous;
}
// previous needs a link to us
if (current != null)
{
current.NextAce = a;
}
current = a;
if (root == null)
{
root = current;
}
previous = a;
}
return root;
}
// Returns the linked list as an array
internal static PolicyAce[] GetArrayRepresentation(PolicyAce head)
{
int numElems = 0;
PolicyAce next = head;
do
{
if (next == null)
{
break;
}
next = next.NextAce;
numElems++;
} while (true);
var arr = new PolicyAce[numElems];
int count = 0;
next = head;
do
{
if (next == null)
{
break;
}
arr[count] = next;
next = next.NextAce;
count++;
} while (true);
return arr;
}
// [Obsolete]
public PolicyAce SetPolicyRoot(PolicyAce root)
{
PolicyRoot = root;
_Digest = null;
return(PolicyRoot);
}
/// <summary>
/// Sets the current policy tree to a policy branch represented by its leaf ACE.
/// A policy branch can be constructed by means of the following expressions:
/// new TpmAce1().And(new TpmAce2()).And(new TpmAce3());
/// or
/// new TpmAce1().AddNextAce(new TpmAce2()).AddNextAce(new TpmAce3());
/// </summary>
public void Set (PolicyAce leaf)
{
if (leaf == null)
{
PolicyRoot = null;
return;
}
// The construction policyTree.Set()
// evaluates to ace4. We have to go back to the root.
if (String.IsNullOrEmpty(leaf.BranchIdentifier))
{
leaf.BranchIdentifier = "leaf";
}
do
{
PolicyRoot = leaf;
leaf = leaf.PreviousAce;
} while (leaf != null);
}
/// <summary>
/// Add an "OR-branch"
/// </summary>
/// <param name="newAce"></param>
/// <returns></returns>
public PolicyAce AddPolicyBranch(PolicyAce newAce)
{
PolicyBranches.Add(newAce);
newAce.PreviousAce = this;
return newAce;
}
/// <summary>
/// Create a simple policy chain (no ORs).
/// </summary>
public void Create(PolicyAce[] singlePolicyChain)
{
// ReSharper disable once RedundantExplicitArraySize
var arr = new PolicyAce[1][] {singlePolicyChain};
CreateNormalizedPolicy(arr);
}
public PolicyAce SetPolicyRoot(PolicyAce newRoot)
{
PolicyRoot = newRoot;
return(PolicyRoot);
}
public PolicyAce And(PolicyAce nextAce)
{
return AddNextAce(nextAce);
}
/// <summary>
/// Add an "OR-branch"
/// </summary>
/// <param name="newAce"></param>
/// <returns></returns>
public PolicyAce AddPolicyBranch(PolicyAce newAce)
{
PolicyBranches.Add(newAce);
newAce.PreviousAce = this;
return(newAce);
}
/// <summary>
/// Check to see if all branches have an ID and that the IDs are unique.
/// </summary>
/// <param name="branchIdToFind"></param>
/// <param name="matchingAce"></param>
internal void CheckPolicy(string branchIdToFind, ref PolicyAce matchingAce)
{
PolicyContainsOrs = false;
BranchIdCollection = new HashSet <string>();
CheckBranchIDs(PolicyRoot, branchIdToFind, ref matchingAce);
}
public PolicyAce And(PolicyAce nextAce)
{
return(AddNextAce(nextAce));
}
// [Obsolete]
public PolicyAce SetPolicyRoot(PolicyAce root)
{
PolicyRoot = root;
return PolicyRoot;
}