Initial version of tpm_init, a library for taking ownership of the TPM.

tpm.h

+// Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Tpm - class for handling init TPM initialization for Chrome OS
+
+#include <base/lock.h>
+#include <base/logging.h>
+#include <base/scoped_ptr.h>
+#include <chromeos/utility.h>
+#include <trousers/tss.h>
+#include <trousers/trousers.h>
+
+#include "crypto.h"
+#include "secure_blob.h"
+
+#ifndef TPM_INIT_TPM_H_
+#define TPM_INIT_TPM_H_
+
+namespace tpm_init {
+
+class Tpm {
+ public:
+
+  // Default constructor
+  Tpm();
+
+  virtual ~Tpm();
+
+  // Initializes the Tpm instance
+  //
+  // Parameters
+  virtual bool Init();
+
+  // Tries to connect to the TPM
+  virtual bool Connect();
+
+  // Returns true if this instance is connected to the TPM
+  virtual bool IsConnected();
+
+  // Disconnects from the TPM
+  virtual void Disconnect();
+
+  // Returns the number of simultaneously-loaded RSA keys that this TPM supports
+  int GetMaxRsaKeyCount();
+
+  // Returns the owner password if this instance was used to take ownership.
+  // This will only occur when the TPM is unowned, which will be on OOBE
+  //
+  // Parameters
+  //   owner_password (OUT) - The random owner password used
+  bool GetOwnerPassword(chromeos::Blob* owner_password);
+
+  // Returns whether or not the TPM is enabled.  This method call returns a
+  // cached result because querying the TPM directly will block if ownership is
+  // currently being taken (such as on a separate thread).
+  bool IsEnabled() const { return !is_disabled_; }
+
+  // Returns whether or not the TPM is owned.  This method call returns a cached
+  // result because querying the TPM directly will block if ownership is
+  // currently being taken (such as on a separate thread).
+  bool IsOwned() const { return is_owned_; }
+
+  // Runs the TPM initialization sequence.  This may take a long time due to the
+  // call to Tspi_TPM_TakeOwnership.
+  bool InitializeTpm();
+
+ private:
+  // Attempts to connect to tcsd
+  //
+  // Parameters
+  //   context_handle (OUT) - The context handle to the session on success
+  bool OpenAndConnectTpm(TSS_HCONTEXT* context_handle);
+
+  // Returns the maximum simultaneously-loaded RSA key count for the TPM
+  // specified by the context handle
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  int GetMaxRsaKeyCountForContext(TSS_HCONTEXT context_handle);
+
+  // Returns whether or not the TPM is disabled by checking a flag in the TPM's
+  // entry in /sys/class/misc
+  bool IsDisabledCheckViaSysfs();
+
+  // Returns whether or not the TPM is owned by checking a flag in the TPM's
+  // entry in /sys/class/misc
+  bool IsOwnedCheckViaSysfs();
+
+  // Returns whether or not the TPM is disabled using a call to
+  // Tspi_TPM_GetCapability
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  bool IsDisabledCheckViaContext(TSS_HCONTEXT context_handle);
+
+  // Returns whether or not the TPM is owned using a call to
+  // Tspi_TPM_GetCapability
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  bool IsOwnedCheckViaContext(TSS_HCONTEXT context_handle);
+
+  // Attempts to create the endorsement key in the TPM
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  bool CreateEndorsementKey(TSS_HCONTEXT context_handle);
+
+  // Checks to see if the endorsement key is available by attempting to get its
+  // public key
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  bool IsEndorsementKeyAvailable(TSS_HCONTEXT context_handle);
+
+  // Creates a random owner password
+  //
+  // Parameters
+  //   password (OUT) - the generated password
+  void CreateOwnerPassword(SecureBlob* password);
+
+  // Attempts to take ownership of the TPM
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  //   max_timeout_tries - The maximum number of attempts to make if the call
+  //                       times out, which it may occasionally do
+  bool TakeOwnership(TSS_HCONTEXT context_handle, int max_timeout_tries);
+
+  // Zeros the SRK password (sets it to an empty string)
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  //   owner_password - The owner password for the TPM
+  bool ZeroSrkPassword(TSS_HCONTEXT context_handle,
+                       const SecureBlob& owner_password);
+
+  // Removes usage restrictions on the SRK
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  //   owner_password - The owner password for the TPM
+  bool UnrestrictSrk(TSS_HCONTEXT context_handle,
+                     const SecureBlob& owner_password);
+
+  // Gets a handle to the TPM from the specified context
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  //   tpm_handle (OUT) - The handle for the TPM on success
+  bool GetTpm(TSS_HCONTEXT context_handle, TSS_HTPM* tpm_handle);
+
+  // Gets a handle to the TPM from the specified context with the given owner
+  // password
+  //
+  // Parameters
+  //   context_handle - The context handle for the TPM session
+  //   owner_password - The owner password to use when getting the handle
+  //   tpm_handle (OUT) - The handle for the TPM on success
+  bool GetTpmWithAuth(TSS_HCONTEXT context_handle,
+                      const SecureBlob& owner_password,
+                      TSS_HTPM* tpm_handle);
+
+  // The context handle for this TPM session
+  TSS_HCONTEXT context_handle_;
+
+  // The default Crypto instance to use (for generating the random owner
+  // password)
+  scoped_ptr<Crypto> default_crypto_;
+
+  // The actual Crypto instance to use
+  Crypto* crypto_;
+
+  // If TPM ownership is taken, owner_password_ contains the password used
+  SecureBlob owner_password_;
+
+  // Used to provide thread-safe access to owner_password_, as it is set in the
+  // initialization background thread.
+  Lock password_sync_lock_;
+
+  // Indicates if the TPM is disabled
+  bool is_disabled_;
+
+  // Indicates if the TPM is owned
+  bool is_owned_;
+
+  DISALLOW_COPY_AND_ASSIGN(Tpm);
+};
+
+}  // namespace tpm_init
+
+#endif  // TPM_INIT_TPM_H_