upload android base code part6

android/system/tpm/trunks/hmac_session.h

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+//
+// Copyright (C) 2015 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef TRUNKS_HMAC_SESSION_H_
+#define TRUNKS_HMAC_SESSION_H_
+
+#include <string>
+
+#include <base/macros.h>
+
+#include "trunks/tpm_generated.h"
+
+namespace trunks {
+
+class AuthorizationDelegate;
+
+// HmacSession is an interface for managing hmac backed sessions for
+// authorization and parameter encryption.
+class HmacSession {
+ public:
+  HmacSession() {}
+  virtual ~HmacSession() {}
+
+  // Returns an authorization delegate for this session. Ownership of the
+  // delegate pointer is retained by the session.
+  virtual AuthorizationDelegate* GetDelegate() = 0;
+
+  // Starts a salted session which is bound to |bind_entity| with
+  // |bind_authorization_value|. Encryption is enabled if |enable_encryption| is
+  // true. The session remains active until this object is destroyed or another
+  // session is started with a call to Start*Session.
+  virtual TPM_RC StartBoundSession(TPMI_DH_ENTITY bind_entity,
+                                   const std::string& bind_authorization_value,
+                                   bool enable_encryption) = 0;
+
+  // Starts a salted, unbound session. Encryption is enabled if
+  // |enable_encryption| is true. The session remains active until this object
+  // is destroyed or another session is started with a call to Start*Session.
+  virtual TPM_RC StartUnboundSession(bool enable_encryption) = 0;
+
+  // Sets the current entity authorization value. This can be safely called
+  // while the session is active and subsequent commands will use the value.
+  virtual void SetEntityAuthorizationValue(const std::string& value) = 0;
+
+  // Sets the future_authorization_value field in the HmacDelegate. This
+  // is used in response validation for the TPM2_HierarchyChangeAuth command.
+  // We need to perform this because the HMAC value returned from
+  // HierarchyChangeAuth uses the new auth_value.
+  virtual void SetFutureAuthorizationValue(const std::string& value) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(HmacSession);
+};
+
+}  // namespace trunks
+
+#endif  // TRUNKS_HMAC_SESSION_H_