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      1 //
      2 // Copyright (C) 2015 The Android Open Source Project
      3 //
      4 // Licensed under the Apache License, Version 2.0 (the "License");
      5 // you may not use this file except in compliance with the License.
      6 // You may obtain a copy of the License at
      7 //
      8 //      http://www.apache.org/licenses/LICENSE-2.0
      9 //
     10 // Unless required by applicable law or agreed to in writing, software
     11 // distributed under the License is distributed on an "AS IS" BASIS,
     12 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13 // See the License for the specific language governing permissions and
     14 // limitations under the License.
     15 //
     16 
     17 #ifndef TRUNKS_POLICY_SESSION_H_
     18 #define TRUNKS_POLICY_SESSION_H_
     19 
     20 #include <string>
     21 #include <vector>
     22 
     23 #include <base/macros.h>
     24 
     25 #include "trunks/tpm_generated.h"
     26 
     27 namespace trunks {
     28 
     29 class AuthorizationDelegate;
     30 
     31 // PolicySession is an interface for managing policy backed sessions for
     32 // authorization and parameter encryption.
     33 class PolicySession {
     34  public:
     35   PolicySession() {}
     36   virtual ~PolicySession() {}
     37 
     38   // Returns an authorization delegate for this session. Ownership of the
     39   // delegate pointer is retained by the session.
     40   virtual AuthorizationDelegate* GetDelegate() = 0;
     41 
     42   // Starts a salted session which is bound to |bind_entity| with
     43   // |bind_authorization_value|. Encryption is enabled if |enable_encryption| is
     44   // true. The session remains active until this object is destroyed or another
     45   // session is started with a call to Start*Session.
     46   virtual TPM_RC StartBoundSession(TPMI_DH_ENTITY bind_entity,
     47                                    const std::string& bind_authorization_value,
     48                                    bool enable_encryption) = 0;
     49 
     50   // Starts a salted, unbound session. Encryption is enabled if
     51   // |enable_encryption| is true. The session remains active until this object
     52   // is destroyed or another session is started with a call to Start*Session.
     53   virtual TPM_RC StartUnboundSession(bool enable_encryption) = 0;
     54 
     55   // This method is used to get the current PolicyDigest of the PolicySession.
     56   virtual TPM_RC GetDigest(std::string* digest) = 0;
     57 
     58   // This method is used to construct a complex policy. It takes a list
     59   // of policy digests. After the command is executed, the policy represented
     60   // by this session is the OR of the provided policies.
     61   virtual TPM_RC PolicyOR(const std::vector<std::string>& digests) = 0;
     62 
     63   // This method binds the PolicySession to a provided PCR value. If the empty
     64   // string is provided, the PolicySession is bound to the current PCR value.
     65   virtual TPM_RC PolicyPCR(uint32_t pcr_index,
     66                            const std::string& pcr_value) = 0;
     67 
     68   // This method binds the PolicySession to a specified CommandCode.
     69   // Once called, this Session can only be used to authorize actions on the
     70   // provided CommandCode.
     71   virtual TPM_RC PolicyCommandCode(TPM_CC command_code) = 0;
     72 
     73   // This method specifies that Authorization Values need to be included in
     74   // HMAC computation done by the AuthorizationDelegate.
     75   virtual TPM_RC PolicyAuthValue() = 0;
     76 
     77   // Reset a policy session to its original state.
     78   virtual TPM_RC PolicyRestart() = 0;
     79 
     80   // Sets the current entity authorization value. This can be safely called
     81   // while the session is active and subsequent commands will use the value.
     82   virtual void SetEntityAuthorizationValue(const std::string& value) = 0;
     83 
     84  private:
     85   DISALLOW_COPY_AND_ASSIGN(PolicySession);
     86 };
     87 
     88 }  // namespace trunks
     89 
     90 #endif  // TRUNKS_POLICY_SESSION_H_
     91