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      1 /*
      2  * Copyright (C) 2016 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 KEYSTORE_USER_STATE_H_
     18 #define KEYSTORE_USER_STATE_H_
     19 
     20 #include <sys/types.h>
     21 
     22 #include <openssl/aes.h>
     23 
     24 #include <utils/String8.h>
     25 
     26 #include <keystore/keystore.h>
     27 
     28 #include "entropy.h"
     29 
     30 class UserState {
     31   public:
     32     explicit UserState(uid_t userId);
     33     ~UserState();
     34 
     35     bool initialize();
     36 
     37     uid_t getUserId() const { return mUserId; }
     38     const char* getUserDirName() const { return mUserDir; }
     39 
     40     const char* getMasterKeyFileName() const { return mMasterKeyFile; }
     41 
     42     void setState(State state);
     43     State getState() const { return mState; }
     44 
     45     int8_t getRetry() const { return mRetry; }
     46 
     47     void zeroizeMasterKeysInMemory();
     48     bool deleteMasterKey();
     49 
     50     ResponseCode initialize(const android::String8& pw, Entropy* entropy);
     51 
     52     ResponseCode copyMasterKey(UserState* src);
     53     ResponseCode copyMasterKeyFile(UserState* src);
     54     ResponseCode writeMasterKey(const android::String8& pw, Entropy* entropy);
     55     ResponseCode readMasterKey(const android::String8& pw, Entropy* entropy);
     56 
     57     AES_KEY* getEncryptionKey() { return &mMasterKeyEncryption; }
     58     AES_KEY* getDecryptionKey() { return &mMasterKeyDecryption; }
     59 
     60     bool reset();
     61 
     62   private:
     63     static const int MASTER_KEY_SIZE_BYTES = 16;
     64     static const int MASTER_KEY_SIZE_BITS = MASTER_KEY_SIZE_BYTES * 8;
     65 
     66     static const int MAX_RETRY = 4;
     67     static const size_t SALT_SIZE = 16;
     68 
     69     void generateKeyFromPassword(uint8_t* key, ssize_t keySize, const android::String8& pw,
     70                                  uint8_t* salt);
     71     bool generateSalt(Entropy* entropy);
     72     bool generateMasterKey(Entropy* entropy);
     73     void setupMasterKeys();
     74 
     75     uid_t mUserId;
     76 
     77     char* mUserDir;
     78     char* mMasterKeyFile;
     79 
     80     State mState;
     81     int8_t mRetry;
     82 
     83     uint8_t mMasterKey[MASTER_KEY_SIZE_BYTES];
     84     uint8_t mSalt[SALT_SIZE];
     85 
     86     AES_KEY mMasterKeyEncryption;
     87     AES_KEY mMasterKeyDecryption;
     88 };
     89 
     90 #endif  // KEYSTORE_USER_STATE_H_
     91