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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     UserState(uid_t userId);
33     ~UserState();
34 
35     bool initialize();
36 
getUserId()37     uid_t getUserId() const { return mUserId; }
getUserDirName()38     const char* getUserDirName() const { return mUserDir; }
39 
getMasterKeyFileName()40     const char* getMasterKeyFileName() const { return mMasterKeyFile; }
41 
42     void setState(State state);
getState()43     State getState() const { return mState; }
44 
getRetry()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 
getEncryptionKey()57     AES_KEY* getEncryptionKey() { return &mMasterKeyEncryption; }
getDecryptionKey()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