KeyguardSecurityModel.java revision cc4104fd71225ed092f16b11882d9a10084e34ac 
1/*
2 * Copyright (C) 2012 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 */
16package com.android.internal.policy.impl.keyguard;
17
18import android.app.admin.DevicePolicyManager;
19import android.content.Context;
20
21import com.android.internal.telephony.IccCardConstants;
22import com.android.internal.widget.LockPatternUtils;
23
24public class KeyguardSecurityModel {
25    /**
26     * The different types of security available for {@link Mode#UnlockScreen}.
27     * @see com.android.internal.policy.impl.LockPatternKeyguardView#getUnlockMode()
28     */
29    enum SecurityMode {
30        None, // No security enabled
31        Pattern, // Unlock by drawing a pattern.
32        Password, // Unlock by entering a password or PIN
33        Biometric, // Unlock with a biometric key (e.g. finger print or face unlock)
34        Account, // Unlock by entering an account's login and password.
35        SimPin, // Unlock by entering a sim pin.
36        SimPuk // Unlock by entering a sim puk
37    }
38
39    private Context mContext;
40    private LockPatternUtils mLockPatternUtils;
41
42    KeyguardSecurityModel(Context context) {
43        mContext = context;
44        mLockPatternUtils = new LockPatternUtils(context);
45    }
46
47    void setLockPatternUtils(LockPatternUtils utils) {
48        mLockPatternUtils = utils;
49    }
50
51    /**
52     * Returns true if biometric unlock is installed and selected.  If this returns false there is
53     * no need to even construct the biometric unlock.
54     */
55    private boolean isBiometricUnlockEnabled() {
56        return mLockPatternUtils.usingBiometricWeak()
57                && mLockPatternUtils.isBiometricWeakInstalled();
58    }
59
60    /**
61     * Returns true if a condition is currently suppressing the biometric unlock.  If this returns
62     * true there is no need to even construct the biometric unlock.
63     */
64    private boolean isBiometricUnlockSuppressed() {
65        KeyguardUpdateMonitor monitor = KeyguardUpdateMonitor.getInstance(mContext);
66        final boolean backupIsTimedOut = monitor.getFailedUnlockAttempts() >=
67                LockPatternUtils.FAILED_ATTEMPTS_BEFORE_TIMEOUT;
68        return monitor.getMaxBiometricUnlockAttemptsReached() || backupIsTimedOut
69                || monitor.didBiometricUnlockUserSwitch();
70    }
71
72    SecurityMode getSecurityMode() {
73        KeyguardUpdateMonitor updateMonitor = KeyguardUpdateMonitor.getInstance(mContext);
74        final IccCardConstants.State simState = updateMonitor.getSimState();
75        SecurityMode mode = SecurityMode.None;
76        if (simState == IccCardConstants.State.PIN_REQUIRED) {
77            mode = SecurityMode.SimPin;
78        } else if (simState == IccCardConstants.State.PUK_REQUIRED
79                && mLockPatternUtils.isPukUnlockScreenEnable()) {
80            mode = SecurityMode.SimPuk;
81        } else {
82            final int security = mLockPatternUtils.getKeyguardStoredPasswordQuality();
83            switch (security) {
84                case DevicePolicyManager.PASSWORD_QUALITY_NUMERIC:
85                case DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC:
86                case DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC:
87                case DevicePolicyManager.PASSWORD_QUALITY_COMPLEX:
88                    mode = mLockPatternUtils.isLockPasswordEnabled() ?
89                            SecurityMode.Password : SecurityMode.None;
90                    break;
91
92                case DevicePolicyManager.PASSWORD_QUALITY_SOMETHING:
93                case DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED:
94                    if (mLockPatternUtils.isLockPatternEnabled()) {
95                        mode = mLockPatternUtils.isPermanentlyLocked() ?
96                            SecurityMode.Account : SecurityMode.Pattern;
97                    }
98                    break;
99
100                default:
101                    throw new IllegalStateException("Unknown unlock mode:" + mode);
102            }
103        }
104        return mode;
105    }
106
107    /**
108     * Some unlock methods can have an alternate, such as biometric unlocks (e.g. face unlock).
109     * This function decides if an alternate unlock is available and returns it. Otherwise,
110     * returns @param mode.
111     *
112     * @param mode the mode we want the alternate for
113     * @return alternate or the given mode
114     */
115    SecurityMode getAlternateFor(SecurityMode mode) {
116        if (isBiometricUnlockEnabled() && !isBiometricUnlockSuppressed()
117                && (mode == SecurityMode.Password || mode == SecurityMode.Pattern)) {
118            return SecurityMode.Biometric;
119        }
120        return mode; // no alternate, return what was given
121    }
122
123    /**
124     * Some unlock methods can have a backup which gives the user another way to get into
125     * the device. This is currently only supported for Biometric and Pattern unlock.
126     *
127     * @return backup method or current security mode
128     */
129    SecurityMode getBackupSecurityMode() {
130        SecurityMode mode = getSecurityMode();
131
132        // Note that getAlternateFor() cannot be called here because we want to get the backup for
133        // biometric unlock even if it's suppressed; it just has to be enabled.
134        if (isBiometricUnlockEnabled()
135                && (mode == SecurityMode.Password || mode == SecurityMode.Pattern)) {
136            mode = SecurityMode.Biometric;
137        }
138        switch(mode) {
139            case Biometric:
140                return getSecurityMode();
141            case Pattern:
142                return SecurityMode.Account;
143        }
144        return mode; // no backup, return current security mode
145    }
146}
147