Android example source code file (LockPatternUtils.java)
The LockPatternUtils.java Android example source code/*
* Copyright (C) 2007 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.
*/
package com.android.internal.widget;
import android.app.admin.DevicePolicyManager;
import android.content.ContentResolver;
import android.content.Context;
import android.os.RemoteException;
import android.os.ServiceManager;
import android.os.SystemClock;
import android.provider.Settings;
import android.security.MessageDigest;
import android.telephony.TelephonyManager;
import android.text.TextUtils;
import android.util.Log;
import android.widget.Button;
import com.android.internal.R;
import com.android.internal.telephony.ITelephony;
import com.google.android.collect.Lists;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.List;
/**
* Utilities for the lock patten and its settings.
*/
public class LockPatternUtils {
private static final String TAG = "LockPatternUtils";
private static final String LOCK_PATTERN_FILE = "/system/gesture.key";
private static final String LOCK_PASSWORD_FILE = "/system/password.key";
/**
* The maximum number of incorrect attempts before the user is prevented
* from trying again for {@link #FAILED_ATTEMPT_TIMEOUT_MS}.
*/
public static final int FAILED_ATTEMPTS_BEFORE_TIMEOUT = 5;
/**
* The number of incorrect attempts before which we fall back on an alternative
* method of verifying the user, and resetting their lock pattern.
*/
public static final int FAILED_ATTEMPTS_BEFORE_RESET = 20;
/**
* How long the user is prevented from trying again after entering the
* wrong pattern too many times.
*/
public static final long FAILED_ATTEMPT_TIMEOUT_MS = 30000L;
/**
* The interval of the countdown for showing progress of the lockout.
*/
public static final long FAILED_ATTEMPT_COUNTDOWN_INTERVAL_MS = 1000L;
/**
* The minimum number of dots in a valid pattern.
*/
public static final int MIN_LOCK_PATTERN_SIZE = 4;
/**
* The minimum number of dots the user must include in a wrong pattern
* attempt for it to be counted against the counts that affect
* {@link #FAILED_ATTEMPTS_BEFORE_TIMEOUT} and {@link #FAILED_ATTEMPTS_BEFORE_RESET}
*/
public static final int MIN_PATTERN_REGISTER_FAIL = 3;
private final static String LOCKOUT_PERMANENT_KEY = "lockscreen.lockedoutpermanently";
private final static String LOCKOUT_ATTEMPT_DEADLINE = "lockscreen.lockoutattemptdeadline";
private final static String PATTERN_EVER_CHOSEN_KEY = "lockscreen.patterneverchosen";
public final static String PASSWORD_TYPE_KEY = "lockscreen.password_type";
private final static String LOCK_PASSWORD_SALT_KEY = "lockscreen.password_salt";
private final Context mContext;
private final ContentResolver mContentResolver;
private DevicePolicyManager mDevicePolicyManager;
private static String sLockPatternFilename;
private static String sLockPasswordFilename;
public DevicePolicyManager getDevicePolicyManager() {
if (mDevicePolicyManager == null) {
mDevicePolicyManager =
(DevicePolicyManager)mContext.getSystemService(Context.DEVICE_POLICY_SERVICE);
if (mDevicePolicyManager == null) {
Log.e(TAG, "Can't get DevicePolicyManagerService: is it running?",
new IllegalStateException("Stack trace:"));
}
}
return mDevicePolicyManager;
}
/**
* @param contentResolver Used to look up and save settings.
*/
public LockPatternUtils(Context context) {
mContext = context;
mContentResolver = context.getContentResolver();
// Initialize the location of gesture lock file
if (sLockPatternFilename == null) {
sLockPatternFilename = android.os.Environment.getDataDirectory()
.getAbsolutePath() + LOCK_PATTERN_FILE;
sLockPasswordFilename = android.os.Environment.getDataDirectory()
.getAbsolutePath() + LOCK_PASSWORD_FILE;
}
}
public int getRequestedMinimumPasswordLength() {
return getDevicePolicyManager().getPasswordMinimumLength(null);
}
/**
* Gets the device policy password mode. If the mode is non-specific, returns
* MODE_PATTERN which allows the user to choose anything.
*/
public int getRequestedPasswordQuality() {
return getDevicePolicyManager().getPasswordQuality(null);
}
/**
* Returns the actual password mode, as set by keyguard after updating the password.
*
* @return
*/
public void reportFailedPasswordAttempt() {
getDevicePolicyManager().reportFailedPasswordAttempt();
}
public void reportSuccessfulPasswordAttempt() {
getDevicePolicyManager().reportSuccessfulPasswordAttempt();
}
/**
* Check to see if a pattern matches the saved pattern. If no pattern exists,
* always returns true.
* @param pattern The pattern to check.
* @return Whether the pattern matches the stored one.
*/
public boolean checkPattern(List<LockPatternView.Cell> pattern) {
try {
// Read all the bytes from the file
RandomAccessFile raf = new RandomAccessFile(sLockPatternFilename, "r");
final byte[] stored = new byte[(int) raf.length()];
int got = raf.read(stored, 0, stored.length);
raf.close();
if (got <= 0) {
return true;
}
// Compare the hash from the file with the entered pattern's hash
return Arrays.equals(stored, LockPatternUtils.patternToHash(pattern));
} catch (FileNotFoundException fnfe) {
return true;
} catch (IOException ioe) {
return true;
}
}
/**
* Check to see if a password matches the saved password. If no password exists,
* always returns true.
* @param password The password to check.
* @return Whether the password matches the stored one.
*/
public boolean checkPassword(String password) {
try {
// Read all the bytes from the file
RandomAccessFile raf = new RandomAccessFile(sLockPasswordFilename, "r");
final byte[] stored = new byte[(int) raf.length()];
int got = raf.read(stored, 0, stored.length);
raf.close();
if (got <= 0) {
return true;
}
// Compare the hash from the file with the entered password's hash
return Arrays.equals(stored, passwordToHash(password));
} catch (FileNotFoundException fnfe) {
return true;
} catch (IOException ioe) {
return true;
}
}
/**
* Checks to see if the given file exists and contains any data. Returns true if it does,
* false otherwise.
* @param filename
* @return true if file exists and is non-empty.
*/
private boolean nonEmptyFileExists(String filename) {
try {
// Check if we can read a byte from the file
RandomAccessFile raf = new RandomAccessFile(filename, "r");
raf.readByte();
raf.close();
return true;
} catch (FileNotFoundException fnfe) {
return false;
} catch (IOException ioe) {
return false;
}
}
/**
* Check to see if the user has stored a lock pattern.
* @return Whether a saved pattern exists.
*/
public boolean savedPatternExists() {
return nonEmptyFileExists(sLockPatternFilename);
}
/**
* Check to see if the user has stored a lock pattern.
* @return Whether a saved pattern exists.
*/
public boolean savedPasswordExists() {
return nonEmptyFileExists(sLockPasswordFilename);
}
/**
* Return true if the user has ever chosen a pattern. This is true even if the pattern is
* currently cleared.
*
* @return True if the user has ever chosen a pattern.
*/
public boolean isPatternEverChosen() {
return getBoolean(PATTERN_EVER_CHOSEN_KEY);
}
/**
* Used by device policy manager to validate the current password
* information it has.
*/
public int getActivePasswordQuality() {
int activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED;
switch (getKeyguardStoredPasswordQuality()) {
case DevicePolicyManager.PASSWORD_QUALITY_SOMETHING:
if (isLockPatternEnabled()) {
activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_SOMETHING;
}
break;
case DevicePolicyManager.PASSWORD_QUALITY_NUMERIC:
if (isLockPasswordEnabled()) {
activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_NUMERIC;
}
break;
case DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC:
if (isLockPasswordEnabled()) {
activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC;
}
break;
case DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC:
if (isLockPasswordEnabled()) {
activePasswordQuality = DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC;
}
break;
}
return activePasswordQuality;
}
/**
* Clear any lock pattern or password.
*/
public void clearLock() {
getDevicePolicyManager().setActivePasswordState(
DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED, 0);
saveLockPassword(null, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
setLockPatternEnabled(false);
saveLockPattern(null);
setLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
}
/**
* Save a lock pattern.
* @param pattern The new pattern to save.
*/
public void saveLockPattern(List<LockPatternView.Cell> pattern) {
// Compute the hash
final byte[] hash = LockPatternUtils.patternToHash(pattern);
try {
// Write the hash to file
RandomAccessFile raf = new RandomAccessFile(sLockPatternFilename, "rw");
// Truncate the file if pattern is null, to clear the lock
if (pattern == null) {
raf.setLength(0);
} else {
raf.write(hash, 0, hash.length);
}
raf.close();
DevicePolicyManager dpm = getDevicePolicyManager();
if (pattern != null) {
setBoolean(PATTERN_EVER_CHOSEN_KEY, true);
setLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
dpm.setActivePasswordState(
DevicePolicyManager.PASSWORD_QUALITY_SOMETHING, pattern.size());
} else {
dpm.setActivePasswordState(
DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED, 0);
}
} catch (FileNotFoundException fnfe) {
// Cant do much, unless we want to fail over to using the settings provider
Log.e(TAG, "Unable to save lock pattern to " + sLockPatternFilename);
} catch (IOException ioe) {
// Cant do much
Log.e(TAG, "Unable to save lock pattern to " + sLockPatternFilename);
}
}
/**
* Compute the password quality from the given password string.
*/
static public int computePasswordQuality(String password) {
boolean hasDigit = false;
boolean hasNonDigit = false;
final int len = password.length();
for (int i = 0; i < len; i++) {
if (Character.isDigit(password.charAt(i))) {
hasDigit = true;
} else {
hasNonDigit = true;
}
}
if (hasNonDigit && hasDigit) {
return DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC;
}
if (hasNonDigit) {
return DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC;
}
if (hasDigit) {
return DevicePolicyManager.PASSWORD_QUALITY_NUMERIC;
}
return DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED;
}
/**
* Save a lock password. Does not ensure that the password is as good
* as the requested mode, but will adjust the mode to be as good as the
* pattern.
* @param password The password to save
* @param quality {@see DevicePolicyManager#getPasswordQuality(android.content.ComponentName)}
*/
public void saveLockPassword(String password, int quality) {
// Compute the hash
final byte[] hash = passwordToHash(password);
try {
// Write the hash to file
RandomAccessFile raf = new RandomAccessFile(sLockPasswordFilename, "rw");
// Truncate the file if pattern is null, to clear the lock
if (password == null) {
raf.setLength(0);
} else {
raf.write(hash, 0, hash.length);
}
raf.close();
DevicePolicyManager dpm = getDevicePolicyManager();
if (password != null) {
int computedQuality = computePasswordQuality(password);
setLong(PASSWORD_TYPE_KEY, computedQuality);
if (computedQuality != DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED) {
dpm.setActivePasswordState(computedQuality, password.length());
} else {
// The password is not anything.
dpm.setActivePasswordState(
DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED, 0);
}
} else {
dpm.setActivePasswordState(
DevicePolicyManager.PASSWORD_QUALITY_UNSPECIFIED, 0);
}
} catch (FileNotFoundException fnfe) {
// Cant do much, unless we want to fail over to using the settings provider
Log.e(TAG, "Unable to save lock pattern to " + sLockPasswordFilename);
} catch (IOException ioe) {
// Cant do much
Log.e(TAG, "Unable to save lock pattern to " + sLockPasswordFilename);
}
}
/**
* Retrieves the quality mode we're in.
* {@see DevicePolicyManager#getPasswordQuality(android.content.ComponentName)}
*
* @return stored password quality
*/
public int getKeyguardStoredPasswordQuality() {
return (int) getLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING);
}
/**
* Deserialize a pattern.
* @param string The pattern serialized with {@link #patternToString}
* @return The pattern.
*/
public static List<LockPatternView.Cell> stringToPattern(String string) {
List<LockPatternView.Cell> result = Lists.newArrayList();
final byte[] bytes = string.getBytes();
for (int i = 0; i < bytes.length; i++) {
byte b = bytes[i];
result.add(LockPatternView.Cell.of(b / 3, b % 3));
}
return result;
}
/**
* Serialize a pattern.
* @param pattern The pattern.
* @return The pattern in string form.
*/
public static String patternToString(List<LockPatternView.Cell> pattern) {
if (pattern == null) {
return "";
}
final int patternSize = pattern.size();
byte[] res = new byte[patternSize];
for (int i = 0; i < patternSize; i++) {
LockPatternView.Cell cell = pattern.get(i);
res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
}
return new String(res);
}
/*
* Generate an SHA-1 hash for the pattern. Not the most secure, but it is
* at least a second level of protection. First level is that the file
* is in a location only readable by the system process.
* @param pattern the gesture pattern.
* @return the hash of the pattern in a byte array.
*/
private static byte[] patternToHash(List<LockPatternView.Cell> pattern) {
if (pattern == null) {
return null;
}
final int patternSize = pattern.size();
byte[] res = new byte[patternSize];
for (int i = 0; i < patternSize; i++) {
LockPatternView.Cell cell = pattern.get(i);
res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
}
try {
MessageDigest md = MessageDigest.getInstance("SHA-1");
byte[] hash = md.digest(res);
return hash;
} catch (NoSuchAlgorithmException nsa) {
return res;
}
}
private String getSalt() {
long salt = getLong(LOCK_PASSWORD_SALT_KEY, 0);
if (salt == 0) {
try {
salt = SecureRandom.getInstance("SHA1PRNG").nextLong();
setLong(LOCK_PASSWORD_SALT_KEY, salt);
Log.v(TAG, "Initialized lock password salt");
} catch (NoSuchAlgorithmException e) {
// Throw an exception rather than storing a password we'll never be able to recover
throw new IllegalStateException("Couldn't get SecureRandom number", e);
}
}
return Long.toHexString(salt);
}
/*
* Generate a hash for the given password. To avoid brute force attacks, we use a salted hash.
* Not the most secure, but it is at least a second level of protection. First level is that
* the file is in a location only readable by the system process.
* @param password the gesture pattern.
* @return the hash of the pattern in a byte array.
*/
public byte[] passwordToHash(String password) {
if (password == null) {
return null;
}
String algo = null;
byte[] hashed = null;
try {
byte[] saltedPassword = (password + getSalt()).getBytes();
byte[] sha1 = MessageDigest.getInstance(algo = "SHA-1").digest(saltedPassword);
byte[] md5 = MessageDigest.getInstance(algo = "MD5").digest(saltedPassword);
hashed = (toHex(sha1) + toHex(md5)).getBytes();
} catch (NoSuchAlgorithmException e) {
Log.w(TAG, "Failed to encode string because of missing algorithm: " + algo);
}
return hashed;
}
private static String toHex(byte[] ary) {
final String hex = "0123456789ABCDEF";
String ret = "";
for (int i = 0; i < ary.length; i++) {
ret += hex.charAt((ary[i] >> 4) & 0xf);
ret += hex.charAt(ary[i] & 0xf);
}
return ret;
}
/**
* @return Whether the lock password is enabled.
*/
public boolean isLockPasswordEnabled() {
long mode = getLong(PASSWORD_TYPE_KEY, 0);
return savedPasswordExists() &&
(mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC
|| mode == DevicePolicyManager.PASSWORD_QUALITY_NUMERIC
|| mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC);
}
/**
* @return Whether the lock pattern is enabled.
*/
public boolean isLockPatternEnabled() {
return getBoolean(Settings.Secure.LOCK_PATTERN_ENABLED)
&& getLong(PASSWORD_TYPE_KEY, DevicePolicyManager.PASSWORD_QUALITY_SOMETHING)
== DevicePolicyManager.PASSWORD_QUALITY_SOMETHING;
}
/**
* Set whether the lock pattern is enabled.
*/
public void setLockPatternEnabled(boolean enabled) {
setBoolean(Settings.Secure.LOCK_PATTERN_ENABLED, enabled);
}
/**
* @return Whether the visible pattern is enabled.
*/
public boolean isVisiblePatternEnabled() {
return getBoolean(Settings.Secure.LOCK_PATTERN_VISIBLE);
}
/**
* Set whether the visible pattern is enabled.
*/
public void setVisiblePatternEnabled(boolean enabled) {
setBoolean(Settings.Secure.LOCK_PATTERN_VISIBLE, enabled);
}
/**
* @return Whether tactile feedback for the pattern is enabled.
*/
public boolean isTactileFeedbackEnabled() {
return getBoolean(Settings.Secure.LOCK_PATTERN_TACTILE_FEEDBACK_ENABLED);
}
/**
* Set whether tactile feedback for the pattern is enabled.
*/
public void setTactileFeedbackEnabled(boolean enabled) {
setBoolean(Settings.Secure.LOCK_PATTERN_TACTILE_FEEDBACK_ENABLED, enabled);
}
/**
* Set and store the lockout deadline, meaning the user can't attempt his/her unlock
* pattern until the deadline has passed.
* @return the chosen deadline.
*/
public long setLockoutAttemptDeadline() {
final long deadline = SystemClock.elapsedRealtime() + FAILED_ATTEMPT_TIMEOUT_MS;
setLong(LOCKOUT_ATTEMPT_DEADLINE, deadline);
return deadline;
}
/**
* @return The elapsed time in millis in the future when the user is allowed to
* attempt to enter his/her lock pattern, or 0 if the user is welcome to
* enter a pattern.
*/
public long getLockoutAttemptDeadline() {
final long deadline = getLong(LOCKOUT_ATTEMPT_DEADLINE, 0L);
final long now = SystemClock.elapsedRealtime();
if (deadline < now || deadline > (now + FAILED_ATTEMPT_TIMEOUT_MS)) {
return 0L;
}
return deadline;
}
/**
* @return Whether the user is permanently locked out until they verify their
* credentials. Occurs after {@link #FAILED_ATTEMPTS_BEFORE_RESET} failed
* attempts.
*/
public boolean isPermanentlyLocked() {
return getBoolean(LOCKOUT_PERMANENT_KEY);
}
/**
* Set the state of whether the device is permanently locked, meaning the user
* must authenticate via other means.
*
* @param locked Whether the user is permanently locked out until they verify their
* credentials. Occurs after {@link #FAILED_ATTEMPTS_BEFORE_RESET} failed
* attempts.
*/
public void setPermanentlyLocked(boolean locked) {
setBoolean(LOCKOUT_PERMANENT_KEY, locked);
}
/**
* @return A formatted string of the next alarm (for showing on the lock screen),
* or null if there is no next alarm.
*/
public String getNextAlarm() {
String nextAlarm = Settings.System.getString(mContentResolver,
Settings.System.NEXT_ALARM_FORMATTED);
if (nextAlarm == null || TextUtils.isEmpty(nextAlarm)) {
return null;
}
return nextAlarm;
}
private boolean getBoolean(String secureSettingKey) {
return 1 ==
android.provider.Settings.Secure.getInt(mContentResolver, secureSettingKey, 0);
}
private void setBoolean(String secureSettingKey, boolean enabled) {
android.provider.Settings.Secure.putInt(mContentResolver, secureSettingKey,
enabled ? 1 : 0);
}
private long getLong(String secureSettingKey, long def) {
return android.provider.Settings.Secure.getLong(mContentResolver, secureSettingKey, def);
}
private void setLong(String secureSettingKey, long value) {
android.provider.Settings.Secure.putLong(mContentResolver, secureSettingKey, value);
}
public boolean isSecure() {
long mode = getKeyguardStoredPasswordQuality();
final boolean isPattern = mode == DevicePolicyManager.PASSWORD_QUALITY_SOMETHING;
final boolean isPassword = mode == DevicePolicyManager.PASSWORD_QUALITY_NUMERIC
|| mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHABETIC
|| mode == DevicePolicyManager.PASSWORD_QUALITY_ALPHANUMERIC;
final boolean secure = isPattern && isLockPatternEnabled() && savedPatternExists()
|| isPassword && savedPasswordExists();
return secure;
}
/**
* Sets the text on the emergency button to indicate what action will be taken.
* If there's currently a call in progress, the button will take them to the call
* @param button the button to update
*/
public void updateEmergencyCallButtonState(Button button) {
int newState = TelephonyManager.getDefault().getCallState();
int textId;
if (newState == TelephonyManager.CALL_STATE_OFFHOOK) {
// show "return to call" text and show phone icon
textId = R.string.lockscreen_return_to_call;
int phoneCallIcon = R.drawable.stat_sys_phone_call;
button.setCompoundDrawablesWithIntrinsicBounds(phoneCallIcon, 0, 0, 0);
} else {
textId = R.string.lockscreen_emergency_call;
int emergencyIcon = R.drawable.ic_emergency;
button.setCompoundDrawablesWithIntrinsicBounds(emergencyIcon, 0, 0, 0);
}
button.setText(textId);
}
/**
* Resumes a call in progress. Typically launched from the EmergencyCall button
* on various lockscreens.
*
* @return true if we were able to tell InCallScreen to show.
*/
public boolean resumeCall() {
ITelephony phone = ITelephony.Stub.asInterface(ServiceManager.checkService("phone"));
try {
if (phone != null && phone.showCallScreen()) {
return true;
}
} catch (RemoteException e) {
// What can we do?
}
return false;
}
}
Other Android examples (source code examples)Here is a short list of links related to this Android LockPatternUtils.java source code file: |
The search page
Other Android source code examples at this package level
Click here to learn more about this project
