From 2dfb55090f169e55627f6e180bd8be40516778bf Mon Sep 17 00:00:00 2001
From: Bhavuk Jain <bhavukj@google.com>
Date: Fri, 20 Jan 2023 06:26:55 +0000
Subject: [PATCH] Changes for storing the PIN length

This CL aims at making changes for storing the PIN length in device
encrypted storage. This would happen in two places, one when user
successfuly unlocks the device and other when user is updating the PIN
on their device.

Test: Tested by building and flashing on local, and checking if PIN length is stored by printing the value using logcat. Disabled feature flag to make sure that if it's disabled, the PIN length isn't stored.
Bug: b/262929169
Change-Id: I1ea2b07688e1486f2ef47513218409b7f7fe4a7d
---
 .../internal/widget/LockPatternChecker.java   |  7 +++++++
 .../internal/widget/LockPatternUtils.java     | 20 +++++++++++++++++++
 .../locksettings/LockSettingsService.java     |  8 ++++++++
 3 files changed, 35 insertions(+)

diff --git a/core/java/com/android/internal/widget/LockPatternChecker.java b/core/java/com/android/internal/widget/LockPatternChecker.java
index 5adbc583140fe..e56c381ead339 100644
--- a/core/java/com/android/internal/widget/LockPatternChecker.java
+++ b/core/java/com/android/internal/widget/LockPatternChecker.java
@@ -1,7 +1,10 @@
 package com.android.internal.widget;
 
+import static android.provider.DeviceConfig.NAMESPACE_AUTO_PIN_CONFIRMATION;
+
 import android.annotation.NonNull;
 import android.os.AsyncTask;
+import android.provider.DeviceConfig;
 
 import com.android.internal.widget.LockPatternUtils.RequestThrottledException;
 
@@ -117,6 +120,10 @@ public final class LockPatternChecker {
             @Override
             protected void onPostExecute(Boolean result) {
                 callback.onChecked(result, mThrottleTimeout);
+                if (DeviceConfig.getBoolean(NAMESPACE_AUTO_PIN_CONFIRMATION,
+                        "enable_auto_pin_confirmation", false)) {
+                    utils.setPinLength(userId, credentialCopy.size());
+                }
                 credentialCopy.zeroize();
             }
 
diff --git a/core/java/com/android/internal/widget/LockPatternUtils.java b/core/java/com/android/internal/widget/LockPatternUtils.java
index 86fd9569c61e9..981fbe78032aa 100644
--- a/core/java/com/android/internal/widget/LockPatternUtils.java
+++ b/core/java/com/android/internal/widget/LockPatternUtils.java
@@ -151,6 +151,8 @@ public class LockPatternUtils {
     @Deprecated
     public final static String LOCKSCREEN_WIDGETS_ENABLED = "lockscreen.widgets_enabled";
 
+    public static final String PIN_LENGTH = "lockscreen.pin_length";
+
     public final static String PASSWORD_HISTORY_KEY = "lockscreen.passwordhistory";
 
     private static final String LOCK_SCREEN_OWNER_INFO = Settings.Secure.LOCK_SCREEN_OWNER_INFO;
@@ -565,6 +567,24 @@ public class LockPatternUtils {
         return getBoolean(PATTERN_EVER_CHOSEN_KEY, false, userId);
     }
 
+    /**
+     * Used for setting the length of the PIN set by a particular user.
+     * @param userId user id of the user whose pin length we save
+     * @param val value of length of pin
+     */
+    public void setPinLength(int userId, long val) {
+        setLong(PIN_LENGTH, val, userId);
+    }
+
+    /**
+     * Returns the length of the PIN set by a particular user.
+     * @param userId user id of the user whose pin length we have to return
+     * @return the length of the pin set by user and -1 if nothing
+     */
+    public long getPinLength(int userId) {
+        return getLong(PIN_LENGTH, -1, userId);
+    }
+
     /**
      * Records that the user has chosen a pattern at some time, even if the pattern is
      * currently cleared.
diff --git a/services/core/java/com/android/server/locksettings/LockSettingsService.java b/services/core/java/com/android/server/locksettings/LockSettingsService.java
index 48e0c300979c0..ebc18bcd2369a 100644
--- a/services/core/java/com/android/server/locksettings/LockSettingsService.java
+++ b/services/core/java/com/android/server/locksettings/LockSettingsService.java
@@ -29,6 +29,7 @@ import static android.app.admin.DevicePolicyResources.Strings.Core.PROFILE_ENCRY
 import static android.content.Context.KEYGUARD_SERVICE;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.os.UserHandle.USER_ALL;
+import static android.provider.DeviceConfig.NAMESPACE_AUTO_PIN_CONFIRMATION;
 
 import static com.android.internal.widget.LockPatternUtils.CREDENTIAL_TYPE_NONE;
 import static com.android.internal.widget.LockPatternUtils.CREDENTIAL_TYPE_PASSWORD;
@@ -1689,6 +1690,13 @@ public class LockSettingsService extends ILockSettings.Stub {
         if (newCredential.isPattern()) {
             setBoolean(LockPatternUtils.PATTERN_EVER_CHOSEN_KEY, true, userHandle);
         }
+        if (DeviceConfig.getBoolean(NAMESPACE_AUTO_PIN_CONFIRMATION,
+                "enable_auto_pin_confirmation", /* defaultValue= */ false)) {
+            if (newCredential.isPin()) {
+                setLong(LockPatternUtils.PIN_LENGTH, newCredential.size(), userHandle);
+            }
+        }
+
         updatePasswordHistory(newCredential, userHandle);
         mContext.getSystemService(TrustManager.class).reportEnabledTrustAgentsChanged(userHandle);
     }