From d63d0e12cc6db7e2f2bb84edb794254b6b94f58e Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Wed, 26 Jan 2022 05:22:38 +0000
Subject: [PATCH] Stop trying to update FDE password from LockSettingsService

Since FDE is no longer supported, updating the FDE password never does
anything.  Stop trying to do so.  Remove updateEncryptionPassword() from
ILockSettings, since its only caller outside of LockSettingsService
itself was in LockPatternUtils, and the previous CL removed that caller.

Bug: 208476087
Change-Id: I46c2a472177836f0c9084e4c3b4ed2e6c0ab61d5
(cherry picked from commit 3762ada110e11b051badb6ff2f4109083721d627)
Merged-In: I46c2a472177836f0c9084e4c3b4ed2e6c0ab61d5
---
 .../internal/widget/ILockSettings.aidl        |  1 -
 .../locksettings/LockSettingsService.java     | 53 ++-----------------
 2 files changed, 4 insertions(+), 50 deletions(-)

diff --git a/core/java/com/android/internal/widget/ILockSettings.aidl b/core/java/com/android/internal/widget/ILockSettings.aidl
index d16d9c6194038..654b46164dcf9 100644
--- a/core/java/com/android/internal/widget/ILockSettings.aidl
+++ b/core/java/com/android/internal/widget/ILockSettings.aidl
@@ -95,5 +95,4 @@ interface ILockSettings {
     boolean hasSecureLockScreen();
     boolean tryUnlockWithCachedUnifiedChallenge(int userId);
     void removeCachedUnifiedChallenge(int userId);
-    void updateEncryptionPassword(int type, in byte[] password);
 }
diff --git a/services/core/java/com/android/server/locksettings/LockSettingsService.java b/services/core/java/com/android/server/locksettings/LockSettingsService.java
index 7d5b7e535ca93..45f85edeff7e6 100644
--- a/services/core/java/com/android/server/locksettings/LockSettingsService.java
+++ b/services/core/java/com/android/server/locksettings/LockSettingsService.java
@@ -1761,7 +1761,10 @@ public class LockSettingsService extends ILockSettings.Stub {
     }
 
     private void onPostPasswordChanged(LockscreenCredential newCredential, int userHandle) {
-        updateEncryptionPasswordIfNeeded(newCredential, userHandle);
+        if (userHandle == UserHandle.USER_SYSTEM && isDeviceEncryptionEnabled() &&
+            shouldEncryptWithCredentials() && newCredential.isNone()) {
+            setCredentialRequiredToDecrypt(false);
+        }
         if (newCredential.isPattern()) {
             setBoolean(LockPatternUtils.PATTERN_EVER_CHOSEN_KEY, true, userHandle);
         }
@@ -1769,26 +1772,6 @@ public class LockSettingsService extends ILockSettings.Stub {
         mContext.getSystemService(TrustManager.class).reportEnabledTrustAgentsChanged(userHandle);
     }
 
-    /**
-     * Update device encryption password if calling user is USER_SYSTEM and device supports
-     * encryption.
-     */
-    private void updateEncryptionPasswordIfNeeded(LockscreenCredential credential, int userHandle) {
-        // Update the device encryption password.
-        if (userHandle != UserHandle.USER_SYSTEM || !isDeviceEncryptionEnabled()) {
-            return;
-        }
-        if (!shouldEncryptWithCredentials()) {
-            updateEncryptionPassword(StorageManager.CRYPT_TYPE_DEFAULT, null);
-            return;
-        }
-        if (credential.isNone()) {
-            // Set the encryption password to default.
-            setCredentialRequiredToDecrypt(false);
-        }
-        updateEncryptionPassword(credential.getStorageCryptType(), credential.getCredential());
-    }
-
     /**
      * Store the hash of the *current* password in the password history list, if device policy
      * enforces password history requirement.
@@ -1883,34 +1866,6 @@ public class LockSettingsService extends ILockSettings.Stub {
         }
     }
 
-    /** Update the encryption password if it is enabled **/
-    @Override
-    public void updateEncryptionPassword(final int type, final byte[] password) {
-        if (!hasSecureLockScreen() && password != null && password.length != 0) {
-            throw new UnsupportedOperationException(
-                    "This operation requires the lock screen feature.");
-        }
-        if (!isDeviceEncryptionEnabled()) {
-            return;
-        }
-        final IBinder service = ServiceManager.getService("mount");
-        if (service == null) {
-            Slog.e(TAG, "Could not find the mount service to update the encryption password");
-            return;
-        }
-
-        // TODO(b/120484642): This is a location where we still use a String for vold
-        String passwordString = password != null ? new String(password) : null;
-        mHandler.post(() -> {
-            IStorageManager storageManager = mInjector.getStorageManager();
-            try {
-                storageManager.changeEncryptionPassword(type, passwordString);
-            } catch (RemoteException e) {
-                Slog.e(TAG, "Error changing encryption password", e);
-            }
-        });
-    }
-
     @VisibleForTesting /** Note: this method is overridden in unit tests */
     protected void tieProfileLockToParent(int userId, LockscreenCredential password) {
         if (DEBUG) Slog.v(TAG, "tieProfileLockToParent for user: " + userId);