Merge "Add toggle to allow or disable null algorithms"

src/com/android/settings/network/telephony/NullAlgorithmsPreferenceController.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2022 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.settings.network.telephony;
+
+import android.content.Context;
+import android.provider.DeviceConfig;
+import android.telephony.TelephonyManager;
+import android.util.Log;
+
+/**
+ * Preference controller for "Allow Null Algorithms"
+ *
+ * <p>This preference controller is toggling null algorithms is not a per-sim operation.
+ */
+public class NullAlgorithmsPreferenceController extends TelephonyTogglePreferenceController {
+
+    // log tags have a char limit of 24 so we can't use the class name
+    private static final String LOG_TAG = "NullAlgosController";
+
+    private TelephonyManager mTelephonyManager;
+
+    /**
+     * Class constructor of "Allow Null Algorithms" toggle.
+     *
+     * @param context of settings
+     * @param key     assigned within UI entry of XML file
+     */
+    public NullAlgorithmsPreferenceController(Context context, String key) {
+        super(context, key);
+        mTelephonyManager = mContext.getSystemService(TelephonyManager.class);
+    }
+
+    /**
+     * Get the {@link com.android.settings.core.BasePreferenceController.AvailabilityStatus} for
+     * this preference given a {@code subId}. This dictates whether the setting is available on
+     * the device, and if it is not, offers some context as to why.
+     */
+    @Override
+    public int getAvailabilityStatus(int subId) {
+        if (mTelephonyManager == null) {
+            Log.w(LOG_TAG,
+                    "Telephony manager not yet initialized. Marking availability as "
+                            + "CONDITIONALLY_UNAVAILABLE");
+            mTelephonyManager = mContext.getSystemService(TelephonyManager.class);
+            return CONDITIONALLY_UNAVAILABLE;
+        }
+
+        if (!DeviceConfig.getBoolean(DeviceConfig.NAMESPACE_CELLULAR_SECURITY,
+                TelephonyManager.PROPERTY_ENABLE_NULL_CIPHER_TOGGLE, false)) {
+            Log.i(LOG_TAG, "Null cipher toggle is disabled by DeviceConfig");
+            return CONDITIONALLY_UNAVAILABLE;
+        }
+
+        try {
+            mTelephonyManager.isNullCipherAndIntegrityPreferenceEnabled();
+        } catch (UnsupportedOperationException e) {
+            Log.i(LOG_TAG, "Null cipher enablement is unsupported: " + e.getMessage());
+            return UNSUPPORTED_ON_DEVICE;
+        }
+
+        return AVAILABLE;
+    }
+
+    /**
+     * Return {@code true} if null algorithms are currently allowed.
+     *
+     * <p><b>NOTE:</b> This method returns the active state of the preference controller and is not
+     * the parameter passed into {@link #setChecked(boolean)}, which is instead the requested future
+     * state.
+     */
+    @Override
+    public boolean isChecked() {
+        return mTelephonyManager.isNullCipherAndIntegrityPreferenceEnabled();
+    }
+
+    /**
+     * Called when a user preference changes on the toggle. We pass this info on to the Telephony
+     * Framework so that the modem can be updated with the user's preference.
+     *
+     * <p>See {@link com.android.settings.core.TogglePreferenceController#setChecked(boolean)} for
+     * details.
+     *
+     * @param isChecked The toggle value that we're being requested to enforce. A value of {@code
+     *                  false} denotes that null ciphers will be disabled by the modem after this
+     *                  function
+     *                  completes, if it is not already.
+     */
+    @Override
+    public boolean setChecked(boolean isChecked) {
+        if (isChecked) {
+            Log.i(LOG_TAG, "Enabling null algorithms");
+        } else {
+            Log.i(LOG_TAG, "Disabling null algorithms");
+        }
+        mTelephonyManager.setNullCipherAndIntegrityEnabled(isChecked);
+        return true;
+    }
+}