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Unverified Commit 61fac218 authored by Oliver Scott's avatar Oliver Scott Committed by Michael Bestas
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Implement backup/restore for network policy 

Modify network policy XML parser helper functions for backup/restore scenarios

Issue: calyxos#384
Change-Id: I77158b344a47138a17fbce72d3ecb3be6927b870
(cherry picked from commit 9ac27e3b850921a83c52aaa0da798320517b0d5e)
parent 22ad5e7d

core/java/android/net/INetworkPolicyManager.aidl

+3 −0
Original line number Diff line number Diff line
@@ -78,4 +78,7 @@ interface INetworkPolicyManager { 
    void factoryReset(String subscriber);



    boolean isUidNetworkingBlocked(int uid, boolean meteredNetwork);



    byte[] getBackupPayload();

    void applyRestore(in byte[] payload);

}

core/java/com/android/server/backup/NetworkPolicyBackupHelper.java

0 → 100644
+73 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2021 The Calyx Institute

 *

 * 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.server.backup;



import android.app.backup.BlobBackupHelper;

import android.content.Context;

import android.net.INetworkPolicyManager;

import android.os.ServiceManager;

import android.util.Log;

import android.util.Slog;



public class NetworkPolicyBackupHelper extends BlobBackupHelper {

    private static final String TAG = "NetworkPolicyBackupHelper";

    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);



    // Current version of the blob schema

    static final int BLOB_VERSION = 1;



    // Key under which the payload blob is stored

    static final String KEY_NETWORK_POLICY = "network_policy";



    public NetworkPolicyBackupHelper() {

        super(BLOB_VERSION, KEY_NETWORK_POLICY);

    }



    @Override

    protected byte[] getBackupPayload(String key) {

        byte[] newPayload = null;

        if (KEY_NETWORK_POLICY.equals(key)) {

            try {

                INetworkPolicyManager npm = INetworkPolicyManager.Stub.asInterface(

                        ServiceManager.getService(Context.NETWORK_POLICY_SERVICE));

                newPayload = npm.getBackupPayload();

            } catch (Exception e) {

                // Treat as no data

                Slog.e(TAG, "Couldn't communicate with network policy manager");

                newPayload = null;

            }

        }

        return newPayload;

    }



    @Override

    protected void applyRestoredPayload(String key, byte[] payload) {

        if (DEBUG) {

            Slog.v(TAG, "Got restore of " + key);

        }



        if (KEY_NETWORK_POLICY.equals(key)) {

            try {

                INetworkPolicyManager.Stub.asInterface(

                        ServiceManager.getService(Context.NETWORK_POLICY_SERVICE))

                        .applyRestore(payload);

            } catch (Exception e) {

                Slog.e(TAG, "Couldn't communicate with network policy manager");

            }

        }

    }

}

services/core/java/com/android/server/backup/SystemBackupAgent.java

+2 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ public class SystemBackupAgent extends BackupAgentHelper { 
    private static final String ACCOUNT_MANAGER_HELPER = "account_manager";

    private static final String SLICES_HELPER = "slices";

    private static final String PEOPLE_HELPER = "people";

    private static final String NETWORK_POLICY_HELPER = "network_policy";



    // These paths must match what the WallpaperManagerService uses.  The leaf *_FILENAME

    // are also used in the full-backup file format, so must not change unless steps are
@@ -101,6 +102,7 @@ public class SystemBackupAgent extends BackupAgentHelper { 
        addHelper(ACCOUNT_MANAGER_HELPER, new AccountManagerBackupHelper());

        addHelper(SLICES_HELPER, new SliceBackupHelper(this));

        addHelper(PEOPLE_HELPER, new PeopleBackupHelper(mUserId));

        addHelper(NETWORK_POLICY_HELPER, new NetworkPolicyBackupHelper());

    }



    @Override

services/core/java/com/android/server/net/NetworkPolicyManagerService.java

+80 −11
Original line number Diff line number Diff line
@@ -252,6 +252,8 @@ import org.xmlpull.v1.XmlPullParser; 
import org.xmlpull.v1.XmlPullParserException;

import org.xmlpull.v1.XmlSerializer;



import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileDescriptor;

import java.io.FileInputStream;
@@ -377,6 +379,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
    private static final String ATTR_OWNER_PACKAGE = "ownerPackage";

    private static final String ATTR_NETWORK_TYPES = "networkTypes";

    private static final String ATTR_XML_UTILS_NAME = "name";

    private static final String ATTR_USER_ID = "userId";



    private static final String ACTION_ALLOW_BACKGROUND =

            "com.android.server.net.action.ALLOW_BACKGROUND";
@@ -2215,7 +2218,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        FileInputStream fis = null;

        try {

            fis = mPolicyFile.openRead();

            readPolicyXml(fis);

            readPolicyXml(fis, false);

        } catch (FileNotFoundException e) {

            // missing policy is okay, probably first boot

            upgradeDefaultBackgroundDataUL();
@@ -2226,7 +2229,8 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        }

    }



    private void readPolicyXml(InputStream inputStream) {

    private void readPolicyXml(InputStream inputStream, boolean forRestore) throws IOException,

            XmlPullParserException {

        final XmlPullParser in = Xml.newPullParser();

        in.setInput(inputStream, StandardCharsets.UTF_8.name());
@@ -2366,7 +2370,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
                            SubscriptionPlan.class, mSubscriptionPlans.get(subId), plan));

                    mSubscriptionPlansOwner.put(subId, ownerPackage);

                } else if (TAG_UID_POLICY.equals(tag)) {

                    final int uid = readIntAttribute(in, ATTR_UID);

                    int uid = readUidAttribute(in, forRestore);

                    final int policy = readIntAttribute(in, ATTR_POLICY);



                    if (UserHandle.isApp(uid)) {
@@ -2389,10 +2393,10 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
                } else if (TAG_WHITELIST.equals(tag)) {

                    insideWhitelist = true;

                } else if (TAG_RESTRICT_BACKGROUND.equals(tag) && insideWhitelist) {

                    final int uid = readIntAttribute(in, ATTR_UID);

                    int uid = readUidAttribute(in, forRestore);

                    whitelistedRestrictBackground.append(uid, true);

                } else if (TAG_REVOKED_RESTRICT_BACKGROUND.equals(tag) && insideWhitelist) {

                    final int uid = readIntAttribute(in, ATTR_UID);

                    int uid = readUidAttribute(in, forRestore);

                    mRestrictBackgroundWhitelistRevokedUids.put(uid, true);

                }

            } else if (type == END_TAG) {
@@ -2487,9 +2491,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        FileOutputStream fos = null;

        try {

            fos = mPolicyFile.startWrite();



            writePolicyXml(fos);



            writePolicyXml(fos, false);

            mPolicyFile.finishWrite(fos);

        } catch (IOException e) {

            if (fos != null) {
@@ -2498,7 +2500,7 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        }

    }



    private void writePolicyXml(OutputStream outputStream) {

    private void writePolicyXml(OutputStream outputStream, boolean forBackup) throws IOException {

        XmlSerializer out = new FastXmlSerializer();

        out.setOutput(outputStream, StandardCharsets.UTF_8.name());

        out.startDocument(null, true);
@@ -2578,7 +2580,12 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
            if (policy == POLICY_NONE) continue;



            out.startTag(null, TAG_UID_POLICY);

            if (!forBackup) {

                writeIntAttribute(out, ATTR_UID, uid);

            } else {

                writeStringAttribute(out, ATTR_XML_UTILS_NAME, getPackageForUid(uid));

                writeIntAttribute(out, ATTR_USER_ID, UserHandle.getUserId(uid));

            }

            writeIntAttribute(out, ATTR_POLICY, policy);

            out.endTag(null, TAG_UID_POLICY);

        }
@@ -2593,7 +2600,12 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        for (int i = 0; i < size; i++) {

            final int uid = mRestrictBackgroundWhitelistRevokedUids.keyAt(i);

            out.startTag(null, TAG_REVOKED_RESTRICT_BACKGROUND);

            if (!forBackup) {

                writeIntAttribute(out, ATTR_UID, uid);

            } else {

                writeStringAttribute(out, ATTR_XML_UTILS_NAME, getPackageForUid(uid));

                writeIntAttribute(out, ATTR_USER_ID, UserHandle.getUserId(uid));

            }

            out.endTag(null, TAG_REVOKED_RESTRICT_BACKGROUND);

        }
@@ -2602,6 +2614,44 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        out.endDocument();

    }



    @Override

    public byte[] getBackupPayload() {

        enforceSystemCaller();

        if (LOGD) Slog.d(TAG, "getBackupPayload");

        final ByteArrayOutputStream baos = new ByteArrayOutputStream();

        try {

            writePolicyXml(baos, true);

            return baos.toByteArray();

        } catch (IOException e) {

            Slog.w(TAG, "getBackupPayload: error writing payload", e);

        }

        return null;

    }



    @Override

    public void applyRestore(byte[] payload) {

        enforceSystemCaller();

        if (LOGD) Slog.d(TAG, "applyRestore payload="

                + (payload != null ? new String(payload, StandardCharsets.UTF_8) : null));

        if (payload == null) {

            Slog.w(TAG, "applyRestore: no payload to restore");

            return;

        }



        // clear any existing policy and read from disk

        mNetworkPolicy.clear();

        mSubscriptionPlans.clear();

        mSubscriptionPlansOwner.clear();

        mUidPolicy.clear();



        final ByteArrayInputStream bais = new ByteArrayInputStream(payload);

        try {

            readPolicyXml(bais, true);

        } catch (IOException | XmlPullParserException e) {

            Slog.w(TAG, "applyRestore: error reading payload", e);

        }

    }



    @Override

    public void setUidPolicy(int uid, int policy) {

        mContext.enforceCallingOrSelfPermission(MANAGE_NETWORK_POLICY, TAG);
@@ -2810,6 +2860,12 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        }

    }



    private void enforceSystemCaller() {

        if (Binder.getCallingUid() != android.os.Process.SYSTEM_UID) {

            throw new SecurityException("Caller must be system");

        }

    }



    @Override

    public void registerListener(INetworkPolicyListener listener) {

        // TODO: Remove CONNECTIVITY_INTERNAL and the *AnyPermissionOf methods above after all apps
@@ -5502,6 +5558,19 @@ public class NetworkPolicyManagerService extends INetworkPolicyManager.Stub { 
        }

    }



    private int readUidAttribute(XmlPullParser in, boolean forRestore) throws IOException {

        if (!forRestore) {

            return readIntAttribute(in, ATTR_UID);

        } else {

            return getUidForPackage(readStringAttribute(in, ATTR_XML_UTILS_NAME),

                    readIntAttribute(in, ATTR_USER_ID));

        }

    }



    private String getPackageForUid(int uid) {

        return mContext.getPackageManager().getPackagesForUid(uid)[0];

    }



    private int getUidForPackage(String packageName, int userId) {

        try {

            return mContext.getPackageManager().getPackageUidAsUser(packageName,