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1 /*
2 
3  * Copyright (C) 2017 The Android Open Source Project
4  *
5  * Licensed under the Apache License, Version 2.0 (the "License");
6  * you may not use this file except in compliance with the License.
7  * You may obtain a copy of the License at
8  *
9  *      http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17 
18 package com.android.settings.accounts;
19 
20 import android.accounts.Account;
21 import android.accounts.AuthenticatorDescription;
22 import android.content.ClipData;
23 import android.content.Context;
24 import android.content.Intent;
25 import android.content.pm.ActivityInfo;
26 import android.content.pm.ApplicationInfo;
27 import android.content.pm.PackageManager;
28 import android.content.pm.PackageManager.NameNotFoundException;
29 import android.content.pm.ResolveInfo;
30 import android.content.res.Resources;
31 import android.content.res.Resources.Theme;
32 import android.os.UserHandle;
33 import android.text.TextUtils;
34 import android.util.Log;
35 
36 import androidx.preference.Preference;
37 import androidx.preference.Preference.OnPreferenceClickListener;
38 import androidx.preference.PreferenceFragmentCompat;
39 import androidx.preference.PreferenceGroup;
40 import androidx.preference.PreferenceScreen;
41 
42 import com.android.settings.R;
43 import com.android.settings.core.SubSettingLauncher;
44 import com.android.settings.location.LocationSettings;
45 import com.android.settings.utils.LocalClassLoaderContextThemeWrapper;
46 import com.android.settingslib.accounts.AuthenticatorHelper;
47 import com.android.settingslib.core.instrumentation.Instrumentable;
48 
49 /**
50  * Class to load the preference screen to be added to the settings page for the specific account
51  * type as specified in the account-authenticator.
52  */
53 public class AccountTypePreferenceLoader {
54 
55     private static final String TAG = "AccountTypePrefLoader";
56     private static final String ACCOUNT_KEY = "account"; // to pass to auth settings
57     // Action name for the broadcast intent when the Google account preferences page is launching
58     // the location settings.
59     private static final String LAUNCHING_LOCATION_SETTINGS =
60         "com.android.settings.accounts.LAUNCHING_LOCATION_SETTINGS";
61 
62     private AuthenticatorHelper mAuthenticatorHelper;
63     private UserHandle mUserHandle;
64     private PreferenceFragmentCompat mFragment;
65 
AccountTypePreferenceLoader(PreferenceFragmentCompat fragment, AuthenticatorHelper authenticatorHelper, UserHandle userHandle)66     public AccountTypePreferenceLoader(PreferenceFragmentCompat fragment,
67             AuthenticatorHelper authenticatorHelper, UserHandle userHandle) {
68         mFragment = fragment;
69         mAuthenticatorHelper = authenticatorHelper;
70         mUserHandle = userHandle;
71     }
72 
73     /**
74      * Gets the preferences.xml file associated with a particular account type.
75      * @param accountType the type of account
76      * @return a PreferenceScreen inflated from accountPreferenceId.
77      */
addPreferencesForType(final String accountType, PreferenceScreen parent)78     public PreferenceScreen addPreferencesForType(final String accountType,
79             PreferenceScreen parent) {
80         PreferenceScreen prefs = null;
81         if (mAuthenticatorHelper.containsAccountType(accountType)) {
82             AuthenticatorDescription desc = null;
83             try {
84                 desc = mAuthenticatorHelper.getAccountTypeDescription(accountType);
85                 if (desc != null && desc.accountPreferencesId != 0) {
86                     // Load the context of the target package, then apply the
87                     // base Settings theme (no references to local resources)
88                     // and create a context theme wrapper so that we get the
89                     // correct text colors. Control colors will still be wrong,
90                     // but there's not much we can do about it since we can't
91                     // reference local color resources.
92                     final Context targetCtx = mFragment.getActivity().createPackageContextAsUser(
93                             desc.packageName, 0, mUserHandle);
94                     final Theme baseTheme = mFragment.getResources().newTheme();
95                     baseTheme.applyStyle(R.style.Theme_SettingsBase, true);
96                     final Context themedCtx =
97                             new LocalClassLoaderContextThemeWrapper(getClass(), targetCtx, 0);
98                     themedCtx.getTheme().setTo(baseTheme);
99                     prefs = mFragment.getPreferenceManager().inflateFromResource(themedCtx,
100                             desc.accountPreferencesId, parent);
101                 }
102             } catch (PackageManager.NameNotFoundException e) {
103                 Log.w(TAG, "Couldn't load preferences.xml file from " + desc.packageName);
104             } catch (Resources.NotFoundException e) {
105                 Log.w(TAG, "Couldn't load preferences.xml file from " + desc.packageName);
106             }
107         }
108         return prefs;
109     }
110 
111     /**
112      * Recursively filters through the preference list provided by GoogleLoginService.
113      *
114      * This method removes all the invalid intent from the list, adds account name as extra into the
115      * intent, and hack the location settings to start it as a fragment.
116      */
updatePreferenceIntents(PreferenceGroup prefs, final String acccountType, Account account)117     public void updatePreferenceIntents(PreferenceGroup prefs, final String acccountType,
118             Account account) {
119         final PackageManager pm = mFragment.getActivity().getPackageManager();
120         for (int i = 0; i < prefs.getPreferenceCount(); ) {
121             Preference pref = prefs.getPreference(i);
122             if (pref instanceof PreferenceGroup) {
123                 updatePreferenceIntents((PreferenceGroup) pref, acccountType, account);
124             }
125             Intent intent = pref.getIntent();
126             if (intent != null) {
127                 // Hack. Launch "Location" as fragment instead of as activity.
128                 //
129                 // When "Location" is launched as activity via Intent, there's no "Up" button at the
130                 // top left, and if there's another running instance of "Location" activity, the
131                 // back stack would usually point to some other place so the user won't be able to
132                 // go back to the previous page by "back" key. Using fragment is a much easier
133                 // solution to those problems.
134                 //
135                 // If we set Intent to null and assign a fragment to the PreferenceScreen item here,
136                 // in order to make it work as expected, we still need to modify the container
137                 // PreferenceActivity, override onPreferenceStartFragment() and call
138                 // startPreferencePanel() there. In order to inject the title string there, more
139                 // dirty further hack is still needed. It's much easier and cleaner to listen to
140                 // preference click event here directly.
141                 if (TextUtils.equals(intent.getAction(),
142                         android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS)) {
143                     // The OnPreferenceClickListener overrides the click event completely. No intent
144                     // will get fired.
145                     pref.setOnPreferenceClickListener(new FragmentStarter(
146                         LocationSettings.class.getName(), R.string.location_settings_title));
147                 } else {
148                     ResolveInfo ri = pm.resolveActivityAsUser(intent,
149                         PackageManager.MATCH_DEFAULT_ONLY, mUserHandle.getIdentifier());
150                     if (ri == null) {
151                         prefs.removePreference(pref);
152                         continue;
153                     }
154                     intent.putExtra(ACCOUNT_KEY, account);
155                     intent.setFlags(intent.getFlags() | Intent.FLAG_ACTIVITY_NEW_TASK);
156                     pref.setOnPreferenceClickListener(new OnPreferenceClickListener() {
157                         @Override
158                         public boolean onPreferenceClick(Preference preference) {
159                             Intent prefIntent = preference.getIntent();
160                                 /*
161                                  * Check the intent to see if it resolves to a exported=false
162                                  * activity that doesn't share a uid with the authenticator.
163                                  *
164                                  * Otherwise the intent is considered unsafe in that it will be
165                                  * exploiting the fact that settings has system privileges.
166                                  */
167                             if (isSafeIntent(pm, prefIntent, acccountType)) {
168                                 // Explicitly set an empty ClipData to ensure that we don't offer to
169                                 // promote any Uris contained inside for granting purposes
170                                 prefIntent.setClipData(ClipData.newPlainText(null, null));
171                                 mFragment.getActivity().startActivityAsUser(
172                                     prefIntent, mUserHandle);
173                             } else {
174                                 Log.e(TAG,
175                                     "Refusing to launch authenticator intent because"
176                                         + "it exploits Settings permissions: "
177                                         + prefIntent);
178                             }
179                             return true;
180                         }
181                     });
182                 }
183             }
184             i++;
185         }
186     }
187 
188     /**
189      * Determines if the supplied Intent is safe. A safe intent is one that is
190      * will launch a exported=true activity or owned by the same uid as the
191      * authenticator supplying the intent.
192      */
isSafeIntent(PackageManager pm, Intent intent, String acccountType)193     private boolean isSafeIntent(PackageManager pm, Intent intent, String acccountType) {
194         AuthenticatorDescription authDesc =
195             mAuthenticatorHelper.getAccountTypeDescription(acccountType);
196         ResolveInfo resolveInfo = pm.resolveActivityAsUser(intent, 0, mUserHandle.getIdentifier());
197         if (resolveInfo == null) {
198             return false;
199         }
200         ActivityInfo resolvedActivityInfo = resolveInfo.activityInfo;
201         ApplicationInfo resolvedAppInfo = resolvedActivityInfo.applicationInfo;
202         try {
203             // Allows to launch only authenticator owned activities.
204             ApplicationInfo authenticatorAppInf = pm.getApplicationInfo(authDesc.packageName, 0);
205             return resolvedAppInfo.uid == authenticatorAppInf.uid;
206         } catch (NameNotFoundException e) {
207             Log.e(TAG,
208                 "Intent considered unsafe due to exception.",
209                 e);
210             return false;
211         }
212     }
213 
214     /** Listens to a preference click event and starts a fragment */
215     private class FragmentStarter
216         implements Preference.OnPreferenceClickListener {
217         private final String mClass;
218         private final int mTitleRes;
219 
220         /**
221          * @param className the class name of the fragment to be started.
222          * @param title the title resource id of the started preference panel.
223          */
FragmentStarter(String className, int title)224         public FragmentStarter(String className, int title) {
225             mClass = className;
226             mTitleRes = title;
227         }
228 
229         @Override
onPreferenceClick(Preference preference)230         public boolean onPreferenceClick(Preference preference) {
231             final int metricsCategory = (mFragment instanceof Instrumentable)
232                     ? ((Instrumentable) mFragment).getMetricsCategory()
233                     : Instrumentable.METRICS_CATEGORY_UNKNOWN;
234             new SubSettingLauncher(preference.getContext())
235                     .setTitleRes(mTitleRes)
236                     .setDestination(mClass)
237                     .setSourceMetricsCategory(metricsCategory)
238                     .launch();
239 
240             // Hack: announce that the Google account preferences page is launching the location
241             // settings
242             if (mClass.equals(LocationSettings.class.getName())) {
243                 Intent intent = new Intent(LAUNCHING_LOCATION_SETTINGS);
244                 mFragment.getActivity().sendBroadcast(
245                     intent, android.Manifest.permission.WRITE_SECURE_SETTINGS);
246             }
247             return true;
248         }
249     }
250 
251 }
252