Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2013 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.server.firewall; |
| 18 | |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 19 | import android.app.AppGlobals; |
Ben Gruver | f5323fe | 2013-07-31 15:09:51 -0700 | [diff] [blame] | 20 | import android.content.ComponentName; |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 21 | import android.content.Intent; |
| 22 | import android.content.pm.ApplicationInfo; |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 23 | import android.content.pm.IPackageManager; |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 24 | import android.os.Process; |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 25 | import android.os.RemoteException; |
| 26 | import android.util.Slog; |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 27 | import org.xmlpull.v1.XmlPullParser; |
| 28 | import org.xmlpull.v1.XmlPullParserException; |
| 29 | |
| 30 | import java.io.IOException; |
| 31 | |
| 32 | class SenderFilter { |
| 33 | private static final String ATTR_TYPE = "type"; |
| 34 | |
| 35 | private static final String VAL_SIGNATURE = "signature"; |
| 36 | private static final String VAL_SYSTEM = "system"; |
| 37 | private static final String VAL_SYSTEM_OR_SIGNATURE = "system|signature"; |
| 38 | private static final String VAL_USER_ID = "userId"; |
| 39 | |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 40 | static boolean isPrivilegedApp(int callerUid, int callerPid) { |
| 41 | if (callerUid == Process.SYSTEM_UID || callerUid == 0 || |
| 42 | callerPid == Process.myPid() || callerPid == 0) { |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 43 | return true; |
| 44 | } |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 45 | |
| 46 | IPackageManager pm = AppGlobals.getPackageManager(); |
| 47 | try { |
| 48 | return (pm.getFlagsForUid(callerUid) & ApplicationInfo.FLAG_PRIVILEGED) != 0; |
| 49 | } catch (RemoteException ex) { |
| 50 | Slog.e(IntentFirewall.TAG, "Remote exception while retrieving uid flags", |
| 51 | ex); |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 52 | } |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 53 | |
| 54 | return false; |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 55 | } |
| 56 | |
| 57 | public static final FilterFactory FACTORY = new FilterFactory("sender") { |
| 58 | @Override |
| 59 | public Filter newFilter(XmlPullParser parser) throws IOException, XmlPullParserException { |
| 60 | String typeString = parser.getAttributeValue(null, ATTR_TYPE); |
| 61 | if (typeString == null) { |
| 62 | throw new XmlPullParserException("type attribute must be specified for <sender>", |
| 63 | parser, null); |
| 64 | } |
| 65 | if (typeString.equals(VAL_SYSTEM)) { |
| 66 | return SYSTEM; |
| 67 | } else if (typeString.equals(VAL_SIGNATURE)) { |
| 68 | return SIGNATURE; |
| 69 | } else if (typeString.equals(VAL_SYSTEM_OR_SIGNATURE)) { |
| 70 | return SYSTEM_OR_SIGNATURE; |
| 71 | } else if (typeString.equals(VAL_USER_ID)) { |
| 72 | return USER_ID; |
| 73 | } |
| 74 | throw new XmlPullParserException( |
| 75 | "Invalid type attribute for <sender>: " + typeString, parser, null); |
| 76 | } |
| 77 | }; |
| 78 | |
| 79 | private static final Filter SIGNATURE = new Filter() { |
| 80 | @Override |
Ben Gruver | f5323fe | 2013-07-31 15:09:51 -0700 | [diff] [blame] | 81 | public boolean matches(IntentFirewall ifw, ComponentName resolvedComponent, Intent intent, |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 82 | int callerUid, int callerPid, String resolvedType, int receivingUid) { |
| 83 | return ifw.signaturesMatch(callerUid, receivingUid); |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 84 | } |
| 85 | }; |
| 86 | |
| 87 | private static final Filter SYSTEM = new Filter() { |
| 88 | @Override |
Ben Gruver | f5323fe | 2013-07-31 15:09:51 -0700 | [diff] [blame] | 89 | public boolean matches(IntentFirewall ifw, ComponentName resolvedComponent, Intent intent, |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 90 | int callerUid, int callerPid, String resolvedType, int receivingUid) { |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 91 | return isPrivilegedApp(callerUid, callerPid); |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 92 | } |
| 93 | }; |
| 94 | |
| 95 | private static final Filter SYSTEM_OR_SIGNATURE = new Filter() { |
| 96 | @Override |
Ben Gruver | f5323fe | 2013-07-31 15:09:51 -0700 | [diff] [blame] | 97 | public boolean matches(IntentFirewall ifw, ComponentName resolvedComponent, Intent intent, |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 98 | int callerUid, int callerPid, String resolvedType, int receivingUid) { |
Ben Gruver | dd72c9e | 2013-08-06 12:34:17 -0700 | [diff] [blame] | 99 | return isPrivilegedApp(callerUid, callerPid) || |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 100 | ifw.signaturesMatch(callerUid, receivingUid); |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 101 | } |
| 102 | }; |
| 103 | |
| 104 | private static final Filter USER_ID = new Filter() { |
| 105 | @Override |
Ben Gruver | f5323fe | 2013-07-31 15:09:51 -0700 | [diff] [blame] | 106 | public boolean matches(IntentFirewall ifw, ComponentName resolvedComponent, Intent intent, |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 107 | int callerUid, int callerPid, String resolvedType, int receivingUid) { |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 108 | // This checks whether the caller is either the system process, or has the same user id |
| 109 | // I.e. the same app, or an app that uses the same shared user id. |
| 110 | // This is the same set of applications that would be able to access the component if |
| 111 | // it wasn't exported. |
Ben Gruver | 49660c7 | 2013-08-06 19:54:08 -0700 | [diff] [blame] | 112 | return ifw.checkComponentPermission(null, callerPid, callerUid, receivingUid, false); |
Ben Gruver | 4efe940 | 2013-04-02 21:18:41 -0700 | [diff] [blame] | 113 | } |
| 114 | }; |
| 115 | } |