| /* |
| * Copyright (C) 2012 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.server.pm; |
| |
| import android.content.pm.ApplicationInfo; |
| import android.content.pm.PackageParser; |
| import android.content.pm.Signature; |
| import android.os.Environment; |
| import android.util.Slog; |
| import android.util.Xml; |
| |
| import com.android.internal.util.XmlUtils; |
| |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.FileNotFoundException; |
| import java.io.FileReader; |
| import java.io.IOException; |
| |
| import java.util.HashMap; |
| |
| import org.xmlpull.v1.XmlPullParser; |
| import org.xmlpull.v1.XmlPullParserException; |
| |
| /** |
| * Centralized access to SELinux MMAC (middleware MAC) implementation. |
| * {@hide} |
| */ |
| public final class SELinuxMMAC { |
| |
| private static final String TAG = "SELinuxMMAC"; |
| |
| private static final boolean DEBUG_POLICY = false; |
| private static final boolean DEBUG_POLICY_INSTALL = DEBUG_POLICY || false; |
| |
| // Signature seinfo values read from policy. |
| private static final HashMap<Signature, String> sSigSeinfo = |
| new HashMap<Signature, String>(); |
| |
| // Package name seinfo values read from policy. |
| private static final HashMap<String, String> sPackageSeinfo = |
| new HashMap<String, String>(); |
| |
| // Locations of potential install policy files. |
| private static final File[] INSTALL_POLICY_FILE = { |
| new File(Environment.getDataDirectory(), "security/mac_permissions.xml"), |
| new File(Environment.getRootDirectory(), "etc/security/mac_permissions.xml"), |
| null}; |
| |
| private static void flushInstallPolicy() { |
| sSigSeinfo.clear(); |
| sPackageSeinfo.clear(); |
| } |
| |
| /** |
| * Parses an MMAC install policy from a predefined list of locations. |
| * @param none |
| * @return boolean indicating whether an install policy was correctly parsed. |
| */ |
| public static boolean readInstallPolicy() { |
| |
| return readInstallPolicy(INSTALL_POLICY_FILE); |
| } |
| |
| /** |
| * Parses an MMAC install policy given as an argument. |
| * @param File object representing the path of the policy. |
| * @return boolean indicating whether the install policy was correctly parsed. |
| */ |
| public static boolean readInstallPolicy(File policyFile) { |
| |
| return readInstallPolicy(new File[]{policyFile,null}); |
| } |
| |
| private static boolean readInstallPolicy(File[] policyFiles) { |
| |
| FileReader policyFile = null; |
| int i = 0; |
| while (policyFile == null && policyFiles != null && policyFiles[i] != null) { |
| try { |
| policyFile = new FileReader(policyFiles[i]); |
| break; |
| } catch (FileNotFoundException e) { |
| Slog.d(TAG,"Couldn't find install policy " + policyFiles[i].getPath()); |
| } |
| i++; |
| } |
| |
| if (policyFile == null) { |
| Slog.d(TAG, "No policy file found. All seinfo values will be null."); |
| return false; |
| } |
| |
| Slog.d(TAG, "Using install policy file " + policyFiles[i].getPath()); |
| |
| flushInstallPolicy(); |
| |
| try { |
| XmlPullParser parser = Xml.newPullParser(); |
| parser.setInput(policyFile); |
| |
| XmlUtils.beginDocument(parser, "policy"); |
| while (true) { |
| XmlUtils.nextElement(parser); |
| if (parser.getEventType() == XmlPullParser.END_DOCUMENT) { |
| break; |
| } |
| |
| String tagName = parser.getName(); |
| if ("signer".equals(tagName)) { |
| String cert = parser.getAttributeValue(null, "signature"); |
| if (cert == null) { |
| Slog.w(TAG, "<signer> without signature at " |
| + parser.getPositionDescription()); |
| XmlUtils.skipCurrentTag(parser); |
| continue; |
| } |
| Signature signature; |
| try { |
| signature = new Signature(cert); |
| } catch (IllegalArgumentException e) { |
| Slog.w(TAG, "<signer> with bad signature at " |
| + parser.getPositionDescription(), e); |
| XmlUtils.skipCurrentTag(parser); |
| continue; |
| } |
| String seinfo = readSeinfoTag(parser); |
| if (seinfo != null) { |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "<signer> tag: (" + cert + ") assigned seinfo=" |
| + seinfo); |
| |
| sSigSeinfo.put(signature, seinfo); |
| } |
| } else if ("default".equals(tagName)) { |
| String seinfo = readSeinfoTag(parser); |
| if (seinfo != null) { |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "<default> tag assigned seinfo=" + seinfo); |
| |
| // The 'null' signature is the default seinfo value |
| sSigSeinfo.put(null, seinfo); |
| } |
| } else if ("package".equals(tagName)) { |
| String pkgName = parser.getAttributeValue(null, "name"); |
| if (pkgName == null) { |
| Slog.w(TAG, "<package> without name at " |
| + parser.getPositionDescription()); |
| XmlUtils.skipCurrentTag(parser); |
| continue; |
| } |
| String seinfo = readSeinfoTag(parser); |
| if (seinfo != null) { |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "<package> tag: (" + pkgName + |
| ") assigned seinfo=" + seinfo); |
| |
| sPackageSeinfo.put(pkgName, seinfo); |
| } |
| } else { |
| XmlUtils.skipCurrentTag(parser); |
| continue; |
| } |
| } |
| } catch (XmlPullParserException e) { |
| Slog.w(TAG, "Got execption parsing ", e); |
| } catch (IOException e) { |
| Slog.w(TAG, "Got execption parsing ", e); |
| } |
| try { |
| policyFile.close(); |
| } catch (IOException e) { |
| //omit |
| } |
| return true; |
| } |
| |
| private static String readSeinfoTag(XmlPullParser parser) throws |
| IOException, XmlPullParserException { |
| |
| int type; |
| int outerDepth = parser.getDepth(); |
| String seinfo = null; |
| while ((type=parser.next()) != XmlPullParser.END_DOCUMENT |
| && (type != XmlPullParser.END_TAG |
| || parser.getDepth() > outerDepth)) { |
| if (type == XmlPullParser.END_TAG |
| || type == XmlPullParser.TEXT) { |
| continue; |
| } |
| |
| String tagName = parser.getName(); |
| if ("seinfo".equals(tagName)) { |
| String seinfoValue = parser.getAttributeValue(null, "value"); |
| if (validateValue(seinfoValue)) { |
| seinfo = seinfoValue; |
| } else { |
| Slog.w(TAG, "<seinfo> without valid value at " |
| + parser.getPositionDescription()); |
| } |
| } |
| XmlUtils.skipCurrentTag(parser); |
| } |
| return seinfo; |
| } |
| |
| /** |
| * General validation routine for tag values. |
| * Returns a boolean indicating if the passed string |
| * contains only letters or underscores. |
| */ |
| private static boolean validateValue(String name) { |
| if (name == null) |
| return false; |
| |
| final int N = name.length(); |
| if (N == 0) |
| return false; |
| |
| for (int i = 0; i < N; i++) { |
| final char c = name.charAt(i); |
| if ((c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && (c != '_')) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * Labels a package based on an seinfo tag from install policy. |
| * The label is attached to the ApplicationInfo instance of the package. |
| * @param PackageParser.Package object representing the package |
| * to labeled. |
| * @return String holding the value of the seinfo label that was assigned. |
| * Value may be null which indicates no seinfo label was assigned. |
| */ |
| public static void assignSeinfoValue(PackageParser.Package pkg) { |
| |
| /* |
| * Non system installed apps should be treated the same. This |
| * means that any post-loaded apk will be assigned the default |
| * tag, if one exists in the policy, else null, without respect |
| * to the signing key. |
| */ |
| if (((pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0) || |
| ((pkg.applicationInfo.flags & ApplicationInfo.FLAG_UPDATED_SYSTEM_APP) != 0)) { |
| |
| // We just want one of the signatures to match. |
| for (Signature s : pkg.mSignatures) { |
| if (s == null) |
| continue; |
| |
| if (sSigSeinfo.containsKey(s)) { |
| String seinfo = pkg.applicationInfo.seinfo = sSigSeinfo.get(s); |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "package (" + pkg.packageName + |
| ") labeled with seinfo=" + seinfo); |
| |
| return; |
| } |
| } |
| |
| // Check for seinfo labeled by package. |
| if (sPackageSeinfo.containsKey(pkg.packageName)) { |
| String seinfo = pkg.applicationInfo.seinfo = sPackageSeinfo.get(pkg.packageName); |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "package (" + pkg.packageName + |
| ") labeled with seinfo=" + seinfo); |
| return; |
| } |
| } |
| |
| // If we have a default seinfo value then great, otherwise |
| // we set a null object and that is what we started with. |
| String seinfo = pkg.applicationInfo.seinfo = sSigSeinfo.get(null); |
| if (DEBUG_POLICY_INSTALL) |
| Slog.i(TAG, "package (" + pkg.packageName + |
| ") labeled with seinfo=" + (seinfo == null ? "null" : seinfo)); |
| } |
| } |