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/*
* Copyright (C) 2013 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.updates;
import android.content.Context;
import android.content.Intent;
import android.os.SystemProperties;
import android.provider.Settings;
import android.util.Base64;
import android.util.Slog;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import libcore.io.ErrnoException;
import libcore.io.IoUtils;
import libcore.io.Libcore;
public class SELinuxPolicyInstallReceiver extends ConfigUpdateInstallReceiver {
private static final String TAG = "SELinuxPolicyInstallReceiver";
private static final String sepolicyPath = "sepolicy";
private static final String fileContextsPath = "file_contexts";
private static final String propertyContextsPath = "property_contexts";
private static final String seappContextsPath = "seapp_contexts";
public SELinuxPolicyInstallReceiver() {
super("/data/security/bundle", "sepolicy_bundle", "metadata/", "version");
}
private void backupContexts(File contexts) {
new File(contexts, seappContextsPath).renameTo(
new File(contexts, seappContextsPath + "_backup"));
new File(contexts, propertyContextsPath).renameTo(
new File(contexts, propertyContextsPath + "_backup"));
new File(contexts, fileContextsPath).renameTo(
new File(contexts, fileContextsPath + "_backup"));
new File(contexts, sepolicyPath).renameTo(
new File(contexts, sepolicyPath + "_backup"));
}
private void copyUpdate(File contexts) {
new File(updateDir, seappContextsPath).renameTo(new File(contexts, seappContextsPath));
new File(updateDir, propertyContextsPath).renameTo(new File(contexts, propertyContextsPath));
new File(updateDir, fileContextsPath).renameTo(new File(contexts, fileContextsPath));
new File(updateDir, sepolicyPath).renameTo(new File(contexts, sepolicyPath));
}
private int readInt(BufferedInputStream reader) throws IOException {
int value = 0;
for (int i=0; i < 4; i++) {
value = (value << 8) | reader.read();
}
return value;
}
private int[] readChunkLengths(BufferedInputStream bundle) throws IOException {
int[] chunks = new int[4];
chunks[0] = readInt(bundle);
chunks[1] = readInt(bundle);
chunks[2] = readInt(bundle);
chunks[3] = readInt(bundle);
return chunks;
}
private void installFile(File destination, BufferedInputStream stream, int length)
throws IOException {
byte[] chunk = new byte[length];
stream.read(chunk, 0, length);
writeUpdate(updateDir, destination, Base64.decode(chunk, Base64.DEFAULT));
}
private void unpackBundle() throws IOException {
BufferedInputStream stream = new BufferedInputStream(new FileInputStream(updateContent));
try {
int[] chunkLengths = readChunkLengths(stream);
installFile(new File(updateDir, seappContextsPath), stream, chunkLengths[0]);
installFile(new File(updateDir, propertyContextsPath), stream, chunkLengths[1]);
installFile(new File(updateDir, fileContextsPath), stream, chunkLengths[2]);
installFile(new File(updateDir, sepolicyPath), stream, chunkLengths[3]);
} finally {
IoUtils.closeQuietly(stream);
}
}
private void applyUpdate() throws IOException, ErrnoException {
Slog.i(TAG, "Applying SELinux policy");
File contexts = new File(updateDir.getParentFile(), "contexts");
File current = new File(updateDir.getParentFile(), "current");
File update = new File(updateDir.getParentFile(), "update");
File tmp = new File(updateDir.getParentFile(), "tmp");
if (current.exists()) {
Libcore.os.symlink(updateDir.getPath(), update.getPath());
Libcore.os.rename(update.getPath(), current.getPath());
} else {
Libcore.os.symlink(updateDir.getPath(), current.getPath());
}
contexts.mkdirs();
backupContexts(contexts);
copyUpdate(contexts);
Libcore.os.symlink(contexts.getPath(), tmp.getPath());
Libcore.os.rename(tmp.getPath(), current.getPath());
SystemProperties.set("selinux.reload_policy", "1");
}
private void setEnforcingMode(Context context) {
String mode = Settings.Global.getString(context.getContentResolver(),
Settings.Global.SELINUX_STATUS);
if ("1".equals(mode)) {
Slog.i(TAG, "Setting enforcing mode");
SystemProperties.set("persist.selinux.enforcing", mode);
} else if ("0".equals(mode)) {
Slog.i(TAG, "Tried to set permissive mode, ignoring");
} else {
Slog.e(TAG, "Got invalid enforcing mode: " + mode);
}
}
@Override
protected void postInstall(Context context, Intent intent) {
try {
unpackBundle();
applyUpdate();
setEnforcingMode(context);
} catch (IllegalArgumentException e) {
Slog.e(TAG, "SELinux policy update malformed: ", e);
} catch (IOException e) {
Slog.e(TAG, "Could not update selinux policy: ", e);
} catch (ErrnoException e) {
Slog.e(TAG, "Could not update selinux policy: ", e);
}
}
}
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