265 lines
11 KiB
Java
265 lines
11 KiB
Java
/*
|
|
* 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.updates;
|
|
|
|
import android.content.BroadcastReceiver;
|
|
import android.content.ContentResolver;
|
|
import android.content.Context;
|
|
import android.content.Intent;
|
|
import android.provider.Settings;
|
|
import android.os.FileUtils;
|
|
import android.util.Base64;
|
|
import android.util.EventLog;
|
|
import android.util.Slog;
|
|
|
|
import com.android.server.EventLogTags;
|
|
|
|
import java.io.ByteArrayInputStream;
|
|
import java.io.File;
|
|
import java.io.FileNotFoundException;
|
|
import java.io.FileOutputStream;
|
|
import java.io.InputStream;
|
|
import java.io.IOException;
|
|
import java.security.cert.Certificate;
|
|
import java.security.cert.CertificateException;
|
|
import java.security.cert.CertificateFactory;
|
|
import java.security.cert.X509Certificate;
|
|
import java.security.MessageDigest;
|
|
import java.security.NoSuchAlgorithmException;
|
|
import java.security.Signature;
|
|
import java.security.SignatureException;
|
|
|
|
import libcore.io.IoUtils;
|
|
|
|
public class ConfigUpdateInstallReceiver extends BroadcastReceiver {
|
|
|
|
private static final String TAG = "ConfigUpdateInstallReceiver";
|
|
|
|
private static final String EXTRA_CONTENT_PATH = "CONTENT_PATH";
|
|
private static final String EXTRA_REQUIRED_HASH = "REQUIRED_HASH";
|
|
private static final String EXTRA_SIGNATURE = "SIGNATURE";
|
|
private static final String EXTRA_VERSION_NUMBER = "VERSION";
|
|
|
|
private static final String UPDATE_CERTIFICATE_KEY = "config_update_certificate";
|
|
|
|
private final File updateDir;
|
|
private final File updateContent;
|
|
private final File updateVersion;
|
|
|
|
public ConfigUpdateInstallReceiver(String updateDir, String updateContentPath,
|
|
String updateMetadataPath, String updateVersionPath) {
|
|
this.updateDir = new File(updateDir);
|
|
this.updateContent = new File(updateDir, updateContentPath);
|
|
File updateMetadataDir = new File(updateDir, updateMetadataPath);
|
|
this.updateVersion = new File(updateMetadataDir, updateVersionPath);
|
|
}
|
|
|
|
@Override
|
|
public void onReceive(final Context context, final Intent intent) {
|
|
new Thread() {
|
|
@Override
|
|
public void run() {
|
|
try {
|
|
// get the certificate from Settings.Secure
|
|
X509Certificate cert = getCert(context.getContentResolver());
|
|
// get the content path from the extras
|
|
byte[] altContent = getAltContent(intent);
|
|
// get the version from the extras
|
|
int altVersion = getVersionFromIntent(intent);
|
|
// get the previous value from the extras
|
|
String altRequiredHash = getRequiredHashFromIntent(intent);
|
|
// get the signature from the extras
|
|
String altSig = getSignatureFromIntent(intent);
|
|
// get the version currently being used
|
|
int currentVersion = getCurrentVersion();
|
|
// get the hash of the currently used value
|
|
String currentHash = getCurrentHash(getCurrentContent());
|
|
if (!verifyVersion(currentVersion, altVersion)) {
|
|
Slog.i(TAG, "Not installing, new version is <= current version");
|
|
} else if (!verifyPreviousHash(currentHash, altRequiredHash)) {
|
|
EventLog.writeEvent(EventLogTags.CONFIG_INSTALL_FAILED,
|
|
"Current hash did not match required value");
|
|
} else if (!verifySignature(altContent, altVersion, altRequiredHash, altSig,
|
|
cert)) {
|
|
EventLog.writeEvent(EventLogTags.CONFIG_INSTALL_FAILED,
|
|
"Signature did not verify");
|
|
} else {
|
|
// install the new content
|
|
Slog.i(TAG, "Found new update, installing...");
|
|
install(altContent, altVersion);
|
|
Slog.i(TAG, "Installation successful");
|
|
postInstall(context, intent);
|
|
}
|
|
} catch (Exception e) {
|
|
Slog.e(TAG, "Could not update content!", e);
|
|
// keep the error message <= 100 chars
|
|
String errMsg = e.toString();
|
|
if (errMsg.length() > 100) {
|
|
errMsg = errMsg.substring(0, 99);
|
|
}
|
|
EventLog.writeEvent(EventLogTags.CONFIG_INSTALL_FAILED, errMsg);
|
|
}
|
|
}
|
|
}.start();
|
|
}
|
|
|
|
private X509Certificate getCert(ContentResolver cr) {
|
|
// get the cert from settings
|
|
String cert = Settings.Secure.getString(cr, UPDATE_CERTIFICATE_KEY);
|
|
// convert it into a real certificate
|
|
try {
|
|
byte[] derCert = Base64.decode(cert.getBytes(), Base64.DEFAULT);
|
|
InputStream istream = new ByteArrayInputStream(derCert);
|
|
CertificateFactory cf = CertificateFactory.getInstance("X.509");
|
|
return (X509Certificate) cf.generateCertificate(istream);
|
|
} catch (CertificateException e) {
|
|
throw new IllegalStateException("Got malformed certificate from settings, ignoring");
|
|
}
|
|
}
|
|
|
|
private String getContentFromIntent(Intent i) {
|
|
String extraValue = i.getStringExtra(EXTRA_CONTENT_PATH);
|
|
if (extraValue == null) {
|
|
throw new IllegalStateException("Missing required content path, ignoring.");
|
|
}
|
|
return extraValue;
|
|
}
|
|
|
|
private int getVersionFromIntent(Intent i) throws NumberFormatException {
|
|
String extraValue = i.getStringExtra(EXTRA_VERSION_NUMBER);
|
|
if (extraValue == null) {
|
|
throw new IllegalStateException("Missing required version number, ignoring.");
|
|
}
|
|
return Integer.parseInt(extraValue.trim());
|
|
}
|
|
|
|
private String getRequiredHashFromIntent(Intent i) {
|
|
String extraValue = i.getStringExtra(EXTRA_REQUIRED_HASH);
|
|
if (extraValue == null) {
|
|
throw new IllegalStateException("Missing required previous hash, ignoring.");
|
|
}
|
|
return extraValue.trim();
|
|
}
|
|
|
|
private String getSignatureFromIntent(Intent i) {
|
|
String extraValue = i.getStringExtra(EXTRA_SIGNATURE);
|
|
if (extraValue == null) {
|
|
throw new IllegalStateException("Missing required signature, ignoring.");
|
|
}
|
|
return extraValue.trim();
|
|
}
|
|
|
|
private int getCurrentVersion() throws NumberFormatException {
|
|
try {
|
|
String strVersion = IoUtils.readFileAsString(updateVersion.getCanonicalPath()).trim();
|
|
return Integer.parseInt(strVersion);
|
|
} catch (IOException e) {
|
|
Slog.i(TAG, "Couldn't find current metadata, assuming first update");
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
private byte[] getAltContent(Intent i) throws IOException {
|
|
return IoUtils.readFileAsByteArray(getContentFromIntent(i));
|
|
}
|
|
|
|
private byte[] getCurrentContent() {
|
|
try {
|
|
return IoUtils.readFileAsByteArray(updateContent.getCanonicalPath());
|
|
} catch (IOException e) {
|
|
Slog.i(TAG, "Failed to read current content, assuming first update!");
|
|
return null;
|
|
}
|
|
}
|
|
|
|
private static String getCurrentHash(byte[] content) {
|
|
if (content == null) {
|
|
return "0";
|
|
}
|
|
try {
|
|
MessageDigest dgst = MessageDigest.getInstance("SHA512");
|
|
byte[] fingerprint = dgst.digest(content);
|
|
return IntegralToString.bytesToHexString(fingerprint, false);
|
|
} catch (NoSuchAlgorithmException e) {
|
|
throw new AssertionError(e);
|
|
}
|
|
}
|
|
|
|
private boolean verifyVersion(int current, int alternative) {
|
|
return (current < alternative);
|
|
}
|
|
|
|
private boolean verifyPreviousHash(String current, String required) {
|
|
// this is an optional value- if the required field is NONE then we ignore it
|
|
if (required.equals("NONE")) {
|
|
return true;
|
|
}
|
|
// otherwise, verify that we match correctly
|
|
return current.equals(required);
|
|
}
|
|
|
|
private boolean verifySignature(byte[] content, int version, String requiredPrevious,
|
|
String signature, X509Certificate cert) throws Exception {
|
|
Signature signer = Signature.getInstance("SHA512withRSA");
|
|
signer.initVerify(cert);
|
|
signer.update(content);
|
|
signer.update(Long.toString(version).getBytes());
|
|
signer.update(requiredPrevious.getBytes());
|
|
return signer.verify(Base64.decode(signature.getBytes(), Base64.DEFAULT));
|
|
}
|
|
|
|
private void writeUpdate(File dir, File file, byte[] content) throws IOException {
|
|
FileOutputStream out = null;
|
|
File tmp = null;
|
|
try {
|
|
// create the parents for the destination file
|
|
File parent = file.getParentFile();
|
|
parent.mkdirs();
|
|
// check that they were created correctly
|
|
if (!parent.exists()) {
|
|
throw new IOException("Failed to create directory " + parent.getCanonicalPath());
|
|
}
|
|
// create the temporary file
|
|
tmp = File.createTempFile("journal", "", dir);
|
|
// mark tmp -rw-r--r--
|
|
tmp.setReadable(true, false);
|
|
// write to it
|
|
out = new FileOutputStream(tmp);
|
|
out.write(content);
|
|
// sync to disk
|
|
out.getFD().sync();
|
|
// atomic rename
|
|
if (!tmp.renameTo(file)) {
|
|
throw new IOException("Failed to atomically rename " + file.getCanonicalPath());
|
|
}
|
|
} finally {
|
|
if (tmp != null) {
|
|
tmp.delete();
|
|
}
|
|
IoUtils.closeQuietly(out);
|
|
}
|
|
}
|
|
|
|
protected void install(byte[] content, int version) throws IOException {
|
|
writeUpdate(updateDir, updateContent, content);
|
|
writeUpdate(updateDir, updateVersion, Long.toString(version).getBytes());
|
|
}
|
|
|
|
protected void postInstall(Context context, Intent intent) {
|
|
}
|
|
}
|