/*
* Copyright (C) 2008 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.signapk;
import org.bouncycastle.asn1.ASN1InputStream;
import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.DEROutputStream;
import org.bouncycastle.asn1.cms.CMSObjectIdentifiers;
import org.bouncycastle.cert.jcajce.JcaCertStore;
import org.bouncycastle.cms.CMSException;
import org.bouncycastle.cms.CMSProcessableByteArray;
import org.bouncycastle.cms.CMSSignedData;
import org.bouncycastle.cms.CMSSignedDataGenerator;
import org.bouncycastle.cms.CMSTypedData;
import org.bouncycastle.cms.jcajce.JcaSignerInfoGeneratorBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.operator.ContentSigner;
import org.bouncycastle.operator.OperatorCreationException;
import org.bouncycastle.operator.jcajce.JcaContentSignerBuilder;
import org.bouncycastle.operator.jcajce.JcaDigestCalculatorProviderBuilder;
import org.bouncycastle.util.encoders.Base64;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
import java.security.DigestOutputStream;
import java.security.GeneralSecurityException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.MessageDigest;
import java.security.PrivateKey;
import java.security.Provider;
import java.security.Security;
import java.security.cert.CertificateEncodingException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.KeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.Map;
import java.util.TreeMap;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.JarOutputStream;
import java.util.jar.Manifest;
import java.util.regex.Pattern;
import javax.crypto.Cipher;
import javax.crypto.EncryptedPrivateKeyInfo;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
/**
* Command line tool to sign JAR files (including APKs and OTA updates) in
* a way compatible with the mincrypt verifier, using SHA1 and RSA keys.
*/
class SignApk {
private static final String CERT_SF_NAME = "META-INF/CERT.SF";
private static final String CERT_RSA_NAME = "META-INF/CERT.RSA";
private static final String OTACERT_NAME = "META-INF/com/android/otacert";
private static Provider sBouncyCastleProvider;
// Files matching this pattern are not copied to the output.
private static Pattern stripPattern =
Pattern.compile("^META-INF/(.*)[.](SF|RSA|DSA)$");
private static X509Certificate readPublicKey(File file)
throws IOException, GeneralSecurityException {
FileInputStream input = new FileInputStream(file);
try {
CertificateFactory cf = CertificateFactory.getInstance("X.509");
return (X509Certificate) cf.generateCertificate(input);
} finally {
input.close();
}
}
/**
* Reads the password from stdin and returns it as a string.
*
* @param keyFile The file containing the private key. Used to prompt the user.
*/
private static String readPassword(File keyFile) {
// TODO: use Console.readPassword() when it's available.
System.out.print("Enter password for " + keyFile + " (password will not be hidden): ");
System.out.flush();
BufferedReader stdin = new BufferedReader(new InputStreamReader(System.in));
try {
return stdin.readLine();
} catch (IOException ex) {
return null;
}
}
/**
* Decrypt an encrypted PKCS 8 format private key.
*
* Based on ghstark's post on Aug 6, 2006 at
* http://forums.sun.com/thread.jspa?threadID=758133&messageID=4330949
*
* @param encryptedPrivateKey The raw data of the private key
* @param keyFile The file containing the private key
*/
private static KeySpec decryptPrivateKey(byte[] encryptedPrivateKey, File keyFile)
throws GeneralSecurityException {
EncryptedPrivateKeyInfo epkInfo;
try {
epkInfo = new EncryptedPrivateKeyInfo(encryptedPrivateKey);
} catch (IOException ex) {
// Probably not an encrypted key.
return null;
}
char[] password = readPassword(keyFile).toCharArray();
SecretKeyFactory skFactory = SecretKeyFactory.getInstance(epkInfo.getAlgName());
Key key = skFactory.generateSecret(new PBEKeySpec(password));
Cipher cipher = Cipher.getInstance(epkInfo.getAlgName());
cipher.init(Cipher.DECRYPT_MODE, key, epkInfo.getAlgParameters());
try {
return epkInfo.getKeySpec(cipher);
} catch (InvalidKeySpecException ex) {
System.err.println("signapk: Password for " + keyFile + " may be bad.");
throw ex;
}
}
/** Read a PKCS 8 format private key. */
private static PrivateKey readPrivateKey(File file)
throws IOException, GeneralSecurityException {
DataInputStream input = new DataInputStream(new FileInputStream(file));
try {
byte[] bytes = new byte[(int) file.length()];
input.read(bytes);
KeySpec spec = decryptPrivateKey(bytes, file);
if (spec == null) {
spec = new PKCS8EncodedKeySpec(bytes);
}
try {
return KeyFactory.getInstance("RSA").generatePrivate(spec);
} catch (InvalidKeySpecException ex) {
return KeyFactory.getInstance("DSA").generatePrivate(spec);
}
} finally {
input.close();
}
}
/** Add the SHA1 of every file to the manifest, creating it if necessary. */
private static Manifest addDigestsToManifest(JarFile jar)
throws IOException, GeneralSecurityException {
Manifest input = jar.getManifest();
Manifest output = new Manifest();
Attributes main = output.getMainAttributes();
if (input != null) {
main.putAll(input.getMainAttributes());
} else {
main.putValue("Manifest-Version", "1.0");
main.putValue("Created-By", "1.0 (Android SignApk)");
}
MessageDigest md = MessageDigest.getInstance("SHA1");
byte[] buffer = new byte[4096];
int num;
// We sort the input entries by name, and add them to the
// output manifest in sorted order. We expect that the output
// map will be deterministic.
TreeMap<String, JarEntry> byName = new TreeMap<String, JarEntry>();
for (Enumeration<JarEntry> e = jar.entries(); e.hasMoreElements(); ) {
JarEntry entry = e.nextElement();
byName.put(entry.getName(), entry);
}
for (JarEntry entry: byName.values()) {
String name = entry.getName();
if (!entry.isDirectory() && !name.equals(JarFile.MANIFEST_NAME) &&
!name.equals(CERT_SF_NAME) && !name.equals(CERT_RSA_NAME) &&
!name.equals(OTACERT_NAME) &&
(stripPattern == null ||
!stripPattern.matcher(name).matches())) {
InputStream data = jar.getInputStream(entry);
while ((num = data.read(buffer)) > 0) {
md.update(buffer, 0, num);
}
Attributes attr = null;
if (input != null) attr = input.getAttributes(name);
attr = attr != null ? new Attributes(attr) : new Attributes();
attr.putValue("SHA1-Digest",
new String(Base64.encode(md.digest()), "ASCII"));
output.getEntries().put(name, attr);
}
}
return output;
}
/**
* Add a copy of the public key to the archive; this should
* exactly match one of the files in
* /system/etc/security/otacerts.zip on the device. (The same
* cert can be extracted from the CERT.RSA file but this is much
* easier to get at.)
*/
private static void addOtacert(JarOutputStream outputJar,
File publicKeyFile,
long timestamp,
Manifest manifest)
throws IOException, GeneralSecurityException {
MessageDigest md = MessageDigest.getInstance("SHA1");
JarEntry je = new JarEntry(OTACERT_NAME);
je.setTime(timestamp);
outputJar.putNextEntry(je);
FileInputStream input = new FileInputStream(publicKeyFile);
byte[] b = new byte[4096];
int read;
while ((read = input.read(b)) != -1) {
outputJar.write(b, 0, read);
md.update(b, 0, read);
}
input.close();
Attributes attr = new Attributes();
attr.putValue("SHA1-Digest",
new String(Base64.encode(md.digest()), "ASCII"));
manifest.getEntries().put(OTACERT_NAME, attr);
}
/** Write to another stream and track how many bytes have been
* written.
*/
private static class CountOutputStream extends FilterOutputStream {
private int mCount;
public CountOutputStream(OutputStream out) {
super(out);
mCount = 0;
}
@Override
public void write(int b) throws IOException {
super.write(b);
mCount++;
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
super.write(b, off, len);
mCount += len;
}
public int size() {
return mCount;
}
}
/** Write a .SF file with a digest of the specified manifest. */
private static void writeSignatureFile(Manifest manifest, OutputStream out)
throws IOException, GeneralSecurityException {
Manifest sf = new Manifest();
Attributes main = sf.getMainAttributes();
main.putValue("Signature-Version", "1.0");
main.putValue("Created-By", "1.0 (Android SignApk)");
MessageDigest md = MessageDigest.getInstance("SHA1");
PrintStream print = new PrintStream(
new DigestOutputStream(new ByteArrayOutputStream(), md),
true, "UTF-8");
// Digest of the entire manifest
manifest.write(print);
print.flush();
main.putValue("SHA1-Digest-Manifest",
new String(Base64.encode(md.digest()), "ASCII"));
Map<String, Attributes> entries = manifest.getEntries();
for (Map.Entry<String, Attributes> entry : entries.entrySet()) {
// Digest of the manifest stanza for this entry.
print.print("Name: " + entry.getKey() + "\r\n");
for (Map.Entry<Object, Object> att : entry.getValue().entrySet()) {
print.print(att.getKey() + ": " + att.getValue() + "\r\n");
}
print.print("\r\n");
print.flush();
Attributes sfAttr = new Attributes();
sfAttr.putValue("SHA1-Digest",
new String(Base64.encode(md.digest()), "ASCII"));
sf.getEntries().put(entry.getKey(), sfAttr);
}
CountOutputStream cout = new CountOutputStream(out);
sf.write(cout);
// A bug in the java.util.jar implementation of Android platforms
// up to version 1.6 will cause a spurious IOException to be thrown
// if the length of the signature file is a multiple of 1024 bytes.
// As a workaround, add an extra CRLF in this case.
if ((cout.size() % 1024) == 0) {
cout.write('\r');
cout.write('\n');
}
}
private static class CMSByteArraySlice implements CMSTypedData {
private final ASN1ObjectIdentifier type;
private final byte[] data;
private final int offset;
private final int length;
public CMSByteArraySlice(byte[] data, int offset, int length) {
this.data = data;
this.offset = offset;
this.length = length;
this.type = new ASN1ObjectIdentifier(CMSObjectIdentifiers.data.getId());
}
public Object getContent() {
throw new UnsupportedOperationException();
}
public ASN1ObjectIdentifier getContentType() {
return type;
}
public void write(OutputStream out) throws IOException {
out.write(data, offset, length);
}
}
/** Sign data and write the digital signature to 'out'. */
private static void writeSignatureBlock(
CMSTypedData data, X509Certificate publicKey, PrivateKey privateKey,
OutputStream out)
throws IOException,
CertificateEncodingException,
OperatorCreationException,
CMSException {
ArrayList<X509Certificate> certList = new ArrayList<X509Certificate>(1);
certList.add(publicKey);
JcaCertStore certs = new JcaCertStore(certList);
CMSSignedDataGenerator gen = new CMSSignedDataGenerator();
ContentSigner sha1Signer = new JcaContentSignerBuilder("SHA1withRSA")
.setProvider(sBouncyCastleProvider)
.build(privateKey);
gen.addSignerInfoGenerator(
new JcaSignerInfoGeneratorBuilder(
new JcaDigestCalculatorProviderBuilder()
.setProvider(sBouncyCastleProvider)
.build())
.setDirectSignature(true)
.build(sha1Signer, publicKey));
gen.addCertificates(certs);
CMSSignedData sigData = gen.generate(data, false);
ASN1InputStream asn1 = new ASN1InputStream(sigData.getEncoded());
DEROutputStream dos = new DEROutputStream(out);
dos.writeObject(asn1.readObject());
}
private static void signWholeOutputFile(byte[] zipData,
OutputStream outputStream,
X509Certificate publicKey,
PrivateKey privateKey)
throws IOException,
CertificateEncodingException,
OperatorCreationException,
CMSException {
// For a zip with no archive comment, the
// end-of-central-directory record will be 22 bytes long, so
// we expect to find the EOCD marker 22 bytes from the end.
if (zipData[zipData.length-22] != 0x50 ||
zipData[zipData.length-21] != 0x4b ||
zipData[zipData.length-20] != 0x05 ||
zipData[zipData.length-19] != 0x06) {
throw new IllegalArgumentException("zip data already has an archive comment");
}
ByteArrayOutputStream temp = new ByteArrayOutputStream();
// put a readable message and a null char at the start of the
// archive comment, so that tools that display the comment
// (hopefully) show something sensible.
// TODO: anything more useful we can put in this message?
byte[] message = "signed by SignApk".getBytes("UTF-8");
temp.write(message);
temp.write(0);
writeSignatureBlock(new CMSByteArraySlice(zipData, 0, zipData.length-2),
publicKey, privateKey, temp);
int total_size = temp.size() + 6;
if (total_size > 0xffff) {
throw new IllegalArgumentException("signature is too big for ZIP file comment");
}
// signature starts this many bytes from the end of the file
int signature_start = total_size - message.length - 1;
temp.write(signature_start & 0xff);
temp.write((signature_start >> 8) & 0xff);
// Why the 0xff bytes? In a zip file with no archive comment,
// bytes [-6:-2] of the file are the little-endian offset from
// the start of the file to the central directory. So for the
// two high bytes to be 0xff 0xff, the archive would have to
// be nearly 4GB in size. So it's unlikely that a real
// commentless archive would have 0xffs here, and lets us tell
// an old signed archive from a new one.
temp.write(0xff);
temp.write(0xff);
temp.write(total_size & 0xff);
temp.write((total_size >> 8) & 0xff);
temp.flush();
// Signature verification checks that the EOCD header is the
// last such sequence in the file (to avoid minzip finding a
// fake EOCD appended after the signature in its scan). The
// odds of producing this sequence by chance are very low, but
// let's catch it here if it does.
byte[] b = temp.toByteArray();
for (int i = 0; i < b.length-3; ++i) {
if (b[i] == 0x50 && b[i+1] == 0x4b && b[i+2] == 0x05 && b[i+3] == 0x06) {
throw new IllegalArgumentException("found spurious EOCD header at " + i);
}
}
outputStream.write(zipData, 0, zipData.length-2);
outputStream.write(total_size & 0xff);
outputStream.write((total_size >> 8) & 0xff);
temp.writeTo(outputStream);
}
/**
* Copy all the files in a manifest from input to output. We set
* the modification times in the output to a fixed time, so as to
* reduce variation in the output file and make incremental OTAs
* more efficient.
*/
private static void copyFiles(Manifest manifest,
JarFile in, JarOutputStream out, long timestamp) throws IOException {
byte[] buffer = new byte[4096];
int num;
Map<String, Attributes> entries = manifest.getEntries();
ArrayList<String> names = new ArrayList<String>(entries.keySet());
Collections.sort(names);
for (String name : names) {
JarEntry inEntry = in.getJarEntry(name);
JarEntry outEntry = null;
if (inEntry.getMethod() == JarEntry.STORED) {
// Preserve the STORED method of the input entry.
outEntry = new JarEntry(inEntry);
} else {
// Create a new entry so that the compressed len is recomputed.
outEntry = new JarEntry(name);
}
outEntry.setTime(timestamp);
out.putNextEntry(outEntry);
InputStream data = in.getInputStream(inEntry);
while ((num = data.read(buffer)) > 0) {
out.write(buffer, 0, num);
}
out.flush();
}
}
public static void main(String[] args) {
if (args.length != 4 && args.length != 5) {
System.err.println("Usage: signapk [-w] " +
"publickey.x509[.pem] privatekey.pk8 " +
"input.jar output.jar");
System.exit(2);
}
sBouncyCastleProvider = new BouncyCastleProvider();
Security.addProvider(sBouncyCastleProvider);
boolean signWholeFile = false;
int argstart = 0;
if (args[0].equals("-w")) {
signWholeFile = true;
argstart = 1;
}
JarFile inputJar = null;
JarOutputStream outputJar = null;
FileOutputStream outputFile = null;
try {
File publicKeyFile = new File(args[argstart+0]);
X509Certificate publicKey = readPublicKey(publicKeyFile);
// Assume the certificate is valid for at least an hour.
long timestamp = publicKey.getNotBefore().getTime() + 3600L * 1000;
PrivateKey privateKey = readPrivateKey(new File(args[argstart+1]));
inputJar = new JarFile(new File(args[argstart+2]), false); // Don't verify.
OutputStream outputStream = null;
if (signWholeFile) {
outputStream = new ByteArrayOutputStream();
} else {
outputStream = outputFile = new FileOutputStream(args[argstart+3]);
}
outputJar = new JarOutputStream(outputStream);
// For signing .apks, use the maximum compression to make
// them as small as possible (since they live forever on
// the system partition). For OTA packages, use the
// default compression level, which is much much faster
// and produces output that is only a tiny bit larger
// (~0.1% on full OTA packages I tested).
if (!signWholeFile) {
outputJar.setLevel(9);
}
JarEntry je;
Manifest manifest = addDigestsToManifest(inputJar);
// Everything else
copyFiles(manifest, inputJar, outputJar, timestamp);
// otacert
if (signWholeFile) {
addOtacert(outputJar, publicKeyFile, timestamp, manifest);
}
// MANIFEST.MF
je = new JarEntry(JarFile.MANIFEST_NAME);
je.setTime(timestamp);
outputJar.putNextEntry(je);
manifest.write(outputJar);
// CERT.SF
je = new JarEntry(CERT_SF_NAME);
je.setTime(timestamp);
outputJar.putNextEntry(je);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
writeSignatureFile(manifest, baos);
byte[] signedData = baos.toByteArray();
outputJar.write(signedData);
// CERT.RSA
je = new JarEntry(CERT_RSA_NAME);
je.setTime(timestamp);
outputJar.putNextEntry(je);
writeSignatureBlock(new CMSProcessableByteArray(signedData),
publicKey, privateKey, outputJar);
outputJar.close();
outputJar = null;
outputStream.flush();
if (signWholeFile) {
outputFile = new FileOutputStream(args[argstart+3]);
signWholeOutputFile(((ByteArrayOutputStream)outputStream).toByteArray(),
outputFile, publicKey, privateKey);
}
} catch (Exception e) {
e.printStackTrace();
System.exit(1);
} finally {
try {
if (inputJar != null) inputJar.close();
if (outputFile != null) outputFile.close();
} catch (IOException e) {
e.printStackTrace();
System.exit(1);
}
}
}
}