Java对Android apk进行编辑 添加渠道标识 等三方信息
程序员文章站
2022-06-22 23:20:14
前言 项目中的手机客户端需要根据下载用户的不同附带不同的信息，所以就需要在WEB服务器端动态生成APK，于是有了下面的经历。历程 1.一开始的想法就是在APK本身就是个ZIP压缩包嘛，我把他解压缩，在里面中放一个配置文件，然后下载的时候，WEB服务器根据用户信息的不同动态替换这个配置文件，最后重新压缩成apk，然后APP运行的时候，读取这个配置文件就可以了。代码写好了，生成的安装包放手机一安装，安装包解析失败！ 2.于是各种找资料，好多博客里面也都写Java动态往APK中添加配置文件，...
前言
项目中的手机客户端需要根据下载用户的不同附带不同的信息，所以就需要在WEB服务器端动态生成APK，于是有了下面的经历。
历程
1.一开始的想法就是在APK本身就是个ZIP压缩包嘛，我把他解压缩，在里面中放一个配置文件，然后下载的时候，WEB服务器根据用户信息的不同动态替换这个配置文件，最后重新压缩成apk，然后APP运行的时候，读取这个配置文件就可以了。代码写好了，生成的安装包放手机一安装，安装包解析失败！
2.于是各种找资料，好多博客里面也都写Java动态往APK中添加配置文件，修改配置文件，可年代已经久远，加上本人手机安卓9.0了，估计是不行。于是找到一个往ZIP的comment区添加信息的博客，是一种新思路。于是复制代码实现了这个功能，往comments区添加信息，读取信息都可以，但安装的时候还是失败了。博主写的签名时只勾选V1的操作也试了，还是不行，还是不行。原文链接：https://www.jianshu.com/p/013f953d4508
3.感觉高版本对安装包的解析太严格了，于是又找资料，幸运的发现了美团的github项目：https://github.com/Meituan-Dianping/walle，美团的多渠道打包工具，提供了一个walle-cli-all.jar包，在这个项目下找不到，在另一个项目中找到了这包，先没写代码，用这个包直接运行试了下，添加了一些渠道信息和额外信息，可以运行，放到手机上，安装成功了，有点激动，终于找到个可用的办法了！
代码
代码不是我原创的，是美团的github项目上下下来的，下面粘贴处我用到的核心代码。
往APK中写入信息：
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.UUID;
public final class PayloadWriter {
private PayloadWriter() {
super();
}
/**
* put (id, String) into apk, update if id exists
* @param apkFile apk file
* @param id id
* @param string string content
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void put(final File apkFile, final int id, final String string) throws IOException, SignatureNotFoundException {
put(apkFile, id, string, false);
}
/**
* put (id, String) into apk, update if id exists
* @param apkFile apk file
* @param id id
* @param string string
* @param lowMemory if need low memory operation, maybe a little slower
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void put(final File apkFile, final int id, final String string, final boolean lowMemory) throws IOException, SignatureNotFoundException {
final byte[] bytes = string.getBytes(ApkUtil.DEFAULT_CHARSET);
final ByteBuffer byteBuffer = ByteBuffer.allocate(bytes.length);
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.put(bytes, 0, bytes.length);
byteBuffer.flip();
put(apkFile, id, byteBuffer, lowMemory);
}
/**
* put (id, buffer) into apk, update if id exists
*
* @param apkFile apk file
* @param id id
* @param buffer buffer
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void put(final File apkFile, final int id, final ByteBuffer buffer) throws IOException, SignatureNotFoundException {
put(apkFile, id, buffer, false);
}
/**
* put (id, buffer) into apk, update if id exists
* @param apkFile apk file
* @param id id
* @param buffer buffer
* @param lowMemory if need low memory operation, maybe a little slower
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void put(final File apkFile, final int id, final ByteBuffer buffer, final boolean lowMemory) throws IOException, SignatureNotFoundException {
final Map<Integer, ByteBuffer> idValues = new HashMap<Integer, ByteBuffer>();
idValues.put(id, buffer);
putAll(apkFile, idValues, lowMemory);
}
/**
* put new idValues into apk, update if id exists
*
* @param apkFile apk file
* @param idValues id value. NOTE: use unknown IDs. DO NOT use ID that have already been used. See <a href='https://source.android.com/security/apksigning/v2.html'>APK Signature Scheme v2</a>
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void putAll(final File apkFile, final Map<Integer, ByteBuffer> idValues) throws IOException, SignatureNotFoundException {
putAll(apkFile, idValues, false);
}
/**
* put new idValues into apk, update if id exists
*
* @param apkFile apk file
* @param idValues id value. NOTE: use unknown IDs. DO NOT use ID that have already been used. See <a href='https://source.android.com/security/apksigning/v2.html'>APK Signature Scheme v2</a>
* @param lowMemory if need low memory operation, maybe a little slower
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void putAll(final File apkFile, final Map<Integer, ByteBuffer> idValues, final boolean lowMemory) throws IOException, SignatureNotFoundException {
handleApkSigningBlock(apkFile, new ApkSigningBlockHandler() {
@Override
public ApkSigningBlock handle(final Map<Integer, ByteBuffer> originIdValues) {
if (idValues != null && !idValues.isEmpty()) {
originIdValues.putAll(idValues);
}
final ApkSigningBlock apkSigningBlock = new ApkSigningBlock();
final Set<Map.Entry<Integer, ByteBuffer>> entrySet = originIdValues.entrySet();
for (Map.Entry<Integer, ByteBuffer> entry : entrySet) {
final ApkSigningPayload payload = new ApkSigningPayload(entry.getKey(), entry.getValue());
apkSigningBlock.addPayload(payload);
}
return apkSigningBlock;
}
}, lowMemory);
}
/**
* remove content by id
*
* @param apkFile apk file
* @param id id
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void remove(final File apkFile, final int id) throws IOException, SignatureNotFoundException {
remove(apkFile, id, false);
}
/**
* remove content by id
*
* @param apkFile apk file
* @param id id
* @param lowMemory if need low memory operation, maybe a little slower
* @throws IOException
* @throws SignatureNotFoundException
*/
public static void remove(final File apkFile, final int id, final boolean lowMemory) throws IOException, SignatureNotFoundException {
PayloadWriter.handleApkSigningBlock(apkFile, new PayloadWriter.ApkSigningBlockHandler() {
@Override
public ApkSigningBlock handle(final Map<Integer, ByteBuffer> originIdValues) {
final ApkSigningBlock apkSigningBlock = new ApkSigningBlock();
final Set<Map.Entry<Integer, ByteBuffer>> entrySet = originIdValues.entrySet();
for (Map.Entry<Integer, ByteBuffer> entry : entrySet) {
if (entry.getKey() != id) {
final ApkSigningPayload payload = new ApkSigningPayload(entry.getKey(), entry.getValue());
apkSigningBlock.addPayload(payload);
}
}
return apkSigningBlock;
}
}, lowMemory);
}
interface ApkSigningBlockHandler {
ApkSigningBlock handle(Map<Integer, ByteBuffer> originIdValues);
}
static void handleApkSigningBlock(final File apkFile, final ApkSigningBlockHandler handler, final boolean lowMemory) throws IOException, SignatureNotFoundException {
RandomAccessFile fIn = null;
FileChannel fileChannel = null;
try {
fIn = new RandomAccessFile(apkFile, "rw");
fileChannel = fIn.getChannel();
final long commentLength = ApkUtil.getCommentLength(fileChannel);
final long centralDirStartOffset = ApkUtil.findCentralDirStartOffset(fileChannel, commentLength);
// Find the APK Signing Block. The block immediately precedes the Central Directory.
final Pair<ByteBuffer, Long> apkSigningBlockAndOffset = ApkUtil.findApkSigningBlock(fileChannel, centralDirStartOffset);
final ByteBuffer apkSigningBlock2 = apkSigningBlockAndOffset.getFirst();
final long apkSigningBlockOffset = apkSigningBlockAndOffset.getSecond();
final Map<Integer, ByteBuffer> originIdValues = ApkUtil.findIdValues(apkSigningBlock2);
// Find the APK Signature Scheme v2 Block inside the APK Signing Block.
final ByteBuffer apkSignatureSchemeV2Block = originIdValues.get(ApkUtil.APK_SIGNATURE_SCHEME_V2_BLOCK_ID);
if (apkSignatureSchemeV2Block == null) {
throw new IOException(
"No APK Signature Scheme v2 block in APK Signing Block");
}
final boolean needPadding = originIdValues.remove(ApkUtil.VERITY_PADDING_BLOCK_ID) != null;
final ApkSigningBlock apkSigningBlock = handler.handle(originIdValues);
// replace VERITY_PADDING_BLOCK with new one
if (needPadding) {
// uint64: size (excluding this field)
// repeated ID-value pairs:
// uint64: size (excluding this field)
// uint32: ID
// (size - 4) bytes: value
// (extra dummy ID-value for padding to make block size a multiple of 4096 bytes)
// uint64: size (same as the one above)
// uint128: magic
int blocksSize = 0;
for (ApkSigningPayload payload : apkSigningBlock.getPayloads()) {
blocksSize += payload.getTotalSize();
}
int resultSize = 8 + blocksSize + 8 + 16; // size(uint64) + pairs size + size(uint64) + magic(uint128)
if (resultSize % ApkUtil.ANDROID_COMMON_PAGE_ALIGNMENT_BYTES != 0) {
int padding = ApkUtil.ANDROID_COMMON_PAGE_ALIGNMENT_BYTES - 12 // size(uint64) + id(uint32)
- (resultSize % ApkUtil.ANDROID_COMMON_PAGE_ALIGNMENT_BYTES);
if (padding < 0) {
padding += ApkUtil.ANDROID_COMMON_PAGE_ALIGNMENT_BYTES;
}
final ByteBuffer dummy = ByteBuffer.allocate(padding).order(ByteOrder.LITTLE_ENDIAN);
apkSigningBlock.addPayload(new ApkSigningPayload(ApkUtil.VERITY_PADDING_BLOCK_ID,dummy));
}
}
if (apkSigningBlockOffset != 0 && centralDirStartOffset != 0) {
// read CentralDir
fIn.seek(centralDirStartOffset);
byte[] centralDirBytes = null;
File tempCentralBytesFile = null;
// read CentralDir
if (lowMemory) {
tempCentralBytesFile = new File(apkFile.getParent(), UUID.randomUUID().toString());
FileOutputStream outStream = null;
try {
outStream = new FileOutputStream(tempCentralBytesFile);
final byte[] buffer = new byte[1024];
int len;
while ((len = fIn.read(buffer)) > 0){
outStream.write(buffer, 0, len);
}
} finally {
if (outStream != null) {
outStream.close();
}
}
} else {
centralDirBytes = new byte[(int) (fileChannel.size() - centralDirStartOffset)];
fIn.read(centralDirBytes);
}
//update apk sign
fileChannel.position(apkSigningBlockOffset);
final long length = apkSigningBlock.writeApkSigningBlock(fIn);
// update CentralDir
if (lowMemory) {
FileInputStream inputStream = null;
try {
inputStream = new FileInputStream(tempCentralBytesFile);
final byte[] buffer = new byte[1024];
int len;
while ((len = inputStream.read(buffer)) > 0){
fIn.write(buffer, 0, len);
}
} finally {
if (inputStream != null) {
inputStream.close();
}
tempCentralBytesFile.delete();
}
} else {
// store CentralDir
fIn.write(centralDirBytes);
}
// update length
fIn.setLength(fIn.getFilePointer());
// update CentralDir Offset
// End of central directory record (EOCD)
// Offset Bytes Description[23]
// 0 4 End of central directory signature = 0x06054b50
// 4 2 Number of this disk
// 6 2 Disk where central directory starts
// 8 2 Number of central directory records on this disk
// 10 2 Total number of central directory records
// 12 4 Size of central directory (bytes)
// 16 4 Offset of start of central directory, relative to start of archive
// 20 2 Comment length (n)
// 22 n Comment
fIn.seek(fileChannel.size() - commentLength - 6);
// 6 = 2(Comment length) + 4 (Offset of start of central directory, relative to start of archive)
final ByteBuffer temp = ByteBuffer.allocate(4);
temp.order(ByteOrder.LITTLE_ENDIAN);
temp.putInt((int) (centralDirStartOffset + length + 8 - (centralDirStartOffset - apkSigningBlockOffset)));
// 8 = size of block in bytes (excluding this field) (uint64)
temp.flip();
fIn.write(temp.array());
}
} finally {
if (fileChannel != null) {
fileChannel.close();
}
if (fIn != null) {
fIn.close();
}
}
}
public static void main(String[] args) {
try {
put(new File("C:\\Users\\Plum\\Downloads\\app.apk"), ApkUtil.APK_CHANNEL_BLOCK_ID,"附加信息");
} catch (IOException | SignatureNotFoundException e) {
e.printStackTrace();
}
}
}
读取APK中的信息
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.io.UnsupportedEncodingException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Arrays;
import java.util.Map;
public final class PayloadReader {
private PayloadReader() {
super();
}
/**
* get string (UTF-8) by id
*
* @param apkFile apk file
* @return null if not found
*/
public static String getString(final File apkFile, final int id) {
final byte[] bytes = PayloadReader.get(apkFile, id);
if (bytes == null) {
return null;
}
try {
return new String(bytes, ApkUtil.DEFAULT_CHARSET);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
return null;
}
/**
* get bytes by id <br/>
*
* @param apkFile apk file
* @param id id
* @return bytes
*/
public static byte[] get(final File apkFile, final int id) {
final Map<Integer, ByteBuffer> idValues = getAll(apkFile);
if (idValues == null) {
return null;
}
final ByteBuffer byteBuffer = idValues.get(id);
if (byteBuffer == null) {
return null;
}
return getBytes(byteBuffer);
}
/**
* get data from byteBuffer
*
* @param byteBuffer buffer
* @return useful data
*/
private static byte[] getBytes(final ByteBuffer byteBuffer) {
final byte[] array = byteBuffer.array();
final int arrayOffset = byteBuffer.arrayOffset();
return Arrays.copyOfRange(array, arrayOffset + byteBuffer.position(),
arrayOffset + byteBuffer.limit());
}
/**
* get all custom (id, buffer) <br/>
* Note: get final from byteBuffer, please use {@link PayloadReader#getBytes getBytes}
*
* @param apkFile apk file
* @return all custom (id, buffer)
*/
private static Map<Integer, ByteBuffer> getAll(final File apkFile) {
Map<Integer, ByteBuffer> idValues = null;
try {
RandomAccessFile randomAccessFile = null;
FileChannel fileChannel = null;
try {
randomAccessFile = new RandomAccessFile(apkFile, "r");
fileChannel = randomAccessFile.getChannel();
final ByteBuffer apkSigningBlock2 = ApkUtil.findApkSigningBlock(fileChannel).getFirst();
idValues = ApkUtil.findIdValues(apkSigningBlock2);
} catch (IOException ignore) {
} finally {
try {
if (fileChannel != null) {
fileChannel.close();
}
} catch (IOException ignore) {
}
try {
if (randomAccessFile != null) {
randomAccessFile.close();
}
} catch (IOException ignore) {
}
}
} catch (SignatureNotFoundException ignore) {
}
return idValues;
}
}
用到的其他工具类
/**
* Pair of two elements.
*/
final class Pair<A, B> {
private final A mFirst;
private final B mSecond;
private Pair(final A first, final B second) {
mFirst = first;
mSecond = second;
}
public static <A, B> Pair<A, B> of(final A first, final B second) {
return new Pair<A, B>(first, second);
}
public A getFirst() {
return mFirst;
}
public B getSecond() {
return mSecond;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((mFirst == null) ? 0 : mFirst.hashCode());
result = prime * result + ((mSecond == null) ? 0 : mSecond.hashCode());
return result;
}
@Override
public boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (obj == null) {
return false;
}
if (getClass() != obj.getClass()) {
return false;
}
@SuppressWarnings("rawtypes")
final Pair other = (Pair) obj;
if (mFirst == null) {
if (other.mFirst != null) {
return false;
}
} else if (!mFirst.equals(other.mFirst)) {
return false;
}
if (mSecond == null) {
if (other.mSecond != null) {
return false;
}
} else if (!mSecond.equals(other.mSecond)) {
return false;
}
return true;
}
}
public class SignatureNotFoundException extends Exception {
private static final long serialVersionUID = 1L;
public SignatureNotFoundException(final String message) {
super(message);
}
public SignatureNotFoundException(final String message, final Throwable cause) {
super(message, cause);
}
}
import java.io.DataOutput;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.ArrayList;
import java.util.List;
/**
* https://source.android.com/security/apksigning/v2.html
* https://en.wikipedia.org/wiki/Zip_(file_format)
*/
class ApkSigningBlock {
// The format of the APK Signing Block is as follows (all numeric fields are little-endian):
// .size of block in bytes (excluding this field) (uint64)
// .Sequence of uint64-length-prefixed ID-value pairs:
// *ID (uint32)
// *value (variable-length: length of the pair - 4 bytes)
// .size of block in bytes—same as the very first field (uint64)
// .magic “APK Sig Block 42” (16 bytes)
// FORMAT:
// OFFSET DATA TYPE DESCRIPTION
// * @+0 bytes uint64: size in bytes (excluding this field)
// * @+8 bytes payload
// * @-24 bytes uint64: size in bytes (same as the one above)
// * @-16 bytes uint128: magic
// payload 有 8字节的大小，4字节的ID，还有payload的内容组成
private final List<ApkSigningPayload> payloads;
ApkSigningBlock() {
super();
payloads = new ArrayList<ApkSigningPayload>();
}
public final List<ApkSigningPayload> getPayloads() {
return payloads;
}
public void addPayload(final ApkSigningPayload payload) {
payloads.add(payload);
}
public long writeApkSigningBlock(final DataOutput dataOutput) throws IOException {
long length = 24; // 24 = 8(size of block in bytes—same as the very first field (uint64)) + 16 (magic “APK Sig Block 42” (16 bytes))
for (int index = 0; index < payloads.size(); ++index) {
final ApkSigningPayload payload = payloads.get(index);
final byte[] bytes = payload.getByteBuffer();
length += 12 + bytes.length; // 12 = 8(uint64-length-prefixed) + 4 (ID (uint32))
}
ByteBuffer byteBuffer = ByteBuffer.allocate(8); // Long.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putLong(length);
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
for (int index = 0; index < payloads.size(); ++index) {
final ApkSigningPayload payload = payloads.get(index);
final byte[] bytes = payload.getByteBuffer();
byteBuffer = ByteBuffer.allocate(8); // Long.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putLong(bytes.length + (8 - 4)); // Long.BYTES - Integer.BYTES
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
byteBuffer = ByteBuffer.allocate(4); // Integer.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putInt(payload.getId());
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
dataOutput.write(bytes);
}
byteBuffer = ByteBuffer.allocate(8); // Long.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putLong(length);
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
byteBuffer = ByteBuffer.allocate(8); // Long.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putLong(ApkUtil.APK_SIG_BLOCK_MAGIC_LO);
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
byteBuffer = ByteBuffer.allocate(8); // Long.BYTES
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
byteBuffer.putLong(ApkUtil.APK_SIG_BLOCK_MAGIC_HI);
byteBuffer.flip();
dataOutput.write(byteBuffer.array());
return length;
}
}
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Arrays;
class ApkSigningPayload {
private final int id;
private final ByteBuffer buffer;
private final int totalSize;
ApkSigningPayload(final int id, final ByteBuffer buffer) {
super();
this.id = id;
if (buffer.order() != ByteOrder.LITTLE_ENDIAN) {
throw new IllegalArgumentException("ByteBuffer byte order must be little endian");
}
this.buffer = buffer;
// assume buffer is not consumed
this.totalSize = 8 + 4 + buffer.remaining(); // size + id + value
}
public int getId() {
return id;
}
public byte[] getByteBuffer() {
final byte[] array = buffer.array();
final int arrayOffset = buffer.arrayOffset();
return Arrays.copyOfRange(array, arrayOffset + buffer.position(),
arrayOffset + buffer.limit());
}
/**
* Total bytes of this block
*/
public int getTotalSize() {
return totalSize;
}
}
import java.io.IOException;
import java.nio.BufferUnderflowException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.channels.FileChannel;
import java.util.LinkedHashMap;
import java.util.Map;
final class ApkUtil {
private ApkUtil() {
super();
}
/**
* APK Signing Block Magic Code: magic “APK Sig Block 42” (16 bytes)
* "APK Sig Block 42" : 41 50 4B 20 53 69 67 20 42 6C 6F 63 6B 20 34 32
*/
public static final long APK_SIG_BLOCK_MAGIC_HI = 0x3234206b636f6c42L; // LITTLE_ENDIAN, High
public static final long APK_SIG_BLOCK_MAGIC_LO = 0x20676953204b5041L; // LITTLE_ENDIAN, Low
private static final int APK_SIG_BLOCK_MIN_SIZE = 32;
/*
The v2 signature of the APK is stored as an ID-value pair with ID 0x7109871a
(https://source.android.com/security/apksigning/v2.html#apk-signing-block)
*/
public static final int APK_SIGNATURE_SCHEME_V2_BLOCK_ID = 0x7109871a;
/**
* The padding in APK SIG BLOCK (V3 scheme introduced)
* See https://android.googlesource.com/platform/tools/apksig/+/master/src/main/java/com/android/apksig/internal/apk/ApkSigningBlockUtils.java
*/
public static final int VERITY_PADDING_BLOCK_ID = 0x42726577;
public static final int ANDROID_COMMON_PAGE_ALIGNMENT_BYTES = 4096;
// Our Channel Block ID
public static final int APK_CHANNEL_BLOCK_ID = 0x71777777;
public static final String DEFAULT_CHARSET = "UTF-8";
private static final int ZIP_EOCD_REC_MIN_SIZE = 22;
private static final int ZIP_EOCD_REC_SIG = 0x06054b50;
private static final int UINT16_MAX_VALUE = 0xffff;
private static final int ZIP_EOCD_COMMENT_LENGTH_FIELD_OFFSET = 20;
public static long getCommentLength(final FileChannel fileChannel) throws IOException {
// End of central directory record (EOCD)
// Offset Bytes Description[23]
// 0 4 End of central directory signature = 0x06054b50
// 4 2 Number of this disk
// 6 2 Disk where central directory starts
// 8 2 Number of central directory records on this disk
// 10 2 Total number of central directory records
// 12 4 Size of central directory (bytes)
// 16 4 Offset of start of central directory, relative to start of archive
// 20 2 Comment length (n)
// 22 n Comment
// 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.
final long archiveSize = fileChannel.size();
if (archiveSize < ZIP_EOCD_REC_MIN_SIZE) {
throw new IOException("APK too small for ZIP End of Central Directory (EOCD) record");
}
// ZIP End of Central Directory (EOCD) record is located at the very end of the ZIP archive.
// The record can be identified by its 4-byte signature/magic which is located at the very
// beginning of the record. A complication is that the record is variable-length because of
// the comment field.
// The algorithm for locating the ZIP EOCD record is as follows. We search backwards from
// end of the buffer for the EOCD record signature. Whenever we find a signature, we check
// the candidate record's comment length is such that the remainder of the record takes up
// exactly the remaining bytes in the buffer. The search is bounded because the maximum
// size of the comment field is 65535 bytes because the field is an unsigned 16-bit number.
final long maxCommentLength = Math.min(archiveSize - ZIP_EOCD_REC_MIN_SIZE, UINT16_MAX_VALUE);
final long eocdWithEmptyCommentStartPosition = archiveSize - ZIP_EOCD_REC_MIN_SIZE;
for (int expectedCommentLength = 0; expectedCommentLength <= maxCommentLength;
expectedCommentLength++) {
final long eocdStartPos = eocdWithEmptyCommentStartPosition - expectedCommentLength;
final ByteBuffer byteBuffer = ByteBuffer.allocate(4);
fileChannel.position(eocdStartPos);
fileChannel.read(byteBuffer);
byteBuffer.order(ByteOrder.LITTLE_ENDIAN);
if (byteBuffer.getInt(0) == ZIP_EOCD_REC_SIG) {
final ByteBuffer commentLengthByteBuffer = ByteBuffer.allocate(2);
fileChannel.position(eocdStartPos + ZIP_EOCD_COMMENT_LENGTH_FIELD_OFFSET);
fileChannel.read(commentLengthByteBuffer);
commentLengthByteBuffer.order(ByteOrder.LITTLE_ENDIAN);
final int actualCommentLength = commentLengthByteBuffer.getShort(0);
if (actualCommentLength == expectedCommentLength) {
return actualCommentLength;
}
}
}
throw new IOException("ZIP End of Central Directory (EOCD) record not found");
}
public static long findCentralDirStartOffset(final FileChannel fileChannel) throws IOException {
return findCentralDirStartOffset(fileChannel, getCommentLength(fileChannel));
}
public static long findCentralDirStartOffset(final FileChannel fileChannel, final long commentLength) throws IOException {
// End of central directory record (EOCD)
// Offset Bytes Description[23]
// 0 4 End of central directory signature = 0x06054b50
// 4 2 Number of this disk
// 6 2 Disk where central directory starts
// 8 2 Number of central directory records on this disk
// 10 2 Total number of central directory records
// 12 4 Size of central directory (bytes)
// 16 4 Offset of start of central directory, relative to start of archive
// 20 2 Comment length (n)
// 22 n Comment
// 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.
final ByteBuffer zipCentralDirectoryStart = ByteBuffer.allocate(4);
zipCentralDirectoryStart.order(ByteOrder.LITTLE_ENDIAN);
fileChannel.position(fileChannel.size() - commentLength - 6); // 6 = 2 (Comment length) + 4 (Offset of start of central directory, relative to start of archive)
fileChannel.read(zipCentralDirectoryStart);
final long centralDirStartOffset = zipCentralDirectoryStart.getInt(0);
return centralDirStartOffset;
}
public static Pair<ByteBuffer, Long> findApkSigningBlock(
final FileChannel fileChannel) throws IOException, SignatureNotFoundException {
final long centralDirOffset = findCentralDirStartOffset(fileChannel);
return findApkSigningBlock(fileChannel, centralDirOffset);
}
public static Pair<ByteBuffer, Long> findApkSigningBlock(
final FileChannel fileChannel, final long centralDirOffset) throws IOException, SignatureNotFoundException {
// Find the APK Signing Block. The block immediately precedes the Central Directory.
// FORMAT:
// OFFSET DATA TYPE DESCRIPTION
// * @+0 bytes uint64: size in bytes (excluding this field)
// * @+8 bytes payload
// * @-24 bytes uint64: size in bytes (same as the one above)
// * @-16 bytes uint128: magic
if (centralDirOffset < APK_SIG_BLOCK_MIN_SIZE) {
throw new SignatureNotFoundException(
"APK too small for APK Signing Block. ZIP Central Directory offset: "
+ centralDirOffset);
}
// Read the magic and offset in file from the footer section of the block:
// * uint64: size of block
// * 16 bytes: magic
fileChannel.position(centralDirOffset - 24);
final ByteBuffer footer = ByteBuffer.allocate(24);
fileChannel.read(footer);
footer.order(ByteOrder.LITTLE_ENDIAN);
if ((footer.getLong(8) != APK_SIG_BLOCK_MAGIC_LO)
|| (footer.getLong(16) != APK_SIG_BLOCK_MAGIC_HI)) {
throw new SignatureNotFoundException(
"No APK Signing Block before ZIP Central Directory");
}
// Read and compare size fields
final long apkSigBlockSizeInFooter = footer.getLong(0);
if ((apkSigBlockSizeInFooter < footer.capacity())
|| (apkSigBlockSizeInFooter > Integer.MAX_VALUE - 8)) {
throw new SignatureNotFoundException(
"APK Signing Block size out of range: " + apkSigBlockSizeInFooter);
}
final int totalSize = (int) (apkSigBlockSizeInFooter + 8);
final long apkSigBlockOffset = centralDirOffset - totalSize;
if (apkSigBlockOffset < 0) {
throw new SignatureNotFoundException(
"APK Signing Block offset out of range: " + apkSigBlockOffset);
}
fileChannel.position(apkSigBlockOffset);
final ByteBuffer apkSigBlock = ByteBuffer.allocate(totalSize);
fileChannel.read(apkSigBlock);
apkSigBlock.order(ByteOrder.LITTLE_ENDIAN);
final long apkSigBlockSizeInHeader = apkSigBlock.getLong(0);
if (apkSigBlockSizeInHeader != apkSigBlockSizeInFooter) {
throw new SignatureNotFoundException(
"APK Signing Block sizes in header and footer do not match: "
+ apkSigBlockSizeInHeader + " vs " + apkSigBlockSizeInFooter);
}
return Pair.of(apkSigBlock, apkSigBlockOffset);
}
public static Map<Integer, ByteBuffer> findIdValues(final ByteBuffer apkSigningBlock) throws SignatureNotFoundException {
checkByteOrderLittleEndian(apkSigningBlock);
// FORMAT:
// OFFSET DATA TYPE DESCRIPTION
// * @+0 bytes uint64: size in bytes (excluding this field)
// * @+8 bytes pairs
// * @-24 bytes uint64: size in bytes (same as the one above)
// * @-16 bytes uint128: magic
final ByteBuffer pairs = sliceFromTo(apkSigningBlock, 8, apkSigningBlock.capacity() - 24);
final Map<Integer, ByteBuffer> idValues = new LinkedHashMap<Integer, ByteBuffer>(); // keep order
int entryCount = 0;
while (pairs.hasRemaining()) {
entryCount++;
if (pairs.remaining() < 8) {
throw new SignatureNotFoundException(
"Insufficient data to read size of APK Signing Block entry #" + entryCount);
}
final long lenLong = pairs.getLong();
if ((lenLong < 4) || (lenLong > Integer.MAX_VALUE)) {
throw new SignatureNotFoundException(
"APK Signing Block entry #" + entryCount
+ " size out of range: " + lenLong);
}
final int len = (int) lenLong;
final int nextEntryPos = pairs.position() + len;
if (len > pairs.remaining()) {
throw new SignatureNotFoundException(
"APK Signing Block entry #" + entryCount + " size out of range: " + len
+ ", available: " + pairs.remaining());
}
final int id = pairs.getInt();
idValues.put(id, getByteBuffer(pairs, len - 4));
pairs.position(nextEntryPos);
}
return idValues;
}
/**
* Returns new byte buffer whose content is a shared subsequence of this buffer's content
* between the specified start (inclusive) and end (exclusive) positions. As opposed to
* {@link ByteBuffer#slice()}, the returned buffer's byte order is the same as the source
* buffer's byte order.
*/
private static ByteBuffer sliceFromTo(final ByteBuffer source, final int start, final int end) {
if (start < 0) {
throw new IllegalArgumentException("start: " + start);
}
if (end < start) {
throw new IllegalArgumentException("end < start: " + end + " < " + start);
}
final int capacity = source.capacity();
if (end > source.capacity()) {
throw new IllegalArgumentException("end > capacity: " + end + " > " + capacity);
}
final int originalLimit = source.limit();
final int originalPosition = source.position();
try {
source.position(0);
source.limit(end);
source.position(start);
final ByteBuffer result = source.slice();
result.order(source.order());
return result;
} finally {
source.position(0);
source.limit(originalLimit);
source.position(originalPosition);
}
}
/**
* Relative <em>get</em> method for reading {@code size} number of bytes from the current
* position of this buffer.
* <p>
* <p>This method reads the next {@code size} bytes at this buffer's current position,
* returning them as a {@code ByteBuffer} with start set to 0, limit and capacity set to
* {@code size}, byte order set to this buffer's byte order; and then increments the position by
* {@code size}.
*/
private static ByteBuffer getByteBuffer(final ByteBuffer source, final int size)
throws BufferUnderflowException {
if (size < 0) {
throw new IllegalArgumentException("size: " + size);
}
final int originalLimit = source.limit();
final int position = source.position();
final int limit = position + size;
if ((limit < position) || (limit > originalLimit)) {
throw new BufferUnderflowException();
}
source.limit(limit);
try {
final ByteBuffer result = source.slice();
result.order(source.order());
source.position(limit);
return result;
} finally {
source.limit(originalLimit);
}
}
private static void checkByteOrderLittleEndian(final ByteBuffer buffer) {
if (buffer.order() != ByteOrder.LITTLE_ENDIAN) {
throw new IllegalArgumentException("ByteBuffer byte order must be little endian");
}
}
}
总结
可以看出，现在高版本安卓对安装包的校验很严格，所以，普通的替换配置文件决定不行的，一替换，就破坏签名了，是我太年轻。直接往安装包的comments区写信息，以前可行，但现在也不行了。美团的这个工具，我也没看的很透很懂，只是知道他的原理还是往comments区添加信息，只是添加过程中对安装包的签名信息做了一些处理。
本文地址：https://blog.csdn.net/fujiakai/article/details/109625568