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ARSC/AXML Parser Rework (#3131)
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* Supports ASRC with null renamed package.
* Rework ASRC Chunk parser to a loop to break assumption of order of chunks
* Break out unknown skips for alignment to ResourceTypes.h
* Add verbose information for file skips
* Add test for protected apk sample
* Rework chunk parsing for StringBlock
* Refactor AXML Parser to support proper header reading
* Fix parsing if attribute size reported does not align to actual size
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@iBotPeaches
iBotPeaches authored Jul 12, 2023
1 parent 8634050 commit bdbe138
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Showing 10 changed files with 368 additions and 315 deletions.
11 changes: 6 additions & 5 deletions brut.apktool/apktool-lib/src/main/java/brut/androlib/res/ResourcesDecoder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -190,19 +190,20 @@ private void adjustPackageManifest(ResTable resTable, String filePath)
// compare resources.arsc package name to the one present in AndroidManifest
ResPackage resPackage = resTable.getCurrentResPackage();
String pkgOriginal = resPackage.getName();
String packageRenamed = resTable.getPackageRenamed();
String pkgRenamed = resTable.getPackageRenamed();

resTable.setPackageId(resPackage.getId());
resTable.setPackageOriginal(pkgOriginal);

// 1) Check if pkgOriginal is null (empty resources.arsc)
// 2) Check if pkgOriginal === mPackageRenamed
// 3) Check if pkgOriginal is ignored via IGNORED_PACKAGES
if (pkgOriginal == null || pkgOriginal.equalsIgnoreCase(packageRenamed)
// 2) Check if pkgRenamed is null
// 3) Check if pkgOriginal === mPackageRenamed
// 4) Check if pkgOriginal is ignored via IGNORED_PACKAGES
if (pkgOriginal == null || pkgRenamed == null || pkgOriginal.equalsIgnoreCase(pkgRenamed)
|| (Arrays.asList(IGNORED_PACKAGES).contains(pkgOriginal))) {
LOGGER.info("Regular manifest package...");
} else {
LOGGER.info("Renamed manifest package found! Replacing " + packageRenamed + " with " + pkgOriginal);
LOGGER.info("Renamed manifest package found! Replacing " + pkgRenamed + " with " + pkgOriginal);
ResXmlPatcher.renameManifestPackage(new File(filePath), pkgOriginal);
}
}
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2 changes: 1 addition & 1 deletion brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/ResTable.java
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Expand Up @@ -364,7 +364,7 @@ private void initPackageInfo() throws AndrolibException {
}

// only put rename-manifest-package into apktool.yml, if the change will be required
if (!renamed.equalsIgnoreCase(original)) {
if (renamed != null && !renamed.equalsIgnoreCase(original)) {
mApkInfo.packageInfo.renameManifestPackage = renamed;
}
mApkInfo.packageInfo.forcedPackageId = String.valueOf(id);
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26 changes: 21 additions & 5 deletions brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/arsc/ARSCHeader.java
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Original file line number Diff line number Diff line change
Expand Up @@ -43,21 +43,37 @@ public static ARSCHeader read(ExtDataInput in, CountingInputStream countIn) thro
try {
type = in.readShort();
} catch (EOFException ex) {
return new ARSCHeader(TYPE_NONE, 0, 0, countIn.getCount());
return new ARSCHeader(RES_NONE_TYPE, 0, 0, countIn.getCount());
}
return new ARSCHeader(type, in.readShort(), in.readInt(), start);
}

public final static short TYPE_NONE = -1;
public final static short TYPE_STRING_POOL = 0x0001;
public final static short TYPE_TABLE = 0x0002;
public final static short TYPE_XML = 0x0003;
public void skipChunk(ExtDataInput in) throws IOException {
in.skipBytes(chunkSize - headerSize);
}

public final static short RES_NONE_TYPE = -1;
public final static short RES_NULL_TYPE = 0x0000;
public final static short RES_STRING_POOL_TYPE = 0x0001;
public final static short RES_TABLE_TYPE = 0x0002;
public final static short RES_XML_TYPE = 0x0003;

// RES_TABLE_TYPE Chunks
public final static short XML_TYPE_PACKAGE = 0x0200;
public final static short XML_TYPE_TYPE = 0x0201;
public final static short XML_TYPE_SPEC_TYPE = 0x0202;
public final static short XML_TYPE_LIBRARY = 0x0203;
public final static short XML_TYPE_OVERLAY = 0x0204;
public final static short XML_TYPE_OVERLAY_POLICY = 0x0205;
public final static short XML_TYPE_STAGED_ALIAS = 0x0206;

// RES_XML_TYPE Chunks
public final static short RES_XML_FIRST_CHUNK_TYPE = 0x0100;
public final static short RES_XML_START_NAMESPACE_TYPE = 0x0100;
public final static short RES_XML_END_NAMESPACE_TYPE = 0x0101;
public final static short RES_XML_START_ELEMENT_TYPE = 0x0102;
public final static short RES_XML_END_ELEMENT_TYPE = 0x0103;
public final static short RES_XML_CDATA_TYPE = 0x0104;
public final static short RES_XML_LAST_CHUNK_TYPE = 0x017f;
public final static short RES_XML_RESOURCE_MAP_TYPE = 0x0180;
}
182 changes: 90 additions & 92 deletions brut.apktool/apktool-lib/src/main/java/brut/androlib/res/decoder/ARSCDecoder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -33,10 +33,7 @@
import java.io.IOException;
import java.io.InputStream;
import java.math.BigInteger;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.*;
import java.util.logging.Logger;

public class ARSCDecoder {
Expand All @@ -50,7 +47,7 @@ public static ARSCData decode(InputStream arscStream, boolean findFlagsOffsets,
throws AndrolibException {
try {
ARSCDecoder decoder = new ARSCDecoder(arscStream, resTable, findFlagsOffsets, keepBroken);
ResPackage[] pkgs = decoder.readTableHeader();
ResPackage[] pkgs = decoder.readResourceTable();
return new ARSCData(pkgs, decoder.mFlagsOffsets == null
? null
: decoder.mFlagsOffsets.toArray(new FlagsOffset[0]));
Expand All @@ -74,19 +71,85 @@ private ARSCDecoder(InputStream arscStream, ResTable resTable, boolean storeFlag
mKeepBroken = keepBroken;
}

private ResPackage[] readTableHeader() throws IOException, AndrolibException {
nextChunkCheckType(ARSCHeader.TYPE_TABLE);
int packageCount = mIn.readInt();
private ResPackage[] readResourceTable() throws IOException, AndrolibException {
Set<ResPackage> pkgs = new LinkedHashSet<>();
ResTypeSpec typeSpec;

mTableStrings = StringBlock.read(mIn);
ResPackage[] packages = new ResPackage[packageCount];
chunkLoop:
for (;;) {
nextChunk();

switch (mHeader.type) {
case ARSCHeader.RES_NULL_TYPE:
readUnknownChunk();
break;
case ARSCHeader.RES_STRING_POOL_TYPE:
readStringPoolChunk();
break;
case ARSCHeader.RES_TABLE_TYPE:
readTableChunk();
break;

// Chunk types in RES_TABLE_TYPE
case ARSCHeader.XML_TYPE_PACKAGE:
mTypeIdOffset = 0;
pkgs.add(readTablePackage());
break;
case ARSCHeader.XML_TYPE_TYPE:
readTableType();
break;
case ARSCHeader.XML_TYPE_SPEC_TYPE:
typeSpec = readTableSpecType();
addTypeSpec(typeSpec);
break;
case ARSCHeader.XML_TYPE_LIBRARY:
readLibraryType();
break;
case ARSCHeader.XML_TYPE_OVERLAY:
readOverlaySpec();
break;
case ARSCHeader.XML_TYPE_OVERLAY_POLICY:
readOverlayPolicySpec();
break;
case ARSCHeader.XML_TYPE_STAGED_ALIAS:
readStagedAliasSpec();
break;
default:
if (mHeader.type != ARSCHeader.RES_NONE_TYPE) {
LOGGER.severe(String.format("Unknown chunk type: %04x", mHeader.type));
}
break chunkLoop;
}
}

nextChunk();
for (int i = 0; i < packageCount; i++) {
mTypeIdOffset = 0;
packages[i] = readTablePackage();
if (mPkg.getResSpecCount() > 0) {
addMissingResSpecs();
}
return packages;

// We've detected sparse resources, lets record this so we can rebuild in that same format (sparse/not)
// with aapt2. aapt1 will ignore this.
if (! mResTable.getSparseResources()) {
mResTable.setSparseResources(true);
}

return pkgs.toArray(new ResPackage[0]);
}

private void readStringPoolChunk() throws IOException, AndrolibException {
checkChunkType(ARSCHeader.RES_STRING_POOL_TYPE);
mTableStrings = StringBlock.readWithoutChunk(mIn, mHeader.chunkSize);
}

private void readTableChunk() throws IOException, AndrolibException {
checkChunkType(ARSCHeader.RES_TABLE_TYPE);
mIn.skipInt(); // packageCount
}

private void readUnknownChunk() throws IOException, AndrolibException {
checkChunkType(ARSCHeader.RES_NULL_TYPE);

LOGGER.warning("Skipping unknown chunk data of size " + mHeader.chunkSize);
mHeader.skipChunk(mIn);
}

private ResPackage readTablePackage() throws IOException, AndrolibException {
Expand Down Expand Up @@ -121,38 +184,12 @@ private ResPackage readTablePackage() throws IOException, AndrolibException {
LOGGER.warning("Please report this application to Apktool for a fix: https://github.com/iBotPeaches/Apktool/issues/1728");
}

mTypeNames = StringBlock.read(mIn);
mSpecNames = StringBlock.read(mIn);
mTypeNames = StringBlock.readWithChunk(mIn);
mSpecNames = StringBlock.readWithChunk(mIn);

mResId = id << 24;
mPkg = new ResPackage(mResTable, id, name);

nextChunk();

chunkLoop:
for (;;) {
switch (mHeader.type) {
case ARSCHeader.XML_TYPE_TYPE:
case ARSCHeader.XML_TYPE_SPEC_TYPE:
readTableTypeSpec();
break;
case ARSCHeader.XML_TYPE_LIBRARY:
readLibraryType();
break;
case ARSCHeader.XML_TYPE_OVERLAY:
readOverlaySpec();
break;
case ARSCHeader.XML_TYPE_OVERLAY_POLICY:
readOverlayPolicySpec();
break;
case ARSCHeader.XML_TYPE_STAGED_ALIAS:
readStagedAliasSpec();
break;
default:
break chunkLoop;
}
}

return mPkg;
}

Expand All @@ -168,8 +205,6 @@ private void readLibraryType() throws AndrolibException, IOException {
packageName = mIn.readNullEndedString(128, true);
LOGGER.info(String.format("Decoding Shared Library (%s), pkgId: %d", packageName, packageId));
}

nextChunk();
}

private void readStagedAliasSpec() throws IOException {
Expand All @@ -178,17 +213,13 @@ private void readStagedAliasSpec() throws IOException {
for (int i = 0; i < count; i++) {
LOGGER.fine(String.format("Skipping staged alias stagedId (%h) finalId: %h", mIn.readInt(), mIn.readInt()));
}

nextChunk();
}

private void readOverlaySpec() throws AndrolibException, IOException {
checkChunkType(ARSCHeader.XML_TYPE_OVERLAY);
String name = mIn.readNullEndedString(256, true);
String actor = mIn.readNullEndedString(256, true);
LOGGER.fine(String.format("Overlay name: \"%s\", actor: \"%s\")", name, actor));

nextChunk();
}

private void readOverlayPolicySpec() throws AndrolibException, IOException {
Expand All @@ -199,48 +230,13 @@ private void readOverlayPolicySpec() throws AndrolibException, IOException {
for (int i = 0; i < count; i++) {
LOGGER.fine(String.format("Skipping overlay (%h)", mIn.readInt()));
}

nextChunk();
}

private void readTableTypeSpec() throws AndrolibException, IOException {
mTypeSpec = readSingleTableTypeSpec();
addTypeSpec(mTypeSpec);

int type = nextChunk().type;
ResTypeSpec resTypeSpec;

while (type == ARSCHeader.XML_TYPE_SPEC_TYPE) {
resTypeSpec = readSingleTableTypeSpec();
addTypeSpec(resTypeSpec);
type = nextChunk().type;

// We've detected sparse resources, lets record this so we can rebuild in that same format (sparse/not)
// with aapt2. aapt1 will ignore this.
if (! mResTable.getSparseResources()) {
mResTable.setSparseResources(true);
}
}

while (type == ARSCHeader.XML_TYPE_TYPE) {
readTableType();

// skip "TYPE 8 chunks" and/or padding data at the end of this chunk
if (mCountIn.getCount() < mHeader.endPosition) {
LOGGER.warning("Unknown data detected. Skipping: " + (mHeader.endPosition - mCountIn.getCount()) + " byte(s)");
mCountIn.skip(mHeader.endPosition - mCountIn.getCount());
}

type = nextChunk().type;

addMissingResSpecs();
}
}

private ResTypeSpec readSingleTableTypeSpec() throws AndrolibException, IOException {
private ResTypeSpec readTableSpecType() throws AndrolibException, IOException {
checkChunkType(ARSCHeader.XML_TYPE_SPEC_TYPE);
int id = mIn.readUnsignedByte();
mIn.skipBytes(3);
mIn.skipBytes(1); // reserved0
mIn.skipBytes(2); // reserved1
int entryCount = mIn.readInt();

if (mFlagsOffsets != null) {
Expand All @@ -250,6 +246,7 @@ private ResTypeSpec readSingleTableTypeSpec() throws AndrolibException, IOExcept
mIn.skipBytes(entryCount * 4); // flags
mTypeSpec = new ResTypeSpec(mTypeNames.getString(id - 1), mResTable, mPkg, id, entryCount);
mPkg.addType(mTypeSpec);

return mTypeSpec;
}

Expand Down Expand Up @@ -311,6 +308,12 @@ private ResType readTableType() throws IOException, AndrolibException {
readEntry(readEntryData());
}

// skip "TYPE 8 chunks" and/or padding data at the end of this chunk
if (mCountIn.getCount() < mHeader.endPosition) {
long bytesSkipped = mCountIn.skip(mHeader.endPosition - mCountIn.getCount());
LOGGER.warning("Unknown data detected. Skipping: " + bytesSkipped + " byte(s)");
}

return mType;
}

Expand Down Expand Up @@ -616,11 +619,6 @@ private void checkChunkType(int expectedType) throws AndrolibException {
}
}

private void nextChunkCheckType(int expectedType) throws IOException, AndrolibException {
nextChunk();
checkChunkType(expectedType);
}

private final ExtDataInput mIn;
private final ResTable mResTable;
private final CountingInputStream mCountIn;
Expand Down
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