/* * Copyright (C) 2022 GrapheneOS * SPDX-License-Identifier: Apache-2.0 */ package com.android.internal.gmscompat; import android.annotation.Nullable; import android.app.compat.gms.GmsCompat; import android.content.pm.ParceledListSlice; import android.content.pm.StringParceledListSlice; import android.os.Parcel; import android.os.Parcelable; import android.util.ArrayMap; import android.util.Log; import java.lang.reflect.Method; import java.util.Collections; import java.util.List; import libcore.util.SneakyThrow; public class StubDef implements Parcelable { private static final String TAG = "StubDef"; public int type; public long integerVal; public double doubleVal; public String stringVal; private volatile Class parcelListType; public static final int VOID = 0; public static final int NULL = 1; // only for types that implement Parcelable public static final int NULL_STRING = 2; public static final int NULL_ARRAY = 3; public static final int EMPTY_BYTE_ARRAY = 4; public static final int EMPTY_INT_ARRAY = 5; public static final int EMPTY_LONG_ARRAY = 6; public static final int EMPTY_STRING = 7; public static final int EMPTY_LIST = 8; public static final int EMPTY_MAP = 9; public static final int BOOLEAN = 10; public static final int BYTE = 11; public static final int INT = 12; public static final int LONG = 13; public static final int FLOAT = 14; public static final int DOUBLE = 15; public static final int STRING = 16; public static final int THROW = 17; // see com.android.modules.utils.SynchronousResultReceiver.Result#getValue() public static final int DEFAULT = 18; public static final int FIND_MODE_Parcel = 0; public static final int FIND_MODE_SynchronousResultReceiver = 1; @Nullable public static StubDef find(StackTraceElement[] stackTrace, GmsCompatConfig config, int mode) { int firstIndex; if (mode == FIND_MODE_Parcel) { // first four stack trace entries are known: // android.os.Parcel.createExceptionOrNull // android.os.Parcel.createException // android.os.Parcel.readException // android.os.Parcel.readException firstIndex = 4; } else if (mode == FIND_MODE_SynchronousResultReceiver) { // first entry is from GmsModuleHooks method firstIndex = 1; } else { return null; } ClassLoader defaultClassLoader = GmsCompat.appContext().getClassLoader(); StackTraceElement targetMethod = null; Class stubProxyClass = null; String stubProxyMethodName = null; // Iterate through the stack trace to find out which API call caused the exception for (int i = firstIndex; i < stackTrace.length; ++i) { StackTraceElement ste = stackTrace[i]; String className = ste.getClassName(); Class class_; try { class_ = Class.forName(className, false, defaultClassLoader); } catch (ClassNotFoundException cnfe) { class_ = null; } if (class_ != null) { ClassLoader classLoader = class_.getClassLoader(); if (classLoader == null) { return null; } String loaderName = classLoader.getClass().getName(); if ("java.lang.BootClassLoader".equals(loaderName)) { if (stubProxyClass == null && className.endsWith("$Stub$Proxy")) { stubProxyClass = class_; stubProxyMethodName = ste.getMethodName(); } if (!className.startsWith("java.lang.reflect.")) { // app classes are never loaded with BootClassLoader continue; } // else target method is the previous entry that was invoked via reflection } } if (mode == FIND_MODE_Parcel && stubProxyClass == null) { return null; } if (i == firstIndex) { return null; } targetMethod = stackTrace[i - 1]; break; } if (targetMethod == null) { return null; } ArrayMap classStubs = config.stubs.get(targetMethod.getClassName()); if (classStubs == null) { return null; } StubDef stub = classStubs.get(targetMethod.getMethodName()); if (stub == null) { return null; } if (stub.type == EMPTY_LIST && stub.parcelListType == null) { if (stubProxyClass == null) { Log.d(TAG, "stub proxy class not found for " + targetMethod); return null; } for (Method m : stubProxyClass.getDeclaredMethods()) { if (stubProxyMethodName.equals(m.getName())) { stub.parcelListType = m.getReturnType(); break; } } if (stub.parcelListType == null) { Log.d(TAG, "stub proxy method not found for " + targetMethod); return null; } } return stub; } public boolean stubOutMethod(Parcel p) { p.setDataPosition(0); p.setDataSize(0); final long integer = integerVal; switch (type) { case VOID: break; case NULL: p.writeTypedObject((Parcelable) null, 0); break; case NULL_STRING: p.writeString(null); break; case NULL_ARRAY: p.writeInt(-1); break; case EMPTY_BYTE_ARRAY: p.writeByteArray(new byte[0]); break; case EMPTY_INT_ARRAY: p.writeIntArray(new int[0]); break; case EMPTY_LONG_ARRAY: p.writeLongArray(new long[0]); break; case EMPTY_STRING: p.writeString(""); break; case EMPTY_LIST: { Class t = parcelListType; if (t == List.class) { p.writeList(Collections.emptyList()); } else { String listTypeName = t.getName(); // There is android.content.pm.ParceledListSlice and // com.android.modules.utils.ParceledListSlice. // Moreover, when the latter is used in an APEX, it's prefixed like this: // com.android.wifi.x.com.android.modules.utils.ParceledListSlice // Same applies to StringParceledListSlice. if (listTypeName.endsWith(".ParceledListSlice")) { p.writeTypedObject(ParceledListSlice.emptyList(), 0); } else if (listTypeName.endsWith(".StringParceledListSlice")) { p.writeTypedObject(StringParceledListSlice.emptyList(), 0); } else { Log.d(TAG, "unknown parcel list type " + listTypeName); return false; } } break; } case EMPTY_MAP: p.writeMap(Collections.emptyMap()); break; case BOOLEAN: p.writeBoolean(integer != 0); break; case BYTE: p.writeByte((byte) integer); break; case INT: p.writeInt((int) integer); break; case LONG: p.writeLong(integer); break; case FLOAT: p.writeFloat((float) doubleVal); break; case DOUBLE: p.writeDouble(doubleVal); break; case STRING: p.writeString(stringVal); break; case THROW: { Throwable t; try { Class class_ = Class.forName(stringVal); t = (Throwable) class_.newInstance(); } catch (ReflectiveOperationException e) { Log.e(TAG, "", e); return false; } SneakyThrow.sneakyThrow(t); break; } default: Log.i(TAG, "unknown type " + type); // it's fine that Parcel is reset at this point, it won't be read: // a pending exception will be thrown when this method returns false return false; } p.setDataPosition(0); return true; } @Override public int describeContents() { return 0; } @Override public void writeToParcel(Parcel p, int flags) { p.writeInt(type); p.writeLong(integerVal); p.writeDouble(doubleVal); p.writeString(stringVal); } public static final Parcelable.Creator CREATOR = new Creator<>() { @Override public StubDef createFromParcel(Parcel p) { StubDef d = new StubDef(); d.type = p.readInt(); d.integerVal = p.readLong(); d.doubleVal = p.readDouble(); d.stringVal = p.readString(); return d; } @Override public StubDef[] newArray(int size) { return new StubDef[size]; } }; }