ghidra/Ghidra/Features/Decompiler/ghidra_scripts/classrecovery/SpecialVtable.java
ghidra007 b04d5335ca GP-4376 Updated gcc class recovery to allow for special typeinfos that
are not in program memory or external block. Also updated to add a check
for unhandled relocations. Also updated to allow for non-mangled
typeinfo-name strings.
2024-04-04 16:46:02 +00:00

136 lines
3.7 KiB
Java

/* ###
* IP: GHIDRA
*
* 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 classrecovery;
import java.util.List;
import ghidra.program.model.address.Address;
import ghidra.program.model.listing.Program;
import ghidra.program.model.reloc.Relocation;
import ghidra.program.model.reloc.Relocation.Status;
import ghidra.program.model.reloc.RelocationTable;
import ghidra.program.model.symbol.Namespace;
import ghidra.program.model.symbol.Symbol;
import ghidra.util.exception.CancelledException;
import ghidra.util.task.TaskMonitor;
public class SpecialVtable extends Vtable {
Address refFromTypeinfos;
public SpecialVtable(Program program, Address vtableAddress, GccTypeinfoRef typeinfoRef, boolean inExternalMemory, Namespace classNamespace, TaskMonitor monitor) throws CancelledException {
super(program, vtableAddress, typeinfoRef, true, inExternalMemory, monitor);
this.classNamespace = classNamespace;
}
@Override
protected void setup() throws CancelledException {
if(inExternalMemory) {
refFromTypeinfos = vtableAddress;
isConstruction = false;
isPrimary = true;
typeinfoAddress = vtableAddress;
length = defaultPointerSize;
hasVfunctions = false;
return;
}
typeinfoRefAddress = vtableAddress.add(defaultPointerSize);
// check for vtable has memory but all zeros or has possible invalid values which in both
// cases would make the pointer to special typeinfo invalid
if (hasSpecialCopyUnhandledRelocation(vtableAddress)) {
isConstruction = false;
isPrimary = true;
typeinfoAddress = null;
length = 3 * defaultPointerSize; //actually prob 11*defPtr but are all zeros in this case
hasVfunctions = true; // they are null though so will count as num=0, need this to be true so check for refs to vfunction top will work
numVfunctions = 0;
vfunctionTop = vtableAddress.add(2 * defaultPointerSize);
return;
}
setTypeinfoAddress();
if(!isValid) {
return;
}
setTopOffsetValue();
if(!isValid) {
return;
}
isPrimary = true;
setHasVfunctions();
if(!isValid) {
return;
}
isConstruction = false;
if (classNamespace == null) {
classNamespace = typeinfoNamespace;
}
setLength();
}
public Address getRefFromTypeinfos() {
return refFromTypeinfos;
}
private boolean hasSpecialCopyUnhandledRelocation(Address address) {
RelocationTable relocationTable = program.getRelocationTable();
List<Relocation> relocations = relocationTable.getRelocations(address);
for (Relocation relocation : relocations) {
Status status = relocation.getStatus();
if (status == Status.UNSUPPORTED) {
String symbolName = relocation.getSymbolName();
if (symbolName == null || !symbolName.contains("class_type_info")) {
continue;
}
//if relocation symbol is the same as the symbol at the relcation address
//then this situation is not an issue - it indicates a copy relocation at the
//location of the special typeinfo vtable which is a use case that can be handled
Symbol symbolAtAddress = program.getSymbolTable()
.getSymbol(symbolName, address, program.getGlobalNamespace());
if (symbolAtAddress != null) {
return true;
}
}
}
return false;
}
}