ghidra/Ghidra/Debug/Debugger/ghidra_scripts/DebuggerEmuExampleScript.java

211 lines
8 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.
*/
//An example emulation script that integrates well with the Debgger UI.
//It provides the set-up code and then demonstrates some use cases.
//It should work with any x64 program, but some snippets may require specific conditions.
//It should be easily ported to other platforms just by adjusting register names.
//@author
//@category Emulation
//@keybinding
//@menupath
//@toolbar
import java.nio.charset.Charset;
import java.util.List;
import ghidra.app.plugin.assembler.Assembler;
import ghidra.app.plugin.assembler.Assemblers;
import ghidra.app.plugin.core.debug.service.emulation.BytesDebuggerPcodeEmulator;
import ghidra.app.plugin.core.debug.service.emulation.ProgramEmulationUtils;
import ghidra.app.plugin.processors.sleigh.SleighLanguage;
import ghidra.app.script.GhidraScript;
import ghidra.app.services.DebuggerTraceManagerService;
import ghidra.app.services.ProgramManager;
import ghidra.framework.plugintool.PluginTool;
import ghidra.pcode.emu.PcodeThread;
import ghidra.pcode.exec.*;
import ghidra.pcode.exec.trace.TraceSleighUtils;
import ghidra.pcode.utils.Utils;
import ghidra.program.database.ProgramDB;
import ghidra.program.model.address.Address;
import ghidra.program.model.address.AddressSpace;
import ghidra.program.model.lang.LanguageID;
import ghidra.program.model.listing.InstructionIterator;
import ghidra.program.model.listing.Program;
import ghidra.program.model.mem.Memory;
import ghidra.trace.model.Trace;
import ghidra.trace.model.thread.TraceThread;
import ghidra.trace.model.time.TraceSnapshot;
import ghidra.trace.model.time.TraceTimeManager;
import ghidra.util.database.UndoableTransaction;
public class DebuggerEmuExampleScript extends GhidraScript {
private final static Charset UTF8 = Charset.forName("utf8");
@Override
protected void run() throws Exception {
/*
* First, get all the services and stuff:
*/
PluginTool tool = state.getTool();
ProgramManager programManager = tool.getService(ProgramManager.class);
DebuggerTraceManagerService traceManager =
tool.getService(DebuggerTraceManagerService.class);
SleighLanguage language = (SleighLanguage) getLanguage(new LanguageID("x86:LE:64:default"));
/*
* I'll generate a new program, because I don't want to require the user to pick something
* specific.
*/
Address entry;
Address injectHere;
Program program = null;
try {
program =
new ProgramDB("emu_example", language, language.getDefaultCompilerSpec(), this);
// Save the program into the project so it has a URL for the trace's static mapping
tool.getProject()
.getProjectData()
.getRootFolder()
.createFile("emu_example", program, monitor);
try (UndoableTransaction tid = UndoableTransaction.start(program, "Init")) {
AddressSpace space = program.getAddressFactory().getDefaultAddressSpace();
entry = space.getAddress(0x00400000);
Address dataEntry = space.getAddress(0x00600000);
Memory memory = program.getMemory();
memory.createInitializedBlock(".text", entry, 0x1000, (byte) 0, monitor, false);
Assembler asm = Assemblers.getAssembler(program);
InstructionIterator ii = asm.assemble(entry,
"MOV RCX, 0x" + dataEntry,
"MOV RAX, 1",
"SYSCALL",
"MOV RAX, 2",
"SYSCALL");
ii.next(); // drop MOV RCX
injectHere = ii.next().getAddress();
memory.createInitializedBlock(".data", dataEntry, 0x1000, (byte) 0, monitor, false);
memory.setBytes(dataEntry, "Hello, World!\n".getBytes(UTF8));
}
program.save("Init", monitor);
// Display the program in the UI
programManager.openProgram(program);
}
finally {
if (program != null) {
program.release(this);
}
}
/*
* Now, load the program into a trace. This doesn't copy any bytes, it just sets up a static
* mapping. The emulator will know how to read through to the mapped program. We use a
* utility, which is the same used by the "Emulate Program" action in the UI. It will load
* the program, allocate a stack, and initialize the first thread to the given entry.
*/
Trace trace = null;
try {
trace = ProgramEmulationUtils.launchEmulationTrace(program, entry, this);
// Display the trace in the UI
traceManager.openTrace(trace);
traceManager.activateTrace(trace);
}
finally {
if (trace != null) {
trace.release(this);
}
}
// Get the initial thread
TraceThread traceThread = trace.getThreadManager().getAllThreads().iterator().next();
traceManager.activateThread(traceThread);
/*
* Instead of using the UI's emulator, this script will create its own with a custom
* library. This emulator will still know how to integrate with the UI, reading through to
* open programs and writing state back into the trace.
*/
BytesDebuggerPcodeEmulator emulator = new BytesDebuggerPcodeEmulator(tool, trace, 0, null) {
@Override
protected PcodeUseropLibrary<byte[]> createUseropLibrary() {
return new DemoPcodeUseropLibrary(language, DebuggerEmuExampleScript.this);
}
};
// Conventionally, emulator threads are named after their trace thread's path.
PcodeThread<byte[]> thread = emulator.getThread(traceThread.getPath(), true);
/*
* Inject a call to our custom print userop. Otherwise, the language itself will never
* invoke it.
*/
emulator.inject(injectHere, List.of(
"print_utf8(RCX);",
"emu_exec_decoded();"));
/*
* Run the experiment: This should interrupt on the second SYSCALL, because any value other
* than 1 calls emu_swi.
*
* For demonstration, we'll record a trace snapshot for every step of emulation. This is not
* ordinarily recommended except for very small experiments. A more reasonable approach in
* practice may be to snapshot on specific breakpoints.
*/
TraceTimeManager time = trace.getTimeManager();
TraceSnapshot snapshot = time.getSnapshot(0, true);
try (UndoableTransaction tid = UndoableTransaction.start(trace, "Emulate")) {
for (int i = 0; i < 10; i++) {
println("Executing: " + thread.getCounter());
thread.stepInstruction();
snapshot =
time.createSnapshot("Stepped to " + thread.getCounter());
emulator.writeDown(trace, snapshot.getKey(), 0);
}
printerr("We should not have completed 10 steps!");
}
catch (InterruptPcodeExecutionException e) {
println("Terminated via interrupt. Good.");
}
// Display the final snapshot in the UI
traceManager.activateSnap(snapshot.getKey());
/*
* Inspect the machine. You can always do this by accessing the state directly, but for
* anything other than simple variables, you may find compiling an expression more
* convenient.
*
* This works the same as in the stand-alone case.
*/
println("RCX = " +
Utils.bytesToLong(thread.getState().getVar(language.getRegister("RCX")), 8,
language.isBigEndian()));
println("RCX = " + Utils.bytesToLong(
SleighProgramCompiler.compileExpression(language, "RCX").evaluate(thread.getExecutor()),
8, language.isBigEndian()));
println("RCX+4 = " +
Utils.bytesToLong(SleighProgramCompiler.compileExpression(language, "RCX+4")
.evaluate(thread.getExecutor()),
8, language.isBigEndian()));
/*
* To evaluate a Sleigh expression against the trace: The result is the same as evaluating
* directly against the emulator, but these work with any trace, no matter the original data
* source (live target, emulated, imported, etc.) It's also built into utilities, making it
* easier to use.
*/
println("RCX+4 (trace) = " +
TraceSleighUtils.evaluate("RCX+4", trace, snapshot.getKey(), traceThread, 0));
}
}