110 lines
3.6 KiB
C++
110 lines
3.6 KiB
C++
//===-- lldb-expression-fuzzer.cpp ---------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===---------------------------------------------------------------------===//
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//
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// \file
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// This file is a fuzzer for LLDB's expression evaluator. It uses protobufs
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// and the libprotobuf-mutator to create valid C-like inputs for the
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// expression evaluator.
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//
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//===---------------------------------------------------------------------===//
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#include <string>
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#include "cxx_proto.pb.h"
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#include "handle-cxx/handle_cxx.h"
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#include "lldb/API/SBBreakpoint.h"
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#include "lldb/API/SBDebugger.h"
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#include "lldb/API/SBError.h"
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#include "lldb/API/SBLaunchInfo.h"
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#include "lldb/API/SBProcess.h"
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#include "lldb/API/SBTarget.h"
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#include "proto-to-cxx/proto_to_cxx.h"
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#include "src/libfuzzer/libfuzzer_macro.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Support/Error.h"
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#include "llvm/Support/FileSystem.h"
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#include "llvm/Support/FormatVariadic.h"
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#include "llvm/Support/WithColor.h"
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using namespace lldb;
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using namespace llvm;
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using namespace clang_fuzzer;
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const char *target_path = nullptr;
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void ReportError(llvm::StringRef message) {
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WithColor::error() << message << '\n';
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exit(1);
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}
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extern "C" int LLVMFuzzerInitialize(int *argc, char ***argv) {
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#if !defined(_WIN32)
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signal(SIGPIPE, SIG_IGN);
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#endif
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// `target_path` can be set by either the "--lldb_fuzzer_target" commandline
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// flag or the "LLDB_FUZZER_TARGET" environment variable. Arbitrarily, we
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// always do flag parsing and only check the environment variable if the
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// commandline flag is not set.
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for (int i = 1; i < *argc; ++i) {
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auto this_arg = llvm::StringRef((*argv)[i]);
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WithColor::note() << "argv[" << i << "] = " << this_arg << "\n";
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if (this_arg.consume_front("--lldb_fuzzer_target="))
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target_path = this_arg.data();
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}
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if (!target_path)
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target_path = ::getenv("LLDB_FUZZER_TARGET");
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if (!target_path)
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ReportError("No target path specified. Set one either as an environment "
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"variable (i.e. LLDB_FUZZER_TARGET=target_path) or pass as a "
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"command line flag (i.e. --lldb_fuzzer_target=target_path).");
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if (!sys::fs::exists(target_path))
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ReportError(formatv("target path '{0}' does not exist", target_path).str());
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SBDebugger::Initialize();
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return 0;
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}
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DEFINE_BINARY_PROTO_FUZZER(const clang_fuzzer::Function &input) {
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std::string expression = clang_fuzzer::FunctionToString(input);
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// Create a debugger and a target
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SBDebugger debugger = SBDebugger::Create(false);
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if (!debugger.IsValid())
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ReportError("Couldn't create debugger");
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SBTarget target = debugger.CreateTarget(target_path);
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if (!target.IsValid())
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ReportError(formatv("Couldn't create target '{0}'", target_path).str());
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// Create a breakpoint on the only line in the program
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SBBreakpoint breakpoint = target.BreakpointCreateByName("main", target_path);
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if (!breakpoint.IsValid())
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ReportError("Couldn't create breakpoint");
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// Create launch info and error for launching the process
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SBLaunchInfo launch_info = target.GetLaunchInfo();
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SBError error;
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// Launch the process and evaluate the fuzzer's input data
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// as an expression
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SBProcess process = target.Launch(launch_info, error);
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if (!process.IsValid() || error.Fail())
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ReportError("Couldn't launch process");
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SBValue value = target.EvaluateExpression(expression.c_str());
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debugger.DeleteTarget(target);
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SBDebugger::Destroy(debugger);
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SBModule::GarbageCollectAllocatedModules();
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}
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