396 lines
13 KiB
C++
396 lines
13 KiB
C++
//===- FuzzerTracePC.cpp - PC tracing--------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// Trace PCs.
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// This module implements __sanitizer_cov_trace_pc_guard[_init],
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// the callback required for -fsanitize-coverage=trace-pc-guard instrumentation.
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//
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//===----------------------------------------------------------------------===//
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#include "FuzzerCorpus.h"
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#include "FuzzerDefs.h"
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#include "FuzzerDictionary.h"
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#include "FuzzerExtFunctions.h"
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#include "FuzzerIO.h"
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#include "FuzzerTracePC.h"
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#include "FuzzerUtil.h"
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#include "FuzzerValueBitMap.h"
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#include <map>
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#include <set>
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#include <sstream>
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// The coverage counters and PCs.
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// These are declared as global variables named "__sancov_*" to simplify
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// experiments with inlined instrumentation.
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alignas(64) ATTRIBUTE_INTERFACE
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uint8_t __sancov_trace_pc_guard_8bit_counters[fuzzer::TracePC::kNumPCs];
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ATTRIBUTE_INTERFACE
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uintptr_t __sancov_trace_pc_pcs[fuzzer::TracePC::kNumPCs];
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namespace fuzzer {
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TracePC TPC;
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uint8_t *TracePC::Counters() const {
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return __sancov_trace_pc_guard_8bit_counters;
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}
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uintptr_t *TracePC::PCs() const {
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return __sancov_trace_pc_pcs;
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}
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size_t TracePC::GetTotalPCCoverage() {
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size_t Res = 0;
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for (size_t i = 1, N = GetNumPCs(); i < N; i++)
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if (PCs()[i])
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Res++;
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return Res;
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}
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void TracePC::HandleInit(uint32_t *Start, uint32_t *Stop) {
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if (Start == Stop || *Start) return;
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assert(NumModules < sizeof(Modules) / sizeof(Modules[0]));
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for (uint32_t *P = Start; P < Stop; P++) {
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NumGuards++;
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if (NumGuards == kNumPCs) {
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RawPrint(
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"WARNING: The binary has too many instrumented PCs.\n"
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" You may want to reduce the size of the binary\n"
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" for more efficient fuzzing and precise coverage data\n");
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}
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*P = NumGuards % kNumPCs;
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}
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Modules[NumModules].Start = Start;
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Modules[NumModules].Stop = Stop;
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NumModules++;
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}
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void TracePC::PrintModuleInfo() {
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Printf("INFO: Loaded %zd modules (%zd guards): ", NumModules, NumGuards);
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for (size_t i = 0; i < NumModules; i++)
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Printf("[%p, %p), ", Modules[i].Start, Modules[i].Stop);
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Printf("\n");
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}
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ATTRIBUTE_NO_SANITIZE_ALL
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void TracePC::HandleCallerCallee(uintptr_t Caller, uintptr_t Callee) {
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const uintptr_t kBits = 12;
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const uintptr_t kMask = (1 << kBits) - 1;
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uintptr_t Idx = (Caller & kMask) | ((Callee & kMask) << kBits);
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ValueProfileMap.AddValueModPrime(Idx);
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}
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void TracePC::InitializePrintNewPCs() {
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if (!DoPrintNewPCs) return;
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assert(!PrintedPCs);
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PrintedPCs = new std::set<uintptr_t>;
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for (size_t i = 1; i < GetNumPCs(); i++)
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if (PCs()[i])
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PrintedPCs->insert(PCs()[i]);
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}
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void TracePC::PrintNewPCs() {
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if (!DoPrintNewPCs) return;
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assert(PrintedPCs);
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for (size_t i = 1; i < GetNumPCs(); i++)
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if (PCs()[i] && PrintedPCs->insert(PCs()[i]).second)
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PrintPC("\tNEW_PC: %p %F %L\n", "\tNEW_PC: %p\n", PCs()[i]);
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}
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void TracePC::PrintCoverage() {
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if (!EF->__sanitizer_symbolize_pc ||
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!EF->__sanitizer_get_module_and_offset_for_pc) {
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Printf("INFO: __sanitizer_symbolize_pc or "
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"__sanitizer_get_module_and_offset_for_pc is not available,"
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" not printing coverage\n");
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return;
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}
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std::map<std::string, std::vector<uintptr_t>> CoveredPCsPerModule;
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std::map<std::string, uintptr_t> ModuleOffsets;
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std::set<std::string> CoveredDirs, CoveredFiles, CoveredFunctions,
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CoveredLines;
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Printf("COVERAGE:\n");
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for (size_t i = 1; i < GetNumPCs(); i++) {
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uintptr_t PC = PCs()[i];
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if (!PC) continue;
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std::string FileStr = DescribePC("%s", PC);
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if (!IsInterestingCoverageFile(FileStr)) continue;
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std::string FixedPCStr = DescribePC("%p", PC);
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std::string FunctionStr = DescribePC("%F", PC);
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std::string LineStr = DescribePC("%l", PC);
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char ModulePathRaw[4096] = ""; // What's PATH_MAX in portable C++?
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void *OffsetRaw = nullptr;
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if (!EF->__sanitizer_get_module_and_offset_for_pc(
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reinterpret_cast<void *>(PC), ModulePathRaw,
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sizeof(ModulePathRaw), &OffsetRaw))
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continue;
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std::string Module = ModulePathRaw;
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uintptr_t FixedPC = std::stoull(FixedPCStr, 0, 16);
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uintptr_t PcOffset = reinterpret_cast<uintptr_t>(OffsetRaw);
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ModuleOffsets[Module] = FixedPC - PcOffset;
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CoveredPCsPerModule[Module].push_back(PcOffset);
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CoveredFunctions.insert(FunctionStr);
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CoveredFiles.insert(FileStr);
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CoveredDirs.insert(DirName(FileStr));
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if (!CoveredLines.insert(FileStr + ":" + LineStr).second)
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continue;
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Printf("COVERED: %s %s:%s\n", FunctionStr.c_str(),
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FileStr.c_str(), LineStr.c_str());
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}
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std::string CoveredDirsStr;
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for (auto &Dir : CoveredDirs) {
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if (!CoveredDirsStr.empty())
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CoveredDirsStr += ",";
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CoveredDirsStr += Dir;
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}
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Printf("COVERED_DIRS: %s\n", CoveredDirsStr.c_str());
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for (auto &M : CoveredPCsPerModule) {
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std::set<std::string> UncoveredFiles, UncoveredFunctions;
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std::map<std::string, std::set<int> > UncoveredLines; // Func+File => lines
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auto &ModuleName = M.first;
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auto &CoveredOffsets = M.second;
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uintptr_t ModuleOffset = ModuleOffsets[ModuleName];
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std::sort(CoveredOffsets.begin(), CoveredOffsets.end());
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Printf("MODULE_WITH_COVERAGE: %s\n", ModuleName.c_str());
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// sancov does not yet fully support DSOs.
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// std::string Cmd = "sancov -print-coverage-pcs " + ModuleName;
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std::string Cmd = DisassembleCmd(ModuleName) + " | " +
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SearchRegexCmd("call.*__sanitizer_cov_trace_pc_guard");
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std::string SanCovOutput;
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if (!ExecuteCommandAndReadOutput(Cmd, &SanCovOutput)) {
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Printf("INFO: Command failed: %s\n", Cmd.c_str());
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continue;
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}
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std::istringstream ISS(SanCovOutput);
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std::string S;
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while (std::getline(ISS, S, '\n')) {
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size_t PcOffsetEnd = S.find(':');
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if (PcOffsetEnd == std::string::npos)
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continue;
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S.resize(PcOffsetEnd);
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uintptr_t PcOffset = std::stoull(S, 0, 16);
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if (!std::binary_search(CoveredOffsets.begin(), CoveredOffsets.end(),
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PcOffset)) {
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uintptr_t PC = ModuleOffset + PcOffset;
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auto FileStr = DescribePC("%s", PC);
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if (!IsInterestingCoverageFile(FileStr)) continue;
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if (CoveredFiles.count(FileStr) == 0) {
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UncoveredFiles.insert(FileStr);
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continue;
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}
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auto FunctionStr = DescribePC("%F", PC);
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if (CoveredFunctions.count(FunctionStr) == 0) {
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UncoveredFunctions.insert(FunctionStr);
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continue;
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}
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std::string LineStr = DescribePC("%l", PC);
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uintptr_t Line = std::stoi(LineStr);
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std::string FileLineStr = FileStr + ":" + LineStr;
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if (CoveredLines.count(FileLineStr) == 0)
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UncoveredLines[FunctionStr + " " + FileStr].insert(Line);
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}
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}
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for (auto &FileLine: UncoveredLines)
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for (int Line : FileLine.second)
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Printf("UNCOVERED_LINE: %s:%d\n", FileLine.first.c_str(), Line);
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for (auto &Func : UncoveredFunctions)
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Printf("UNCOVERED_FUNC: %s\n", Func.c_str());
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for (auto &File : UncoveredFiles)
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Printf("UNCOVERED_FILE: %s\n", File.c_str());
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}
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}
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inline ALWAYS_INLINE uintptr_t GetPreviousInstructionPc(uintptr_t PC) {
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// TODO: this implementation is x86 only.
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// see sanitizer_common GetPreviousInstructionPc for full implementation.
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return PC - 1;
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}
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void TracePC::DumpCoverage() {
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if (EF->__sanitizer_dump_coverage) {
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std::vector<uintptr_t> PCsCopy(GetNumPCs());
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for (size_t i = 0; i < GetNumPCs(); i++)
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PCsCopy[i] = PCs()[i] ? GetPreviousInstructionPc(PCs()[i]) : 0;
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EF->__sanitizer_dump_coverage(PCsCopy.data(), PCsCopy.size());
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}
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}
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// Value profile.
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// We keep track of various values that affect control flow.
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// These values are inserted into a bit-set-based hash map.
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// Every new bit in the map is treated as a new coverage.
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//
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// For memcmp/strcmp/etc the interesting value is the length of the common
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// prefix of the parameters.
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// For cmp instructions the interesting value is a XOR of the parameters.
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// The interesting value is mixed up with the PC and is then added to the map.
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ATTRIBUTE_NO_SANITIZE_ALL
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void TracePC::AddValueForMemcmp(void *caller_pc, const void *s1, const void *s2,
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size_t n, bool StopAtZero) {
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if (!n) return;
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size_t Len = std::min(n, Word::GetMaxSize());
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const uint8_t *A1 = reinterpret_cast<const uint8_t *>(s1);
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const uint8_t *A2 = reinterpret_cast<const uint8_t *>(s2);
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uint8_t B1[Word::kMaxSize];
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uint8_t B2[Word::kMaxSize];
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// Copy the data into locals in this non-msan-instrumented function
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// to avoid msan complaining further.
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size_t Hash = 0; // Compute some simple hash of both strings.
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for (size_t i = 0; i < Len; i++) {
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B1[i] = A1[i];
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B2[i] = A2[i];
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size_t T = B1[i];
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Hash ^= (T << 8) | B2[i];
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}
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size_t I = 0;
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for (; I < Len; I++)
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if (B1[I] != B2[I] || (StopAtZero && B1[I] == 0))
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break;
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size_t PC = reinterpret_cast<size_t>(caller_pc);
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size_t Idx = (PC & 4095) | (I << 12);
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ValueProfileMap.AddValue(Idx);
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TORCW.Insert(Idx ^ Hash, Word(B1, Len), Word(B2, Len));
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}
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template <class T>
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ATTRIBUTE_TARGET_POPCNT ALWAYS_INLINE
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ATTRIBUTE_NO_SANITIZE_ALL
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void TracePC::HandleCmp(uintptr_t PC, T Arg1, T Arg2) {
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uint64_t ArgXor = Arg1 ^ Arg2;
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uint64_t ArgDistance = __builtin_popcountll(ArgXor) + 1; // [1,65]
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uintptr_t Idx = ((PC & 4095) + 1) * ArgDistance;
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if (sizeof(T) == 4)
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TORC4.Insert(ArgXor, Arg1, Arg2);
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else if (sizeof(T) == 8)
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TORC8.Insert(ArgXor, Arg1, Arg2);
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ValueProfileMap.AddValue(Idx);
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}
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} // namespace fuzzer
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extern "C" {
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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void __sanitizer_cov_trace_pc_guard(uint32_t *Guard) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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uint32_t Idx = *Guard;
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__sancov_trace_pc_pcs[Idx] = PC;
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__sancov_trace_pc_guard_8bit_counters[Idx]++;
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}
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// Best-effort support for -fsanitize-coverage=trace-pc, which is available
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// in both Clang and GCC.
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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void __sanitizer_cov_trace_pc() {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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uintptr_t Idx = PC & (((uintptr_t)1 << fuzzer::TracePC::kTracePcBits) - 1);
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__sancov_trace_pc_pcs[Idx] = PC;
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__sancov_trace_pc_guard_8bit_counters[Idx]++;
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}
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ATTRIBUTE_INTERFACE
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void __sanitizer_cov_trace_pc_guard_init(uint32_t *Start, uint32_t *Stop) {
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fuzzer::TPC.HandleInit(Start, Stop);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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void __sanitizer_cov_trace_pc_indir(uintptr_t Callee) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCallerCallee(PC, Callee);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Arg1, Arg2);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t *Cases) {
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uint64_t N = Cases[0];
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uint64_t ValSizeInBits = Cases[1];
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uint64_t *Vals = Cases + 2;
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// Skip the most common and the most boring case.
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if (Vals[N - 1] < 256 && Val < 256)
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return;
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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size_t i;
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uint64_t Token = 0;
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for (i = 0; i < N; i++) {
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Token = Val ^ Vals[i];
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if (Val < Vals[i])
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break;
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}
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if (ValSizeInBits == 16)
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fuzzer::TPC.HandleCmp(PC + i, static_cast<uint16_t>(Token), (uint16_t)(0));
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else if (ValSizeInBits == 32)
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fuzzer::TPC.HandleCmp(PC + i, static_cast<uint32_t>(Token), (uint32_t)(0));
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else
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fuzzer::TPC.HandleCmp(PC + i, Token, (uint64_t)(0));
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_div4(uint32_t Val) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Val, (uint32_t)0);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_div8(uint64_t Val) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Val, (uint64_t)0);
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}
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ATTRIBUTE_INTERFACE
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ATTRIBUTE_NO_SANITIZE_ALL
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ATTRIBUTE_TARGET_POPCNT
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void __sanitizer_cov_trace_gep(uintptr_t Idx) {
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uintptr_t PC = reinterpret_cast<uintptr_t>(__builtin_return_address(0));
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fuzzer::TPC.HandleCmp(PC, Idx, (uintptr_t)0);
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}
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} // extern "C"
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