1 //===- FuzzerDriver.cpp - FuzzerDriver function and flags -----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // FuzzerDriver and flag parsing.
9 //===----------------------------------------------------------------------===//
10
11 #include "FuzzerCommand.h"
12 #include "FuzzerCorpus.h"
13 #include "FuzzerFork.h"
14 #include "FuzzerIO.h"
15 #include "FuzzerInterface.h"
16 #include "FuzzerInternal.h"
17 #include "FuzzerMerge.h"
18 #include "FuzzerMutate.h"
19 #include "FuzzerPlatform.h"
20 #include "FuzzerRandom.h"
21 #include "FuzzerTracePC.h"
22 #include <algorithm>
23 #include <atomic>
24 #include <chrono>
25 #include <cstdlib>
26 #include <cstring>
27 #include <mutex>
28 #include <string>
29 #include <thread>
30 #include <fstream>
31
32 // This function should be present in the libFuzzer so that the client
33 // binary can test for its existence.
34 #if LIBFUZZER_MSVC
__libfuzzer_is_present()35 extern "C" void __libfuzzer_is_present() {}
36 #pragma comment(linker, "/include:__libfuzzer_is_present")
37 #else
__libfuzzer_is_present()38 extern "C" __attribute__((used)) void __libfuzzer_is_present() {}
39 #endif // LIBFUZZER_MSVC
40
41 namespace fuzzer {
42
43 // Program arguments.
44 struct FlagDescription {
45 const char *Name;
46 const char *Description;
47 int Default;
48 int *IntFlag;
49 const char **StrFlag;
50 unsigned int *UIntFlag;
51 };
52
53 struct {
54 #define FUZZER_DEPRECATED_FLAG(Name)
55 #define FUZZER_FLAG_INT(Name, Default, Description) int Name;
56 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description) unsigned int Name;
57 #define FUZZER_FLAG_STRING(Name, Description) const char *Name;
58 #include "FuzzerFlags.def"
59 #undef FUZZER_DEPRECATED_FLAG
60 #undef FUZZER_FLAG_INT
61 #undef FUZZER_FLAG_UNSIGNED
62 #undef FUZZER_FLAG_STRING
63 } Flags;
64
65 static const FlagDescription FlagDescriptions [] {
66 #define FUZZER_DEPRECATED_FLAG(Name) \
67 {#Name, "Deprecated; don't use", 0, nullptr, nullptr, nullptr},
68 #define FUZZER_FLAG_INT(Name, Default, Description) \
69 {#Name, Description, Default, &Flags.Name, nullptr, nullptr},
70 #define FUZZER_FLAG_UNSIGNED(Name, Default, Description) \
71 {#Name, Description, static_cast<int>(Default), \
72 nullptr, nullptr, &Flags.Name},
73 #define FUZZER_FLAG_STRING(Name, Description) \
74 {#Name, Description, 0, nullptr, &Flags.Name, nullptr},
75 #include "FuzzerFlags.def"
76 #undef FUZZER_DEPRECATED_FLAG
77 #undef FUZZER_FLAG_INT
78 #undef FUZZER_FLAG_UNSIGNED
79 #undef FUZZER_FLAG_STRING
80 };
81
82 static const size_t kNumFlags =
83 sizeof(FlagDescriptions) / sizeof(FlagDescriptions[0]);
84
85 static Vector<std::string> *Inputs;
86 static std::string *ProgName;
87
PrintHelp()88 static void PrintHelp() {
89 Printf("Usage:\n");
90 auto Prog = ProgName->c_str();
91 Printf("\nTo run fuzzing pass 0 or more directories.\n");
92 Printf("%s [-flag1=val1 [-flag2=val2 ...] ] [dir1 [dir2 ...] ]\n", Prog);
93
94 Printf("\nTo run individual tests without fuzzing pass 1 or more files:\n");
95 Printf("%s [-flag1=val1 [-flag2=val2 ...] ] file1 [file2 ...]\n", Prog);
96
97 Printf("\nFlags: (strictly in form -flag=value)\n");
98 size_t MaxFlagLen = 0;
99 for (size_t F = 0; F < kNumFlags; F++)
100 MaxFlagLen = std::max(strlen(FlagDescriptions[F].Name), MaxFlagLen);
101
102 for (size_t F = 0; F < kNumFlags; F++) {
103 const auto &D = FlagDescriptions[F];
104 if (strstr(D.Description, "internal flag") == D.Description) continue;
105 Printf(" %s", D.Name);
106 for (size_t i = 0, n = MaxFlagLen - strlen(D.Name); i < n; i++)
107 Printf(" ");
108 Printf("\t");
109 Printf("%d\t%s\n", D.Default, D.Description);
110 }
111 Printf("\nFlags starting with '--' will be ignored and "
112 "will be passed verbatim to subprocesses.\n");
113 }
114
FlagValue(const char * Param,const char * Name)115 static const char *FlagValue(const char *Param, const char *Name) {
116 size_t Len = strlen(Name);
117 if (Param[0] == '-' && strstr(Param + 1, Name) == Param + 1 &&
118 Param[Len + 1] == '=')
119 return &Param[Len + 2];
120 return nullptr;
121 }
122
123 // Avoid calling stol as it triggers a bug in clang/glibc build.
MyStol(const char * Str)124 static long MyStol(const char *Str) {
125 long Res = 0;
126 long Sign = 1;
127 if (*Str == '-') {
128 Str++;
129 Sign = -1;
130 }
131 for (size_t i = 0; Str[i]; i++) {
132 char Ch = Str[i];
133 if (Ch < '0' || Ch > '9')
134 return Res;
135 Res = Res * 10 + (Ch - '0');
136 }
137 return Res * Sign;
138 }
139
ParseOneFlag(const char * Param)140 static bool ParseOneFlag(const char *Param) {
141 if (Param[0] != '-') return false;
142 if (Param[1] == '-') {
143 static bool PrintedWarning = false;
144 if (!PrintedWarning) {
145 PrintedWarning = true;
146 Printf("INFO: libFuzzer ignores flags that start with '--'\n");
147 }
148 for (size_t F = 0; F < kNumFlags; F++)
149 if (FlagValue(Param + 1, FlagDescriptions[F].Name))
150 Printf("WARNING: did you mean '%s' (single dash)?\n", Param + 1);
151 return true;
152 }
153 for (size_t F = 0; F < kNumFlags; F++) {
154 const char *Name = FlagDescriptions[F].Name;
155 const char *Str = FlagValue(Param, Name);
156 if (Str) {
157 if (FlagDescriptions[F].IntFlag) {
158 int Val = MyStol(Str);
159 *FlagDescriptions[F].IntFlag = Val;
160 if (Flags.verbosity >= 2)
161 Printf("Flag: %s %d\n", Name, Val);
162 return true;
163 } else if (FlagDescriptions[F].UIntFlag) {
164 unsigned int Val = std::stoul(Str);
165 *FlagDescriptions[F].UIntFlag = Val;
166 if (Flags.verbosity >= 2)
167 Printf("Flag: %s %u\n", Name, Val);
168 return true;
169 } else if (FlagDescriptions[F].StrFlag) {
170 *FlagDescriptions[F].StrFlag = Str;
171 if (Flags.verbosity >= 2)
172 Printf("Flag: %s %s\n", Name, Str);
173 return true;
174 } else { // Deprecated flag.
175 Printf("Flag: %s: deprecated, don't use\n", Name);
176 return true;
177 }
178 }
179 }
180 Printf("\n\nWARNING: unrecognized flag '%s'; "
181 "use -help=1 to list all flags\n\n", Param);
182 return true;
183 }
184
185 // We don't use any library to minimize dependencies.
ParseFlags(const Vector<std::string> & Args,const ExternalFunctions * EF)186 static void ParseFlags(const Vector<std::string> &Args,
187 const ExternalFunctions *EF) {
188 for (size_t F = 0; F < kNumFlags; F++) {
189 if (FlagDescriptions[F].IntFlag)
190 *FlagDescriptions[F].IntFlag = FlagDescriptions[F].Default;
191 if (FlagDescriptions[F].UIntFlag)
192 *FlagDescriptions[F].UIntFlag =
193 static_cast<unsigned int>(FlagDescriptions[F].Default);
194 if (FlagDescriptions[F].StrFlag)
195 *FlagDescriptions[F].StrFlag = nullptr;
196 }
197
198 // Disable len_control by default, if LLVMFuzzerCustomMutator is used.
199 if (EF->LLVMFuzzerCustomMutator) {
200 Flags.len_control = 0;
201 Printf("INFO: found LLVMFuzzerCustomMutator (%p). "
202 "Disabling -len_control by default.\n", EF->LLVMFuzzerCustomMutator);
203 }
204
205 Inputs = new Vector<std::string>;
206 for (size_t A = 1; A < Args.size(); A++) {
207 if (ParseOneFlag(Args[A].c_str())) {
208 if (Flags.ignore_remaining_args)
209 break;
210 continue;
211 }
212 Inputs->push_back(Args[A]);
213 }
214 }
215
216 static std::mutex Mu;
217
PulseThread()218 static void PulseThread() {
219 while (true) {
220 SleepSeconds(600);
221 std::lock_guard<std::mutex> Lock(Mu);
222 Printf("pulse...\n");
223 }
224 }
225
WorkerThread(const Command & BaseCmd,std::atomic<unsigned> * Counter,unsigned NumJobs,std::atomic<bool> * HasErrors)226 static void WorkerThread(const Command &BaseCmd, std::atomic<unsigned> *Counter,
227 unsigned NumJobs, std::atomic<bool> *HasErrors) {
228 while (true) {
229 unsigned C = (*Counter)++;
230 if (C >= NumJobs) break;
231 std::string Log = "fuzz-" + std::to_string(C) + ".log";
232 Command Cmd(BaseCmd);
233 Cmd.setOutputFile(Log);
234 Cmd.combineOutAndErr();
235 if (Flags.verbosity) {
236 std::string CommandLine = Cmd.toString();
237 Printf("%s\n", CommandLine.c_str());
238 }
239 int ExitCode = ExecuteCommand(Cmd);
240 if (ExitCode != 0)
241 *HasErrors = true;
242 std::lock_guard<std::mutex> Lock(Mu);
243 Printf("================== Job %u exited with exit code %d ============\n",
244 C, ExitCode);
245 fuzzer::CopyFileToErr(Log);
246 }
247 }
248
CloneArgsWithoutX(const Vector<std::string> & Args,const char * X1,const char * X2)249 std::string CloneArgsWithoutX(const Vector<std::string> &Args,
250 const char *X1, const char *X2) {
251 std::string Cmd;
252 for (auto &S : Args) {
253 if (FlagValue(S.c_str(), X1) || FlagValue(S.c_str(), X2))
254 continue;
255 Cmd += S + " ";
256 }
257 return Cmd;
258 }
259
RunInMultipleProcesses(const Vector<std::string> & Args,unsigned NumWorkers,unsigned NumJobs)260 static int RunInMultipleProcesses(const Vector<std::string> &Args,
261 unsigned NumWorkers, unsigned NumJobs) {
262 std::atomic<unsigned> Counter(0);
263 std::atomic<bool> HasErrors(false);
264 Command Cmd(Args);
265 Cmd.removeFlag("jobs");
266 Cmd.removeFlag("workers");
267 Vector<std::thread> V;
268 std::thread Pulse(PulseThread);
269 Pulse.detach();
270 for (unsigned i = 0; i < NumWorkers; i++)
271 V.push_back(std::thread(WorkerThread, std::ref(Cmd), &Counter, NumJobs, &HasErrors));
272 for (auto &T : V)
273 T.join();
274 return HasErrors ? 1 : 0;
275 }
276
RssThread(Fuzzer * F,size_t RssLimitMb)277 static void RssThread(Fuzzer *F, size_t RssLimitMb) {
278 while (true) {
279 SleepSeconds(1);
280 size_t Peak = GetPeakRSSMb();
281 if (Peak > RssLimitMb)
282 F->RssLimitCallback();
283 }
284 }
285
StartRssThread(Fuzzer * F,size_t RssLimitMb)286 static void StartRssThread(Fuzzer *F, size_t RssLimitMb) {
287 if (!RssLimitMb)
288 return;
289 std::thread T(RssThread, F, RssLimitMb);
290 T.detach();
291 }
292
RunOneTest(Fuzzer * F,const char * InputFilePath,size_t MaxLen)293 int RunOneTest(Fuzzer *F, const char *InputFilePath, size_t MaxLen) {
294 Unit U = FileToVector(InputFilePath);
295 if (MaxLen && MaxLen < U.size())
296 U.resize(MaxLen);
297 F->ExecuteCallback(U.data(), U.size());
298 F->TryDetectingAMemoryLeak(U.data(), U.size(), true);
299 return 0;
300 }
301
AllInputsAreFiles()302 static bool AllInputsAreFiles() {
303 if (Inputs->empty()) return false;
304 for (auto &Path : *Inputs)
305 if (!IsFile(Path))
306 return false;
307 return true;
308 }
309
GetDedupTokenFromCmdOutput(const std::string & S)310 static std::string GetDedupTokenFromCmdOutput(const std::string &S) {
311 auto Beg = S.find("DEDUP_TOKEN:");
312 if (Beg == std::string::npos)
313 return "";
314 auto End = S.find('\n', Beg);
315 if (End == std::string::npos)
316 return "";
317 return S.substr(Beg, End - Beg);
318 }
319
CleanseCrashInput(const Vector<std::string> & Args,const FuzzingOptions & Options)320 int CleanseCrashInput(const Vector<std::string> &Args,
321 const FuzzingOptions &Options) {
322 if (Inputs->size() != 1 || !Flags.exact_artifact_path) {
323 Printf("ERROR: -cleanse_crash should be given one input file and"
324 " -exact_artifact_path\n");
325 exit(1);
326 }
327 std::string InputFilePath = Inputs->at(0);
328 std::string OutputFilePath = Flags.exact_artifact_path;
329 Command Cmd(Args);
330 Cmd.removeFlag("cleanse_crash");
331
332 assert(Cmd.hasArgument(InputFilePath));
333 Cmd.removeArgument(InputFilePath);
334
335 auto TmpFilePath = TempPath("CleanseCrashInput", ".repro");
336 Cmd.addArgument(TmpFilePath);
337 Cmd.setOutputFile(getDevNull());
338 Cmd.combineOutAndErr();
339
340 std::string CurrentFilePath = InputFilePath;
341 auto U = FileToVector(CurrentFilePath);
342 size_t Size = U.size();
343
344 const Vector<uint8_t> ReplacementBytes = {' ', 0xff};
345 for (int NumAttempts = 0; NumAttempts < 5; NumAttempts++) {
346 bool Changed = false;
347 for (size_t Idx = 0; Idx < Size; Idx++) {
348 Printf("CLEANSE[%d]: Trying to replace byte %zd of %zd\n", NumAttempts,
349 Idx, Size);
350 uint8_t OriginalByte = U[Idx];
351 if (ReplacementBytes.end() != std::find(ReplacementBytes.begin(),
352 ReplacementBytes.end(),
353 OriginalByte))
354 continue;
355 for (auto NewByte : ReplacementBytes) {
356 U[Idx] = NewByte;
357 WriteToFile(U, TmpFilePath);
358 auto ExitCode = ExecuteCommand(Cmd);
359 RemoveFile(TmpFilePath);
360 if (!ExitCode) {
361 U[Idx] = OriginalByte;
362 } else {
363 Changed = true;
364 Printf("CLEANSE: Replaced byte %zd with 0x%x\n", Idx, NewByte);
365 WriteToFile(U, OutputFilePath);
366 break;
367 }
368 }
369 }
370 if (!Changed) break;
371 }
372 return 0;
373 }
374
MinimizeCrashInput(const Vector<std::string> & Args,const FuzzingOptions & Options)375 int MinimizeCrashInput(const Vector<std::string> &Args,
376 const FuzzingOptions &Options) {
377 if (Inputs->size() != 1) {
378 Printf("ERROR: -minimize_crash should be given one input file\n");
379 exit(1);
380 }
381 std::string InputFilePath = Inputs->at(0);
382 Command BaseCmd(Args);
383 BaseCmd.removeFlag("minimize_crash");
384 BaseCmd.removeFlag("exact_artifact_path");
385 assert(BaseCmd.hasArgument(InputFilePath));
386 BaseCmd.removeArgument(InputFilePath);
387 if (Flags.runs <= 0 && Flags.max_total_time == 0) {
388 Printf("INFO: you need to specify -runs=N or "
389 "-max_total_time=N with -minimize_crash=1\n"
390 "INFO: defaulting to -max_total_time=600\n");
391 BaseCmd.addFlag("max_total_time", "600");
392 }
393
394 BaseCmd.combineOutAndErr();
395
396 std::string CurrentFilePath = InputFilePath;
397 while (true) {
398 Unit U = FileToVector(CurrentFilePath);
399 Printf("CRASH_MIN: minimizing crash input: '%s' (%zd bytes)\n",
400 CurrentFilePath.c_str(), U.size());
401
402 Command Cmd(BaseCmd);
403 Cmd.addArgument(CurrentFilePath);
404
405 Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
406 std::string CmdOutput;
407 bool Success = ExecuteCommand(Cmd, &CmdOutput);
408 if (Success) {
409 Printf("ERROR: the input %s did not crash\n", CurrentFilePath.c_str());
410 exit(1);
411 }
412 Printf("CRASH_MIN: '%s' (%zd bytes) caused a crash. Will try to minimize "
413 "it further\n",
414 CurrentFilePath.c_str(), U.size());
415 auto DedupToken1 = GetDedupTokenFromCmdOutput(CmdOutput);
416 if (!DedupToken1.empty())
417 Printf("CRASH_MIN: DedupToken1: %s\n", DedupToken1.c_str());
418
419 std::string ArtifactPath =
420 Flags.exact_artifact_path
421 ? Flags.exact_artifact_path
422 : Options.ArtifactPrefix + "minimized-from-" + Hash(U);
423 Cmd.addFlag("minimize_crash_internal_step", "1");
424 Cmd.addFlag("exact_artifact_path", ArtifactPath);
425 Printf("CRASH_MIN: executing: %s\n", Cmd.toString().c_str());
426 CmdOutput.clear();
427 Success = ExecuteCommand(Cmd, &CmdOutput);
428 Printf("%s", CmdOutput.c_str());
429 if (Success) {
430 if (Flags.exact_artifact_path) {
431 CurrentFilePath = Flags.exact_artifact_path;
432 WriteToFile(U, CurrentFilePath);
433 }
434 Printf("CRASH_MIN: failed to minimize beyond %s (%d bytes), exiting\n",
435 CurrentFilePath.c_str(), U.size());
436 break;
437 }
438 auto DedupToken2 = GetDedupTokenFromCmdOutput(CmdOutput);
439 if (!DedupToken2.empty())
440 Printf("CRASH_MIN: DedupToken2: %s\n", DedupToken2.c_str());
441
442 if (DedupToken1 != DedupToken2) {
443 if (Flags.exact_artifact_path) {
444 CurrentFilePath = Flags.exact_artifact_path;
445 WriteToFile(U, CurrentFilePath);
446 }
447 Printf("CRASH_MIN: mismatch in dedup tokens"
448 " (looks like a different bug). Won't minimize further\n");
449 break;
450 }
451
452 CurrentFilePath = ArtifactPath;
453 Printf("*********************************\n");
454 }
455 return 0;
456 }
457
MinimizeCrashInputInternalStep(Fuzzer * F,InputCorpus * Corpus)458 int MinimizeCrashInputInternalStep(Fuzzer *F, InputCorpus *Corpus) {
459 assert(Inputs->size() == 1);
460 std::string InputFilePath = Inputs->at(0);
461 Unit U = FileToVector(InputFilePath);
462 Printf("INFO: Starting MinimizeCrashInputInternalStep: %zd\n", U.size());
463 if (U.size() < 2) {
464 Printf("INFO: The input is small enough, exiting\n");
465 exit(0);
466 }
467 F->SetMaxInputLen(U.size());
468 F->SetMaxMutationLen(U.size() - 1);
469 F->MinimizeCrashLoop(U);
470 Printf("INFO: Done MinimizeCrashInputInternalStep, no crashes found\n");
471 exit(0);
472 return 0;
473 }
474
Merge(Fuzzer * F,FuzzingOptions & Options,const Vector<std::string> & Args,const Vector<std::string> & Corpora,const char * CFPathOrNull)475 void Merge(Fuzzer *F, FuzzingOptions &Options, const Vector<std::string> &Args,
476 const Vector<std::string> &Corpora, const char *CFPathOrNull) {
477 if (Corpora.size() < 2) {
478 Printf("INFO: Merge requires two or more corpus dirs\n");
479 exit(0);
480 }
481
482 Vector<SizedFile> OldCorpus, NewCorpus;
483 GetSizedFilesFromDir(Corpora[0], &OldCorpus);
484 for (size_t i = 1; i < Corpora.size(); i++)
485 GetSizedFilesFromDir(Corpora[i], &NewCorpus);
486 std::sort(OldCorpus.begin(), OldCorpus.end());
487 std::sort(NewCorpus.begin(), NewCorpus.end());
488
489 std::string CFPath = CFPathOrNull ? CFPathOrNull : TempPath("Merge", ".txt");
490 Vector<std::string> NewFiles;
491 Set<uint32_t> NewFeatures, NewCov;
492 CrashResistantMerge(Args, OldCorpus, NewCorpus, &NewFiles, {}, &NewFeatures,
493 {}, &NewCov, CFPath, true);
494 for (auto &Path : NewFiles)
495 F->WriteToOutputCorpus(FileToVector(Path, Options.MaxLen));
496 // We are done, delete the control file if it was a temporary one.
497 if (!Flags.merge_control_file)
498 RemoveFile(CFPath);
499
500 exit(0);
501 }
502
AnalyzeDictionary(Fuzzer * F,const Vector<Unit> & Dict,UnitVector & Corpus)503 int AnalyzeDictionary(Fuzzer *F, const Vector<Unit>& Dict,
504 UnitVector& Corpus) {
505 Printf("Started dictionary minimization (up to %d tests)\n",
506 Dict.size() * Corpus.size() * 2);
507
508 // Scores and usage count for each dictionary unit.
509 Vector<int> Scores(Dict.size());
510 Vector<int> Usages(Dict.size());
511
512 Vector<size_t> InitialFeatures;
513 Vector<size_t> ModifiedFeatures;
514 for (auto &C : Corpus) {
515 // Get coverage for the testcase without modifications.
516 F->ExecuteCallback(C.data(), C.size());
517 InitialFeatures.clear();
518 TPC.CollectFeatures([&](size_t Feature) {
519 InitialFeatures.push_back(Feature);
520 });
521
522 for (size_t i = 0; i < Dict.size(); ++i) {
523 Vector<uint8_t> Data = C;
524 auto StartPos = std::search(Data.begin(), Data.end(),
525 Dict[i].begin(), Dict[i].end());
526 // Skip dictionary unit, if the testcase does not contain it.
527 if (StartPos == Data.end())
528 continue;
529
530 ++Usages[i];
531 while (StartPos != Data.end()) {
532 // Replace all occurrences of dictionary unit in the testcase.
533 auto EndPos = StartPos + Dict[i].size();
534 for (auto It = StartPos; It != EndPos; ++It)
535 *It ^= 0xFF;
536
537 StartPos = std::search(EndPos, Data.end(),
538 Dict[i].begin(), Dict[i].end());
539 }
540
541 // Get coverage for testcase with masked occurrences of dictionary unit.
542 F->ExecuteCallback(Data.data(), Data.size());
543 ModifiedFeatures.clear();
544 TPC.CollectFeatures([&](size_t Feature) {
545 ModifiedFeatures.push_back(Feature);
546 });
547
548 if (InitialFeatures == ModifiedFeatures)
549 --Scores[i];
550 else
551 Scores[i] += 2;
552 }
553 }
554
555 Printf("###### Useless dictionary elements. ######\n");
556 for (size_t i = 0; i < Dict.size(); ++i) {
557 // Dictionary units with positive score are treated as useful ones.
558 if (Scores[i] > 0)
559 continue;
560
561 Printf("\"");
562 PrintASCII(Dict[i].data(), Dict[i].size(), "\"");
563 Printf(" # Score: %d, Used: %d\n", Scores[i], Usages[i]);
564 }
565 Printf("###### End of useless dictionary elements. ######\n");
566 return 0;
567 }
568
ParseSeedInuts(const char * seed_inputs)569 Vector<std::string> ParseSeedInuts(const char *seed_inputs) {
570 // Parse -seed_inputs=file1,file2,... or -seed_inputs=@seed_inputs_file
571 Vector<std::string> Files;
572 if (!seed_inputs) return Files;
573 std::string SeedInputs;
574 if (Flags.seed_inputs[0] == '@')
575 SeedInputs = FileToString(Flags.seed_inputs + 1); // File contains list.
576 else
577 SeedInputs = Flags.seed_inputs; // seed_inputs contains the list.
578 if (SeedInputs.empty()) {
579 Printf("seed_inputs is empty or @file does not exist.\n");
580 exit(1);
581 }
582 // Parse SeedInputs.
583 size_t comma_pos = 0;
584 while ((comma_pos = SeedInputs.find_last_of(',')) != std::string::npos) {
585 Files.push_back(SeedInputs.substr(comma_pos + 1));
586 SeedInputs = SeedInputs.substr(0, comma_pos);
587 }
588 Files.push_back(SeedInputs);
589 return Files;
590 }
591
ReadCorpora(const Vector<std::string> & CorpusDirs,const Vector<std::string> & ExtraSeedFiles)592 static Vector<SizedFile> ReadCorpora(const Vector<std::string> &CorpusDirs,
593 const Vector<std::string> &ExtraSeedFiles) {
594 Vector<SizedFile> SizedFiles;
595 size_t LastNumFiles = 0;
596 for (auto &Dir : CorpusDirs) {
597 GetSizedFilesFromDir(Dir, &SizedFiles);
598 Printf("INFO: % 8zd files found in %s\n", SizedFiles.size() - LastNumFiles,
599 Dir.c_str());
600 LastNumFiles = SizedFiles.size();
601 }
602 for (auto &File : ExtraSeedFiles)
603 if (auto Size = FileSize(File))
604 SizedFiles.push_back({File, Size});
605 return SizedFiles;
606 }
607
FuzzerDriver(int * argc,char *** argv,UserCallback Callback)608 int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) {
609 using namespace fuzzer;
610 assert(argc && argv && "Argument pointers cannot be nullptr");
611 std::string Argv0((*argv)[0]);
612 EF = new ExternalFunctions();
613 if (EF->LLVMFuzzerInitialize)
614 EF->LLVMFuzzerInitialize(argc, argv);
615 if (EF->__msan_scoped_disable_interceptor_checks)
616 EF->__msan_scoped_disable_interceptor_checks();
617 const Vector<std::string> Args(*argv, *argv + *argc);
618 assert(!Args.empty());
619 ProgName = new std::string(Args[0]);
620 if (Argv0 != *ProgName) {
621 Printf("ERROR: argv[0] has been modified in LLVMFuzzerInitialize\n");
622 exit(1);
623 }
624 ParseFlags(Args, EF);
625 if (Flags.help) {
626 PrintHelp();
627 return 0;
628 }
629
630 if (Flags.close_fd_mask & 2)
631 DupAndCloseStderr();
632 if (Flags.close_fd_mask & 1)
633 CloseStdout();
634
635 if (Flags.jobs > 0 && Flags.workers == 0) {
636 Flags.workers = std::min(NumberOfCpuCores() / 2, Flags.jobs);
637 if (Flags.workers > 1)
638 Printf("Running %u workers\n", Flags.workers);
639 }
640
641 if (Flags.workers > 0 && Flags.jobs > 0)
642 return RunInMultipleProcesses(Args, Flags.workers, Flags.jobs);
643
644 FuzzingOptions Options;
645 Options.Verbosity = Flags.verbosity;
646 Options.MaxLen = Flags.max_len;
647 Options.LenControl = Flags.len_control;
648 Options.UnitTimeoutSec = Flags.timeout;
649 Options.ErrorExitCode = Flags.error_exitcode;
650 Options.TimeoutExitCode = Flags.timeout_exitcode;
651 Options.IgnoreTimeouts = Flags.ignore_timeouts;
652 Options.IgnoreOOMs = Flags.ignore_ooms;
653 Options.IgnoreCrashes = Flags.ignore_crashes;
654 Options.MaxTotalTimeSec = Flags.max_total_time;
655 Options.DoCrossOver = Flags.cross_over;
656 Options.MutateDepth = Flags.mutate_depth;
657 Options.ReduceDepth = Flags.reduce_depth;
658 Options.UseCounters = Flags.use_counters;
659 Options.UseMemmem = Flags.use_memmem;
660 Options.UseCmp = Flags.use_cmp;
661 Options.UseValueProfile = Flags.use_value_profile;
662 Options.Shrink = Flags.shrink;
663 Options.ReduceInputs = Flags.reduce_inputs;
664 Options.ShuffleAtStartUp = Flags.shuffle;
665 Options.PreferSmall = Flags.prefer_small;
666 Options.ReloadIntervalSec = Flags.reload;
667 Options.OnlyASCII = Flags.only_ascii;
668 Options.DetectLeaks = Flags.detect_leaks;
669 Options.PurgeAllocatorIntervalSec = Flags.purge_allocator_interval;
670 Options.TraceMalloc = Flags.trace_malloc;
671 Options.RssLimitMb = Flags.rss_limit_mb;
672 Options.MallocLimitMb = Flags.malloc_limit_mb;
673 if (!Options.MallocLimitMb)
674 Options.MallocLimitMb = Options.RssLimitMb;
675 if (Flags.runs >= 0)
676 Options.MaxNumberOfRuns = Flags.runs;
677 if (!Inputs->empty() && !Flags.minimize_crash_internal_step)
678 Options.OutputCorpus = (*Inputs)[0];
679 Options.ReportSlowUnits = Flags.report_slow_units;
680 if (Flags.artifact_prefix)
681 Options.ArtifactPrefix = Flags.artifact_prefix;
682 if (Flags.exact_artifact_path)
683 Options.ExactArtifactPath = Flags.exact_artifact_path;
684 Vector<Unit> Dictionary;
685 if (Flags.dict)
686 if (!ParseDictionaryFile(FileToString(Flags.dict), &Dictionary))
687 return 1;
688 if (Flags.verbosity > 0 && !Dictionary.empty())
689 Printf("Dictionary: %zd entries\n", Dictionary.size());
690 bool RunIndividualFiles = AllInputsAreFiles();
691 Options.SaveArtifacts =
692 !RunIndividualFiles || Flags.minimize_crash_internal_step;
693 Options.PrintNewCovPcs = Flags.print_pcs;
694 Options.PrintNewCovFuncs = Flags.print_funcs;
695 Options.PrintFinalStats = Flags.print_final_stats;
696 Options.PrintCorpusStats = Flags.print_corpus_stats;
697 Options.PrintCoverage = Flags.print_coverage;
698 if (Flags.exit_on_src_pos)
699 Options.ExitOnSrcPos = Flags.exit_on_src_pos;
700 if (Flags.exit_on_item)
701 Options.ExitOnItem = Flags.exit_on_item;
702 if (Flags.focus_function)
703 Options.FocusFunction = Flags.focus_function;
704 if (Flags.data_flow_trace)
705 Options.DataFlowTrace = Flags.data_flow_trace;
706 if (Flags.features_dir)
707 Options.FeaturesDir = Flags.features_dir;
708 if (Flags.collect_data_flow)
709 Options.CollectDataFlow = Flags.collect_data_flow;
710 if (Flags.stop_file)
711 Options.StopFile = Flags.stop_file;
712 Options.Entropic = Flags.entropic;
713 Options.EntropicFeatureFrequencyThreshold =
714 (size_t)Flags.entropic_feature_frequency_threshold;
715 Options.EntropicNumberOfRarestFeatures =
716 (size_t)Flags.entropic_number_of_rarest_features;
717 if (Options.Entropic) {
718 if (!Options.FocusFunction.empty()) {
719 Printf("ERROR: The parameters `--entropic` and `--focus_function` cannot "
720 "be used together.\n");
721 exit(1);
722 }
723 Printf("INFO: Running with entropic power schedule (0x%X, %d).\n",
724 Options.EntropicFeatureFrequencyThreshold,
725 Options.EntropicNumberOfRarestFeatures);
726 }
727 struct EntropicOptions Entropic;
728 Entropic.Enabled = Options.Entropic;
729 Entropic.FeatureFrequencyThreshold =
730 Options.EntropicFeatureFrequencyThreshold;
731 Entropic.NumberOfRarestFeatures = Options.EntropicNumberOfRarestFeatures;
732
733 unsigned Seed = Flags.seed;
734 // Initialize Seed.
735 if (Seed == 0)
736 Seed =
737 std::chrono::system_clock::now().time_since_epoch().count() + GetPid();
738 if (Flags.verbosity)
739 Printf("INFO: Seed: %u\n", Seed);
740
741 if (Flags.collect_data_flow && !Flags.fork && !Flags.merge) {
742 if (RunIndividualFiles)
743 return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
744 ReadCorpora({}, *Inputs));
745 else
746 return CollectDataFlow(Flags.collect_data_flow, Flags.data_flow_trace,
747 ReadCorpora(*Inputs, {}));
748 }
749
750 Random Rand(Seed);
751 auto *MD = new MutationDispatcher(Rand, Options);
752 auto *Corpus = new InputCorpus(Options.OutputCorpus, Entropic);
753 auto *F = new Fuzzer(Callback, *Corpus, *MD, Options);
754
755 for (auto &U: Dictionary)
756 if (U.size() <= Word::GetMaxSize())
757 MD->AddWordToManualDictionary(Word(U.data(), U.size()));
758
759 // Threads are only supported by Chrome. Don't use them with emscripten
760 // for now.
761 #if !LIBFUZZER_EMSCRIPTEN
762 StartRssThread(F, Flags.rss_limit_mb);
763 #endif // LIBFUZZER_EMSCRIPTEN
764
765 Options.HandleAbrt = Flags.handle_abrt;
766 Options.HandleBus = Flags.handle_bus;
767 Options.HandleFpe = Flags.handle_fpe;
768 Options.HandleIll = Flags.handle_ill;
769 Options.HandleInt = Flags.handle_int;
770 Options.HandleSegv = Flags.handle_segv;
771 Options.HandleTerm = Flags.handle_term;
772 Options.HandleXfsz = Flags.handle_xfsz;
773 Options.HandleUsr1 = Flags.handle_usr1;
774 Options.HandleUsr2 = Flags.handle_usr2;
775 Options.HandleTrap = Flags.handle_trap;
776 Options.HandleProt = Flags.handle_prot;
777 SetSignalHandler(Options);
778
779 std::atexit(Fuzzer::StaticExitCallback);
780
781 if (Flags.minimize_crash)
782 return MinimizeCrashInput(Args, Options);
783
784 if (Flags.minimize_crash_internal_step)
785 return MinimizeCrashInputInternalStep(F, Corpus);
786
787 if (Flags.cleanse_crash)
788 return CleanseCrashInput(Args, Options);
789
790 if (RunIndividualFiles) {
791 Options.SaveArtifacts = false;
792 int Runs = std::max(1, Flags.runs);
793 Printf("%s: Running %zd inputs %d time(s) each.\n", ProgName->c_str(),
794 Inputs->size(), Runs);
795 for (auto &Path : *Inputs) {
796 auto StartTime = system_clock::now();
797 Printf("Running: %s\n", Path.c_str());
798 for (int Iter = 0; Iter < Runs; Iter++)
799 RunOneTest(F, Path.c_str(), Options.MaxLen);
800 auto StopTime = system_clock::now();
801 auto MS = duration_cast<milliseconds>(StopTime - StartTime).count();
802 Printf("Executed %s in %zd ms\n", Path.c_str(), (long)MS);
803 }
804 Printf("***\n"
805 "*** NOTE: fuzzing was not performed, you have only\n"
806 "*** executed the target code on a fixed set of inputs.\n"
807 "***\n");
808 F->PrintFinalStats();
809 exit(0);
810 }
811
812 if (Flags.fork)
813 FuzzWithFork(F->GetMD().GetRand(), Options, Args, *Inputs, Flags.fork);
814
815 if (Flags.merge)
816 Merge(F, Options, Args, *Inputs, Flags.merge_control_file);
817
818 if (Flags.merge_inner) {
819 const size_t kDefaultMaxMergeLen = 1 << 20;
820 if (Options.MaxLen == 0)
821 F->SetMaxInputLen(kDefaultMaxMergeLen);
822 assert(Flags.merge_control_file);
823 F->CrashResistantMergeInternalStep(Flags.merge_control_file);
824 exit(0);
825 }
826
827 if (Flags.analyze_dict) {
828 size_t MaxLen = INT_MAX; // Large max length.
829 UnitVector InitialCorpus;
830 for (auto &Inp : *Inputs) {
831 Printf("Loading corpus dir: %s\n", Inp.c_str());
832 ReadDirToVectorOfUnits(Inp.c_str(), &InitialCorpus, nullptr,
833 MaxLen, /*ExitOnError=*/false);
834 }
835
836 if (Dictionary.empty() || Inputs->empty()) {
837 Printf("ERROR: can't analyze dict without dict and corpus provided\n");
838 return 1;
839 }
840 if (AnalyzeDictionary(F, Dictionary, InitialCorpus)) {
841 Printf("Dictionary analysis failed\n");
842 exit(1);
843 }
844 Printf("Dictionary analysis succeeded\n");
845 exit(0);
846 }
847
848 auto CorporaFiles = ReadCorpora(*Inputs, ParseSeedInuts(Flags.seed_inputs));
849 F->Loop(CorporaFiles);
850
851 if (Flags.verbosity)
852 Printf("Done %zd runs in %zd second(s)\n", F->getTotalNumberOfRuns(),
853 F->secondsSinceProcessStartUp());
854 F->PrintFinalStats();
855
856 exit(0); // Don't let F destroy itself.
857 }
858
859 // Storage for global ExternalFunctions object.
860 ExternalFunctions *EF = nullptr;
861
862 } // namespace fuzzer
863