From 711b9806547b0392ff636499cebfb73f72d4c595 Mon Sep 17 00:00:00 2001 From: Matt Morehouse Date: Thu, 3 Sep 2020 07:58:45 -0700 Subject: [PATCH] [fuzzer] Create user provided fuzzer writeable directories when requested if they dont exist Currently, libFuzzer will exit with an error message if a non-existent directory is provided for any of the appropriate arguments. For cases where libFuzzer is used in a specialized embedded environment, it would be much easier to have libFuzzer create the directories for the user. This patch accommodates for this scenario by allowing the user to provide the argument `-create_missing_dirs=1` which makes libFuzzer attempt to create the `artifact_prefix`, `exact_artifact_path`, `features_dir` and/or corpus directory if they don't already exist rather than throw an error and exit. Split off from D84808 as requested [here](https://reviews.llvm.org/D84808#2208546). Reviewed By: morehouse Differential Revision: https://reviews.llvm.org/D86733 --- compiler-rt/lib/fuzzer/FuzzerDriver.cpp | 30 ++++++++++++++----- compiler-rt/lib/fuzzer/FuzzerFlags.def | 4 +++ compiler-rt/lib/fuzzer/FuzzerIO.cpp | 32 ++++++++++++++++++++ compiler-rt/lib/fuzzer/FuzzerIO.h | 1 + compiler-rt/test/fuzzer/fuzzer-dirs.test | 38 ++++++++++++++++++++++++ 5 files changed, 98 insertions(+), 7 deletions(-) diff --git a/compiler-rt/lib/fuzzer/FuzzerDriver.cpp b/compiler-rt/lib/fuzzer/FuzzerDriver.cpp index 4669b12786fc2f..2615014a02153d 100644 --- a/compiler-rt/lib/fuzzer/FuzzerDriver.cpp +++ b/compiler-rt/lib/fuzzer/FuzzerDriver.cpp @@ -250,11 +250,26 @@ static void WorkerThread(const Command &BaseCmd, std::atomic *Counter, } } -static void ValidateDirectoryExists(const std::string &Path) { - if (!Path.empty() && !IsDirectory(Path)) { - Printf("ERROR: The required directory \"%s\" does not exist\n", Path.c_str()); +static void ValidateDirectoryExists(const std::string &Path, + bool CreateDirectory) { + if (Path.empty()) { + Printf("ERROR: Provided directory path is an empty string\n"); exit(1); } + + if (IsDirectory(Path)) + return; + + if (CreateDirectory) { + if (!MkDirRecursive(Path)) { + Printf("ERROR: Failed to create directory \"%s\"\n", Path.c_str()); + exit(1); + } + return; + } + + Printf("ERROR: The required directory \"%s\" does not exist\n", Path.c_str()); + exit(1); } std::string CloneArgsWithoutX(const Vector &Args, @@ -691,7 +706,7 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) { std::string OutputCorpusDir = (*Inputs)[0]; if (!IsFile(OutputCorpusDir)) { Options.OutputCorpus = OutputCorpusDir; - ValidateDirectoryExists(Options.OutputCorpus); + ValidateDirectoryExists(Options.OutputCorpus, Flags.create_missing_dirs); } } Options.ReportSlowUnits = Flags.report_slow_units; @@ -705,11 +720,12 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) { if (!IsSeparator(ArtifactPathDir[ArtifactPathDir.length() - 1])) { ArtifactPathDir = DirName(ArtifactPathDir); } - ValidateDirectoryExists(ArtifactPathDir); + ValidateDirectoryExists(ArtifactPathDir, Flags.create_missing_dirs); } if (Flags.exact_artifact_path) { Options.ExactArtifactPath = Flags.exact_artifact_path; - ValidateDirectoryExists(DirName(Options.ExactArtifactPath)); + ValidateDirectoryExists(DirName(Options.ExactArtifactPath), + Flags.create_missing_dirs); } Vector Dictionary; if (Flags.dict) @@ -735,7 +751,7 @@ int FuzzerDriver(int *argc, char ***argv, UserCallback Callback) { Options.DataFlowTrace = Flags.data_flow_trace; if (Flags.features_dir) { Options.FeaturesDir = Flags.features_dir; - ValidateDirectoryExists(Options.FeaturesDir); + ValidateDirectoryExists(Options.FeaturesDir, Flags.create_missing_dirs); } if (Flags.collect_data_flow) Options.CollectDataFlow = Flags.collect_data_flow; diff --git a/compiler-rt/lib/fuzzer/FuzzerFlags.def b/compiler-rt/lib/fuzzer/FuzzerFlags.def index 832224a705d2b6..81147914660320 100644 --- a/compiler-rt/lib/fuzzer/FuzzerFlags.def +++ b/compiler-rt/lib/fuzzer/FuzzerFlags.def @@ -167,3 +167,7 @@ FUZZER_DEPRECATED_FLAG(use_clang_coverage) FUZZER_FLAG_STRING(data_flow_trace, "Experimental: use the data flow trace") FUZZER_FLAG_STRING(collect_data_flow, "Experimental: collect the data flow trace") + +FUZZER_FLAG_INT(create_missing_dirs, 0, "Automatically attempt to create " + "directories for arguments that would normally expect them to already " + "exist (i.e. artifact_prefix, exact_artifact_path, features_dir, corpus)") diff --git a/compiler-rt/lib/fuzzer/FuzzerIO.cpp b/compiler-rt/lib/fuzzer/FuzzerIO.cpp index cbb1dbe1b86d2c..c3330c3425d091 100644 --- a/compiler-rt/lib/fuzzer/FuzzerIO.cpp +++ b/compiler-rt/lib/fuzzer/FuzzerIO.cpp @@ -144,6 +144,38 @@ void VPrintf(bool Verbose, const char *Fmt, ...) { fflush(OutputFile); } +static bool MkDirRecursiveInner(const std::string &Leaf) { + // Prevent chance of potential infinite recursion + if (Leaf == ".") + return true; + + const std::string &Dir = DirName(Leaf); + + if (IsDirectory(Dir)) { + MkDir(Leaf); + return IsDirectory(Leaf); + } + + bool ret = MkDirRecursiveInner(Dir); + if (!ret) { + // Give up early if a previous MkDir failed + return ret; + } + + MkDir(Leaf); + return IsDirectory(Leaf); +} + +bool MkDirRecursive(const std::string &Dir) { + if (Dir.empty()) + return false; + + if (IsDirectory(Dir)) + return true; + + return MkDirRecursiveInner(Dir); +} + void RmDirRecursive(const std::string &Dir) { IterateDirRecursive( Dir, [](const std::string &Path) {}, diff --git a/compiler-rt/lib/fuzzer/FuzzerIO.h b/compiler-rt/lib/fuzzer/FuzzerIO.h index 8def2e96304e75..6e3a0b470c5f6a 100644 --- a/compiler-rt/lib/fuzzer/FuzzerIO.h +++ b/compiler-rt/lib/fuzzer/FuzzerIO.h @@ -64,6 +64,7 @@ size_t FileSize(const std::string &Path); void ListFilesInDirRecursive(const std::string &Dir, long *Epoch, Vector *V, bool TopDir); +bool MkDirRecursive(const std::string &Dir); void RmDirRecursive(const std::string &Dir); // Iterate files and dirs inside Dir, recursively. diff --git a/compiler-rt/test/fuzzer/fuzzer-dirs.test b/compiler-rt/test/fuzzer/fuzzer-dirs.test index 2bf2a8b143300c..c822c2f95c305b 100644 --- a/compiler-rt/test/fuzzer/fuzzer-dirs.test +++ b/compiler-rt/test/fuzzer/fuzzer-dirs.test @@ -16,6 +16,7 @@ RUN: %run %t-SimpleTest %t/SUB1 -runs=0 2>&1 | FileCheck %s --check-prefix=LONG LONG: INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 8192 bytes RUN: rm -rf %t/SUB1 +# Verify error message prints to console when directory does not exist RUN: rm -rf %t.dir && mkdir -p %t.dir RUN: not %run %t-SimpleTest -artifact_prefix=%t.dir/NONEXISTENT_DIR/ 2>&1 | FileCheck %s --check-prefix=NONEXISTENT_DIR_RGX RUN: not %run %t-SimpleTest -artifact_prefix=%t.dir/NONEXISTENT_DIR/myprefix 2>&1 | FileCheck %s --check-prefix=NONEXISTENT_DIR_RGX @@ -23,3 +24,40 @@ RUN: not %run %t-SimpleTest -features_dir=%t.dir/NONEXISTENT_DIR/ 2>&1 | FileChe RUN: not %run %t-SimpleTest %t.dir/NONEXISTENT_DIR 2>&1 | FileCheck %s --check-prefix=NONEXISTENT_DIR_RGX RUN: not %run %t-SimpleTest -exact_artifact_path=%t.dir/NONEXISTENT_DIR/myprefix 2>&1 | FileCheck %s --check-prefix=NONEXISTENT_DIR_RGX NONEXISTENT_DIR_RGX: ERROR: The required directory "{{.*/NONEXISTENT_DIR/?}}" does not exist + +# Verify error message prints to console when given directory is an empty +# string +RUN: not %run %t-SimpleTest "" 2>&1 | FileCheck %s --check-prefix=INVALID_DIR_RGX +INVALID_DIR_RGX: ERROR: Provided directory path is an empty string + +# Verify error message prints to console when directory creation fails +# For platforms without functioning chmod (i.e. Windows), use a forbidden +# character in the directory name. +RUN: rm -rf %t.dir && mkdir -p %t.dir/access_restricted +RUN: chmod u-w %t.dir/access_restricted || true +RUN: not %run %t-SimpleTest -create_missing_dirs=1 %t.dir/access_restricted/?corpus? 2>&1 | FileCheck %s --check-prefix=DIR_CREATION_FAILURE +DIR_CREATION_FAILURE: ERROR: Failed to create directory "{{.*/access_restricted/\?corpus\?}}" + +# Verify directories and sub-directories are created when -create_missing_dirs=1 +RUN: not %run %t-SimpleTest -create_missing_dirs=1 -artifact_prefix=%t.dir/subdira/./././artifacts/ -features_dir=%t.dir/subdirb/dummy_dir/././../subdirb/features/ %t.dir/subdirc/corpus +RUN: test -e %t.dir/subdira/artifacts/ +RUN: test -e %t.dir/subdirb/subdirb/features/ +RUN: test -e %t.dir/subdirc/corpus/ +RUN: test -e %t.dir/subdirb/dummy_dir + +# Verify directories and sub-directories are created for exact_artifact_path +# when -create_missing_dirs=1 +RUN: not %run %t-SimpleTest -create_missing_dirs=1 -exact_artifact_path=%t.dir/subdird/exact_artifacts/abc +RUN: test -e %t.dir/subdird/exact_artifacts/abc + +# Verify directories and sub-directories are created for artifact_prefix when +# it's referring to a file name prefix and -create_missing_dirs=1 +RUN: not %run %t-SimpleTest -create_missing_dirs=1 -artifact_prefix=%t.dir/subdire/myprefix +RUN: test -e %t.dir/subdire/ && not test -e %t.dir/subdire/myprefix + +# Verify directories are created when referring to relative paths and +# -create_missing_dirs=1 +RUN: cd %t.dir && not %run %t-SimpleTest -create_missing_dirs=1 -artifact_prefix=cwd_artifacts/ -features_dir=cwd_features/subdirtest/ ./cwd_corpus +RUN: test -e %t.dir/cwd_artifacts/ +RUN: test -e %t.dir/cwd_features/subdirtest/ +RUN: test -e %t.dir/cwd_corpus/