1 // Copyright 2023 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include <stdlib.h> 6 #include <string> 7 8 #include "base/containers/span.h" 9 #include "base/files/file_path.h" 10 #include "base/files/file_util.h" 11 #include "base/files/scoped_temp_dir.h" 12 #include "base/logging.h" 13 #include "base/nix/mime_util_xdg.h" 14 15 // Entry point for LibFuzzer. LLVMFuzzerTestOneInput(const uint8_t * data_ptr,size_t size)16extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data_ptr, size_t size) { 17 // SAFETY: LibFuzzer provides a valid pointer/size pair. 18 auto data = UNSAFE_BUFFERS(base::span(data_ptr, size)); 19 20 base::ScopedTempDir temp_dir; 21 if (!temp_dir.CreateUniqueTempDir()) { 22 // Not a fuzzer error, so we return 0. 23 LOG(ERROR) << "Failed to create temp dir"; 24 return 0; 25 } 26 27 // The parser reads file $XDG_DATA_DIRS/mime/mime.cache. 28 setenv("XDG_DATA_DIRS", temp_dir.GetPath().value().c_str(), 1); 29 base::FilePath mime_dir = temp_dir.GetPath().Append("mime"); 30 base::FilePath mime_cache = mime_dir.Append("mime.cache"); 31 if (!base::CreateDirectory(mime_dir) || !base::WriteFile(mime_cache, data)) { 32 LOG(ERROR) << "Failed to create " << mime_cache; 33 // Not a fuzzer error, so we return 0. 34 return 0; 35 } 36 37 base::FilePath dummy_path("foo.txt"); 38 std::string type = base::nix::GetFileMimeType(dummy_path); 39 return 0; 40 } 41