1 // Copyright 2018 Google Inc.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 // Adapter utility from fuzzer input to a temporary file, for fuzzing APIs that
16 // require a file instead of an input buffer.
17
18 #ifndef FUZZER_TEMP_FILE_H_
19 #define FUZZER_TEMP_FILE_H_
20
21 #include <stdint.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <unistd.h>
26
27 // Pure-C interface for creating and cleaning up temporary files.
28
fuzzer_get_tmpfile(const uint8_t * data,size_t size)29 static char *fuzzer_get_tmpfile(const uint8_t *data, size_t size)
30 {
31 char *filename_buffer = strdup("/tmp/generate_temporary_file.XXXXXX");
32 if (!filename_buffer) {
33 perror("Failed to allocate file name buffer.");
34 abort();
35 }
36 const int file_descriptor = mkstemp(filename_buffer);
37 if (file_descriptor < 0) {
38 perror("Failed to make temporary file.");
39 abort();
40 }
41 FILE *file = fdopen(file_descriptor, "wb");
42 if (!file) {
43 perror("Failed to open file descriptor.");
44 close(file_descriptor);
45 abort();
46 }
47 const size_t bytes_written = fwrite(data, sizeof(uint8_t), size, file);
48 if (bytes_written < size) {
49 close(file_descriptor);
50 fprintf(stderr, "Failed to write all bytes to file (%zu out of %zu)", bytes_written, size);
51 abort();
52 }
53 fclose(file);
54 return filename_buffer;
55 }
56
fuzzer_release_tmpfile(char * filename)57 static void fuzzer_release_tmpfile(char *filename)
58 {
59 if (unlink(filename) != 0) {
60 perror("WARNING: Failed to delete temporary file.");
61 }
62 free(filename);
63 }
64
65 // C++ RAII object for creating temporary files.
66
67 #ifdef __cplusplus
68 class FuzzerTemporaryFile
69 {
70 public:
FuzzerTemporaryFile(const uint8_t * data,size_t size)71 FuzzerTemporaryFile(const uint8_t *data, size_t size) : filename_(fuzzer_get_tmpfile(data, size)) { }
72
~FuzzerTemporaryFile()73 ~FuzzerTemporaryFile() { fuzzer_release_tmpfile(filename_); }
74
filename()75 const char *filename() const { return filename_; }
76
77 private:
78 char *filename_;
79 };
80 #endif
81
82 #endif // FUZZER_TEMP_FILE_H_
83