2 * Copyright (c) Meta Platforms, Inc. and affiliates.
5 * This source code is licensed under both the BSD-style license (found in the
6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found
7 * in the COPYING file in the root directory of this source tree).
8 * You may select, at your option, one of the above-listed licenses.
11 #define ZSTD_STATIC_LINKING_ONLY
13 #include "zstd_errors.h"
18 #include <sys/types.h>
26 char *perturbed; /* same size as input */
31 const char *dict_file_name;
32 const char *dict_file_dir_name;
41 int error_counts[ZSTD_error_maxCode];
44 static void free_stuff(stuff_t* stuff) {
47 ZSTD_freeDDict(stuff->ddict);
49 ZSTD_freeDCtx(stuff->dctx);
52 static void usage(void) {
53 fprintf(stderr, "check_flipped_bits input_filename [-d dict] [-D dict_dir]\n");
54 fprintf(stderr, "\n");
55 fprintf(stderr, "Arguments:\n");
56 fprintf(stderr, " -d file: path to a dictionary file to use.\n");
57 fprintf(stderr, " -D dir : path to a directory, with files containing dictionaries, of the\n"
58 " form DICTID.zstd-dict, e.g., 12345.zstd-dict.\n");
62 static void print_summary(stuff_t* stuff) {
64 fprintf(stderr, "%9d successful decompressions\n", stuff->success_count);
65 for (error_code = 0; error_code < ZSTD_error_maxCode; error_code++) {
66 int count = stuff->error_counts[error_code];
69 stderr, "%9d failed decompressions with message: %s\n",
70 count, ZSTD_getErrorString(error_code));
75 static char* readFile(const char* filename, size_t* size) {
82 ret = stat(filename, &statbuf);
84 fprintf(stderr, "stat failed: %m\n");
87 if ((statbuf.st_mode & S_IFREG) != S_IFREG) {
88 fprintf(stderr, "Input must be regular file\n");
92 *size = statbuf.st_size;
94 f = fopen(filename, "r");
96 fprintf(stderr, "fopen failed: %m\n");
102 fprintf(stderr, "malloc failed\n");
107 bytes_read = fread(buf, 1, *size, f);
108 if (bytes_read != *size) {
109 fprintf(stderr, "failed to read whole file\n");
117 fprintf(stderr, "fclose failed: %m\n");
125 static ZSTD_DDict* readDict(const char* filename, char **buf, size_t* size, int32_t* dict_id) {
127 *buf = readFile(filename, size);
129 fprintf(stderr, "Opening dictionary file '%s' failed\n", filename);
133 ddict = ZSTD_createDDict_advanced(*buf, *size, ZSTD_dlm_byRef, ZSTD_dct_auto, ZSTD_defaultCMem);
135 fprintf(stderr, "Failed to create ddict.\n");
138 if (dict_id != NULL) {
139 *dict_id = ZSTD_getDictID_fromDDict(ddict);
144 static ZSTD_DDict* readDictByID(stuff_t *stuff, int32_t dict_id, char **buf, size_t* size) {
145 if (stuff->dict_file_dir_name == NULL) {
148 size_t dir_name_len = strlen(stuff->dict_file_dir_name);
149 int dir_needs_separator = 0;
150 size_t dict_file_name_alloc_size = dir_name_len + 1 /* '/' */ + 10 /* max int32_t len */ + strlen(".zstd-dict") + 1 /* '\0' */;
151 char *dict_file_name = malloc(dict_file_name_alloc_size);
153 int32_t read_dict_id;
154 if (dict_file_name == NULL) {
155 fprintf(stderr, "malloc failed.\n");
159 if (dir_name_len > 0 && stuff->dict_file_dir_name[dir_name_len - 1] != '/') {
160 dir_needs_separator = 1;
165 dict_file_name_alloc_size,
167 stuff->dict_file_dir_name,
168 dir_needs_separator ? "/" : "",
171 /* fprintf(stderr, "Loading dict %u from '%s'.\n", dict_id, dict_file_name); */
173 ddict = readDict(dict_file_name, buf, size, &read_dict_id);
175 fprintf(stderr, "Failed to create ddict from '%s'.\n", dict_file_name);
176 free(dict_file_name);
179 if (read_dict_id != dict_id) {
180 fprintf(stderr, "Read dictID (%u) does not match expected (%u).\n", read_dict_id, dict_id);
181 free(dict_file_name);
182 ZSTD_freeDDict(ddict);
186 free(dict_file_name);
191 static int init_stuff(stuff_t* stuff, int argc, char *argv[]) {
192 const char* input_filename;
198 input_filename = argv[1];
199 stuff->input_size = 0;
200 stuff->input = readFile(input_filename, &stuff->input_size);
201 if (stuff->input == NULL) {
202 fprintf(stderr, "Failed to read input file.\n");
206 stuff->perturbed = malloc(stuff->input_size);
207 if (stuff->perturbed == NULL) {
208 fprintf(stderr, "malloc failed.\n");
211 memcpy(stuff->perturbed, stuff->input, stuff->input_size);
213 stuff->output_size = ZSTD_DStreamOutSize();
214 stuff->output = malloc(stuff->output_size);
215 if (stuff->output == NULL) {
216 fprintf(stderr, "malloc failed.\n");
220 stuff->dict_file_name = NULL;
221 stuff->dict_file_dir_name = NULL;
224 stuff->dict_size = 0;
228 if (!strcmp(argv[2], "-d")) {
230 stuff->dict_file_name = argv[3];
235 if (!strcmp(argv[2], "-D")) {
237 stuff->dict_file_dir_name = argv[3];
246 if (stuff->dict_file_dir_name) {
247 int32_t dict_id = ZSTD_getDictID_fromFrame(stuff->input, stuff->input_size);
249 stuff->ddict = readDictByID(stuff, dict_id, &stuff->dict, &stuff->dict_size);
250 if (stuff->ddict == NULL) {
251 fprintf(stderr, "Failed to create cached ddict.\n");
254 stuff->dict_id = dict_id;
257 if (stuff->dict_file_name) {
258 stuff->ddict = readDict(stuff->dict_file_name, &stuff->dict, &stuff->dict_size, &stuff->dict_id);
259 if (stuff->ddict == NULL) {
260 fprintf(stderr, "Failed to create ddict from '%s'.\n", stuff->dict_file_name);
265 stuff->dctx = ZSTD_createDCtx();
266 if (stuff->dctx == NULL) {
270 stuff->success_count = 0;
271 memset(stuff->error_counts, 0, sizeof(stuff->error_counts));
276 static int test_decompress(stuff_t* stuff) {
278 ZSTD_inBuffer in = {stuff->perturbed, stuff->input_size, 0};
279 ZSTD_outBuffer out = {stuff->output, stuff->output_size, 0};
280 ZSTD_DCtx* dctx = stuff->dctx;
281 int32_t custom_dict_id = ZSTD_getDictID_fromFrame(in.src, in.size);
282 char *custom_dict = NULL;
283 size_t custom_dict_size = 0;
284 ZSTD_DDict* custom_ddict = NULL;
286 if (custom_dict_id != 0 && custom_dict_id != stuff->dict_id) {
287 /* fprintf(stderr, "Instead of dict %u, this perturbed blob wants dict %u.\n", stuff->dict_id, custom_dict_id); */
288 custom_ddict = readDictByID(stuff, custom_dict_id, &custom_dict, &custom_dict_size);
291 ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only);
293 if (custom_ddict != NULL) {
294 ZSTD_DCtx_refDDict(dctx, custom_ddict);
296 ZSTD_DCtx_refDDict(dctx, stuff->ddict);
299 while (in.pos != in.size) {
301 ret = ZSTD_decompressStream(dctx, &out, &in);
303 if (ZSTD_isError(ret)) {
304 unsigned int code = ZSTD_getErrorCode(ret);
305 if (code >= ZSTD_error_maxCode) {
306 fprintf(stderr, "Received unexpected error code!\n");
309 stuff->error_counts[code]++;
312 stderr, "Decompression failed: %s\n", ZSTD_getErrorName(ret));
314 if (custom_ddict != NULL) {
315 ZSTD_freeDDict(custom_ddict);
322 stuff->success_count++;
324 if (custom_ddict != NULL) {
325 ZSTD_freeDDict(custom_ddict);
331 static int perturb_bits(stuff_t* stuff) {
334 for (pos = 0; pos < stuff->input_size; pos++) {
335 unsigned char old_val = stuff->input[pos];
336 if (pos % 1000 == 0) {
337 fprintf(stderr, "Perturbing byte %zu / %zu\n", pos, stuff->input_size);
339 for (bit = 0; bit < 8; bit++) {
340 unsigned char new_val = old_val ^ (1 << bit);
341 stuff->perturbed[pos] = new_val;
342 if (test_decompress(stuff)) {
345 "Flipping byte %zu bit %zu (0x%02x -> 0x%02x) "
346 "produced a successful decompression!\n",
347 pos, bit, old_val, new_val);
350 stuff->perturbed[pos] = old_val;
355 static int perturb_bytes(stuff_t* stuff) {
358 for (pos = 0; pos < stuff->input_size; pos++) {
359 unsigned char old_val = stuff->input[pos];
360 if (pos % 1000 == 0) {
361 fprintf(stderr, "Perturbing byte %zu / %zu\n", pos, stuff->input_size);
363 for (new_val = 0; new_val < 256; new_val++) {
364 stuff->perturbed[pos] = new_val;
365 if (test_decompress(stuff)) {
368 "Changing byte %zu (0x%02x -> 0x%02x) "
369 "produced a successful decompression!\n",
370 pos, old_val, (unsigned char)new_val);
373 stuff->perturbed[pos] = old_val;
378 int main(int argc, char* argv[]) {
381 if(!init_stuff(&stuff, argc, argv)) {
382 fprintf(stderr, "Failed to init.\n");
386 if (test_decompress(&stuff)) {
387 fprintf(stderr, "Blob already decompresses successfully!\n");
391 perturb_bits(&stuff);
393 perturb_bytes(&stuff);
395 print_summary(&stuff);