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Date:: Sun Jan 6 12:47:14 2019 UTC
Message:: must use safe iteration over file index entries
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1 /*
2  * Copyright (c) 2018 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <sys/queue.h>
18 #include <sys/stat.h>
19 
20 #include <stdio.h>
21 #include <stdlib.h>
22 #include <string.h>
23 #include <sha1.h>
24 #include <endian.h>
25 
26 #include "got_error.h"
27 
28 #include "got_lib_fileindex.h"
29 
30 const struct got_error *
31 got_fileindex_entry_update(struct got_fileindex_entry *entry,
32     const char *ondisk_path, uint8_t *blob_sha1, uint8_t *commit_sha1)
33 {
34 	struct stat sb;
35 
36 	if (lstat(ondisk_path, &sb) != 0)
37 		return got_error_from_errno();
38 
39 	entry->ctime_sec = sb.st_ctime;
40 	entry->ctime_nsec = sb.st_ctimensec;
41 	entry->mtime_sec = sb.st_mtime;
42 	entry->mtime_nsec = sb.st_mtimensec;
43 	entry->uid = sb.st_uid;
44 	entry->gid = sb.st_gid;
45 	entry->size = (sb.st_size & 0xffffffff);
46 	if (sb.st_mode & S_IFLNK)
47 		entry->mode = GOT_INDEX_ENTRY_MODE_SYMLINK;
48 	else
49 		entry->mode = GOT_INDEX_ENTRY_MODE_REGULAR_FILE;
50 	entry->mode |= ((sb.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO)) <<
51 	    GOT_INDEX_ENTRY_MODE_PERMS_SHIFT);
52 	memcpy(entry->blob_sha1, blob_sha1, SHA1_DIGEST_LENGTH);
53 	memcpy(entry->commit_sha1, commit_sha1, SHA1_DIGEST_LENGTH);
54 
55 	return NULL;
56 }
57 
58 const struct got_error *
59 got_fileindex_entry_alloc(struct got_fileindex_entry **entry,
60     const char *ondisk_path, const char *relpath, uint8_t *blob_sha1,
61     uint8_t *commit_sha1)
62 {
63 	size_t len;
64 
65 	*entry = calloc(1, sizeof(**entry));
66 	if (*entry == NULL)
67 		return got_error_from_errno();
68 
69 	(*entry)->path = strdup(relpath);
70 	if ((*entry)->path == NULL) {
71 		const struct got_error *err = got_error_from_errno();
72 		free(*entry);
73 		*entry = NULL;
74 		return err;
75 	}
76 
77 	len = strlen(relpath);
78 	if (len > GOT_INDEX_ENTRY_F_PATH_LEN)
79 		len = GOT_INDEX_ENTRY_F_PATH_LEN;
80 	(*entry)->flags |= len;
81 
82 	return got_fileindex_entry_update(*entry, ondisk_path, blob_sha1,
83 	    commit_sha1);
84 }
85 
86 void
87 got_fileindex_entry_free(struct got_fileindex_entry *entry)
88 {
89 	free(entry->path);
90 	free(entry);
91 }
92 
93 const struct got_error *
94 got_fileindex_entry_add(struct got_fileindex *fileindex,
95     struct got_fileindex_entry *entry)
96 {
97 	/* TODO keep entries sorted by name */
98 	TAILQ_INSERT_TAIL(&fileindex->entries, entry, entry);
99 	fileindex->nentries++;
100 	return NULL;
101 }
102 
103 void
104 got_fileindex_entry_remove(struct got_fileindex *fileindex,
105     struct got_fileindex_entry *entry)
106 {
107 	TAILQ_REMOVE(&fileindex->entries, entry, entry);
108 	fileindex->nentries--;
109 }
110 
111 struct got_fileindex_entry *
112 got_fileindex_entry_get(struct got_fileindex *fileindex, const char *path)
113 {
114 	struct got_fileindex_entry *entry;
115 	TAILQ_FOREACH(entry, &fileindex->entries, entry) {
116 		if (strcmp(entry->path, path) == 0)
117 			return entry;
118 	}
119 
120 	return NULL;
121 }
122 
123 const struct got_error *
124 got_fileindex_for_each_entry_safe(struct got_fileindex *fileindex,
125     const struct got_error *(cb)(void *, struct got_fileindex_entry *),
126     void *cb_arg)
127 {
128 	const struct got_error *err = NULL;
129 	struct got_fileindex_entry *entry, *tmp;
130 
131 	TAILQ_FOREACH_SAFE(entry, &fileindex->entries, entry, tmp) {
132 		err = cb(cb_arg, entry);
133 		if (err)
134 			break;
135 	}
136 
137 	return err;
138 }
139 
140 struct got_fileindex *
141 got_fileindex_alloc(void)
142 {
143 	struct got_fileindex *fileindex;
144 
145 	fileindex = calloc(1, sizeof(*fileindex));
146 	if (fileindex)
147 		TAILQ_INIT(&fileindex->entries);
148 	return fileindex;
149 }
150 
151 void
152 got_fileindex_free(struct got_fileindex *fileindex)
153 {
154 	struct got_fileindex_entry *entry;
155 
156 	while (!TAILQ_EMPTY(&fileindex->entries)) {
157 		entry = TAILQ_FIRST(&fileindex->entries);
158 		TAILQ_REMOVE(&fileindex->entries, entry, entry);
159 		got_fileindex_entry_free(entry);
160 		fileindex->nentries--;
161 	}
162 	free(fileindex);
163 }
164 
165 static const struct got_error *
166 write_fileindex_val64(SHA1_CTX *ctx, uint64_t val, FILE *outfile)
167 {
168 	size_t n;
169 
170 	val = htobe64(val);
171 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
172 	n = fwrite(&val, 1, sizeof(val), outfile);
173 	if (n != sizeof(val))
174 		return got_ferror(outfile, GOT_ERR_IO);
175 	return NULL;
176 }
177 
178 static const struct got_error *
179 write_fileindex_val32(SHA1_CTX *ctx, uint32_t val, FILE *outfile)
180 {
181 	size_t n;
182 
183 	val = htobe32(val);
184 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
185 	n = fwrite(&val, 1, sizeof(val), outfile);
186 	if (n != sizeof(val))
187 		return got_ferror(outfile, GOT_ERR_IO);
188 	return NULL;
189 }
190 
191 static const struct got_error *
192 write_fileindex_val16(SHA1_CTX *ctx, uint16_t val, FILE *outfile)
193 {
194 	size_t n;
195 
196 	val = htobe16(val);
197 	SHA1Update(ctx, (uint8_t *)&val, sizeof(val));
198 	n = fwrite(&val, 1, sizeof(val), outfile);
199 	if (n != sizeof(val))
200 		return got_ferror(outfile, GOT_ERR_IO);
201 	return NULL;
202 }
203 
204 static const struct got_error *
205 write_fileindex_path(SHA1_CTX *ctx, const char *path, FILE *outfile)
206 {
207 	size_t n, len, pad = 0;
208 	static const uint8_t zero[8] = { 0 };
209 
210 	len = strlen(path);
211 	while ((len + pad) % 8 != 0)
212 		pad++;
213 	if (pad == 0)
214 		pad = 8; /* NUL-terminate */
215 
216 	SHA1Update(ctx, path, len);
217 	n = fwrite(path, 1, len, outfile);
218 	if (n != len)
219 		return got_ferror(outfile, GOT_ERR_IO);
220 	SHA1Update(ctx, zero, pad);
221 	n = fwrite(zero, 1, pad, outfile);
222 	if (n != pad)
223 		return got_ferror(outfile, GOT_ERR_IO);
224 	return NULL;
225 }
226 
227 static const struct got_error *
228 write_fileindex_entry(SHA1_CTX *ctx, struct got_fileindex_entry *entry,
229     FILE *outfile)
230 {
231 	const struct got_error *err;
232 	size_t n;
233 
234 	err = write_fileindex_val64(ctx, entry->ctime_sec, outfile);
235 	if (err)
236 		return err;
237 	err = write_fileindex_val64(ctx, entry->ctime_nsec, outfile);
238 	if (err)
239 		return err;
240 	err = write_fileindex_val64(ctx, entry->mtime_sec, outfile);
241 	if (err)
242 		return err;
243 	err = write_fileindex_val64(ctx, entry->mtime_nsec, outfile);
244 	if (err)
245 		return err;
246 
247 	err = write_fileindex_val32(ctx, entry->uid, outfile);
248 	if (err)
249 		return err;
250 	err = write_fileindex_val32(ctx, entry->gid, outfile);
251 	if (err)
252 		return err;
253 	err = write_fileindex_val32(ctx, entry->size, outfile);
254 	if (err)
255 		return err;
256 
257 	err = write_fileindex_val16(ctx, entry->mode, outfile);
258 	if (err)
259 		return err;
260 
261 	SHA1Update(ctx, entry->blob_sha1, SHA1_DIGEST_LENGTH);
262 	n = fwrite(entry->blob_sha1, 1, SHA1_DIGEST_LENGTH, outfile);
263 	if (n != SHA1_DIGEST_LENGTH)
264 		return got_ferror(outfile, GOT_ERR_IO);
265 
266 	SHA1Update(ctx, entry->commit_sha1, SHA1_DIGEST_LENGTH);
267 	n = fwrite(entry->commit_sha1, 1, SHA1_DIGEST_LENGTH, outfile);
268 	if (n != SHA1_DIGEST_LENGTH)
269 		return got_ferror(outfile, GOT_ERR_IO);
270 
271 	err = write_fileindex_val32(ctx, entry->flags, outfile);
272 	if (err)
273 		return err;
274 
275 	err = write_fileindex_path(ctx, entry->path, outfile);
276 	return err;
277 }
278 
279 const struct got_error *
280 got_fileindex_write(struct got_fileindex *fileindex, FILE *outfile)
281 {
282 	struct got_fileindex_hdr hdr;
283 	struct got_fileindex_entry *entry;
284 	SHA1_CTX ctx;
285 	uint8_t sha1[SHA1_DIGEST_LENGTH];
286 	size_t n;
287 	const size_t len = sizeof(hdr.signature) + sizeof(hdr.version) +
288 	    sizeof(hdr.nentries);
289 	uint8_t buf[len];
290 
291 	SHA1Init(&ctx);
292 
293 	hdr.signature = htobe32(GOT_FILE_INDEX_SIGNATURE);
294 	hdr.version = htobe32(GOT_FILE_INDEX_VERSION);
295 	hdr.nentries = htobe32(fileindex->nentries);
296 
297 	memcpy(buf, &hdr, len);
298 	SHA1Update(&ctx, buf, len);
299 	n = fwrite(buf, 1, len, outfile);
300 	if (n != len)
301 		return got_ferror(outfile, GOT_ERR_IO);
302 
303 	TAILQ_FOREACH(entry, &fileindex->entries, entry) {
304 		const struct got_error *err;
305 		err = write_fileindex_entry(&ctx, entry, outfile);
306 		if (err)
307 			return err;
308 	}
309 
310 	SHA1Final(sha1, &ctx);
311 	n = fwrite(sha1, 1, sizeof(sha1), outfile);
312 	if (n != sizeof(sha1))
313 		return got_ferror(outfile, GOT_ERR_IO);
314 
315 	return NULL;
316 }
317 
318 static const struct got_error *
319 read_fileindex_val64(uint64_t *val, SHA1_CTX *ctx, FILE *infile)
320 {
321 	size_t n;
322 
323 	n = fread(val, 1, sizeof(*val), infile);
324 	if (n != sizeof(*val))
325 		return got_ferror(infile, GOT_ERR_IO);
326 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
327 	*val = be64toh(*val);
328 	return NULL;
329 }
330 
331 static const struct got_error *
332 read_fileindex_val32(uint32_t *val, SHA1_CTX *ctx, FILE *infile)
333 {
334 	size_t n;
335 
336 	n = fread(val, 1, sizeof(*val), infile);
337 	if (n != sizeof(*val))
338 		return got_ferror(infile, GOT_ERR_IO);
339 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
340 	*val = be32toh(*val);
341 	return NULL;
342 }
343 
344 static const struct got_error *
345 read_fileindex_val16(uint16_t *val, SHA1_CTX *ctx, FILE *infile)
346 {
347 	size_t n;
348 
349 	n = fread(val, 1, sizeof(*val), infile);
350 	if (n != sizeof(*val))
351 		return got_ferror(infile, GOT_ERR_IO);
352 	SHA1Update(ctx, (uint8_t *)val, sizeof(*val));
353 	*val = be16toh(*val);
354 	return NULL;
355 }
356 
357 static const struct got_error *
358 read_fileindex_path(char **path, SHA1_CTX *ctx, FILE *infile)
359 {
360 	const struct got_error *err = NULL;
361 	uint8_t buf[8];
362 	size_t n, len = 0, totlen = sizeof(buf);
363 
364 	*path = malloc(totlen);
365 	if (*path == NULL)
366 		return got_error_from_errno();
367 
368 	do {
369 		n = fread(buf, 1, sizeof(buf), infile);
370 		if (n != sizeof(buf))
371 			return got_ferror(infile, GOT_ERR_IO);
372 		if (len + sizeof(buf) > totlen) {
373 			char *p = reallocarray(*path, totlen + sizeof(buf), 1);
374 			if (p == NULL) {
375 				err = got_error_from_errno();
376 				break;
377 			}
378 			totlen += sizeof(buf);
379 			*path = p;
380 		}
381 		SHA1Update(ctx, buf, sizeof(buf));
382 		memcpy(*path + len, buf, sizeof(buf));
383 		len += sizeof(buf);
384 	} while (memchr(buf, '\0', sizeof(buf)) == NULL);
385 
386 	if (err) {
387 		free(*path);
388 		*path = NULL;
389 	}
390 	return err;
391 }
392 
393 static const struct got_error *
394 read_fileindex_entry(struct got_fileindex_entry **entryp, SHA1_CTX *ctx,
395     FILE *infile)
396 {
397 	const struct got_error *err;
398 	struct got_fileindex_entry *entry;
399 	size_t n;
400 
401 	*entryp = NULL;
402 
403 	entry = calloc(1, sizeof(*entry));
404 	if (entry == NULL)
405 		return got_error_from_errno();
406 
407 	err = read_fileindex_val64(&entry->ctime_sec, ctx, infile);
408 	if (err)
409 		goto done;
410 	err = read_fileindex_val64(&entry->ctime_nsec, ctx, infile);
411 	if (err)
412 		goto done;
413 	err = read_fileindex_val64(&entry->mtime_sec, ctx, infile);
414 	if (err)
415 		goto done;
416 	err = read_fileindex_val64(&entry->mtime_nsec, ctx, infile);
417 	if (err)
418 		goto done;
419 
420 	err = read_fileindex_val32(&entry->uid, ctx, infile);
421 	if (err)
422 		goto done;
423 	err = read_fileindex_val32(&entry->gid, ctx, infile);
424 	if (err)
425 		goto done;
426 	err = read_fileindex_val32(&entry->size, ctx, infile);
427 	if (err)
428 		goto done;
429 
430 	err = read_fileindex_val16(&entry->mode, ctx, infile);
431 	if (err)
432 		goto done;
433 
434 	n = fread(entry->blob_sha1, 1, SHA1_DIGEST_LENGTH, infile);
435 	if (n != SHA1_DIGEST_LENGTH) {
436 		err = got_ferror(infile, GOT_ERR_IO);
437 		goto done;
438 	}
439 	SHA1Update(ctx, entry->blob_sha1, SHA1_DIGEST_LENGTH);
440 
441 	n = fread(entry->commit_sha1, 1, SHA1_DIGEST_LENGTH, infile);
442 	if (n != SHA1_DIGEST_LENGTH) {
443 		err = got_ferror(infile, GOT_ERR_IO);
444 		goto done;
445 	}
446 	SHA1Update(ctx, entry->commit_sha1, SHA1_DIGEST_LENGTH);
447 
448 	err = read_fileindex_val32(&entry->flags, ctx, infile);
449 	if (err)
450 		goto done;
451 
452 	err = read_fileindex_path(&entry->path, ctx, infile);
453 done:
454 	if (err)
455 		free(entry);
456 	else
457 		*entryp = entry;
458 	return err;
459 }
460 
461 const struct got_error *
462 got_fileindex_read(struct got_fileindex *fileindex, FILE *infile)
463 {
464 	const struct got_error *err = NULL;
465 	struct got_fileindex_hdr hdr;
466 	SHA1_CTX ctx;
467 	struct got_fileindex_entry *entry;
468 	uint8_t sha1_expected[SHA1_DIGEST_LENGTH];
469 	uint8_t sha1[SHA1_DIGEST_LENGTH];
470 	size_t n;
471 	const size_t len = sizeof(hdr.signature) + sizeof(hdr.version) +
472 	    sizeof(hdr.nentries);
473 	uint8_t buf[len];
474 	int i;
475 
476 	SHA1Init(&ctx);
477 
478 	n = fread(buf, 1, len, infile);
479 	if (n != len) {
480 		if (n == 0) /* EOF */
481 			return NULL;
482 		return got_ferror(infile, GOT_ERR_IO);
483 	}
484 
485 	SHA1Update(&ctx, buf, len);
486 
487 	memcpy(&hdr, buf, len);
488 	hdr.signature = be32toh(hdr.signature);
489 	hdr.version = be32toh(hdr.version);
490 	hdr.nentries = be32toh(hdr.nentries);
491 
492 	if (hdr.signature != GOT_FILE_INDEX_SIGNATURE)
493 		return got_error(GOT_ERR_FILEIDX_SIG);
494 	if (hdr.version != GOT_FILE_INDEX_VERSION)
495 		return got_error(GOT_ERR_FILEIDX_VER);
496 
497 	for (i = 0; i < hdr.nentries; i++) {
498 		err = read_fileindex_entry(&entry, &ctx, infile);
499 		if (err)
500 			return err;
501 		err = got_fileindex_entry_add(fileindex, entry);
502 		if (err)
503 			return err;
504 	}
505 
506 	n = fread(sha1_expected, 1, sizeof(sha1_expected), infile);
507 	if (n != sizeof(sha1_expected))
508 		return got_ferror(infile, GOT_ERR_IO);
509 	SHA1Final(sha1, &ctx);
510 	if (memcmp(sha1, sha1_expected, SHA1_DIGEST_LENGTH) != 0)
511 		return got_error(GOT_ERR_FILEIDX_CSUM);
512 
513 	return NULL;
514 }