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Date:: Sun Nov 11 14:05:43 2018 UTC
Message:: fix error handling in got_pack_stop_privsep_child()
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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/types.h>
18 #include <sys/stat.h>
19 #include <sys/queue.h>
20 #include <sys/uio.h>
21 #include <sys/mman.h>
22 
23 #include <fcntl.h>
24 #include <errno.h>
25 #include <stdio.h>
26 #include <stdint.h>
27 #include <stdlib.h>
28 #include <string.h>
29 #include <limits.h>
30 #include <sha1.h>
31 #include <endian.h>
32 #include <zlib.h>
33 #include <imsg.h>
34 
35 #include "got_error.h"
36 #include "got_object.h"
37 #include "got_opentemp.h"
38 
39 #include "got_lib_sha1.h"
40 #include "got_lib_pack.h"
41 #include "got_lib_path.h"
42 #include "got_lib_delta.h"
43 #include "got_lib_inflate.h"
44 #include "got_lib_object.h"
45 #include "got_lib_privsep.h"
46 
47 #ifndef nitems
48 #define nitems(_a) (sizeof(_a) / sizeof((_a)[0]))
49 #endif
50 
51 #ifndef MIN
52 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
53 #endif
54 
55 static const struct got_error *
56 verify_fanout_table(uint32_t *fanout_table)
57 {
58 	int i;
59 
60 	for (i = 0; i < 0xff - 1; i++) {
61 		if (be32toh(fanout_table[i]) > be32toh(fanout_table[i + 1]))
62 			return got_error(GOT_ERR_BAD_PACKIDX);
63 	}
64 
65 	return NULL;
66 }
67 
68 const struct got_error *
69 got_pack_get_packfile_size(size_t *size, const char *path)
70 {
71 	struct stat sb;
72 	char *dot;
73 
74 	*size = 0;
75 
76 	dot = strrchr(path, '.');
77 	if (dot == NULL)
78 		return got_error(GOT_ERR_BAD_PATH);
79 
80 	/* Path must point to a pack index or to a pack file. */
81 	if (strcmp(dot, GOT_PACKIDX_SUFFIX) == 0) {
82 		const struct got_error *err = NULL;
83 		char *path_pack;
84 		char base_path[PATH_MAX];
85 
86 		/* Convert pack index path to pack file path. */
87 		if (strlcpy(base_path, path, PATH_MAX) > PATH_MAX)
88 			return got_error(GOT_ERR_NO_SPACE);
89 		dot = strrchr(base_path, '.');
90 		if (dot == NULL)
91 			return got_error(GOT_ERR_BAD_PATH);
92 		*dot = '\0';
93 		if (asprintf(&path_pack, "%s.pack", base_path) == -1)
94 			return got_error_from_errno();
95 
96 		if (stat(path_pack, &sb) != 0)
97 			err = got_error_from_errno();
98 		free(path_pack);
99 		if (err)
100 			return err;
101 	} else if (strcmp(dot, GOT_PACKFILE_SUFFIX) == 0) {
102 		if (stat(path, &sb) != 0)
103 			return got_error_from_errno();
104 	} else
105 		return got_error(GOT_ERR_BAD_PATH);
106 
107 	*size = sb.st_size;
108 	return 0;
109 }
110 
111 const struct got_error *
112 got_packidx_init_hdr(struct got_packidx *p, int verify)
113 {
114 	const struct got_error *err = NULL;
115 	struct got_packidx_v2_hdr *h;
116 	SHA1_CTX ctx;
117 	uint8_t sha1[SHA1_DIGEST_LENGTH];
118 	size_t nobj, len_fanout, len_ids, offset, remain;
119 	ssize_t n;
120 
121 	SHA1Init(&ctx);
122 
123 	h = &p->hdr;
124 	offset = 0;
125 	remain = p->len;
126 
127 	if (remain < sizeof(*h->magic)) {
128 		err = got_error(GOT_ERR_BAD_PACKIDX);
129 		goto done;
130 	}
131 	if (p->map)
132 		h->magic = (uint32_t *)(p->map + offset);
133 	else {
134 		h->magic = malloc(sizeof(*h->magic));
135 		if (h->magic == NULL) {
136 			err = got_error_from_errno();
137 			goto done;
138 		}
139 		n = read(p->fd, h->magic, sizeof(*h->magic));
140 		if (n < 0)
141 			err = got_error_from_errno();
142 		else if (n != sizeof(*h->magic)) {
143 			err = got_error(GOT_ERR_BAD_PACKIDX);
144 			goto done;
145 		}
146 	}
147 	if (betoh32(*h->magic) != GOT_PACKIDX_V2_MAGIC) {
148 		err = got_error(GOT_ERR_BAD_PACKIDX);
149 		goto done;
150 	}
151 	offset += sizeof(*h->magic);
152 	remain -= sizeof(*h->magic);
153 
154 	if (verify)
155 		SHA1Update(&ctx, (uint8_t *)h->magic, sizeof(*h->magic));
156 
157 	if (remain < sizeof(*h->version)) {
158 		err = got_error(GOT_ERR_BAD_PACKIDX);
159 		goto done;
160 	}
161 	if (p->map)
162 		h->version = (uint32_t *)(p->map + offset);
163 	else {
164 		h->version = malloc(sizeof(*h->version));
165 		if (h->version == NULL) {
166 			err = got_error_from_errno();
167 			goto done;
168 		}
169 		n = read(p->fd, h->version, sizeof(*h->version));
170 		if (n < 0)
171 			err = got_error_from_errno();
172 		else if (n != sizeof(*h->version)) {
173 			err = got_error(GOT_ERR_BAD_PACKIDX);
174 			goto done;
175 		}
176 	}
177 	if (betoh32(*h->version) != GOT_PACKIDX_VERSION) {
178 		err = got_error(GOT_ERR_BAD_PACKIDX);
179 		goto done;
180 	}
181 	offset += sizeof(*h->version);
182 	remain -= sizeof(*h->version);
183 
184 	if (verify)
185 		SHA1Update(&ctx, (uint8_t *)h->version, sizeof(*h->version));
186 
187 	len_fanout =
188 	    sizeof(*h->fanout_table) * GOT_PACKIDX_V2_FANOUT_TABLE_ITEMS;
189 	if (remain < len_fanout) {
190 		err = got_error(GOT_ERR_BAD_PACKIDX);
191 		goto done;
192 	}
193 	if (p->map)
194 		h->fanout_table = (uint32_t *)(p->map + offset);
195 	else {
196 		h->fanout_table = malloc(len_fanout);
197 		if (h->fanout_table == NULL) {
198 			err = got_error_from_errno();
199 			goto done;
200 		}
201 		n = read(p->fd, h->fanout_table, len_fanout);
202 		if (n < 0)
203 			err = got_error_from_errno();
204 		else if (n != len_fanout) {
205 			err = got_error(GOT_ERR_BAD_PACKIDX);
206 			goto done;
207 		}
208 	}
209 	err = verify_fanout_table(h->fanout_table);
210 	if (err)
211 		goto done;
212 	if (verify)
213 		SHA1Update(&ctx, (uint8_t *)h->fanout_table, len_fanout);
214 	offset += len_fanout;
215 	remain -= len_fanout;
216 
217 	nobj = betoh32(h->fanout_table[0xff]);
218 	len_ids = nobj * sizeof(*h->sorted_ids);
219 	if (len_ids <= nobj || len_ids > remain) {
220 		err = got_error(GOT_ERR_BAD_PACKIDX);
221 		goto done;
222 	}
223 	if (p->map)
224 		h->sorted_ids =
225 		    (struct got_packidx_object_id *)((uint8_t*)(p->map + offset));
226 	else {
227 		h->sorted_ids = malloc(len_ids);
228 		if (h->sorted_ids == NULL) {
229 			err = got_error(GOT_ERR_BAD_PACKIDX);
230 			goto done;
231 		}
232 		n = read(p->fd, h->sorted_ids, len_ids);
233 		if (n < 0)
234 			err = got_error_from_errno();
235 		else if (n != len_ids) {
236 			err = got_error(GOT_ERR_BAD_PACKIDX);
237 			goto done;
238 		}
239 	}
240 	if (verify)
241 		SHA1Update(&ctx, (uint8_t *)h->sorted_ids, len_ids);
242 	offset += len_ids;
243 	remain -= len_ids;
244 
245 	if (remain < nobj * sizeof(*h->crc32)) {
246 		err = got_error(GOT_ERR_BAD_PACKIDX);
247 		goto done;
248 	}
249 	if (p->map)
250 		h->crc32 = (uint32_t *)((uint8_t*)(p->map + offset));
251 	else {
252 		h->crc32 = malloc(nobj * sizeof(*h->crc32));
253 		if (h->crc32 == NULL) {
254 			err = got_error_from_errno();
255 			goto done;
256 		}
257 		n = read(p->fd, h->crc32, nobj * sizeof(*h->crc32));
258 		if (n < 0)
259 			err = got_error_from_errno();
260 		else if (n != nobj * sizeof(*h->crc32)) {
261 			err = got_error(GOT_ERR_BAD_PACKIDX);
262 			goto done;
263 		}
264 	}
265 	if (verify)
266 		SHA1Update(&ctx, (uint8_t *)h->crc32, nobj * sizeof(*h->crc32));
267 	remain -= nobj * sizeof(*h->crc32);
268 	offset += nobj * sizeof(*h->crc32);
269 
270 	if (remain < nobj * sizeof(*h->offsets)) {
271 		err = got_error(GOT_ERR_BAD_PACKIDX);
272 		goto done;
273 	}
274 	if (p->map)
275 		h->offsets = (uint32_t *)((uint8_t*)(p->map + offset));
276 	else {
277 		h->offsets = malloc(nobj * sizeof(*h->offsets));
278 		if (h->offsets == NULL) {
279 			err = got_error_from_errno();
280 			goto done;
281 		}
282 		n = read(p->fd, h->offsets, nobj * sizeof(*h->offsets));
283 		if (n < 0)
284 			err = got_error_from_errno();
285 		else if (n != nobj * sizeof(*h->offsets)) {
286 			err = got_error(GOT_ERR_BAD_PACKIDX);
287 			goto done;
288 		}
289 	}
290 	if (verify)
291 		SHA1Update(&ctx, (uint8_t *)h->offsets,
292 		    nobj * sizeof(*h->offsets));
293 	remain -= nobj * sizeof(*h->offsets);
294 	offset += nobj * sizeof(*h->offsets);
295 
296 	/* Large file offsets are contained only in files > 2GB. */
297 	if (p->len <= 0x80000000)
298 		goto checksum;
299 
300 	if (remain < nobj * sizeof(*h->large_offsets)) {
301 		err = got_error(GOT_ERR_BAD_PACKIDX);
302 		goto done;
303 	}
304 	if (p->map)
305 		h->large_offsets = (uint64_t *)((uint8_t*)(p->map + offset));
306 	else {
307 		h->offsets = malloc(nobj * sizeof(*h->large_offsets));
308 		if (h->offsets == NULL) {
309 			err = got_error_from_errno();
310 			goto done;
311 		}
312 		n = read(p->fd, h->large_offsets,
313 		    nobj * sizeof(*h->large_offsets));
314 		if (n < 0)
315 			err = got_error_from_errno();
316 		else if (n != nobj * sizeof(*h->large_offsets)) {
317 			err = got_error(GOT_ERR_BAD_PACKIDX);
318 			goto done;
319 		}
320 	}
321 	if (verify)
322 		SHA1Update(&ctx, (uint8_t*)h->large_offsets,
323 		    nobj * sizeof(*h->large_offsets));
324 	remain -= nobj * sizeof(*h->large_offsets);
325 	offset += nobj * sizeof(*h->large_offsets);
326 
327 checksum:
328 	if (remain < sizeof(*h->trailer)) {
329 		err = got_error(GOT_ERR_BAD_PACKIDX);
330 		goto done;
331 	}
332 	if (p->map)
333 		h->trailer =
334 		    (struct got_packidx_trailer *)((uint8_t*)(p->map + offset));
335 	else {
336 		h->trailer = malloc(sizeof(*h->trailer));
337 		if (h->trailer == NULL) {
338 			err = got_error_from_errno();
339 			goto done;
340 		}
341 		n = read(p->fd, h->trailer, sizeof(*h->trailer));
342 		if (n < 0)
343 			err = got_error_from_errno();
344 		else if (n != sizeof(*h->trailer)) {
345 			err = got_error(GOT_ERR_BAD_PACKIDX);
346 			goto done;
347 		}
348 	}
349 	if (verify) {
350 		SHA1Update(&ctx, h->trailer->packfile_sha1, SHA1_DIGEST_LENGTH);
351 		SHA1Final(sha1, &ctx);
352 		if (memcmp(h->trailer->packidx_sha1, sha1,
353 		    SHA1_DIGEST_LENGTH) != 0)
354 			err = got_error(GOT_ERR_PACKIDX_CSUM);
355 	}
356 done:
357 	return err;
358 }
359 
360 const struct got_error *
361 got_packidx_open(struct got_packidx **packidx, const char *path, int verify)
362 {
363 	const struct got_error *err = NULL;
364 	struct got_packidx *p;
365 
366 	*packidx = NULL;
367 
368 	p = calloc(1, sizeof(*p));
369 	if (p == NULL)
370 		return got_error_from_errno();
371 
372 	p->fd = open(path, O_RDONLY | O_NOFOLLOW, GOT_DEFAULT_FILE_MODE);
373 	if (p->fd == -1)
374 		return got_error_from_errno();
375 
376 	err = got_pack_get_packfile_size(&p->len, path);
377 	if (err) {
378 		close(p->fd);
379 		free(p);
380 		return err;
381 	}
382 	if (p->len < sizeof(p->hdr)) {
383 		err = got_error(GOT_ERR_BAD_PACKIDX);
384 		close(p->fd);
385 		free(p);
386 		return err;
387 	}
388 
389 	p->path_packidx = strdup(path);
390 	if (p->path_packidx == NULL) {
391 		err = got_error_from_errno();
392 		goto done;
393 	}
394 
395 #ifndef GOT_PACK_NO_MMAP
396 	p->map = mmap(NULL, p->len, PROT_READ, MAP_PRIVATE, p->fd, 0);
397 	if (p->map == MAP_FAILED)
398 		p->map = NULL; /* fall back to read(2) */
399 #endif
400 
401 	err = got_packidx_init_hdr(p, verify);
402 done:
403 	if (err)
404 		got_packidx_close(p);
405 	else
406 		*packidx = p;
407 
408 	return err;
409 }
410 
411 const struct got_error *
412 got_packidx_close(struct got_packidx *packidx)
413 {
414 	const struct got_error *err = NULL;
415 
416 	free(packidx->path_packidx);
417 	if (packidx->map) {
418 		if (munmap(packidx->map, packidx->len) == -1)
419 			err = got_error_from_errno();
420 	} else {
421 		free(packidx->hdr.magic);
422 		free(packidx->hdr.version);
423 		free(packidx->hdr.fanout_table);
424 		free(packidx->hdr.sorted_ids);
425 		free(packidx->hdr.crc32);
426 		free(packidx->hdr.offsets);
427 		free(packidx->hdr.large_offsets);
428 		free(packidx->hdr.trailer);
429 	}
430 	close(packidx->fd);
431 	free(packidx);
432 
433 	return err;
434 }
435 
436 static off_t
437 get_object_offset(struct got_packidx *packidx, int idx)
438 {
439 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
440 	uint32_t offset = betoh32(packidx->hdr.offsets[idx]);
441 	if (offset & GOT_PACKIDX_OFFSET_VAL_IS_LARGE_IDX) {
442 		uint64_t loffset;
443 		idx = offset & GOT_PACKIDX_OFFSET_VAL_MASK;
444 		if (idx < 0 || idx > totobj ||
445 		    packidx->hdr.large_offsets == NULL)
446 			return -1;
447 		loffset = betoh64(packidx->hdr.large_offsets[idx]);
448 		return (loffset > INT64_MAX ? -1 : (off_t)loffset);
449 	}
450 	return (off_t)(offset & GOT_PACKIDX_OFFSET_VAL_MASK);
451 }
452 
453 int
454 got_packidx_get_object_idx(struct got_packidx *packidx, struct got_object_id *id)
455 {
456 	u_int8_t id0 = id->sha1[0];
457 	uint32_t totobj = betoh32(packidx->hdr.fanout_table[0xff]);
458 	int left = 0, right = totobj - 1;
459 
460 	if (id0 > 0)
461 		left = betoh32(packidx->hdr.fanout_table[id0 - 1]);
462 
463 	while (left <= right) {
464 		struct got_packidx_object_id *oid;
465 		int i, cmp;
466 
467 		i = ((left + right) / 2);
468 		oid = &packidx->hdr.sorted_ids[i];
469 		cmp = memcmp(id->sha1, oid->sha1, SHA1_DIGEST_LENGTH);
470 		if (cmp == 0)
471 			return i;
472 		else if (cmp > 0)
473 			left = i + 1;
474 		else if (cmp < 0)
475 			right = i - 1;
476 	}
477 
478 	return -1;
479 }
480 
481 const struct got_error *
482 got_pack_stop_privsep_child(struct got_pack *pack)
483 {
484 	const struct got_error *err = NULL;
485 
486 	if (pack->privsep_child == NULL)
487 		return NULL;
488 
489 	err = got_privsep_send_stop(pack->privsep_child->imsg_fd);
490 	if (err)
491 		return err;
492 	err = got_privsep_wait_for_child(pack->privsep_child->pid);
493 	free(pack->privsep_child);
494 	pack->privsep_child = NULL;
495 	return err;
496 }
497 
498 const struct got_error *
499 got_pack_close(struct got_pack *pack)
500 {
501 	const struct got_error *err = NULL;
502 
503 	err = got_pack_stop_privsep_child(pack);
504 	if (pack->map && munmap(pack->map, pack->filesize) == -1 && !err)
505 		err = got_error_from_errno();
506 	close(pack->fd);
507 	pack->fd = -1;
508 	free(pack->path_packfile);
509 	pack->path_packfile = NULL;
510 	pack->filesize = 0;
511 
512 	return err;
513 }
514 
515 static const struct got_error *
516 parse_object_type_and_size(uint8_t *type, uint64_t *size, size_t *len,
517     struct got_pack *pack, off_t offset)
518 {
519 	uint8_t t = 0;
520 	uint64_t s = 0;
521 	uint8_t sizeN;
522 	size_t mapoff = 0;
523 	int i = 0;
524 
525 	*len = 0;
526 
527 	if (offset >= pack->filesize)
528 		return got_error(GOT_ERR_PACK_OFFSET);
529 
530 	if (pack->map) {
531 		mapoff = (size_t)offset;
532 	} else {
533 		if (lseek(pack->fd, offset, SEEK_SET) == -1)
534 			return got_error_from_errno();
535 	}
536 
537 	do {
538 		/* We do not support size values which don't fit in 64 bit. */
539 		if (i > 9)
540 			return got_error(GOT_ERR_NO_SPACE);
541 
542 		if (pack->map) {
543 			sizeN = *(pack->map + mapoff);
544 			mapoff += sizeof(sizeN);
545 		} else {
546 			ssize_t n = read(pack->fd, &sizeN, sizeof(sizeN));
547 			if (n < 0)
548 				return got_error_from_errno();
549 			if (n != sizeof(sizeN))
550 				return got_error(GOT_ERR_BAD_PACKFILE);
551 		}
552 		*len += sizeof(sizeN);
553 
554 		if (i == 0) {
555 			t = (sizeN & GOT_PACK_OBJ_SIZE0_TYPE_MASK) >>
556 			    GOT_PACK_OBJ_SIZE0_TYPE_MASK_SHIFT;
557 			s = (sizeN & GOT_PACK_OBJ_SIZE0_VAL_MASK);
558 		} else {
559 			size_t shift = 4 + 7 * (i - 1);
560 			s |= ((sizeN & GOT_PACK_OBJ_SIZE_VAL_MASK) << shift);
561 		}
562 		i++;
563 	} while (sizeN & GOT_PACK_OBJ_SIZE_MORE);
564 
565 	*type = t;
566 	*size = s;
567 	return NULL;
568 }
569 
570 static const struct got_error *
571 open_plain_object(struct got_object **obj, const char *path_packfile,
572     struct got_object_id *id, uint8_t type, off_t offset, size_t size, int idx)
573 {
574 	*obj = calloc(1, sizeof(**obj));
575 	if (*obj == NULL)
576 		return got_error_from_errno();
577 
578 	(*obj)->path_packfile = strdup(path_packfile);
579 	if ((*obj)->path_packfile == NULL) {
580 		const struct got_error *err = got_error_from_errno();
581 		free(*obj);
582 		*obj = NULL;
583 		return err;
584 	}
585 
586 	(*obj)->type = type;
587 	(*obj)->flags = GOT_OBJ_FLAG_PACKED;
588 	(*obj)->pack_idx = idx;
589 	(*obj)->hdrlen = 0;
590 	(*obj)->size = size;
591 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
592 	(*obj)->pack_offset = offset;
593 
594 	return NULL;
595 }
596 
597 static const struct got_error *
598 parse_negative_offset(int64_t *offset, size_t *len, struct got_pack *pack,
599     off_t delta_offset)
600 {
601 	int64_t o = 0;
602 	uint8_t offN;
603 	int i = 0;
604 
605 	*len = 0;
606 
607 	do {
608 		/* We do not support offset values which don't fit in 64 bit. */
609 		if (i > 8)
610 			return got_error(GOT_ERR_NO_SPACE);
611 
612 		if (pack->map) {
613 			size_t mapoff;
614 			if (delta_offset >= pack->filesize)
615 				return got_error(GOT_ERR_PACK_OFFSET);
616 			mapoff = (size_t)delta_offset + *len;
617 			offN = *(pack->map + mapoff);
618 		} else {
619 			ssize_t n;
620 			n = read(pack->fd, &offN, sizeof(offN));
621 			if (n < 0)
622 				return got_error_from_errno();
623 			if (n != sizeof(offN))
624 				return got_error(GOT_ERR_BAD_PACKFILE);
625 		}
626 		*len += sizeof(offN);
627 
628 		if (i == 0)
629 			o = (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
630 		else {
631 			o++;
632 			o <<= 7;
633 			o += (offN & GOT_PACK_OBJ_DELTA_OFF_VAL_MASK);
634 		}
635 		i++;
636 	} while (offN & GOT_PACK_OBJ_DELTA_OFF_MORE);
637 
638 	*offset = o;
639 	return NULL;
640 }
641 
642 static const struct got_error *
643 parse_offset_delta(off_t *base_offset, size_t *len, struct got_pack *pack,
644     off_t offset, int tslen)
645 {
646 	const struct got_error *err;
647 	int64_t negoffset;
648 	size_t negofflen;
649 
650 	*len = 0;
651 
652 	err = parse_negative_offset(&negoffset, &negofflen, pack,
653 	    offset + tslen);
654 	if (err)
655 		return err;
656 
657 	/* Compute the base object's offset (must be in the same pack file). */
658 	*base_offset = (offset - negoffset);
659 	if (*base_offset <= 0)
660 		return got_error(GOT_ERR_BAD_PACKFILE);
661 
662 	*len = negofflen;
663 	return NULL;
664 }
665 
666 static const struct got_error *
667 resolve_delta_chain(struct got_delta_chain *, struct got_packidx *,
668     struct got_pack *, off_t, size_t, int, size_t, unsigned int);
669 
670 static const struct got_error *
671 add_delta(struct got_delta_chain *deltas, off_t delta_offset, size_t tslen,
672     int delta_type, size_t delta_size, size_t delta_data_offset,
673     uint8_t *delta_buf, size_t delta_len)
674 {
675 	struct got_delta *delta;
676 
677 	delta = got_delta_open(delta_offset, tslen, delta_type, delta_size,
678 	    delta_data_offset, delta_buf,
679 	    delta_len);
680 	if (delta == NULL)
681 		return got_error_from_errno();
682 	/* delta is freed in got_object_close() */
683 	deltas->nentries++;
684 	SIMPLEQ_INSERT_HEAD(&deltas->entries, delta, entry);
685 	return NULL;
686 }
687 
688 static const struct got_error *
689 resolve_offset_delta(struct got_delta_chain *deltas,
690     struct got_packidx *packidx, struct got_pack *pack, off_t delta_offset,
691     size_t tslen, int delta_type, size_t delta_size, unsigned int recursion)
692 
693 {
694 	const struct got_error *err;
695 	off_t base_offset;
696 	uint8_t base_type;
697 	uint64_t base_size;
698 	size_t base_tslen;
699 	off_t delta_data_offset;
700 	uint8_t *delta_buf;
701 	size_t delta_len, consumed;
702 
703 	err = parse_offset_delta(&base_offset, &consumed, pack,
704 	    delta_offset, tslen);
705 	if (err)
706 		return err;
707 
708 	delta_data_offset = delta_offset + tslen + consumed;
709 	if (delta_data_offset >= pack->filesize)
710 		return got_error(GOT_ERR_PACK_OFFSET);
711 
712 	if (pack->map == NULL) {
713 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
714 		if (delta_data_offset == -1)
715 			return got_error_from_errno();
716 	}
717 
718 	if (pack->map) {
719 		size_t mapoff = (size_t)delta_data_offset;
720 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
721 		    mapoff, pack->filesize - mapoff);
722 		if (err)
723 			return err;
724 	} else {
725 
726 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
727 		if (err)
728 			return err;
729 	}
730 
731 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
732 	    delta_data_offset, delta_buf, delta_len);
733 	if (err)
734 		goto done;
735 
736 	/* An offset delta must be in the same packfile. */
737 	if (base_offset >= pack->filesize) {
738 		err = got_error(GOT_ERR_PACK_OFFSET);
739 		goto done;
740 	}
741 
742 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
743 	    pack, base_offset);
744 	if (err)
745 		goto done;
746 
747 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
748 	    base_tslen, base_type, base_size, recursion - 1);
749 done:
750 	if (err)
751 		free(delta_buf);
752 	return err;
753 }
754 
755 static const struct got_error *
756 resolve_ref_delta(struct got_delta_chain *deltas, struct got_packidx *packidx,
757     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
758     size_t delta_size, unsigned int recursion)
759 {
760 	const struct got_error *err;
761 	struct got_object_id id;
762 	int idx;
763 	off_t base_offset;
764 	uint8_t base_type;
765 	uint64_t base_size;
766 	size_t base_tslen;
767 	off_t delta_data_offset;
768 	uint8_t *delta_buf = NULL;
769 	size_t delta_len;
770 
771 	if (delta_offset >= pack->filesize)
772 		return got_error(GOT_ERR_PACK_OFFSET);
773 	delta_data_offset = delta_offset + tslen;
774 	if (delta_data_offset >= pack->filesize)
775 		return got_error(GOT_ERR_PACK_OFFSET);
776 
777 	if (pack->map == NULL) {
778 		delta_data_offset = lseek(pack->fd, 0, SEEK_CUR);
779 		if (delta_data_offset == -1)
780 			return got_error_from_errno();
781 	}
782 
783 
784 	if (pack->map) {
785 		size_t mapoff = (size_t)delta_data_offset;
786 		memcpy(&id, pack->map + mapoff, sizeof(id));
787 		mapoff += sizeof(id);
788 		err = got_inflate_to_mem_mmap(&delta_buf, &delta_len, pack->map,
789 		    mapoff, pack->filesize - mapoff);
790 		if (err)
791 			goto done;
792 	} else {
793 		ssize_t n = read(pack->fd, &id, sizeof(id));
794 		if (n < 0)
795 			return got_error_from_errno();
796 		if (n != sizeof(id))
797 			return got_error(GOT_ERR_BAD_PACKFILE);
798 		err = got_inflate_to_mem_fd(&delta_buf, &delta_len, pack->fd);
799 		if (err)
800 			goto done;
801 	}
802 
803 	err = add_delta(deltas, delta_offset, tslen, delta_type, delta_size,
804 	    delta_data_offset, delta_buf, delta_len);
805 	if (err)
806 		goto done;
807 
808 	/* Delta base must be in the same pack file. */
809 	idx = got_packidx_get_object_idx(packidx, &id);
810 	if (idx == -1) {
811 		err = got_error(GOT_ERR_BAD_PACKFILE);
812 		goto done;
813 	}
814 
815 	base_offset = get_object_offset(packidx, idx);
816 	if (base_offset == (uint64_t)-1) {
817 		err = got_error(GOT_ERR_BAD_PACKIDX);
818 		goto done;
819 	}
820 
821 	if (base_offset >= pack->filesize) {
822 		err = got_error(GOT_ERR_PACK_OFFSET);
823 		goto done;
824 	}
825 
826 	err = parse_object_type_and_size(&base_type, &base_size, &base_tslen,
827 	    pack, base_offset);
828 	if (err)
829 		goto done;
830 
831 	err = resolve_delta_chain(deltas, packidx, pack, base_offset,
832 	    base_tslen, base_type, base_size, recursion - 1);
833 done:
834 	if (err)
835 		free(delta_buf);
836 	return err;
837 }
838 
839 static const struct got_error *
840 resolve_delta_chain(struct got_delta_chain *deltas, struct got_packidx *packidx,
841     struct got_pack *pack, off_t delta_offset, size_t tslen, int delta_type,
842     size_t delta_size, unsigned int recursion)
843 {
844 	const struct got_error *err = NULL;
845 
846 	if (--recursion == 0)
847 		return got_error(GOT_ERR_RECURSION);
848 
849 	switch (delta_type) {
850 	case GOT_OBJ_TYPE_COMMIT:
851 	case GOT_OBJ_TYPE_TREE:
852 	case GOT_OBJ_TYPE_BLOB:
853 	case GOT_OBJ_TYPE_TAG:
854 		/* Plain types are the final delta base. Recursion ends. */
855 		err = add_delta(deltas, delta_offset, tslen, delta_type,
856 		    delta_size, 0, NULL, 0);
857 		break;
858 	case GOT_OBJ_TYPE_OFFSET_DELTA:
859 		err = resolve_offset_delta(deltas, packidx, pack,
860 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
861 		break;
862 	case GOT_OBJ_TYPE_REF_DELTA:
863 		err = resolve_ref_delta(deltas, packidx, pack,
864 		    delta_offset, tslen, delta_type, delta_size, recursion - 1);
865 		break;
866 	default:
867 		return got_error(GOT_ERR_OBJ_TYPE);
868 	}
869 
870 	return err;
871 }
872 
873 static const struct got_error *
874 open_delta_object(struct got_object **obj, struct got_packidx *packidx,
875     struct got_pack *pack, struct got_object_id *id, off_t offset,
876     size_t tslen, int delta_type, size_t delta_size, int idx)
877 {
878 	const struct got_error *err = NULL;
879 	int resolved_type;
880 
881 	*obj = calloc(1, sizeof(**obj));
882 	if (*obj == NULL)
883 		return got_error_from_errno();
884 
885 	(*obj)->flags = 0;
886 	(*obj)->hdrlen = 0;
887 	(*obj)->size = 0; /* Not known because deltas aren't applied yet. */
888 	memcpy(&(*obj)->id, id, sizeof((*obj)->id));
889 	(*obj)->pack_offset = offset + tslen;
890 
891 	(*obj)->path_packfile = strdup(pack->path_packfile);
892 	if ((*obj)->path_packfile == NULL) {
893 		err = got_error_from_errno();
894 		goto done;
895 	}
896 	(*obj)->flags |= GOT_OBJ_FLAG_PACKED;
897 	(*obj)->pack_idx = idx;
898 
899 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
900 	(*obj)->flags |= GOT_OBJ_FLAG_DELTIFIED;
901 
902 	err = resolve_delta_chain(&(*obj)->deltas, packidx, pack, offset,
903 	    tslen, delta_type, delta_size, GOT_DELTA_CHAIN_RECURSION_MAX);
904 	if (err)
905 		goto done;
906 
907 	err = got_delta_chain_get_base_type(&resolved_type, &(*obj)->deltas);
908 	if (err)
909 		goto done;
910 	(*obj)->type = resolved_type;
911 done:
912 	if (err) {
913 		got_object_close(*obj);
914 		*obj = NULL;
915 	}
916 	return err;
917 }
918 
919 const struct got_error *
920 got_packfile_open_object(struct got_object **obj, struct got_pack *pack,
921     struct got_packidx *packidx, int idx, struct got_object_id *id)
922 {
923 	const struct got_error *err = NULL;
924 	off_t offset;
925 	uint8_t type;
926 	uint64_t size;
927 	size_t tslen;
928 
929 	*obj = NULL;
930 
931 	offset = get_object_offset(packidx, idx);
932 	if (offset == (uint64_t)-1)
933 		return got_error(GOT_ERR_BAD_PACKIDX);
934 
935 	err = parse_object_type_and_size(&type, &size, &tslen, pack, offset);
936 	if (err)
937 		return err;
938 
939 	switch (type) {
940 	case GOT_OBJ_TYPE_COMMIT:
941 	case GOT_OBJ_TYPE_TREE:
942 	case GOT_OBJ_TYPE_BLOB:
943 	case GOT_OBJ_TYPE_TAG:
944 		err = open_plain_object(obj, pack->path_packfile, id, type,
945 		    offset + tslen, size, idx);
946 		break;
947 	case GOT_OBJ_TYPE_OFFSET_DELTA:
948 	case GOT_OBJ_TYPE_REF_DELTA:
949 		err = open_delta_object(obj, packidx, pack, id, offset,
950 		    tslen, type, size, idx);
951 		break;
952 	default:
953 		err = got_error(GOT_ERR_OBJ_TYPE);
954 		break;
955 	}
956 
957 	return err;
958 }
959 
960 static const struct got_error *
961 get_delta_chain_max_size(uint64_t *max_size, struct got_delta_chain *deltas)
962 {
963 	struct got_delta *delta;
964 	uint64_t base_size = 0, result_size = 0;
965 
966 	*max_size = 0;
967 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
968 		/* Plain object types are the delta base. */
969 		if (delta->type != GOT_OBJ_TYPE_COMMIT &&
970 		    delta->type != GOT_OBJ_TYPE_TREE &&
971 		    delta->type != GOT_OBJ_TYPE_BLOB &&
972 		    delta->type != GOT_OBJ_TYPE_TAG) {
973 			const struct got_error *err;
974 			err = got_delta_get_sizes(&base_size, &result_size,
975 			    delta->delta_buf, delta->delta_len);
976 			if (err)
977 				return err;
978 		} else
979 			base_size = delta->size;
980 		if (base_size > *max_size)
981 			*max_size = base_size;
982 		if (result_size > *max_size)
983 			*max_size = result_size;
984 	}
985 
986 	return NULL;
987 }
988 
989 static const struct got_error *
990 dump_delta_chain_to_file(size_t *result_size, struct got_delta_chain *deltas,
991     struct got_pack *pack, FILE *outfile, FILE *base_file, FILE *accum_file)
992 {
993 	const struct got_error *err = NULL;
994 	struct got_delta *delta;
995 	uint8_t *base_buf = NULL, *accum_buf = NULL;
996 	size_t base_bufsz = 0, accum_size = 0;
997 	uint64_t max_size;
998 	int n = 0;
999 
1000 	*result_size = 0;
1001 
1002 	if (SIMPLEQ_EMPTY(&deltas->entries))
1003 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1004 
1005 	/* We process small enough files entirely in memory for speed. */
1006 	err = get_delta_chain_max_size(&max_size, deltas);
1007 	if (err)
1008 		return err;
1009 	if (max_size < GOT_DELTA_RESULT_SIZE_CACHED_MAX) {
1010 		accum_buf = malloc(max_size);
1011 		if (accum_buf == NULL)
1012 			return got_error_from_errno();
1013 		base_file = NULL;
1014 		accum_file = NULL;
1015 	}
1016 
1017 	/* Deltas are ordered in ascending order. */
1018 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1019 		if (n == 0) {
1020 			size_t mapoff;
1021 			off_t delta_data_offset;
1022 
1023 			/* Plain object types are the delta base. */
1024 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1025 			    delta->type != GOT_OBJ_TYPE_TREE &&
1026 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1027 			    delta->type != GOT_OBJ_TYPE_TAG) {
1028 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1029 				goto done;
1030 			}
1031 
1032 			delta_data_offset = delta->offset + delta->tslen;
1033 			if (delta_data_offset >= pack->filesize) {
1034 				err = got_error(GOT_ERR_PACK_OFFSET);
1035 				goto done;
1036 			}
1037 			if (pack->map == NULL) {
1038 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1039 				    == -1) {
1040 					err = got_error_from_errno();
1041 					goto done;
1042 				}
1043 			}
1044 			if (base_file) {
1045 				if (pack->map) {
1046 					mapoff = (size_t)delta_data_offset;
1047 					err = got_inflate_to_file_mmap(
1048 					    &base_bufsz, pack->map, mapoff,
1049 					    pack->filesize - mapoff, base_file);
1050 				} else
1051 					err = got_inflate_to_file_fd(
1052 					    &base_bufsz, pack->fd, base_file);
1053 			} else {
1054 				if (pack->map) {
1055 					mapoff = (size_t)delta_data_offset;
1056 					err = got_inflate_to_mem_mmap(&base_buf,
1057 					    &base_bufsz, pack->map, mapoff,
1058 					    pack->filesize - mapoff);
1059 				} else
1060 					err = got_inflate_to_mem_fd(&base_buf,
1061 					    &base_bufsz, pack->fd);
1062 			}
1063 			if (err)
1064 				goto done;
1065 			n++;
1066 			if (base_file)
1067 				rewind(base_file);
1068 			continue;
1069 		}
1070 
1071 		if (base_buf) {
1072 			err = got_delta_apply_in_mem(base_buf, base_bufsz,
1073 			    delta->delta_buf, delta->delta_len, accum_buf,
1074 			    &accum_size, max_size);
1075 			n++;
1076 		} else {
1077 			err = got_delta_apply(base_file, delta->delta_buf,
1078 			    delta->delta_len,
1079 			    /* Final delta application writes to output file. */
1080 			    ++n < deltas->nentries ? accum_file : outfile,
1081 			    &accum_size);
1082 		}
1083 		if (err)
1084 			goto done;
1085 
1086 		if (n < deltas->nentries) {
1087 			/* Accumulated delta becomes the new base. */
1088 			if (base_buf) {
1089 				uint8_t *tmp = accum_buf;
1090 				/*
1091 				 * Base buffer switches roles with accumulation
1092 				 * buffer. Ensure it can hold the largest
1093 				 * result in the delta chain. The initial
1094 				 * allocation might have been smaller.
1095 				 */
1096 				if (base_bufsz < max_size) {
1097 					uint8_t *p;
1098 					p = reallocarray(base_buf, 1, max_size);
1099 					if (p == NULL) {
1100 						err = got_error_from_errno();
1101 						goto done;
1102 					}
1103 					base_buf = p;
1104 					base_bufsz = max_size;
1105 				}
1106 				accum_buf = base_buf;
1107 				base_buf = tmp;
1108 			} else {
1109 				FILE *tmp = accum_file;
1110 				accum_file = base_file;
1111 				base_file = tmp;
1112 				rewind(base_file);
1113 				rewind(accum_file);
1114 			}
1115 		}
1116 	}
1117 
1118 done:
1119 	free(base_buf);
1120 	if (accum_buf) {
1121 		size_t len = fwrite(accum_buf, 1, accum_size, outfile);
1122 		free(accum_buf);
1123 		if (len != accum_size)
1124 			err = got_ferror(outfile, GOT_ERR_IO);
1125 	}
1126 	if (base_file)
1127 		fclose(base_file);
1128 	if (accum_file)
1129 		fclose(accum_file);
1130 	rewind(outfile);
1131 	if (err == NULL)
1132 		*result_size = accum_size;
1133 	return err;
1134 }
1135 
1136 static const struct got_error *
1137 dump_delta_chain_to_mem(uint8_t **outbuf, size_t *outlen,
1138     struct got_delta_chain *deltas, struct got_pack *pack)
1139 {
1140 	const struct got_error *err = NULL;
1141 	struct got_delta *delta;
1142 	uint8_t *base_buf = NULL, *accum_buf = NULL;
1143 	size_t base_bufsz = 0, accum_size = 0;
1144 	uint64_t max_size;
1145 	int n = 0;
1146 
1147 	*outbuf = NULL;
1148 	*outlen = 0;
1149 
1150 	if (SIMPLEQ_EMPTY(&deltas->entries))
1151 		return got_error(GOT_ERR_BAD_DELTA_CHAIN);
1152 
1153 	err = get_delta_chain_max_size(&max_size, deltas);
1154 	if (err)
1155 		return err;
1156 	accum_buf = malloc(max_size);
1157 	if (accum_buf == NULL)
1158 		return got_error_from_errno();
1159 
1160 	/* Deltas are ordered in ascending order. */
1161 	SIMPLEQ_FOREACH(delta, &deltas->entries, entry) {
1162 		if (n == 0) {
1163 			size_t delta_data_offset;
1164 
1165 			/* Plain object types are the delta base. */
1166 			if (delta->type != GOT_OBJ_TYPE_COMMIT &&
1167 			    delta->type != GOT_OBJ_TYPE_TREE &&
1168 			    delta->type != GOT_OBJ_TYPE_BLOB &&
1169 			    delta->type != GOT_OBJ_TYPE_TAG) {
1170 				err = got_error(GOT_ERR_BAD_DELTA_CHAIN);
1171 				goto done;
1172 			}
1173 
1174 			delta_data_offset = delta->offset + delta->tslen;
1175 			if (delta_data_offset >= pack->filesize) {
1176 				err = got_error(GOT_ERR_PACK_OFFSET);
1177 				goto done;
1178 			}
1179 			if (pack->map) {
1180 				size_t mapoff = (size_t)delta_data_offset;
1181 				err = got_inflate_to_mem_mmap(&base_buf,
1182 				    &base_bufsz, pack->map, mapoff,
1183 				    pack->filesize - mapoff);
1184 			} else {
1185 				if (lseek(pack->fd, delta_data_offset, SEEK_SET)
1186 				    == -1) {
1187 					err = got_error_from_errno();
1188 					goto done;
1189 				}
1190 				err = got_inflate_to_mem_fd(&base_buf,
1191 				    &base_bufsz, pack->fd);
1192 			}
1193 			if (err)
1194 				goto done;
1195 			n++;
1196 			continue;
1197 		}
1198 
1199 		err = got_delta_apply_in_mem(base_buf, base_bufsz,
1200 		    delta->delta_buf, delta->delta_len, accum_buf,
1201 		    &accum_size, max_size);
1202 		n++;
1203 		if (err)
1204 			goto done;
1205 
1206 		if (n < deltas->nentries) {
1207 			/* Accumulated delta becomes the new base. */
1208 			uint8_t *tmp = accum_buf;
1209 			/*
1210 			 * Base buffer switches roles with accumulation buffer.
1211 			 * Ensure it can hold the largest result in the delta
1212 			 * chain. Initial allocation might have been smaller.
1213 			 */
1214 			if (base_bufsz < max_size) {
1215 				uint8_t *p;
1216 				p = reallocarray(base_buf, 1, max_size);
1217 				if (p == NULL) {
1218 					err = got_error_from_errno();
1219 					goto done;
1220 				}
1221 				base_buf = p;
1222 				base_bufsz = max_size;
1223 			}
1224 			accum_buf = base_buf;
1225 			base_buf = tmp;
1226 		}
1227 	}
1228 
1229 done:
1230 	free(base_buf);
1231 	if (err) {
1232 		free(accum_buf);
1233 		*outbuf = NULL;
1234 		*outlen = 0;
1235 	} else {
1236 		*outbuf = accum_buf;
1237 		*outlen = accum_size;
1238 	}
1239 	return err;
1240 }
1241 
1242 const struct got_error *
1243 got_packfile_extract_object(struct got_pack *pack, struct got_object *obj,
1244     FILE *outfile, FILE *base_file, FILE *accum_file)
1245 {
1246 	const struct got_error *err = NULL;
1247 
1248 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1249 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1250 
1251 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1252 		if (obj->pack_offset >= pack->filesize)
1253 			return got_error(GOT_ERR_PACK_OFFSET);
1254 
1255 		if (pack->map) {
1256 			size_t mapoff = (size_t)obj->pack_offset;
1257 			err = got_inflate_to_file_mmap(&obj->size, pack->map,
1258 			    mapoff, pack->filesize - mapoff, outfile);
1259 		} else {
1260 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1261 				return got_error_from_errno();
1262 			err = got_inflate_to_file_fd(&obj->size, pack->fd,
1263 			    outfile);
1264 		}
1265 	} else
1266 		err = dump_delta_chain_to_file(&obj->size, &obj->deltas, pack,
1267 		    outfile, base_file, accum_file);
1268 
1269 	return err;
1270 }
1271 
1272 const struct got_error *
1273 got_packfile_extract_object_to_mem(uint8_t **buf, size_t *len,
1274     struct got_object *obj, struct got_pack *pack)
1275 {
1276 	const struct got_error *err = NULL;
1277 
1278 	if ((obj->flags & GOT_OBJ_FLAG_PACKED) == 0)
1279 		return got_error(GOT_ERR_OBJ_NOT_PACKED);
1280 
1281 	if ((obj->flags & GOT_OBJ_FLAG_DELTIFIED) == 0) {
1282 		if (obj->pack_offset >= pack->filesize)
1283 			return got_error(GOT_ERR_PACK_OFFSET);
1284 		if (pack->map) {
1285 			size_t mapoff = (size_t)obj->pack_offset;
1286 			err = got_inflate_to_mem_mmap(buf, len, pack->map,
1287 			    mapoff, pack->filesize - mapoff);
1288 		} else {
1289 			if (lseek(pack->fd, obj->pack_offset, SEEK_SET) == -1)
1290 				return got_error_from_errno();
1291 			err = got_inflate_to_mem_fd(buf, len, pack->fd);
1292 		}
1293 	} else
1294 		err = dump_delta_chain_to_mem(buf, len, &obj->deltas, pack);
1295 
1296 	return err;
1297 }