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Date:: Mon Sep 10 15:07:59 2018 UTC
Message:: read packed commits with privsep
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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/queue.h>
19 #include <sys/uio.h>
20 #include <sys/syslimits.h>
21 #include <sys/wait.h>
22 
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include <errno.h>
27 #include <stdint.h>
28 #include <poll.h>
29 #include <imsg.h>
30 #include <sha1.h>
31 #include <zlib.h>
32 #include <time.h>
33 
34 #include "got_object.h"
35 #include "got_error.h"
36 
37 #include "got_lib_sha1.h"
38 #include "got_lib_delta.h"
39 #include "got_lib_inflate.h"
40 #include "got_lib_object.h"
41 #include "got_lib_object_parse.h"
42 #include "got_lib_privsep.h"
43 #include "got_lib_pack.h"
44 
45 #ifndef MIN
46 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
47 #endif
48 
49 static const struct got_error *
50 poll_fd(int fd, int events, int timeout)
51 {
52 	struct pollfd pfd[1];
53 	int n;
54 
55 	pfd[0].fd = fd;
56 	pfd[0].events = events;
57 
58 	n = poll(pfd, 1, timeout);
59 	if (n == -1)
60 		return got_error_from_errno();
61 	if (n == 0)
62 		return got_error(GOT_ERR_TIMEOUT);
63 	if (pfd[0].revents & (POLLERR | POLLNVAL))
64 		return got_error_from_errno();
65 	if (pfd[0].revents & (events | POLLHUP))
66 		return NULL;
67 
68 	return got_error(GOT_ERR_INTERRUPT);
69 }
70 
71 static const struct got_error *
72 read_imsg(struct imsgbuf *ibuf)
73 {
74 	const struct got_error *err;
75 	size_t n;
76 
77 	err = poll_fd(ibuf->fd, POLLIN, INFTIM);
78 	if (err)
79 		return err;
80 
81 	n = imsg_read(ibuf);
82 	if (n == -1) {
83 		if (errno == EAGAIN) /* Could be a file-descriptor leak. */
84 			return got_error(GOT_ERR_PRIVSEP_NO_FD);
85 		return got_error(GOT_ERR_PRIVSEP_READ);
86 	}
87 	if (n == 0)
88 		return got_error(GOT_ERR_PRIVSEP_PIPE);
89 
90 	return NULL;
91 }
92 
93 const struct got_error *
94 got_privsep_wait_for_child(pid_t pid)
95 {
96 	int child_status;
97 
98 	waitpid(pid, &child_status, 0);
99 
100 	if (!WIFEXITED(child_status))
101 		return got_error(GOT_ERR_PRIVSEP_DIED);
102 
103 	if (WEXITSTATUS(child_status) != 0)
104 		return got_error(GOT_ERR_PRIVSEP_EXIT);
105 
106 	return NULL;
107 }
108 
109 const struct got_error *
110 got_privsep_recv_imsg(struct imsg *imsg, struct imsgbuf *ibuf, size_t min_datalen)
111 {
112 	const struct got_error *err;
113 	ssize_t n;
114 
115 	n = imsg_get(ibuf, imsg);
116 	if (n == -1)
117 		return got_error_from_errno();
118 
119 	while (n == 0) {
120 		err = read_imsg(ibuf);
121 		if (err)
122 			return err;
123 		n = imsg_get(ibuf, imsg);
124 	}
125 
126 	if (imsg->hdr.len < IMSG_HEADER_SIZE + min_datalen)
127 		return got_error(GOT_ERR_PRIVSEP_LEN);
128 
129 	return NULL;
130 }
131 
132 static const struct got_error *
133 recv_imsg_error(struct imsg *imsg, size_t datalen)
134 {
135 	struct got_imsg_error ierr;
136 
137 	if (datalen != sizeof(ierr))
138 		return got_error(GOT_ERR_PRIVSEP_LEN);
139 
140 	memcpy(&ierr, imsg->data, sizeof(ierr));
141 	if (ierr.code == GOT_ERR_ERRNO) {
142 		static struct got_error serr;
143 		serr.code = GOT_ERR_ERRNO;
144 		serr.msg = strerror(ierr.errno_code);
145 		return &serr;
146 	}
147 
148 	return got_error(ierr.code);
149 }
150 
151 /* Attempt to send an error in an imsg. Complain on stderr as a last resort. */
152 void
153 got_privsep_send_error(struct imsgbuf *ibuf, const struct got_error *err)
154 {
155 	const struct got_error *poll_err;
156 	struct got_imsg_error ierr;
157 	int ret;
158 
159 	ierr.code = err->code;
160 	if (err->code == GOT_ERR_ERRNO)
161 		ierr.errno_code = errno;
162 	else
163 		ierr.errno_code = 0;
164 	ret = imsg_compose(ibuf, GOT_IMSG_ERROR, 0, 0, -1, &ierr, sizeof(ierr));
165 	if (ret != -1) {
166 		fprintf(stderr, "%s: error %d \"%s\": imsg_compose: %s\n",
167 		    getprogname(), err->code, err->msg, strerror(errno));
168 		return;
169 	}
170 
171 	poll_err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
172 	if (poll_err) {
173 		fprintf(stderr, "%s: error %d \"%s\": poll: %s\n",
174 		    getprogname(), err->code, err->msg, poll_err->msg);
175 		return;
176 	}
177 
178 	ret = imsg_flush(ibuf);
179 	if (ret == -1) {
180 		fprintf(stderr, "%s: error %d \"%s\": imsg_flush: %s\n",
181 		    getprogname(), err->code, err->msg, strerror(errno));
182 		return;
183 	}
184 }
185 
186 static const struct got_error *
187 flush_imsg(struct imsgbuf *ibuf)
188 {
189 	const struct got_error *err;
190 
191 	err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
192 	if (err)
193 		return err;
194 
195 	if (imsg_flush(ibuf) == -1)
196 		return got_error_from_errno();
197 
198 	return NULL;
199 }
200 
201 const struct got_error *
202 got_privsep_send_stop(int fd)
203 {
204 	const struct got_error *err = NULL;
205 	struct imsgbuf ibuf;
206 
207 	imsg_init(&ibuf, fd);
208 
209 	if (imsg_compose(&ibuf, GOT_IMSG_STOP, 0, 0, -1, NULL, 0) == -1)
210 		return got_error_from_errno();
211 
212 	err = flush_imsg(&ibuf);
213 	imsg_clear(&ibuf);
214 	return err;
215 }
216 
217 static const struct got_error *
218 send_delta(struct got_delta *delta, struct imsgbuf *ibuf)
219 {
220 	struct got_imsg_delta idelta;
221 	size_t offset, remain;
222 
223 	idelta.offset = delta->offset;
224 	idelta.tslen = delta->tslen;
225 	idelta.type = delta->type;
226 	idelta.size = delta->size;
227 	idelta.data_offset = delta->data_offset;
228 	idelta.delta_len = delta->delta_len;
229 
230 	if (imsg_compose(ibuf, GOT_IMSG_DELTA, 0, 0, -1,
231 	    &idelta, sizeof(idelta)) == -1)
232 		return got_error_from_errno();
233 
234 	if (imsg_flush(ibuf) == -1)
235 		return got_error_from_errno();
236 
237 	offset = 0;
238 	remain = delta->delta_len;
239 	while (remain > 0) {
240 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
241 
242 		if (imsg_compose(ibuf, GOT_IMSG_DELTA_STREAM, 0, 0, -1,
243 		    delta->delta_buf + offset, n) == -1)
244 			return got_error_from_errno();
245 
246 		if (imsg_flush(ibuf) == -1)
247 			return got_error_from_errno();
248 
249 		offset += n;
250 		remain -= n;
251 	}
252 
253 	return NULL;
254 }
255 
256 const struct got_error *
257 got_privsep_send_obj_req(struct imsgbuf *ibuf, int fd, struct got_object *obj)
258 {
259 	const struct got_error *err = NULL;
260 	struct got_imsg_object iobj, *iobjp = NULL;
261 	size_t iobj_size = 0;
262 	int imsg_code = GOT_IMSG_OBJECT_REQUEST;
263 
264 	if (obj) {
265 		switch (obj->type) {
266 		case GOT_OBJ_TYPE_TREE:
267 			imsg_code = GOT_IMSG_TREE_REQUEST;
268 			break;
269 		case GOT_OBJ_TYPE_COMMIT:
270 			imsg_code = GOT_IMSG_COMMIT_REQUEST;
271 			break;
272 		/* Blobs are handled in got_privsep_send_blob_req(). */
273 		default:
274 			return got_error(GOT_ERR_OBJ_TYPE);
275 		}
276 
277 		iobj.type = obj->type;
278 		iobj.flags = obj->flags;
279 		iobj.hdrlen = obj->hdrlen;
280 		iobj.size = obj->size;
281 		iobj.ndeltas = 0;
282 		if (iobj.flags & GOT_OBJ_FLAG_PACKED)
283 			iobj.pack_offset = obj->pack_offset;
284 
285 		iobjp = &iobj;
286 		iobj_size = sizeof(iobj);
287 	}
288 
289 	if (imsg_compose(ibuf, imsg_code, 0, 0, fd, iobjp, iobj_size) == -1)
290 		return got_error_from_errno();
291 
292 	err = flush_imsg(ibuf);
293 	if (err)
294 		return err;
295 
296 	if (obj && obj->flags & GOT_OBJ_FLAG_DELTIFIED) {
297 		struct got_delta *delta;
298 		SIMPLEQ_FOREACH(delta, &obj->deltas.entries, entry) {
299 			err = send_delta(delta, ibuf);
300 			if (err)
301 				break;
302 		}
303 	}
304 
305 	return err;
306 }
307 
308 const struct got_error *
309 got_privsep_send_blob_req(struct imsgbuf *ibuf, int outfd, int infd)
310 {
311 	const struct got_error *err = NULL;
312 
313 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_REQUEST, 0, 0, infd, NULL, 0)
314 	    == -1) {
315 		close(infd);
316 		close(outfd);
317 		return got_error_from_errno();
318 	}
319 
320 	err = flush_imsg(ibuf);
321 	if (err) {
322 		close(outfd);
323 		return err;
324 	}
325 
326 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_OUTFD, 0, 0, outfd, NULL, 0)
327 	    == -1) {
328 		close(outfd);
329 		return got_error_from_errno();
330 	}
331 
332 	return flush_imsg(ibuf);
333 }
334 
335 const struct got_error *
336 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj)
337 {
338 	const struct got_error *err = NULL;
339 	struct got_imsg_object iobj;
340 	struct got_delta *delta;
341 
342 	iobj.type = obj->type;
343 	iobj.flags = obj->flags;
344 	iobj.hdrlen = obj->hdrlen;
345 	iobj.size = obj->size;
346 	iobj.ndeltas = obj->deltas.nentries;
347 	if (iobj.flags & GOT_OBJ_FLAG_PACKED)
348 		iobj.pack_offset = obj->pack_offset;
349 
350 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
351 	    == -1)
352 		return got_error_from_errno();
353 
354 	err = flush_imsg(ibuf);
355 	if (err)
356 		return err;
357 
358 	SIMPLEQ_FOREACH(delta, &obj->deltas.entries, entry) {
359 		err = send_delta(delta, ibuf);
360 		if (err)
361 			break;
362 	}
363 
364 	return err;
365 }
366 
367 static const struct got_error *
368 receive_delta(struct got_delta **delta, struct imsgbuf *ibuf)
369 {
370 	const struct got_error *err = NULL;
371 	struct imsg imsg;
372 	struct got_imsg_delta idelta;
373 	uint8_t *delta_buf = NULL;
374 	const size_t min_datalen =
375 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_delta));
376 	size_t datalen, offset, remain;
377 
378 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
379 	if (err)
380 		return err;
381 
382 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
383 	if (imsg.hdr.type == GOT_IMSG_ERROR)
384 		return recv_imsg_error(&imsg, datalen);
385 
386 	if (imsg.hdr.type != GOT_IMSG_DELTA)
387 		return got_error(GOT_ERR_PRIVSEP_MSG);
388 	if (datalen != sizeof(idelta))
389 		return got_error(GOT_ERR_PRIVSEP_LEN);
390 
391 	memcpy(&idelta, imsg.data, sizeof(idelta));
392 	imsg_free(&imsg);
393 
394 	switch (idelta.type) {
395 	case GOT_OBJ_TYPE_OFFSET_DELTA:
396 	case GOT_OBJ_TYPE_REF_DELTA:
397 		if (idelta.delta_len < GOT_DELTA_STREAM_LENGTH_MIN)
398 			return got_error(GOT_ERR_BAD_DELTA);
399 		break;
400 	default:
401 		if (idelta.delta_len != 0)
402 			return got_error(GOT_ERR_BAD_DELTA);
403 		break;
404 	}
405 
406 	if (idelta.delta_len > 0) {
407 		delta_buf = calloc(1, idelta.delta_len);
408 		if (delta_buf == NULL)
409 			return got_error_from_errno();
410 
411 		offset = 0;
412 		remain = idelta.delta_len;
413 		while (remain > 0) {
414 			size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
415 
416 			err = got_privsep_recv_imsg(&imsg, ibuf, n);
417 			if (err)
418 				return err;
419 
420 			if (imsg.hdr.type == GOT_IMSG_ERROR)
421 				return recv_imsg_error(&imsg, datalen);
422 
423 			if (imsg.hdr.type == GOT_IMSG_STOP)
424 				break;
425 
426 			if (imsg.hdr.type != GOT_IMSG_DELTA_STREAM)
427 				return got_error(GOT_ERR_PRIVSEP_MSG);
428 
429 			datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
430 			if (datalen != n)
431 				return got_error(GOT_ERR_PRIVSEP_LEN);
432 
433 			memcpy(delta_buf + offset, imsg.data, n);
434 			imsg_free(&imsg);
435 
436 			offset += n;
437 			remain -= n;
438 		}
439 	}
440 
441 	*delta = got_delta_open(idelta.offset, idelta.tslen, idelta.type,
442 	    idelta.size, idelta.data_offset, delta_buf, idelta.delta_len);
443 	if (*delta == NULL) {
444 		err = got_error_from_errno();
445 		free(delta_buf);
446 	}
447 
448 	return err;
449 }
450 
451 const struct got_error *
452 got_privsep_get_imsg_obj(struct got_object **obj, struct imsg *imsg,
453     struct imsgbuf *ibuf)
454 {
455 	const struct got_error *err = NULL;
456 	struct got_imsg_object iobj;
457 	size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
458 	int i;
459 
460 	if (datalen != sizeof(iobj))
461 		return got_error(GOT_ERR_PRIVSEP_LEN);
462 
463 	memcpy(&iobj, imsg->data, sizeof(iobj));
464 	if (iobj.ndeltas < 0 ||
465 	    iobj.ndeltas > GOT_DELTA_CHAIN_RECURSION_MAX)
466 		return got_error(GOT_ERR_PRIVSEP_LEN);
467 
468 	if (iobj.ndeltas > 0 &&
469 	    (iobj.flags & GOT_OBJ_FLAG_DELTIFIED) == 0)
470 		return got_error(GOT_ERR_BAD_OBJ_DATA);
471 
472 	*obj = calloc(1, sizeof(**obj));
473 	if (*obj == NULL)
474 		return got_error_from_errno();
475 
476 	(*obj)->type = iobj.type;
477 	(*obj)->flags = iobj.flags;
478 	(*obj)->hdrlen = iobj.hdrlen;
479 	(*obj)->size = iobj.size;
480 	/* id and path_packfile might be copied in by caller */
481 	(*obj)->pack_offset = iobj.pack_offset;
482 	SIMPLEQ_INIT(&(*obj)->deltas.entries);
483 	for (i = 0; i < iobj.ndeltas; i++) {
484 		struct got_delta *delta;
485 		err = receive_delta(&delta, ibuf);
486 		if (err)
487 			break;
488 		(*obj)->deltas.nentries++;
489 		SIMPLEQ_INSERT_TAIL(&(*obj)->deltas.entries, delta,
490 		    entry);
491 	}
492 
493 	return err;
494 }
495 
496 const struct got_error *
497 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
498 {
499 	const struct got_error *err = NULL;
500 	struct imsg imsg;
501 	size_t datalen;
502 	const size_t min_datalen =
503 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
504 
505 	*obj = NULL;
506 
507 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
508 	if (err)
509 		return err;
510 
511 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
512 
513 	switch (imsg.hdr.type) {
514 	case GOT_IMSG_ERROR:
515 		err = recv_imsg_error(&imsg, datalen);
516 		break;
517 	case GOT_IMSG_OBJECT:
518 		err = got_privsep_get_imsg_obj(obj, &imsg, ibuf);
519 		break;
520 	default:
521 		err = got_error(GOT_ERR_PRIVSEP_MSG);
522 		break;
523 	}
524 
525 	imsg_free(&imsg);
526 
527 	return err;
528 }
529 
530 const struct got_error *
531 got_privsep_send_commit(struct imsgbuf *ibuf, struct got_commit_object *commit)
532 {
533 	const struct got_error *err = NULL;
534 	struct got_imsg_commit_object icommit;
535 	uint8_t *buf;
536 	size_t len, total;
537 	struct got_object_qid *qid;
538 
539 	memcpy(icommit.tree_id, commit->tree_id->sha1, sizeof(icommit.tree_id));
540 	icommit.author_len = strlen(commit->author);
541 	memcpy(&icommit.tm_author, &commit->tm_author,
542 	    sizeof(icommit.tm_author));
543 	icommit.committer_len = strlen(commit->committer);
544 	memcpy(&icommit.tm_committer, &commit->tm_committer,
545 	    sizeof(icommit.tm_committer));
546 	icommit.logmsg_len = strlen(commit->logmsg);
547 	icommit.nparents = commit->nparents;
548 
549 	total = sizeof(icommit) + icommit.author_len +
550 	    icommit.committer_len + icommit.logmsg_len +
551 	    icommit.nparents * SHA1_DIGEST_LENGTH;
552 	/* XXX TODO support very large log messages properly */
553 	if (total > MAX_IMSGSIZE)
554 		return got_error(GOT_ERR_NO_SPACE);
555 
556 	buf = malloc(total);
557 	if (buf == NULL)
558 		return got_error_from_errno();
559 
560 	len = 0;
561 	memcpy(buf + len, &icommit, sizeof(icommit));
562 	len += sizeof(icommit);
563 	memcpy(buf + len, commit->author, icommit.author_len);
564 	len += icommit.author_len;
565 	memcpy(buf + len, commit->committer, icommit.committer_len);
566 	len += icommit.committer_len;
567 	memcpy(buf + len, commit->logmsg, icommit.logmsg_len);
568 	len += icommit.logmsg_len;
569 	SIMPLEQ_FOREACH(qid, &commit->parent_ids, entry) {
570 		memcpy(buf + len, qid->id, SHA1_DIGEST_LENGTH);
571 		len += SHA1_DIGEST_LENGTH;
572 	}
573 
574 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
575 		err = got_error_from_errno();
576 		goto done;
577 	}
578 
579 	err = flush_imsg(ibuf);
580 done:
581 	free(buf);
582 	return err;
583 }
584 
585 const struct got_error *
586 got_privsep_recv_commit(struct got_commit_object **commit, struct imsgbuf *ibuf)
587 {
588 	const struct got_error *err = NULL;
589 	struct imsg imsg;
590 	struct got_imsg_commit_object icommit;
591 	size_t len, datalen;
592 	int i;
593 	const size_t min_datalen =
594 	    MIN(sizeof(struct got_imsg_error),
595 	    sizeof(struct got_imsg_commit_object));
596 	uint8_t *data;
597 
598 	*commit = NULL;
599 
600 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
601 	if (err)
602 		return err;
603 
604 	data = imsg.data;
605 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
606 	len = 0;
607 
608 	switch (imsg.hdr.type) {
609 	case GOT_IMSG_ERROR:
610 		err = recv_imsg_error(&imsg, datalen);
611 		break;
612 	case GOT_IMSG_COMMIT:
613 		if (datalen < sizeof(icommit)) {
614 			err = got_error(GOT_ERR_PRIVSEP_LEN);
615 			break;
616 		}
617 
618 		memcpy(&icommit, data, sizeof(icommit));
619 		if (datalen != sizeof(icommit) + icommit.author_len +
620 		    icommit.committer_len + icommit.logmsg_len +
621 		    icommit.nparents * SHA1_DIGEST_LENGTH) {
622 			err = got_error(GOT_ERR_PRIVSEP_LEN);
623 			break;
624 		}
625 		if (icommit.nparents < 0) {
626 			err = got_error(GOT_ERR_PRIVSEP_LEN);
627 			break;
628 		}
629 		len += sizeof(icommit);
630 
631 		*commit = got_object_commit_alloc_partial();
632 		if (*commit == NULL) {
633 			err = got_error_from_errno();
634 			break;
635 		}
636 
637 		memcpy((*commit)->tree_id->sha1, icommit.tree_id,
638 		    SHA1_DIGEST_LENGTH);
639 		memcpy(&(*commit)->tm_author, &icommit.tm_author,
640 		    sizeof((*commit)->tm_author));
641 		memcpy(&(*commit)->tm_committer, &icommit.tm_committer,
642 		    sizeof((*commit)->tm_committer));
643 
644 		if (icommit.author_len == 0) {
645 			(*commit)->author = strdup("");
646 			if ((*commit)->author == NULL) {
647 				err = got_error_from_errno();
648 				break;
649 			}
650 		} else {
651 			(*commit)->author = malloc(icommit.author_len + 1);
652 			if ((*commit)->author == NULL) {
653 				err = got_error_from_errno();
654 				break;
655 			}
656 			memcpy((*commit)->author, data + len,
657 			    icommit.author_len);
658 			(*commit)->author[icommit.author_len] = '\0';
659 		}
660 		len += icommit.author_len;
661 
662 		if (icommit.committer_len == 0) {
663 			(*commit)->committer = strdup("");
664 			if ((*commit)->committer == NULL) {
665 				err = got_error_from_errno();
666 				break;
667 			}
668 		} else {
669 			(*commit)->committer =
670 			    malloc(icommit.committer_len + 1);
671 			if ((*commit)->committer == NULL) {
672 				err = got_error_from_errno();
673 				break;
674 			}
675 			memcpy((*commit)->committer, data + len,
676 			    icommit.committer_len);
677 			(*commit)->committer[icommit.committer_len] = '\0';
678 		}
679 		len += icommit.committer_len;
680 
681 		if (icommit.logmsg_len == 0) {
682 			(*commit)->logmsg = strdup("");
683 			if ((*commit)->logmsg == NULL) {
684 				err = got_error_from_errno();
685 				break;
686 			}
687 		} else {
688 			(*commit)->logmsg = malloc(icommit.logmsg_len + 1);
689 			if ((*commit)->logmsg == NULL) {
690 				err = got_error_from_errno();
691 				break;
692 			}
693 			memcpy((*commit)->logmsg, data + len,
694 			    icommit.logmsg_len);
695 			(*commit)->logmsg[icommit.logmsg_len] = '\0';
696 		}
697 		len += icommit.logmsg_len;
698 
699 		for (i = 0; i < icommit.nparents; i++) {
700 			struct got_object_qid *qid;
701 
702 			qid = calloc(1, sizeof(*qid));
703 			if (qid == NULL) {
704 				err = got_error_from_errno();
705 				break;
706 			}
707 			qid->id = calloc(1, sizeof(*qid->id));
708 			if (qid->id == NULL) {
709 				err = got_error_from_errno();
710 				free(qid);
711 				break;
712 			}
713 
714 			memcpy(qid->id, data + len + i * SHA1_DIGEST_LENGTH,
715 			    sizeof(*qid->id));
716 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, qid, entry);
717 			(*commit)->nparents++;
718 		}
719 		break;
720 	default:
721 		err = got_error(GOT_ERR_PRIVSEP_MSG);
722 		break;
723 	}
724 
725 	imsg_free(&imsg);
726 
727 	return err;
728 }
729 
730 const struct got_error *
731 got_privsep_send_tree(struct imsgbuf *ibuf, struct got_tree_object *tree)
732 {
733 	const struct got_error *err = NULL;
734 	struct got_imsg_tree_object itree;
735 	struct got_tree_entry *te;
736 
737 	itree.nentries = tree->entries.nentries;
738 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
739 	    == -1)
740 		return got_error_from_errno();
741 
742 	err = flush_imsg(ibuf);
743 	if (err)
744 		return err;
745 
746 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
747 		struct got_imsg_tree_entry ite;
748 		uint8_t *buf = NULL;
749 		size_t len = sizeof(ite) + strlen(te->name);
750 
751 		if (len > MAX_IMSGSIZE)
752 			return got_error(GOT_ERR_NO_SPACE);
753 
754 		buf = malloc(len);
755 		if (buf == NULL)
756 			return got_error_from_errno();
757 
758 		memcpy(ite.id, te->id->sha1, sizeof(ite.id));
759 		ite.mode = te->mode;
760 		memcpy(buf, &ite, sizeof(ite));
761 		memcpy(buf + sizeof(ite), te->name, strlen(te->name));
762 
763 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
764 		    buf, len) == -1)
765 			err = got_error_from_errno();
766 		free(buf);
767 		if (err)
768 			return err;
769 
770 		err = flush_imsg(ibuf);
771 		if (err)
772 			return err;
773 	}
774 
775 	return NULL;
776 }
777 
778 const struct got_error *
779 got_privsep_recv_tree(struct got_tree_object **tree, struct imsgbuf *ibuf)
780 {
781 	const struct got_error *err = NULL;
782 	const size_t min_datalen =
783 	    MIN(sizeof(struct got_imsg_error),
784 	    sizeof(struct got_imsg_tree_object));
785 	struct got_imsg_tree_object itree = { 0 };
786 	int nentries = 0;
787 
788 	*tree = NULL;
789 get_more:
790 	err = read_imsg(ibuf);
791 	if (err)
792 		goto done;
793 
794 	while (1) {
795 		struct imsg imsg;
796 		size_t n;
797 		size_t datalen;
798 		struct got_imsg_tree_entry ite;
799 		struct got_tree_entry *te = NULL;
800 
801 		n = imsg_get(ibuf, &imsg);
802 		if (n == 0) {
803 			if (*tree && (*tree)->entries.nentries != nentries)
804 				goto get_more;
805 			break;
806 		}
807 
808 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
809 			return got_error(GOT_ERR_PRIVSEP_LEN);
810 
811 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
812 
813 		switch (imsg.hdr.type) {
814 		case GOT_IMSG_ERROR:
815 			err = recv_imsg_error(&imsg, datalen);
816 			break;
817 		case GOT_IMSG_TREE:
818 			/* This message should only appear once. */
819 			if (*tree != NULL) {
820 				err = got_error(GOT_ERR_PRIVSEP_MSG);
821 				break;
822 			}
823 			if (datalen != sizeof(itree)) {
824 				err = got_error(GOT_ERR_PRIVSEP_LEN);
825 				break;
826 			}
827 			memcpy(&itree, imsg.data, sizeof(itree));
828 			*tree = calloc(1, sizeof(**tree));
829 			if (*tree == NULL) {
830 				err = got_error_from_errno();
831 				break;
832 			}
833 			(*tree)->entries.nentries = itree.nentries;
834 			SIMPLEQ_INIT(&(*tree)->entries.head);
835 			break;
836 		case GOT_IMSG_TREE_ENTRY:
837 			/* This message should be preceeded by GOT_IMSG_TREE. */
838 			if (*tree == NULL) {
839 				err = got_error(GOT_ERR_PRIVSEP_MSG);
840 				break;
841 			}
842 			if (datalen < sizeof(ite) || datalen > MAX_IMSGSIZE) {
843 				err = got_error(GOT_ERR_PRIVSEP_LEN);
844 				break;
845 			}
846 
847 			/* Remaining data contains the entry's name. */
848 			datalen -= sizeof(ite);
849 			memcpy(&ite, imsg.data, sizeof(ite));
850 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
851 				err = got_error(GOT_ERR_PRIVSEP_LEN);
852 				break;
853 			}
854 
855 			te = got_alloc_tree_entry_partial();
856 			if (te == NULL) {
857 				err = got_error_from_errno();
858 				break;
859 			}
860 			te->name = malloc(datalen + 1);
861 			if (te->name == NULL) {
862 				free(te);
863 				err = got_error_from_errno();
864 				break;
865 			}
866 			memcpy(te->name, imsg.data + sizeof(ite), datalen);
867 			te->name[datalen] = '\0';
868 
869 			memcpy(te->id->sha1, ite.id, SHA1_DIGEST_LENGTH);
870 			te->mode = ite.mode;
871 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, te, entry);
872 			nentries++;
873 			break;
874 		default:
875 			err = got_error(GOT_ERR_PRIVSEP_MSG);
876 			break;
877 		}
878 
879 		imsg_free(&imsg);
880 	}
881 done:
882 	if (*tree && (*tree)->entries.nentries != nentries) {
883 		if (err == NULL)
884 			err = got_error(GOT_ERR_PRIVSEP_LEN);
885 		got_object_tree_close(*tree);
886 		*tree = NULL;
887 	}
888 
889 	return err;
890 }
891 
892 const struct got_error *
893 got_privsep_send_blob(struct imsgbuf *ibuf, size_t size)
894 {
895 	struct got_imsg_blob iblob;
896 
897 	iblob.size = size;
898 	/* Data has already been written to file descriptor. */
899 
900 	if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, &iblob, sizeof(iblob))
901 	    == -1)
902 		return got_error_from_errno();
903 
904 	return flush_imsg(ibuf);
905 }
906 
907 const struct got_error *
908 got_privsep_recv_blob(size_t *size, struct imsgbuf *ibuf)
909 {
910 	const struct got_error *err = NULL;
911 	struct imsg imsg;
912 	struct got_imsg_blob iblob;
913 	size_t datalen;
914 
915 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
916 	if (err)
917 		return err;
918 
919 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
920 
921 	switch (imsg.hdr.type) {
922 	case GOT_IMSG_ERROR:
923 		err = recv_imsg_error(&imsg, datalen);
924 		break;
925 	case GOT_IMSG_BLOB:
926 		if (datalen != sizeof(iblob))
927 			err = got_error(GOT_ERR_PRIVSEP_LEN);
928 		memcpy(&iblob, imsg.data, sizeof(iblob));
929 		*size = iblob.size;
930 		/* Data has been written to file descriptor. */
931 		break;
932 	default:
933 		err = got_error(GOT_ERR_PRIVSEP_MSG);
934 		break;
935 	}
936 
937 	imsg_free(&imsg);
938 
939 	return err;
940 }
941 
942 const struct got_error *
943 got_privsep_init_pack_child(struct imsgbuf *ibuf, struct got_pack *pack,
944     struct got_packidx *packidx)
945 {
946 	struct got_imsg_packidx ipackidx;
947 	struct got_imsg_pack ipack;
948 	int fd;
949 
950 	ipackidx.len = packidx->len;
951 	fd = dup(packidx->fd);
952 	if (fd == -1)
953 		return got_error_from_errno();
954 
955 	if (imsg_compose(ibuf, GOT_IMSG_PACKIDX, 0, 0, fd, &ipackidx,
956 	    sizeof(ipackidx)) == -1)
957 		return got_error_from_errno();
958 
959 	if (strlcpy(ipack.path_packfile, pack->path_packfile,
960 	    sizeof(ipack.path_packfile)) >= sizeof(ipack.path_packfile))
961 		return got_error(GOT_ERR_NO_SPACE);
962 	ipack.filesize = pack->filesize;
963 
964 	fd = dup(pack->fd);
965 	if (fd == -1)
966 		return got_error_from_errno();
967 
968 	if (imsg_compose(ibuf, GOT_IMSG_PACK, 0, 0, fd, &ipack, sizeof(ipack))
969 	    == -1)
970 		return got_error_from_errno();
971 
972 	return flush_imsg(ibuf);
973 }
974 
975 const struct got_error *
976 got_privsep_send_packed_obj_req(struct imsgbuf *ibuf, int idx)
977 {
978 	struct got_imsg_packed_object iobj;
979 
980 	iobj.idx = idx;
981 
982 	if (imsg_compose(ibuf, GOT_IMSG_PACKED_OBJECT_REQUEST, 0, 0, -1,
983 	    &iobj, sizeof(iobj)) == -1)
984 		return got_error_from_errno();
985 
986 	return flush_imsg(ibuf);
987 }