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Date:: Thu Feb 21 14:17:36 2019 UTC
Message:: prevent double-close(2) of file descriptors passed in imsg
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1 /*
2  * Copyright (c) 2018, 2019 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 static const struct got_error *
110 recv_imsg_error(struct imsg *imsg, size_t datalen)
111 {
112 	struct got_imsg_error *ierr;
113 
114 	if (datalen != sizeof(*ierr))
115 		return got_error(GOT_ERR_PRIVSEP_LEN);
116 
117 	ierr = imsg->data;
118 	if (ierr->code == GOT_ERR_ERRNO) {
119 		static struct got_error serr;
120 		serr.code = GOT_ERR_ERRNO;
121 		serr.msg = strerror(ierr->errno_code);
122 		return &serr;
123 	}
124 
125 	return got_error(ierr->code);
126 }
127 
128 const struct got_error *
129 got_privsep_recv_imsg(struct imsg *imsg, struct imsgbuf *ibuf,
130     size_t min_datalen)
131 {
132 	const struct got_error *err;
133 	ssize_t n;
134 
135 	n = imsg_get(ibuf, imsg);
136 	if (n == -1)
137 		return got_error_from_errno();
138 
139 	while (n == 0) {
140 		err = read_imsg(ibuf);
141 		if (err)
142 			return err;
143 		n = imsg_get(ibuf, imsg);
144 	}
145 
146 	if (imsg->hdr.len < IMSG_HEADER_SIZE + min_datalen)
147 		return got_error(GOT_ERR_PRIVSEP_LEN);
148 
149 	if (imsg->hdr.type == GOT_IMSG_ERROR) {
150 		size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
151 		return recv_imsg_error(imsg, datalen);
152 	}
153 
154 	return NULL;
155 }
156 
157 /* Attempt to send an error in an imsg. Complain on stderr as a last resort. */
158 void
159 got_privsep_send_error(struct imsgbuf *ibuf, const struct got_error *err)
160 {
161 	const struct got_error *poll_err;
162 	struct got_imsg_error ierr;
163 	int ret;
164 
165 	ierr.code = err->code;
166 	if (err->code == GOT_ERR_ERRNO)
167 		ierr.errno_code = errno;
168 	else
169 		ierr.errno_code = 0;
170 	ret = imsg_compose(ibuf, GOT_IMSG_ERROR, 0, 0, -1, &ierr, sizeof(ierr));
171 	if (ret == -1) {
172 		fprintf(stderr, "%s: error %d \"%s\": imsg_compose: %s\n",
173 		    getprogname(), err->code, err->msg, strerror(errno));
174 		return;
175 	}
176 
177 	poll_err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
178 	if (poll_err) {
179 		fprintf(stderr, "%s: error %d \"%s\": poll: %s\n",
180 		    getprogname(), err->code, err->msg, poll_err->msg);
181 		return;
182 	}
183 
184 	ret = imsg_flush(ibuf);
185 	if (ret == -1) {
186 		fprintf(stderr, "%s: error %d \"%s\": imsg_flush: %s\n",
187 		    getprogname(), err->code, err->msg, strerror(errno));
188 		return;
189 	}
190 }
191 
192 static const struct got_error *
193 flush_imsg(struct imsgbuf *ibuf)
194 {
195 	const struct got_error *err;
196 
197 	err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
198 	if (err)
199 		return err;
200 
201 	if (imsg_flush(ibuf) == -1)
202 		return got_error_from_errno();
203 
204 	return NULL;
205 }
206 
207 const struct got_error *
208 got_privsep_send_stop(int fd)
209 {
210 	const struct got_error *err = NULL;
211 	struct imsgbuf ibuf;
212 
213 	imsg_init(&ibuf, fd);
214 
215 	if (imsg_compose(&ibuf, GOT_IMSG_STOP, 0, 0, -1, NULL, 0) == -1)
216 		return got_error_from_errno();
217 
218 	err = flush_imsg(&ibuf);
219 	imsg_clear(&ibuf);
220 	return err;
221 }
222 
223 const struct got_error *
224 got_privsep_send_obj_req(struct imsgbuf *ibuf, int fd)
225 {
226 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT_REQUEST, 0, 0, fd, NULL, 0)
227 	    == -1)
228 		return got_error_from_errno();
229 
230 	return flush_imsg(ibuf);
231 }
232 
233 const struct got_error *
234 got_privsep_send_commit_req(struct imsgbuf *ibuf, int fd,
235     struct got_object_id *id, int pack_idx)
236 {
237 	const struct got_error *err = NULL;
238 	struct got_imsg_packed_object iobj, *iobjp;
239 	size_t len;
240 
241 	if (id) { /* commit is packed */
242 		iobj.idx = pack_idx;
243 		memcpy(iobj.id, id->sha1, sizeof(iobj.id));
244 		iobjp = &iobj;
245 		len = sizeof(iobj);
246 	} else {
247 		iobjp = NULL;
248 		len = 0;
249 	}
250 
251 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT_REQUEST, 0, 0, fd, iobjp, len)
252 	    == -1) {
253 		err = got_error_from_errno();
254 		close(fd);
255 		return err;
256 	}
257 
258 	return flush_imsg(ibuf);
259 }
260 
261 const struct got_error *
262 got_privsep_send_tree_req(struct imsgbuf *ibuf, int fd,
263     struct got_object_id *id, int pack_idx)
264 {
265 	const struct got_error *err = NULL;
266 	struct got_imsg_packed_object iobj, *iobjp;
267 	size_t len;
268 
269 	if (id) { /* tree is packed */
270 		iobj.idx = pack_idx;
271 		memcpy(iobj.id, id->sha1, sizeof(iobj.id));
272 		iobjp = &iobj;
273 		len = sizeof(iobj);
274 	} else {
275 		iobjp = NULL;
276 		len = 0;
277 	}
278 
279 	if (imsg_compose(ibuf, GOT_IMSG_TREE_REQUEST, 0, 0, fd, iobjp, len)
280 	    == -1) {
281 		err = got_error_from_errno();
282 		close(fd);
283 		return err;
284 	}
285 
286 	return flush_imsg(ibuf);
287 }
288 
289 const struct got_error *
290 got_privsep_send_tag_req(struct imsgbuf *ibuf, int fd,
291     struct got_object_id *id, int pack_idx)
292 {
293 	struct got_imsg_packed_object iobj, *iobjp;
294 	size_t len;
295 
296 	if (id) { /* tag is packed */
297 		iobj.idx = pack_idx;
298 		memcpy(iobj.id, id->sha1, sizeof(iobj.id));
299 		iobjp = &iobj;
300 		len = sizeof(iobj);
301 	} else {
302 		iobjp = NULL;
303 		len = 0;
304 	}
305 
306 	if (imsg_compose(ibuf, GOT_IMSG_TAG_REQUEST, 0, 0, fd, iobjp, len)
307 	    == -1)
308 		return got_error_from_errno();
309 
310 	return flush_imsg(ibuf);
311 }
312 
313 const struct got_error *
314 got_privsep_send_blob_req(struct imsgbuf *ibuf, int infd,
315     struct got_object_id *id, int pack_idx)
316 {
317 	const struct got_error *err = NULL;
318 	struct got_imsg_packed_object iobj, *iobjp;
319 	size_t len;
320 
321 	if (id) { /* blob is packed */
322 		iobj.idx = pack_idx;
323 		memcpy(iobj.id, id->sha1, sizeof(iobj.id));
324 		iobjp = &iobj;
325 		len = sizeof(iobj);
326 	} else {
327 		iobjp = NULL;
328 		len = 0;
329 	}
330 
331 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_REQUEST, 0, 0, infd, iobjp, len)
332 	    == -1) {
333 		err = got_error_from_errno();
334 		close(infd);
335 		return err;
336 	}
337 
338 	return flush_imsg(ibuf);
339 }
340 
341 const struct got_error *
342 got_privsep_send_blob_outfd(struct imsgbuf *ibuf, int outfd)
343 {
344 	const struct got_error *err = NULL;
345 
346 	if (imsg_compose(ibuf, GOT_IMSG_BLOB_OUTFD, 0, 0, outfd, NULL, 0)
347 	    == -1) {
348 		err = got_error_from_errno();
349 		close(outfd);
350 		return err;
351 	}
352 
353 	return flush_imsg(ibuf);
354 }
355 
356 const struct got_error *
357 got_privsep_send_tmpfd(struct imsgbuf *ibuf, int fd)
358 {
359 	const struct got_error *err = NULL;
360 
361 	if (imsg_compose(ibuf, GOT_IMSG_TMPFD, 0, 0, fd, NULL, 0)
362 	    == -1) {
363 		err = got_error_from_errno();
364 		close(fd);
365 		return err;
366 	}
367 
368 	return flush_imsg(ibuf);
369 }
370 
371 const struct got_error *
372 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj)
373 {
374 	struct got_imsg_object iobj;
375 
376 	memcpy(iobj.id, obj->id.sha1, sizeof(iobj.id));
377 	iobj.type = obj->type;
378 	iobj.flags = obj->flags;
379 	iobj.hdrlen = obj->hdrlen;
380 	iobj.size = obj->size;
381 	if (iobj.flags & GOT_OBJ_FLAG_PACKED) {
382 		iobj.pack_offset = obj->pack_offset;
383 		iobj.pack_idx = obj->pack_idx;
384 	}
385 
386 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
387 	    == -1)
388 		return got_error_from_errno();
389 
390 	return flush_imsg(ibuf);
391 }
392 
393 const struct got_error *
394 got_privsep_get_imsg_obj(struct got_object **obj, struct imsg *imsg,
395     struct imsgbuf *ibuf)
396 {
397 	const struct got_error *err = NULL;
398 	struct got_imsg_object *iobj;
399 	size_t datalen = imsg->hdr.len - IMSG_HEADER_SIZE;
400 
401 	if (datalen != sizeof(*iobj))
402 		return got_error(GOT_ERR_PRIVSEP_LEN);
403 	iobj = imsg->data;
404 
405 	*obj = calloc(1, sizeof(**obj));
406 	if (*obj == NULL)
407 		return got_error_from_errno();
408 
409 	memcpy((*obj)->id.sha1, iobj->id, SHA1_DIGEST_LENGTH);
410 	(*obj)->type = iobj->type;
411 	(*obj)->flags = iobj->flags;
412 	(*obj)->hdrlen = iobj->hdrlen;
413 	(*obj)->size = iobj->size;
414 	/* path_packfile is handled by caller */
415 	if (iobj->flags & GOT_OBJ_FLAG_PACKED) {
416 		(*obj)->pack_offset = iobj->pack_offset;
417 		(*obj)->pack_idx = iobj->pack_idx;
418 	}
419 
420 	return err;
421 }
422 
423 const struct got_error *
424 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
425 {
426 	const struct got_error *err = NULL;
427 	struct imsg imsg;
428 	size_t datalen;
429 	const size_t min_datalen =
430 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
431 
432 	*obj = NULL;
433 
434 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
435 	if (err)
436 		return err;
437 
438 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
439 
440 	switch (imsg.hdr.type) {
441 	case GOT_IMSG_OBJECT:
442 		err = got_privsep_get_imsg_obj(obj, &imsg, ibuf);
443 		break;
444 	default:
445 		err = got_error(GOT_ERR_PRIVSEP_MSG);
446 		break;
447 	}
448 
449 	imsg_free(&imsg);
450 
451 	return err;
452 }
453 
454 static const struct got_error *
455 send_commit_logmsg(struct imsgbuf *ibuf, struct got_commit_object *commit,
456     size_t logmsg_len)
457 {
458 	const struct got_error *err = NULL;
459 	size_t offset, remain;
460 
461 	offset = 0;
462 	remain = logmsg_len;
463 	while (remain > 0) {
464 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
465 
466 		if (imsg_compose(ibuf, GOT_IMSG_COMMIT_LOGMSG, 0, 0, -1,
467 		    commit->logmsg + offset, n) == -1) {
468 			err = got_error_from_errno();
469 			break;
470 		}
471 
472 		err = flush_imsg(ibuf);
473 		if (err)
474 			break;
475 
476 		offset += n;
477 		remain -= n;
478 	}
479 
480 	return err;
481 }
482 
483 const struct got_error *
484 got_privsep_send_commit(struct imsgbuf *ibuf, struct got_commit_object *commit)
485 {
486 	const struct got_error *err = NULL;
487 	struct got_imsg_commit_object *icommit;
488 	uint8_t *buf;
489 	size_t len, total;
490 	struct got_object_qid *qid;
491 	size_t author_len = strlen(commit->author);
492 	size_t committer_len = strlen(commit->committer);
493 	size_t logmsg_len = strlen(commit->logmsg);
494 
495 	total = sizeof(*icommit) + author_len + committer_len +
496 	    commit->nparents * SHA1_DIGEST_LENGTH;
497 
498 	buf = malloc(total);
499 	if (buf == NULL)
500 		return got_error_from_errno();
501 
502 	icommit = (struct got_imsg_commit_object *)buf;
503 	memcpy(icommit->tree_id, commit->tree_id->sha1,
504 	    sizeof(icommit->tree_id));
505 	icommit->author_len = author_len;
506 	icommit->author_time = commit->author_time;
507 	icommit->author_gmtoff = commit->author_gmtoff;
508 	icommit->committer_len = committer_len;
509 	icommit->committer_time = commit->committer_time;
510 	icommit->committer_gmtoff = commit->committer_gmtoff;
511 	icommit->logmsg_len = logmsg_len;
512 	icommit->nparents = commit->nparents;
513 
514 	len = sizeof(*icommit);
515 	memcpy(buf + len, commit->author, author_len);
516 	len += author_len;
517 	memcpy(buf + len, commit->committer, committer_len);
518 	len += committer_len;
519 	SIMPLEQ_FOREACH(qid, &commit->parent_ids, entry) {
520 		memcpy(buf + len, qid->id, SHA1_DIGEST_LENGTH);
521 		len += SHA1_DIGEST_LENGTH;
522 	}
523 
524 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
525 		err = got_error_from_errno();
526 		goto done;
527 	}
528 
529 	if (logmsg_len == 0 ||
530 	    logmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
531 		err = flush_imsg(ibuf);
532 		if (err)
533 			goto done;
534 	}
535 	err = send_commit_logmsg(ibuf, commit, logmsg_len);
536 done:
537 	free(buf);
538 	return err;
539 }
540 
541 const struct got_error *
542 got_privsep_recv_commit(struct got_commit_object **commit, struct imsgbuf *ibuf)
543 {
544 	const struct got_error *err = NULL;
545 	struct imsg imsg;
546 	struct got_imsg_commit_object *icommit;
547 	size_t len, datalen;
548 	int i;
549 	const size_t min_datalen =
550 	    MIN(sizeof(struct got_imsg_error),
551 	    sizeof(struct got_imsg_commit_object));
552 
553 	*commit = NULL;
554 
555 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
556 	if (err)
557 		return err;
558 
559 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
560 	len = 0;
561 
562 	switch (imsg.hdr.type) {
563 	case GOT_IMSG_COMMIT:
564 		if (datalen < sizeof(*icommit)) {
565 			err = got_error(GOT_ERR_PRIVSEP_LEN);
566 			break;
567 		}
568 		icommit = imsg.data;
569 		if (datalen != sizeof(*icommit) + icommit->author_len +
570 		    icommit->committer_len +
571 		    icommit->nparents * SHA1_DIGEST_LENGTH) {
572 			err = got_error(GOT_ERR_PRIVSEP_LEN);
573 			break;
574 		}
575 		if (icommit->nparents < 0) {
576 			err = got_error(GOT_ERR_PRIVSEP_LEN);
577 			break;
578 		}
579 		len += sizeof(*icommit);
580 
581 		*commit = got_object_commit_alloc_partial();
582 		if (*commit == NULL) {
583 			err = got_error_from_errno();
584 			break;
585 		}
586 
587 		memcpy((*commit)->tree_id->sha1, icommit->tree_id,
588 		    SHA1_DIGEST_LENGTH);
589 		(*commit)->author_time = icommit->author_time;
590 		(*commit)->author_gmtoff = icommit->author_gmtoff;
591 		(*commit)->committer_time = icommit->committer_time;
592 		(*commit)->committer_gmtoff = icommit->committer_gmtoff;
593 
594 		if (icommit->author_len == 0) {
595 			(*commit)->author = strdup("");
596 			if ((*commit)->author == NULL) {
597 				err = got_error_from_errno();
598 				break;
599 			}
600 		} else {
601 			(*commit)->author = malloc(icommit->author_len + 1);
602 			if ((*commit)->author == NULL) {
603 				err = got_error_from_errno();
604 				break;
605 			}
606 			memcpy((*commit)->author, imsg.data + len,
607 			    icommit->author_len);
608 			(*commit)->author[icommit->author_len] = '\0';
609 		}
610 		len += icommit->author_len;
611 
612 		if (icommit->committer_len == 0) {
613 			(*commit)->committer = strdup("");
614 			if ((*commit)->committer == NULL) {
615 				err = got_error_from_errno();
616 				break;
617 			}
618 		} else {
619 			(*commit)->committer =
620 			    malloc(icommit->committer_len + 1);
621 			if ((*commit)->committer == NULL) {
622 				err = got_error_from_errno();
623 				break;
624 			}
625 			memcpy((*commit)->committer, imsg.data + len,
626 			    icommit->committer_len);
627 			(*commit)->committer[icommit->committer_len] = '\0';
628 		}
629 		len += icommit->committer_len;
630 
631 		if (icommit->logmsg_len == 0) {
632 			(*commit)->logmsg = strdup("");
633 			if ((*commit)->logmsg == NULL) {
634 				err = got_error_from_errno();
635 				break;
636 			}
637 		} else {
638 			size_t offset = 0, remain = icommit->logmsg_len;
639 
640 			(*commit)->logmsg = malloc(icommit->logmsg_len + 1);
641 			if ((*commit)->logmsg == NULL) {
642 				err = got_error_from_errno();
643 				break;
644 			}
645 			while (remain > 0) {
646 				struct imsg imsg_log;
647 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
648 				    remain);
649 
650 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
651 				if (err)
652 					return err;
653 
654 				if (imsg_log.hdr.type != GOT_IMSG_COMMIT_LOGMSG)
655 					return got_error(GOT_ERR_PRIVSEP_MSG);
656 
657 				memcpy((*commit)->logmsg + offset,
658 				    imsg_log.data, n);
659 				imsg_free(&imsg_log);
660 				offset += n;
661 				remain -= n;
662 			}
663 			(*commit)->logmsg[icommit->logmsg_len] = '\0';
664 		}
665 
666 		for (i = 0; i < icommit->nparents; i++) {
667 			struct got_object_qid *qid;
668 
669 			err = got_object_qid_alloc_partial(&qid);
670 			if (err)
671 				break;
672 			memcpy(qid->id, imsg.data + len +
673 			    i * SHA1_DIGEST_LENGTH, sizeof(*qid->id));
674 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, qid, entry);
675 			(*commit)->nparents++;
676 		}
677 		break;
678 	default:
679 		err = got_error(GOT_ERR_PRIVSEP_MSG);
680 		break;
681 	}
682 
683 	imsg_free(&imsg);
684 
685 	return err;
686 }
687 
688 const struct got_error *
689 got_privsep_send_tree(struct imsgbuf *ibuf, struct got_tree_object *tree)
690 {
691 	const struct got_error *err = NULL;
692 	struct got_imsg_tree_object itree;
693 	struct got_tree_entry *te;
694 	size_t totlen;
695 	int nimsg; /* number of imsg queued in ibuf */
696 
697 	itree.nentries = tree->entries.nentries;
698 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
699 	    == -1)
700 		return got_error_from_errno();
701 
702 	totlen = sizeof(itree);
703 	nimsg = 1;
704 	SIMPLEQ_FOREACH(te, &tree->entries.head, entry) {
705 		struct got_imsg_tree_entry *ite;
706 		uint8_t *buf = NULL;
707 		size_t len = sizeof(*ite) + strlen(te->name);
708 
709 		if (len > MAX_IMSGSIZE)
710 			return got_error(GOT_ERR_NO_SPACE);
711 
712 		nimsg++;
713 		if (totlen + len >= MAX_IMSGSIZE - (IMSG_HEADER_SIZE * nimsg)) {
714 			err = flush_imsg(ibuf);
715 			if (err)
716 				return err;
717 			nimsg = 0;
718 		}
719 
720 		buf = malloc(len);
721 		if (buf == NULL)
722 			return got_error_from_errno();
723 
724 		ite = (struct got_imsg_tree_entry *)buf;
725 		memcpy(ite->id, te->id->sha1, sizeof(ite->id));
726 		ite->mode = te->mode;
727 		memcpy(buf + sizeof(*ite), te->name, strlen(te->name));
728 
729 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
730 		    buf, len) == -1)
731 			err = got_error_from_errno();
732 		free(buf);
733 		if (err)
734 			return err;
735 		totlen += len;
736 	}
737 
738 	return flush_imsg(ibuf);
739 }
740 
741 const struct got_error *
742 got_privsep_recv_tree(struct got_tree_object **tree, struct imsgbuf *ibuf)
743 {
744 	const struct got_error *err = NULL;
745 	const size_t min_datalen =
746 	    MIN(sizeof(struct got_imsg_error),
747 	    sizeof(struct got_imsg_tree_object));
748 	struct got_imsg_tree_object *itree;
749 	int nentries = 0;
750 
751 	*tree = NULL;
752 get_more:
753 	err = read_imsg(ibuf);
754 	if (err)
755 		goto done;
756 
757 	while (1) {
758 		struct imsg imsg;
759 		size_t n;
760 		size_t datalen;
761 		struct got_imsg_tree_entry *ite;
762 		struct got_tree_entry *te = NULL;
763 
764 		n = imsg_get(ibuf, &imsg);
765 		if (n == 0) {
766 			if (*tree && (*tree)->entries.nentries != nentries)
767 				goto get_more;
768 			break;
769 		}
770 
771 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
772 			return got_error(GOT_ERR_PRIVSEP_LEN);
773 
774 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
775 
776 		switch (imsg.hdr.type) {
777 		case GOT_IMSG_ERROR:
778 			err = recv_imsg_error(&imsg, datalen);
779 			break;
780 		case GOT_IMSG_TREE:
781 			/* This message should only appear once. */
782 			if (*tree != NULL) {
783 				err = got_error(GOT_ERR_PRIVSEP_MSG);
784 				break;
785 			}
786 			if (datalen != sizeof(*itree)) {
787 				err = got_error(GOT_ERR_PRIVSEP_LEN);
788 				break;
789 			}
790 			itree = imsg.data;
791 			*tree = malloc(sizeof(**tree));
792 			if (*tree == NULL) {
793 				err = got_error_from_errno();
794 				break;
795 			}
796 			(*tree)->entries.nentries = itree->nentries;
797 			SIMPLEQ_INIT(&(*tree)->entries.head);
798 			(*tree)->refcnt = 0;
799 			break;
800 		case GOT_IMSG_TREE_ENTRY:
801 			/* This message should be preceeded by GOT_IMSG_TREE. */
802 			if (*tree == NULL) {
803 				err = got_error(GOT_ERR_PRIVSEP_MSG);
804 				break;
805 			}
806 			if (datalen < sizeof(*ite) || datalen > MAX_IMSGSIZE) {
807 				err = got_error(GOT_ERR_PRIVSEP_LEN);
808 				break;
809 			}
810 
811 			/* Remaining data contains the entry's name. */
812 			datalen -= sizeof(*ite);
813 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
814 				err = got_error(GOT_ERR_PRIVSEP_LEN);
815 				break;
816 			}
817 			ite = imsg.data;
818 
819 			te = got_alloc_tree_entry_partial();
820 			if (te == NULL) {
821 				err = got_error_from_errno();
822 				break;
823 			}
824 			te->name = malloc(datalen + 1);
825 			if (te->name == NULL) {
826 				free(te);
827 				err = got_error_from_errno();
828 				break;
829 			}
830 			memcpy(te->name, imsg.data + sizeof(*ite), datalen);
831 			te->name[datalen] = '\0';
832 
833 			memcpy(te->id->sha1, ite->id, SHA1_DIGEST_LENGTH);
834 			te->mode = ite->mode;
835 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries.head, te, entry);
836 			nentries++;
837 			break;
838 		default:
839 			err = got_error(GOT_ERR_PRIVSEP_MSG);
840 			break;
841 		}
842 
843 		imsg_free(&imsg);
844 	}
845 done:
846 	if (*tree && (*tree)->entries.nentries != nentries) {
847 		if (err == NULL)
848 			err = got_error(GOT_ERR_PRIVSEP_LEN);
849 		got_object_tree_close(*tree);
850 		*tree = NULL;
851 	}
852 
853 	return err;
854 }
855 
856 const struct got_error *
857 got_privsep_send_blob(struct imsgbuf *ibuf, size_t size, size_t hdrlen,
858     const uint8_t *data)
859 {
860 	struct got_imsg_blob iblob;
861 
862 	iblob.size = size;
863 	iblob.hdrlen = hdrlen;
864 
865 	if (data) {
866 		uint8_t *buf;
867 
868 		if (size > GOT_PRIVSEP_INLINE_BLOB_DATA_MAX)
869 			return got_error(GOT_ERR_NO_SPACE);
870 
871 		buf = malloc(sizeof(iblob) + size);
872 		if (buf == NULL)
873 			return got_error_from_errno();
874 
875 		memcpy(buf, &iblob, sizeof(iblob));
876 		memcpy(buf + sizeof(iblob), data, size);
877 		if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, buf,
878 		   sizeof(iblob) + size) == -1) {
879 			free(buf);
880 			return got_error_from_errno();
881 		}
882 		free(buf);
883 	} else {
884 		/* Data has already been written to file descriptor. */
885 		if (imsg_compose(ibuf, GOT_IMSG_BLOB, 0, 0, -1, &iblob,
886 		    sizeof(iblob)) == -1)
887 			return got_error_from_errno();
888 	}
889 
890 
891 	return flush_imsg(ibuf);
892 }
893 
894 const struct got_error *
895 got_privsep_recv_blob(uint8_t **outbuf, size_t *size, size_t *hdrlen,
896     struct imsgbuf *ibuf)
897 {
898 	const struct got_error *err = NULL;
899 	struct imsg imsg;
900 	struct got_imsg_blob *iblob;
901 	size_t datalen;
902 
903 	*outbuf = NULL;
904 
905 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
906 	if (err)
907 		return err;
908 
909 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
910 
911 	switch (imsg.hdr.type) {
912 	case GOT_IMSG_BLOB:
913 		if (datalen < sizeof(*iblob)) {
914 			err = got_error(GOT_ERR_PRIVSEP_LEN);
915 			break;
916 		}
917 		iblob = imsg.data;
918 		*size = iblob->size;
919 		*hdrlen = iblob->hdrlen;
920 
921 		if (datalen == sizeof(*iblob)) {
922 			/* Data has been written to file descriptor. */
923 			break;
924 		}
925 
926 		if (*size > GOT_PRIVSEP_INLINE_BLOB_DATA_MAX) {
927 			err = got_error(GOT_ERR_PRIVSEP_LEN);
928 			break;
929 		}
930 
931 		*outbuf = malloc(*size);
932 		if (*outbuf == NULL) {
933 			err = got_error_from_errno();
934 			break;
935 		}
936 		memcpy(*outbuf, imsg.data + sizeof(*iblob), *size);
937 		break;
938 	default:
939 		err = got_error(GOT_ERR_PRIVSEP_MSG);
940 		break;
941 	}
942 
943 	imsg_free(&imsg);
944 
945 	return err;
946 }
947 
948 static const struct got_error *
949 send_tagmsg(struct imsgbuf *ibuf, struct got_tag_object *tag, size_t tagmsg_len)
950 {
951 	const struct got_error *err = NULL;
952 	size_t offset, remain;
953 
954 	offset = 0;
955 	remain = tagmsg_len;
956 	while (remain > 0) {
957 		size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE, remain);
958 
959 		if (imsg_compose(ibuf, GOT_IMSG_TAG_TAGMSG, 0, 0, -1,
960 		    tag->tagmsg + offset, n) == -1) {
961 			err = got_error_from_errno();
962 			break;
963 		}
964 
965 		err = flush_imsg(ibuf);
966 		if (err)
967 			break;
968 
969 		offset += n;
970 		remain -= n;
971 	}
972 
973 	return err;
974 }
975 
976 const struct got_error *
977 got_privsep_send_tag(struct imsgbuf *ibuf, struct got_tag_object *tag)
978 {
979 	const struct got_error *err = NULL;
980 	struct got_imsg_tag_object *itag;
981 	uint8_t *buf;
982 	size_t len, total;
983 	size_t tag_len = strlen(tag->tag);
984 	size_t tagger_len = strlen(tag->tagger);
985 	size_t tagmsg_len = strlen(tag->tagmsg);
986 
987 	total = sizeof(*itag) + tag_len + tagger_len + tagmsg_len;
988 
989 	buf = malloc(total);
990 	if (buf == NULL)
991 		return got_error_from_errno();
992 
993 	itag = (struct got_imsg_tag_object *)buf;
994 	memcpy(itag->id, tag->id.sha1, sizeof(itag->id));
995 	itag->obj_type = tag->obj_type;
996 	itag->tag_len = tag_len;
997 	itag->tagger_len = tagger_len;
998 	itag->tagger_time = tag->tagger_time;
999 	itag->tagger_gmtoff = tag->tagger_gmtoff;
1000 	itag->tagmsg_len = tagmsg_len;
1001 
1002 	len = sizeof(*itag);
1003 	memcpy(buf + len, tag->tag, tag_len);
1004 	len += tag_len;
1005 	memcpy(buf + len, tag->tagger, tagger_len);
1006 	len += tagger_len;
1007 
1008 	if (imsg_compose(ibuf, GOT_IMSG_TAG, 0, 0, -1, buf, len) == -1) {
1009 		err = got_error_from_errno();
1010 		goto done;
1011 	}
1012 
1013 	if (tagmsg_len == 0 ||
1014 	    tagmsg_len + len > MAX_IMSGSIZE - IMSG_HEADER_SIZE) {
1015 		err = flush_imsg(ibuf);
1016 		if (err)
1017 			goto done;
1018 	}
1019 	err = send_tagmsg(ibuf, tag, tagmsg_len);
1020 done:
1021 	free(buf);
1022 	return err;
1023 }
1024 
1025 const struct got_error *
1026 got_privsep_recv_tag(struct got_tag_object **tag, struct imsgbuf *ibuf)
1027 {
1028 	const struct got_error *err = NULL;
1029 	struct imsg imsg;
1030 	struct got_imsg_tag_object *itag;
1031 	size_t len, datalen;
1032 	const size_t min_datalen =
1033 	    MIN(sizeof(struct got_imsg_error),
1034 	    sizeof(struct got_imsg_tag_object));
1035 
1036 	*tag = NULL;
1037 
1038 	err = got_privsep_recv_imsg(&imsg, ibuf, min_datalen);
1039 	if (err)
1040 		return err;
1041 
1042 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
1043 	len = 0;
1044 
1045 	switch (imsg.hdr.type) {
1046 	case GOT_IMSG_TAG:
1047 		if (datalen < sizeof(*itag)) {
1048 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1049 			break;
1050 		}
1051 		itag = imsg.data;
1052 		if (datalen != sizeof(*itag) + itag->tag_len +
1053 		    itag->tagger_len) {
1054 			err = got_error(GOT_ERR_PRIVSEP_LEN);
1055 			break;
1056 		}
1057 		len += sizeof(*itag);
1058 
1059 		*tag = calloc(1, sizeof(**tag));
1060 		if (*tag == NULL) {
1061 			err = got_error_from_errno();
1062 			break;
1063 		}
1064 
1065 		memcpy((*tag)->id.sha1, itag->id, SHA1_DIGEST_LENGTH);
1066 
1067 		if (itag->tag_len == 0) {
1068 			(*tag)->tag = strdup("");
1069 			if ((*tag)->tag == NULL) {
1070 				err = got_error_from_errno();
1071 				break;
1072 			}
1073 		} else {
1074 			(*tag)->tag = malloc(itag->tag_len + 1);
1075 			if ((*tag)->tag == NULL) {
1076 				err = got_error_from_errno();
1077 				break;
1078 			}
1079 			memcpy((*tag)->tag, imsg.data + len,
1080 			    itag->tag_len);
1081 			(*tag)->tag[itag->tag_len] = '\0';
1082 		}
1083 		len += itag->tag_len;
1084 
1085 		(*tag)->obj_type = itag->obj_type;
1086 		(*tag)->tagger_time = itag->tagger_time;
1087 		(*tag)->tagger_gmtoff = itag->tagger_gmtoff;
1088 
1089 		if (itag->tagger_len == 0) {
1090 			(*tag)->tagger = strdup("");
1091 			if ((*tag)->tagger == NULL) {
1092 				err = got_error_from_errno();
1093 				break;
1094 			}
1095 		} else {
1096 			(*tag)->tagger = malloc(itag->tagger_len + 1);
1097 			if ((*tag)->tagger == NULL) {
1098 				err = got_error_from_errno();
1099 				break;
1100 			}
1101 			memcpy((*tag)->tagger, imsg.data + len,
1102 			    itag->tagger_len);
1103 			(*tag)->tagger[itag->tagger_len] = '\0';
1104 		}
1105 		len += itag->tagger_len;
1106 
1107 		if (itag->tagmsg_len == 0) {
1108 			(*tag)->tagmsg = strdup("");
1109 			if ((*tag)->tagmsg == NULL) {
1110 				err = got_error_from_errno();
1111 				break;
1112 			}
1113 		} else {
1114 			size_t offset = 0, remain = itag->tagmsg_len;
1115 
1116 			(*tag)->tagmsg = malloc(itag->tagmsg_len + 1);
1117 			if ((*tag)->tagmsg == NULL) {
1118 				err = got_error_from_errno();
1119 				break;
1120 			}
1121 			while (remain > 0) {
1122 				struct imsg imsg_log;
1123 				size_t n = MIN(MAX_IMSGSIZE - IMSG_HEADER_SIZE,
1124 				    remain);
1125 
1126 				err = got_privsep_recv_imsg(&imsg_log, ibuf, n);
1127 				if (err)
1128 					return err;
1129 
1130 				if (imsg_log.hdr.type != GOT_IMSG_TAG_TAGMSG)
1131 					return got_error(GOT_ERR_PRIVSEP_MSG);
1132 
1133 				memcpy((*tag)->tagmsg + offset, imsg_log.data,
1134 				    n);
1135 				imsg_free(&imsg_log);
1136 				offset += n;
1137 				remain -= n;
1138 			}
1139 			(*tag)->tagmsg[itag->tagmsg_len] = '\0';
1140 		}
1141 
1142 		break;
1143 	default:
1144 		err = got_error(GOT_ERR_PRIVSEP_MSG);
1145 		break;
1146 	}
1147 
1148 	imsg_free(&imsg);
1149 
1150 	return err;
1151 }
1152 
1153 const struct got_error *
1154 got_privsep_init_pack_child(struct imsgbuf *ibuf, struct got_pack *pack,
1155     struct got_packidx *packidx)
1156 {
1157 	const struct got_error *err = NULL;
1158 	struct got_imsg_packidx ipackidx;
1159 	struct got_imsg_pack ipack;
1160 	int fd;
1161 
1162 	ipackidx.len = packidx->len;
1163 	fd = dup(packidx->fd);
1164 	if (fd == -1)
1165 		return got_error_from_errno();
1166 
1167 	if (imsg_compose(ibuf, GOT_IMSG_PACKIDX, 0, 0, fd, &ipackidx,
1168 	    sizeof(ipackidx)) == -1) {
1169 		err = got_error_from_errno();
1170 		close(fd);
1171 		return err;
1172 	}
1173 
1174 	if (strlcpy(ipack.path_packfile, pack->path_packfile,
1175 	    sizeof(ipack.path_packfile)) >= sizeof(ipack.path_packfile))
1176 		return got_error(GOT_ERR_NO_SPACE);
1177 	ipack.filesize = pack->filesize;
1178 
1179 	fd = dup(pack->fd);
1180 	if (fd == -1)
1181 		return got_error_from_errno();
1182 
1183 	if (imsg_compose(ibuf, GOT_IMSG_PACK, 0, 0, fd, &ipack, sizeof(ipack))
1184 	    == -1) {
1185 		err = got_error_from_errno();
1186 		close(fd);
1187 		return err;
1188 	}
1189 
1190 	return flush_imsg(ibuf);
1191 }
1192 
1193 const struct got_error *
1194 got_privsep_send_packed_obj_req(struct imsgbuf *ibuf, int idx,
1195     struct got_object_id *id)
1196 {
1197 	struct got_imsg_packed_object iobj;
1198 
1199 	iobj.idx = idx;
1200 	memcpy(iobj.id, id->sha1, sizeof(iobj.id));
1201 
1202 	if (imsg_compose(ibuf, GOT_IMSG_PACKED_OBJECT_REQUEST, 0, 0, -1,
1203 	    &iobj, sizeof(iobj)) == -1)
1204 		return got_error_from_errno();
1205 
1206 	return flush_imsg(ibuf);
1207 }
1208 
1209 const struct got_error *
1210 got_privsep_unveil_exec_helpers(void)
1211 {
1212 	if (unveil(GOT_PATH_PROG_READ_PACK, "x") != 0 ||
1213 	    unveil(GOT_PATH_PROG_READ_OBJECT, "x") != 0 ||
1214 	    unveil(GOT_PATH_PROG_READ_COMMIT, "x") != 0 ||
1215 	    unveil(GOT_PATH_PROG_READ_TREE, "x") != 0 ||
1216 	    unveil(GOT_PATH_PROG_READ_BLOB, "x") != 0 ||
1217 	    unveil(GOT_PATH_PROG_READ_TAG, "x") != 0)
1218 		return got_error_from_errno();
1219 
1220 	return NULL;
1221 }