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Date:: Mon Oct 31 08:16:18 2022 UTC
Message:: avoid incomplete writes of pack file data in got-send-pack
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1 /*
2  * Copyright (c) 2019 Ori Bernstein <ori@openbsd.org>
3  * Copyright (c) 2021 Stefan Sperling <stsp@openbsd.org>
4  *
5  * Permission to use, copy, modify, and distribute this software for any
6  * purpose with or without fee is hereby granted, provided that the above
7  * copyright notice and this permission notice appear in all copies.
8  *
9  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16  */
17 
18 #include <sys/types.h>
19 #include <sys/queue.h>
20 #include <sys/uio.h>
21 #include <sys/time.h>
22 #include <sys/stat.h>
23 
24 #include <stdint.h>
25 #include <errno.h>
26 #include <imsg.h>
27 #include <limits.h>
28 #include <signal.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <string.h>
32 #include <ctype.h>
33 #include <sha1.h>
34 #include <fcntl.h>
35 #include <unistd.h>
36 #include <zlib.h>
37 #include <err.h>
38 
39 #include "got_error.h"
40 #include "got_object.h"
41 #include "got_path.h"
42 #include "got_version.h"
43 #include "got_fetch.h"
44 #include "got_reference.h"
45 
46 #include "got_lib_sha1.h"
47 #include "got_lib_delta.h"
48 #include "got_lib_object.h"
49 #include "got_lib_object_parse.h"
50 #include "got_lib_privsep.h"
51 #include "got_lib_pack.h"
52 #include "got_lib_pkt.h"
53 #include "got_lib_gitproto.h"
54 #include "got_lib_ratelimit.h"
55 #include "got_lib_poll.h"
56 
57 #ifndef nitems
58 #define nitems(_a)	(sizeof((_a)) / sizeof((_a)[0]))
59 #endif
60 
61 struct got_object *indexed;
62 static int chattygot;
63 
64 static const struct got_capability got_capabilities[] = {
65 	{ GOT_CAPA_AGENT, "got/" GOT_VERSION_STR },
66 	{ GOT_CAPA_OFS_DELTA, NULL },
67 #if 0
68 	{ GOT_CAPA_SIDE_BAND_64K, NULL },
69 #endif
70 	{ GOT_CAPA_REPORT_STATUS, NULL },
71 	{ GOT_CAPA_DELETE_REFS, NULL },
72 };
73 
74 static const struct got_error *
75 send_upload_progress(struct imsgbuf *ibuf, off_t bytes,
76     struct got_ratelimit *rl)
77 {
78 	const struct got_error *err = NULL;
79 	int elapsed = 0;
80 
81 	if (rl) {
82 		err = got_ratelimit_check(&elapsed, rl);
83 		if (err || !elapsed)
84 			return err;
85 	}
86 
87 	if (imsg_compose(ibuf, GOT_IMSG_SEND_UPLOAD_PROGRESS, 0, 0, -1,
88 	    &bytes, sizeof(bytes)) == -1)
89 		return got_error_from_errno(
90 		    "imsg_compose SEND_UPLOAD_PROGRESS");
91 
92 	return got_privsep_flush_imsg(ibuf);
93 }
94 
95 static const struct got_error *
96 send_pack_request(struct imsgbuf *ibuf)
97 {
98 	if (imsg_compose(ibuf, GOT_IMSG_SEND_PACK_REQUEST, 0, 0, -1,
99 	    NULL, 0) == -1)
100 		return got_error_from_errno("imsg_compose SEND_PACK_REQUEST");
101 	return got_privsep_flush_imsg(ibuf);
102 }
103 
104 static const struct got_error *
105 send_done(struct imsgbuf *ibuf)
106 {
107 	if (imsg_compose(ibuf, GOT_IMSG_SEND_DONE, 0, 0, -1, NULL, 0) == -1)
108 		return got_error_from_errno("imsg_compose SEND_DONE");
109 	return got_privsep_flush_imsg(ibuf);
110 }
111 
112 static const struct got_error *
113 recv_packfd(int *packfd, struct imsgbuf *ibuf)
114 {
115 	const struct got_error *err;
116 	struct imsg imsg;
117 
118 	*packfd = -1;
119 
120 	err = got_privsep_recv_imsg(&imsg, ibuf, 0);
121 	if (err)
122 		return err;
123 
124 	if (imsg.hdr.type == GOT_IMSG_STOP) {
125 		err = got_error(GOT_ERR_CANCELLED);
126 		goto done;
127 	}
128 
129 	if (imsg.hdr.type != GOT_IMSG_SEND_PACKFD) {
130 		err = got_error(GOT_ERR_PRIVSEP_MSG);
131 		goto done;
132 	}
133 
134 	if (imsg.hdr.len - IMSG_HEADER_SIZE != 0) {
135 		err = got_error(GOT_ERR_PRIVSEP_LEN);
136 		goto done;
137 	}
138 
139 	*packfd = imsg.fd;
140 done:
141 	imsg_free(&imsg);
142 	return err;
143 }
144 
145 static const struct got_error *
146 send_pack_file(int sendfd, int packfd, struct imsgbuf *ibuf)
147 {
148 	const struct got_error *err;
149 	unsigned char buf[8192];
150 	ssize_t r;
151 	off_t wtotal = 0;
152 	struct got_ratelimit rl;
153 
154 	if (lseek(packfd, 0L, SEEK_SET) == -1)
155 		return got_error_from_errno("lseek");
156 
157 	got_ratelimit_init(&rl, 0, 500);
158 
159 	for (;;) {
160 		r = read(packfd, buf, sizeof(buf));
161 		if (r == -1)
162 			return got_error_from_errno("read");
163 		if (r == 0)
164 			break;
165 		err = got_poll_write_full(sendfd, buf, r);
166 		if (err)
167 			return NULL;
168 		wtotal += r;
169 		err = send_upload_progress(ibuf, wtotal, &rl);
170 		if (err)
171 			return err;
172 	}
173 
174 	return send_upload_progress(ibuf, wtotal, NULL);
175 }
176 
177 static const struct got_error *
178 send_error(const char *buf, size_t len)
179 {
180 	static char msg[1024];
181 	size_t i;
182 
183 	for (i = 0; i < len && i < sizeof(msg) - 1; i++) {
184 		if (!isprint(buf[i]))
185 			return got_error_msg(GOT_ERR_BAD_PACKET,
186 			    "non-printable error message received from server");
187 		msg[i] = buf[i];
188 	}
189 	msg[i] = '\0';
190 	return got_error_msg(GOT_ERR_SEND_FAILED, msg);
191 }
192 
193 static const struct got_error *
194 send_their_ref(struct imsgbuf *ibuf, struct got_object_id *refid,
195     const char *refname)
196 {
197 	struct ibuf *wbuf;
198 	size_t len, reflen = strlen(refname);
199 
200 	len = sizeof(struct got_imsg_send_remote_ref) + reflen;
201 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
202 		return got_error(GOT_ERR_NO_SPACE);
203 
204 	wbuf = imsg_create(ibuf, GOT_IMSG_SEND_REMOTE_REF, 0, 0, len);
205 	if (wbuf == NULL)
206 		return got_error_from_errno("imsg_create SEND_REMOTE_REF");
207 
208 	/* Keep in sync with struct got_imsg_send_remote_ref definition! */
209 	if (imsg_add(wbuf, refid->sha1, SHA1_DIGEST_LENGTH) == -1)
210 		return got_error_from_errno("imsg_add SEND_REMOTE_REF");
211 	if (imsg_add(wbuf, &reflen, sizeof(reflen)) == -1)
212 		return got_error_from_errno("imsg_add SEND_REMOTE_REF");
213 	if (imsg_add(wbuf, refname, reflen) == -1)
214 		return got_error_from_errno("imsg_add SEND_REMOTE_REF");
215 
216 	wbuf->fd = -1;
217 	imsg_close(ibuf, wbuf);
218 	return got_privsep_flush_imsg(ibuf);
219 }
220 
221 static const struct got_error *
222 send_ref_status(struct imsgbuf *ibuf, const char *refname, int success,
223     struct got_pathlist_head *refs, struct got_pathlist_head *delete_refs)
224 {
225 	struct ibuf *wbuf;
226 	size_t len, reflen = strlen(refname);
227 	struct got_pathlist_entry *pe;
228 	int ref_valid = 0;
229 	char *eol;
230 
231 	eol = strchr(refname, '\n');
232 	if (eol == NULL) {
233 		return got_error_msg(GOT_ERR_BAD_PACKET,
234 		    "unexpected message from server");
235 	}
236 	*eol = '\0';
237 
238 	TAILQ_FOREACH(pe, refs, entry) {
239 		if (strcmp(refname, pe->path) == 0) {
240 			ref_valid = 1;
241 			break;
242 		}
243 	}
244 	if (!ref_valid) {
245 		TAILQ_FOREACH(pe, delete_refs, entry) {
246 			if (strcmp(refname, pe->path) == 0) {
247 				ref_valid = 1;
248 				break;
249 			}
250 		}
251 	}
252 	if (!ref_valid) {
253 		return got_error_msg(GOT_ERR_BAD_PACKET,
254 		    "unexpected message from server");
255 	}
256 
257 	len = sizeof(struct got_imsg_send_ref_status) + reflen;
258 	if (len >= MAX_IMSGSIZE - IMSG_HEADER_SIZE)
259 		return got_error(GOT_ERR_NO_SPACE);
260 
261 	wbuf = imsg_create(ibuf, GOT_IMSG_SEND_REF_STATUS,
262 	    0, 0, len);
263 	if (wbuf == NULL)
264 		return got_error_from_errno("imsg_create SEND_REF_STATUS");
265 
266 	/* Keep in sync with struct got_imsg_send_ref_status definition! */
267 	if (imsg_add(wbuf, &success, sizeof(success)) == -1)
268 		return got_error_from_errno("imsg_add SEND_REF_STATUS");
269 	if (imsg_add(wbuf, &reflen, sizeof(reflen)) == -1)
270 		return got_error_from_errno("imsg_add SEND_REF_STATUS");
271 	if (imsg_add(wbuf, refname, reflen) == -1)
272 		return got_error_from_errno("imsg_add SEND_REF_STATUS");
273 
274 	wbuf->fd = -1;
275 	imsg_close(ibuf, wbuf);
276 	return got_privsep_flush_imsg(ibuf);
277 }
278 
279 static const struct got_error *
280 describe_refchange(int *n, int *sent_my_capabilites,
281     const char *my_capabilities, char *buf, size_t bufsize,
282     const char *refname, const char *old_hashstr, const char *new_hashstr)
283 {
284 	*n = snprintf(buf, bufsize, "%s %s %s",
285 	    old_hashstr, new_hashstr, refname);
286 	if (*n < 0 || (size_t)*n >= bufsize)
287 		return got_error(GOT_ERR_NO_SPACE);
288 
289 	/*
290 	 * We must announce our capabilities along with the first
291 	 * reference. Unfortunately, the protocol requires an embedded
292 	 * NUL as a separator between reference name and capabilities,
293 	 * which we have to deal with here.
294 	 * It also requires a linefeed for terminating packet data.
295 	 */
296 	if (!*sent_my_capabilites && my_capabilities != NULL) {
297 		int m;
298 		if (*n >= bufsize - 1)
299 			return got_error(GOT_ERR_NO_SPACE);
300 		m = snprintf(buf + *n + 1, /* offset after '\0' */
301 		    bufsize - (*n + 1), "%s\n", my_capabilities);
302 		if (m < 0 || *n + m >= bufsize)
303 			return got_error(GOT_ERR_NO_SPACE);
304 		*n += m;
305 		*sent_my_capabilites = 1;
306 	} else {
307 		*n = strlcat(buf, "\n", bufsize);
308 		if (*n >= bufsize)
309 			return got_error(GOT_ERR_NO_SPACE);
310 	}
311 
312 	return NULL;
313 }
314 
315 static const struct got_error *
316 send_pack(int fd, struct got_pathlist_head *refs,
317     struct got_pathlist_head *delete_refs, struct imsgbuf *ibuf)
318 {
319 	const struct got_error *err = NULL;
320 	char buf[GOT_PKT_MAX];
321 	const unsigned char zero_id[SHA1_DIGEST_LENGTH] = { 0 };
322 	char old_hashstr[SHA1_DIGEST_STRING_LENGTH];
323 	char new_hashstr[SHA1_DIGEST_STRING_LENGTH];
324 	struct got_pathlist_head their_refs;
325 	int is_firstpkt = 1;
326 	int n, nsent = 0;
327 	int packfd = -1;
328 	char *id_str = NULL, *refname = NULL;
329 	struct got_object_id *id = NULL;
330 	char *server_capabilities = NULL, *my_capabilities = NULL;
331 	struct got_pathlist_entry *pe;
332 	int sent_my_capabilites = 0;
333 
334 	TAILQ_INIT(&their_refs);
335 
336 	if (TAILQ_EMPTY(refs) && TAILQ_EMPTY(delete_refs))
337 		return got_error(GOT_ERR_SEND_EMPTY);
338 
339 	while (1) {
340 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
341 		if (err)
342 			goto done;
343 		if (n == 0)
344 			break;
345 		if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
346 			err = send_error(&buf[4], n - 4);
347 			goto done;
348 		}
349 		free(id_str);
350 		free(refname);
351 		err = got_gitproto_parse_refline(&id_str, &refname,
352 		    &server_capabilities, buf, n);
353 		if (err)
354 			goto done;
355 		if (is_firstpkt) {
356 			if (chattygot && server_capabilities[0] != '\0')
357 				fprintf(stderr, "%s: server capabilities: %s\n",
358 				    getprogname(), server_capabilities);
359 			err = got_gitproto_match_capabilities(&my_capabilities,
360 			    NULL, server_capabilities, got_capabilities,
361 			    nitems(got_capabilities));
362 			if (err)
363 				goto done;
364 			if (chattygot)
365 				fprintf(stderr, "%s: my capabilities:%s\n",
366 				    getprogname(), my_capabilities);
367 			is_firstpkt = 0;
368 		}
369 		if (strstr(refname, "^{}")) {
370 			if (chattygot) {
371 				fprintf(stderr, "%s: ignoring %s\n",
372 				    getprogname(), refname);
373 			}
374 			continue;
375 		}
376 
377 		id = malloc(sizeof(*id));
378 		if (id == NULL) {
379 			err = got_error_from_errno("malloc");
380 			goto done;
381 		}
382 		if (!got_parse_sha1_digest(id->sha1, id_str)) {
383 			err = got_error(GOT_ERR_BAD_OBJ_ID_STR);
384 			goto done;
385 		}
386 		err = send_their_ref(ibuf, id, refname);
387 		if (err)
388 			goto done;
389 
390 		err = got_pathlist_append(&their_refs, refname, id);
391 		if (err)
392 			goto done;
393 
394 		if (chattygot)
395 			fprintf(stderr, "%s: remote has %s %s\n",
396 			    getprogname(), refname, id_str);
397 		free(id_str);
398 		id_str = NULL;
399 		refname = NULL; /* do not free; owned by their_refs */
400 		id = NULL; /* do not free; owned by their_refs */
401 	}
402 
403 	if (!TAILQ_EMPTY(delete_refs)) {
404 		if (my_capabilities == NULL ||
405 		    strstr(my_capabilities, GOT_CAPA_DELETE_REFS) == NULL) {
406 			err = got_error(GOT_ERR_CAPA_DELETE_REFS);
407 			goto done;
408 		}
409 	}
410 
411 	TAILQ_FOREACH(pe, delete_refs, entry) {
412 		const char *refname = pe->path;
413 		struct got_pathlist_entry *their_pe;
414 		struct got_object_id *their_id = NULL;
415 
416 		TAILQ_FOREACH(their_pe, &their_refs, entry) {
417 			const char *their_refname = their_pe->path;
418 			if (got_path_cmp(refname, their_refname,
419 			    strlen(refname), strlen(their_refname)) == 0) {
420 				their_id = their_pe->data;
421 				break;
422 			}
423 		}
424 		if (their_id == NULL) {
425 			err = got_error_fmt(GOT_ERR_NOT_REF,
426 			    "%s does not exist in remote repository",
427 			    refname);
428 			goto done;
429 		}
430 
431 		got_sha1_digest_to_str(their_id->sha1, old_hashstr,
432 		    sizeof(old_hashstr));
433 		got_sha1_digest_to_str(zero_id, new_hashstr,
434 		    sizeof(new_hashstr));
435 		err = describe_refchange(&n, &sent_my_capabilites,
436 		    my_capabilities, buf, sizeof(buf), refname,
437 		    old_hashstr, new_hashstr);
438 		if (err)
439 			goto done;
440 		err = got_pkt_writepkt(fd, buf, n, chattygot);
441 		if (err)
442 			goto done;
443 		if (chattygot) {
444 			fprintf(stderr, "%s: deleting %s %s\n",
445 			    getprogname(), refname, old_hashstr);
446 		}
447 		nsent++;
448 	}
449 
450 	TAILQ_FOREACH(pe, refs, entry) {
451 		const char *refname = pe->path;
452 		struct got_object_id *id = pe->data;
453 		struct got_object_id *their_id = NULL;
454 		struct got_pathlist_entry *their_pe;
455 
456 		TAILQ_FOREACH(their_pe, &their_refs, entry) {
457 			const char *their_refname = their_pe->path;
458 			if (got_path_cmp(refname, their_refname,
459 			    strlen(refname), strlen(their_refname)) == 0) {
460 				their_id = their_pe->data;
461 				break;
462 			}
463 		}
464 		if (their_id) {
465 			if (got_object_id_cmp(id, their_id) == 0) {
466 				if (chattygot) {
467 					fprintf(stderr,
468 					    "%s: no change for %s\n",
469 					    getprogname(), refname);
470 				}
471 				continue;
472 			}
473 			got_sha1_digest_to_str(their_id->sha1, old_hashstr,
474 			    sizeof(old_hashstr));
475 		} else {
476 			got_sha1_digest_to_str(zero_id, old_hashstr,
477 			    sizeof(old_hashstr));
478 		}
479 		got_sha1_digest_to_str(id->sha1, new_hashstr,
480 		    sizeof(new_hashstr));
481 		err = describe_refchange(&n, &sent_my_capabilites,
482 		    my_capabilities, buf, sizeof(buf), refname,
483 		    old_hashstr, new_hashstr);
484 		if (err)
485 			goto done;
486 		err = got_pkt_writepkt(fd, buf, n, chattygot);
487 		if (err)
488 			goto done;
489 		if (chattygot) {
490 			if (their_id) {
491 				fprintf(stderr, "%s: updating %s %s -> %s\n",
492 				    getprogname(), refname, old_hashstr,
493 				    new_hashstr);
494 			} else {
495 				fprintf(stderr, "%s: creating %s %s\n",
496 				    getprogname(), refname, new_hashstr);
497 			}
498 		}
499 		nsent++;
500 	}
501 	err = got_pkt_flushpkt(fd, chattygot);
502 	if (err)
503 		goto done;
504 
505 	err = send_pack_request(ibuf);
506 	if (err)
507 		goto done;
508 
509 	err = recv_packfd(&packfd, ibuf);
510 	if (err)
511 		goto done;
512 
513 	if (packfd != -1) {
514 		err = send_pack_file(fd, packfd, ibuf);
515 		if (err)
516 			goto done;
517 	}
518 
519 	err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
520 	if (err)
521 		goto done;
522 	if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
523 		err = send_error(&buf[4], n - 4);
524 		goto done;
525 	} else if (n < 10 || strncmp(buf, "unpack ok\n", 10) != 0) {
526 		err = got_error_msg(GOT_ERR_BAD_PACKET,
527 		    "unexpected message from server");
528 		goto done;
529 	}
530 
531 	while (nsent > 0) {
532 		err = got_pkt_readpkt(&n, fd, buf, sizeof(buf), chattygot);
533 		if (err)
534 			goto done;
535 		if (n < 3) {
536 			err = got_error_msg(GOT_ERR_BAD_PACKET,
537 			    "unexpected message from server");
538 			goto done;
539 		} else if (n >= 4 && strncmp(buf, "ERR ", 4) == 0) {
540 			err = send_error(&buf[4], n - 4);
541 			goto done;
542 		} else if (strncmp(buf, "ok ", 3) == 0) {
543 			err = send_ref_status(ibuf, buf + 3, 1,
544 			    refs, delete_refs);
545 			if (err)
546 				goto done;
547 		} else if (strncmp(buf, "ng ", 3) == 0) {
548 			err = send_ref_status(ibuf, buf + 3, 0,
549 			    refs, delete_refs);
550 			if (err)
551 				goto done;
552 		} else {
553 			err = got_error_msg(GOT_ERR_BAD_PACKET,
554 			    "unexpected message from server");
555 			goto done;
556 		}
557 		nsent--;
558 	}
559 
560 	err = send_done(ibuf);
561 done:
562 	TAILQ_FOREACH(pe, &their_refs, entry) {
563 		free((void *)pe->path);
564 		free(pe->data);
565 	}
566 	got_pathlist_free(&their_refs);
567 	free(id_str);
568 	free(id);
569 	free(refname);
570 	free(server_capabilities);
571 	return err;
572 }
573 
574 int
575 main(int argc, char **argv)
576 {
577 	const struct got_error *err = NULL;
578 	int sendfd;
579 	struct imsgbuf ibuf;
580 	struct imsg imsg;
581 	struct got_pathlist_head refs;
582 	struct got_pathlist_head delete_refs;
583 	struct got_pathlist_entry *pe;
584 	struct got_imsg_send_request send_req;
585 	struct got_imsg_send_ref href;
586 	size_t datalen, i;
587 #if 0
588 	static int attached;
589 	while (!attached)
590 		sleep (1);
591 #endif
592 
593 	TAILQ_INIT(&refs);
594 	TAILQ_INIT(&delete_refs);
595 
596 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
597 #ifndef PROFILE
598 	/* revoke access to most system calls */
599 	if (pledge("stdio recvfd", NULL) == -1) {
600 		err = got_error_from_errno("pledge");
601 		got_privsep_send_error(&ibuf, err);
602 		return 1;
603 	}
604 #endif
605 	if ((err = got_privsep_recv_imsg(&imsg, &ibuf, 0)) != 0) {
606 		if (err->code == GOT_ERR_PRIVSEP_PIPE)
607 			err = NULL;
608 		goto done;
609 	}
610 	if (imsg.hdr.type == GOT_IMSG_STOP)
611 		goto done;
612 	if (imsg.hdr.type != GOT_IMSG_SEND_REQUEST) {
613 		err = got_error(GOT_ERR_PRIVSEP_MSG);
614 		goto done;
615 	}
616 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
617 	if (datalen < sizeof(send_req)) {
618 		err = got_error(GOT_ERR_PRIVSEP_LEN);
619 		goto done;
620 	}
621 	memcpy(&send_req, imsg.data, sizeof(send_req));
622 	sendfd = imsg.fd;
623 	imsg_free(&imsg);
624 
625 	if (send_req.verbosity > 0)
626 		chattygot += send_req.verbosity;
627 
628 	for (i = 0; i < send_req.nrefs; i++) {
629 		struct got_object_id *id;
630 		char *refname;
631 
632 		if ((err = got_privsep_recv_imsg(&imsg, &ibuf, 0)) != 0) {
633 			if (err->code == GOT_ERR_PRIVSEP_PIPE)
634 				err = NULL;
635 			goto done;
636 		}
637 		if (imsg.hdr.type == GOT_IMSG_STOP)
638 			goto done;
639 		if (imsg.hdr.type != GOT_IMSG_SEND_REF) {
640 			err = got_error(GOT_ERR_PRIVSEP_MSG);
641 			goto done;
642 		}
643 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
644 		if (datalen < sizeof(href)) {
645 			err = got_error(GOT_ERR_PRIVSEP_LEN);
646 			goto done;
647 		}
648 		memcpy(&href, imsg.data, sizeof(href));
649 		if (datalen - sizeof(href) < href.name_len) {
650 			err = got_error(GOT_ERR_PRIVSEP_LEN);
651 			goto done;
652 		}
653 		refname = malloc(href.name_len + 1);
654 		if (refname == NULL) {
655 			err = got_error_from_errno("malloc");
656 			goto done;
657 		}
658 		memcpy(refname, imsg.data + sizeof(href), href.name_len);
659 		refname[href.name_len] = '\0';
660 
661 		/*
662 		 * Prevent sending of references that won't make any
663 		 * sense outside the local repository's context.
664 		 */
665 		if (strncmp(refname, "refs/got/", 9) == 0 ||
666 		    strncmp(refname, "refs/remotes/", 13) == 0) {
667 			err = got_error_fmt(GOT_ERR_SEND_BAD_REF,
668 			    "%s", refname);
669 			goto done;
670 		}
671 
672 		id = malloc(sizeof(*id));
673 		if (id == NULL) {
674 			free(refname);
675 			err = got_error_from_errno("malloc");
676 			goto done;
677 		}
678 		memcpy(id->sha1, href.id, SHA1_DIGEST_LENGTH);
679 		if (href.delete)
680 			err = got_pathlist_append(&delete_refs, refname, id);
681 		else
682 			err = got_pathlist_append(&refs, refname, id);
683 		if (err) {
684 			free(refname);
685 			free(id);
686 			goto done;
687 		}
688 
689 		imsg_free(&imsg);
690 	}
691 
692 	err = send_pack(sendfd, &refs, &delete_refs, &ibuf);
693 done:
694 	TAILQ_FOREACH(pe, &refs, entry) {
695 		free((char *)pe->path);
696 		free(pe->data);
697 	}
698 	got_pathlist_free(&refs);
699 	TAILQ_FOREACH(pe, &delete_refs, entry) {
700 		free((char *)pe->path);
701 		free(pe->data);
702 	}
703 	got_pathlist_free(&delete_refs);
704 	if (sendfd != -1 && close(sendfd) == -1 && err == NULL)
705 		err = got_error_from_errno("close");
706 	if (err != NULL && err->code != GOT_ERR_CANCELLED)  {
707 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
708 		got_privsep_send_error(&ibuf, err);
709 	}
710 
711 	exit(0);
712 }