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Date:: Mon Apr 23 16:59:39 2018 UTC
Message:: in got_privsep_recv_tree_obj() free tree upon imsg_read() error
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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 
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <errno.h>
25 #include <stdint.h>
26 #include <poll.h>
27 #include <imsg.h>
28 #include <sha1.h>
29 #include <zlib.h>
30 
31 #include "got_object.h"
32 #include "got_error.h"
33 
34 #include "got_lib_sha1.h"
35 #include "got_lib_delta.h"
36 #include "got_lib_zbuf.h"
37 #include "got_lib_object.h"
38 #include "got_lib_privsep.h"
39 
40 #ifndef MIN
41 #define	MIN(_a,_b) ((_a) < (_b) ? (_a) : (_b))
42 #endif
43 
44 static const struct got_error *
45 poll_fd(int fd, int events, int timeout)
46 {
47 	struct pollfd pfd[1];
48 	int n;
49 
50 	pfd[0].fd = fd;
51 	pfd[0].events = events;
52 
53 	n = poll(pfd, 1, timeout);
54 	if (n == -1)
55 		return got_error_from_errno();
56 	if (n == 0)
57 		return got_error(GOT_ERR_TIMEOUT);
58 	if (pfd[0].revents & (POLLERR | POLLNVAL))
59 		return got_error_from_errno();
60 	if (pfd[0].revents & (events | POLLHUP))
61 		return NULL;
62 
63 	return got_error(GOT_ERR_INTERRUPT);
64 }
65 
66 static const struct got_error *
67 read_imsg(struct imsgbuf *ibuf)
68 {
69 	const struct got_error *err;
70 	size_t n;
71 
72 	err = poll_fd(ibuf->fd, POLLIN, INFTIM);
73 	if (err)
74 		return err;
75 
76 	n = imsg_read(ibuf);
77 	if (n == -1) {
78 		if (errno == EAGAIN) /* Could be a file-descriptor leak. */
79 			return got_error(GOT_ERR_PRIVSEP_NO_FD);
80 		return got_error(GOT_ERR_PRIVSEP_READ);
81 	}
82 	if (n == 0)
83 		return got_error(GOT_ERR_PRIVSEP_PIPE);
84 
85 	return NULL;
86 }
87 
88 static const struct got_error *
89 recv_one_imsg(struct imsg *imsg, struct imsgbuf *ibuf, size_t min_datalen)
90 {
91 	const struct got_error *err;
92 	ssize_t n;
93 
94 	err = read_imsg(ibuf);
95 	if (err)
96 		return err;
97 
98 	n = imsg_get(ibuf, imsg);
99 	if (n == 0)
100 		return got_error(GOT_ERR_PRIVSEP_READ);
101 
102 	if (imsg->hdr.len < IMSG_HEADER_SIZE + min_datalen)
103 		return got_error(GOT_ERR_PRIVSEP_LEN);
104 
105 	return NULL;
106 }
107 
108 static const struct got_error *
109 recv_imsg_error(struct imsg *imsg, size_t datalen)
110 {
111 	struct got_imsg_error ierr;
112 
113 	if (datalen != sizeof(ierr))
114 		return got_error(GOT_ERR_PRIVSEP_LEN);
115 
116 	memcpy(&ierr, imsg->data, sizeof(ierr));
117 	if (ierr.code == GOT_ERR_ERRNO) {
118 		static struct got_error serr;
119 		serr.code = GOT_ERR_ERRNO;
120 		serr.msg = strerror(ierr.errno_code);
121 		return &serr;
122 	}
123 
124 	return got_error(ierr.code);
125 }
126 
127 /* Attempt to send an error in an imsg. Complain on stderr as a last resort. */
128 void
129 got_privsep_send_error(struct imsgbuf *ibuf, const struct got_error *err)
130 {
131 	const struct got_error *poll_err;
132 	struct got_imsg_error ierr;
133 	int ret;
134 
135 	ierr.code = err->code;
136 	if (err->code == GOT_ERR_ERRNO)
137 		ierr.errno_code = errno;
138 	else
139 		ierr.errno_code = 0;
140 	ret = imsg_compose(ibuf, GOT_IMSG_ERROR, 0, 0, -1, &ierr, sizeof(ierr));
141 	if (ret != -1) {
142 		fprintf(stderr, "%s: error %d \"%s\": imsg_compose: %s\n",
143 		    getprogname(), err->code, err->msg, strerror(errno));
144 		return;
145 	}
146 
147 	poll_err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
148 	if (poll_err) {
149 		fprintf(stderr, "%s: error %d \"%s\": poll: %s\n",
150 		    getprogname(), err->code, err->msg, poll_err->msg);
151 		return;
152 	}
153 
154 	ret = imsg_flush(ibuf);
155 	if (ret == -1) {
156 		fprintf(stderr, "%s: error %d \"%s\": imsg_flush: %s\n",
157 		    getprogname(), err->code, err->msg, strerror(errno));
158 		return;
159 	}
160 }
161 
162 static const struct got_error *
163 flush_imsg(struct imsgbuf *ibuf)
164 {
165 	const struct got_error *err;
166 
167 	err = poll_fd(ibuf->fd, POLLOUT, INFTIM);
168 	if (err)
169 		return err;
170 
171 	if (imsg_flush(ibuf) == -1)
172 		return got_error_from_errno();
173 
174 	return NULL;
175 }
176 
177 const struct got_error *
178 got_privsep_send_obj(struct imsgbuf *ibuf, struct got_object *obj, int ndeltas)
179 {
180 	struct got_imsg_object iobj;
181 
182 	iobj.type = obj->type;
183 	iobj.flags = obj->flags;
184 	iobj.hdrlen = obj->hdrlen;
185 	iobj.size = obj->size;
186 	iobj.ndeltas = ndeltas;
187 
188 	if (ndeltas > 0) {
189 		/* TODO: Handle deltas */
190 	}
191 
192 	if (imsg_compose(ibuf, GOT_IMSG_OBJECT, 0, 0, -1, &iobj, sizeof(iobj))
193 	    == -1)
194 		return got_error_from_errno();
195 
196 	return flush_imsg(ibuf);
197 }
198 
199 const struct got_error *
200 got_privsep_recv_obj(struct got_object **obj, struct imsgbuf *ibuf)
201 {
202 	const struct got_error *err = NULL;
203 	struct imsg imsg;
204 	struct got_imsg_object iobj;
205 	size_t datalen;
206 	int i;
207 	const size_t min_datalen =
208 	    MIN(sizeof(struct got_imsg_error), sizeof(struct got_imsg_object));
209 
210 	*obj = NULL;
211 
212 	err = recv_one_imsg(&imsg, ibuf, min_datalen);
213 	if (err)
214 		return err;
215 
216 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
217 
218 	switch (imsg.hdr.type) {
219 	case GOT_IMSG_ERROR:
220 		err = recv_imsg_error(&imsg, datalen);
221 		break;
222 	case GOT_IMSG_OBJECT:
223 		if (datalen != sizeof(iobj)) {
224 			err = got_error(GOT_ERR_PRIVSEP_LEN);
225 			break;
226 		}
227 
228 		memcpy(&iobj, imsg.data, sizeof(iobj));
229 		if (iobj.ndeltas < 0 ||
230 		    iobj.ndeltas > GOT_DELTA_CHAIN_RECURSION_MAX) {
231 			err = got_error(GOT_ERR_PRIVSEP_LEN);
232 			break;
233 		}
234 
235 		*obj = calloc(1, sizeof(**obj));
236 		if (*obj == NULL) {
237 			err = got_error_from_errno();
238 			break;
239 		}
240 
241 		(*obj)->type = iobj.type;
242 		(*obj)->hdrlen = iobj.hdrlen;
243 		(*obj)->size = iobj.size;
244 		for (i = 0; i < iobj.ndeltas; i++) {
245 			/* TODO: Handle deltas */
246 		}
247 		break;
248 	default:
249 		err = got_error(GOT_ERR_PRIVSEP_MSG);
250 		break;
251 	}
252 
253 	imsg_free(&imsg);
254 
255 	return err;
256 }
257 
258 const struct got_error *
259 got_privsep_send_commit_obj(struct imsgbuf *ibuf, struct got_commit_object *commit)
260 {
261 	const struct got_error *err = NULL;
262 	struct got_imsg_commit_object icommit;
263 	uint8_t *buf;
264 	size_t len, total;
265 	struct got_parent_id *pid;
266 
267 	memcpy(icommit.tree_id, commit->tree_id->sha1, sizeof(icommit.tree_id));
268 	icommit.author_len = strlen(commit->author);
269 	icommit.committer_len = strlen(commit->committer);
270 	icommit.logmsg_len = strlen(commit->logmsg);
271 	icommit.nparents = commit->nparents;
272 
273 	total = sizeof(icommit) + icommit.author_len +
274 	    icommit.committer_len + icommit.logmsg_len +
275 	    icommit.nparents * SHA1_DIGEST_LENGTH;
276 	/* XXX TODO support very large log messages properly */
277 	if (total > MAX_IMSGSIZE)
278 		return got_error(GOT_ERR_NO_SPACE);
279 
280 	buf = malloc(total);
281 	if (buf == NULL)
282 		return got_error_from_errno();
283 
284 	len = 0;
285 	memcpy(buf + len, &icommit, sizeof(icommit));
286 	len += sizeof(icommit);
287 	memcpy(buf + len, commit->author, icommit.author_len);
288 	len += icommit.author_len;
289 	memcpy(buf + len, commit->committer, icommit.committer_len);
290 	len += icommit.committer_len;
291 	memcpy(buf + len, commit->logmsg, icommit.logmsg_len);
292 	len += icommit.logmsg_len;
293 	SIMPLEQ_FOREACH(pid, &commit->parent_ids, entry) {
294 		memcpy(buf + len, pid->id, SHA1_DIGEST_LENGTH);
295 		len += SHA1_DIGEST_LENGTH;
296 	}
297 
298 	if (imsg_compose(ibuf, GOT_IMSG_COMMIT, 0, 0, -1, buf, len) == -1) {
299 		err = got_error_from_errno();
300 		goto done;
301 	}
302 
303 	err = flush_imsg(ibuf);
304 done:
305 	free(buf);
306 	return err;
307 }
308 const struct got_error *
309 got_privsep_recv_commit_obj(struct got_commit_object **commit,
310     struct imsgbuf *ibuf)
311 {
312 	const struct got_error *err = NULL;
313 	struct imsg imsg;
314 	struct got_imsg_commit_object icommit;
315 	size_t len, datalen;
316 	int i;
317 	const size_t min_datalen =
318 	    MIN(sizeof(struct got_imsg_error),
319 	    sizeof(struct got_imsg_commit_object));
320 	uint8_t *data;
321 
322 	*commit = NULL;
323 
324 	err = recv_one_imsg(&imsg, ibuf, min_datalen);
325 	if (err)
326 		return err;
327 
328 	data = imsg.data;
329 	datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
330 	len = 0;
331 
332 	switch (imsg.hdr.type) {
333 	case GOT_IMSG_ERROR:
334 		err = recv_imsg_error(&imsg, datalen);
335 		break;
336 	case GOT_IMSG_COMMIT:
337 		if (datalen < sizeof(icommit)) {
338 			err = got_error(GOT_ERR_PRIVSEP_LEN);
339 			break;
340 		}
341 
342 		memcpy(&icommit, data, sizeof(icommit));
343 		if (datalen != sizeof(icommit) + icommit.author_len +
344 		    icommit.committer_len + icommit.logmsg_len +
345 		    icommit.nparents * SHA1_DIGEST_LENGTH) {
346 			err = got_error(GOT_ERR_PRIVSEP_LEN);
347 			break;
348 		}
349 		if (icommit.nparents < 0) {
350 			err = got_error(GOT_ERR_PRIVSEP_LEN);
351 			break;
352 		}
353 		len += sizeof(icommit);
354 
355 		*commit = got_object_commit_alloc_partial();
356 		if (*commit == NULL) {
357 			err = got_error_from_errno();
358 			break;
359 		}
360 
361 		memcpy((*commit)->tree_id->sha1, icommit.tree_id,
362 		    SHA1_DIGEST_LENGTH);
363 
364 		if (icommit.author_len == 0) {
365 			(*commit)->author = strdup("");
366 			if ((*commit)->author == NULL) {
367 				err = got_error_from_errno();
368 				break;
369 			}
370 		} else {
371 			(*commit)->author = malloc(icommit.author_len + 1);
372 			if ((*commit)->author == NULL) {
373 				err = got_error_from_errno();
374 				break;
375 			}
376 			memcpy((*commit)->author, data + len,
377 			    icommit.author_len);
378 			(*commit)->author[icommit.author_len] = '\0';
379 		}
380 		len += icommit.author_len;
381 
382 		if (icommit.committer_len == 0) {
383 			(*commit)->committer = strdup("");
384 			if ((*commit)->committer == NULL) {
385 				err = got_error_from_errno();
386 				break;
387 			}
388 		} else {
389 			(*commit)->committer =
390 			    malloc(icommit.committer_len + 1);
391 			if ((*commit)->committer == NULL) {
392 				err = got_error_from_errno();
393 				break;
394 			}
395 			memcpy((*commit)->committer, data + len,
396 			    icommit.committer_len);
397 			(*commit)->committer[icommit.committer_len] = '\0';
398 		}
399 		len += icommit.committer_len;
400 
401 		if (icommit.logmsg_len == 0) {
402 			(*commit)->logmsg = strdup("");
403 			if ((*commit)->logmsg == NULL) {
404 				err = got_error_from_errno();
405 				break;
406 			}
407 		} else {
408 			(*commit)->logmsg = malloc(icommit.logmsg_len + 1);
409 			if ((*commit)->logmsg == NULL) {
410 				err = got_error_from_errno();
411 				break;
412 			}
413 			memcpy((*commit)->logmsg, data + len,
414 			    icommit.logmsg_len);
415 			(*commit)->logmsg[icommit.logmsg_len] = '\0';
416 		}
417 		len += icommit.logmsg_len;
418 
419 		for (i = 0; i < icommit.nparents; i++) {
420 			struct got_parent_id *pid;
421 
422 			pid = calloc(1, sizeof(*pid));
423 			if (pid == NULL) {
424 				err = got_error_from_errno();
425 				break;
426 			}
427 			pid->id = calloc(1, sizeof(*pid->id));
428 			if (pid->id == NULL) {
429 				err = got_error_from_errno();
430 				free(pid);
431 				break;
432 			}
433 
434 			memcpy(pid->id, data + len + i * SHA1_DIGEST_LENGTH,
435 			    sizeof(*pid->id));
436 			SIMPLEQ_INSERT_TAIL(&(*commit)->parent_ids, pid, entry);
437 			(*commit)->nparents++;
438 		}
439 		break;
440 	default:
441 		err = got_error(GOT_ERR_PRIVSEP_MSG);
442 		break;
443 	}
444 
445 	imsg_free(&imsg);
446 
447 	return err;
448 }
449 
450 const struct got_error *
451 got_privsep_send_tree_obj(struct imsgbuf *ibuf, struct got_tree_object *tree)
452 {
453 	const struct got_error *err = NULL;
454 	struct got_imsg_tree_object itree;
455 	struct got_tree_entry *te;
456 
457 	itree.nentries = tree->nentries;
458 	if (imsg_compose(ibuf, GOT_IMSG_TREE, 0, 0, -1, &itree, sizeof(itree))
459 	    == -1)
460 		return got_error_from_errno();
461 
462 	err = flush_imsg(ibuf);
463 	if (err)
464 		return err;
465 
466 	SIMPLEQ_FOREACH(te, &tree->entries, entry) {
467 		struct got_imsg_tree_entry ite;
468 		uint8_t *buf = NULL;
469 		size_t len = sizeof(ite) + strlen(te->name);
470 
471 		if (len > MAX_IMSGSIZE)
472 			return got_error(GOT_ERR_NO_SPACE);
473 
474 		buf = malloc(len);
475 		if (buf == NULL)
476 			return got_error_from_errno();
477 
478 		memcpy(ite.id, te->id->sha1, sizeof(ite.id));
479 		ite.mode = te->mode;
480 		memcpy(buf, &ite, sizeof(ite));
481 		memcpy(buf + sizeof(ite), te->name, strlen(te->name));
482 
483 		if (imsg_compose(ibuf, GOT_IMSG_TREE_ENTRY, 0, 0, -1,
484 		    buf, len) == -1)
485 			err = got_error_from_errno();
486 		free(buf);
487 		if (err)
488 			return err;
489 
490 		err = flush_imsg(ibuf);
491 		if (err)
492 			return err;
493 	}
494 
495 	return NULL;
496 }
497 
498 const struct got_error *
499 got_privsep_recv_tree_obj(struct got_tree_object **tree, struct imsgbuf *ibuf)
500 {
501 	const struct got_error *err = NULL;
502 	const size_t min_datalen =
503 	    MIN(sizeof(struct got_imsg_error),
504 	    sizeof(struct got_imsg_tree_object));
505 	struct got_imsg_tree_object itree = { 0 };
506 	int nentries = 0;
507 
508 	*tree = NULL;
509 get_more:
510 	err = read_imsg(ibuf);
511 	if (err)
512 		goto done;
513 
514 	while (1) {
515 		struct imsg imsg;
516 		size_t n;
517 		size_t datalen;
518 		struct got_imsg_tree_entry ite;
519 		struct got_tree_entry *te = NULL;
520 
521 		n = imsg_get(ibuf, &imsg);
522 		if (n == 0) {
523 			if (*tree && (*tree)->nentries != nentries)
524 				goto get_more;
525 			break;
526 		}
527 
528 		if (imsg.hdr.len < IMSG_HEADER_SIZE + min_datalen)
529 			return got_error(GOT_ERR_PRIVSEP_LEN);
530 
531 		datalen = imsg.hdr.len - IMSG_HEADER_SIZE;
532 
533 		switch (imsg.hdr.type) {
534 		case GOT_IMSG_ERROR:
535 			err = recv_imsg_error(&imsg, datalen);
536 			break;
537 		case GOT_IMSG_TREE:
538 			/* This message should only appear once. */
539 			if (*tree != NULL) {
540 				err = got_error(GOT_ERR_PRIVSEP_MSG);
541 				break;
542 			}
543 			if (datalen != sizeof(itree)) {
544 				err = got_error(GOT_ERR_PRIVSEP_LEN);
545 				break;
546 			}
547 			memcpy(&itree, imsg.data, sizeof(itree));
548 			*tree = calloc(1, sizeof(**tree));
549 			if (*tree == NULL) {
550 				err = got_error_from_errno();
551 				break;
552 			}
553 			(*tree)->nentries = itree.nentries;
554 			SIMPLEQ_INIT(&(*tree)->entries);
555 			break;
556 		case GOT_IMSG_TREE_ENTRY:
557 			/* This message should be preceeded by GOT_IMSG_TREE. */
558 			if (*tree == NULL) {
559 				err = got_error(GOT_ERR_PRIVSEP_MSG);
560 				break;
561 			}
562 			if (datalen < sizeof(ite) || datalen > MAX_IMSGSIZE) {
563 				err = got_error(GOT_ERR_PRIVSEP_LEN);
564 				break;
565 			}
566 
567 			/* Remaining data contains the entry's name. */
568 			datalen -= sizeof(ite);
569 			memcpy(&ite, imsg.data, sizeof(ite));
570 			if (datalen == 0 || datalen > MAX_IMSGSIZE) {
571 				err = got_error(GOT_ERR_PRIVSEP_LEN);
572 				break;
573 			}
574 
575 			te = got_alloc_tree_entry_partial();
576 			if (te == NULL) {
577 				err = got_error_from_errno();
578 				break;
579 			}
580 			te->name = malloc(datalen + 1);
581 			if (te->name == NULL) {
582 				free(te);
583 				err = got_error_from_errno();
584 				break;
585 			}
586 			memcpy(te->name, imsg.data + sizeof(ite), datalen);
587 			te->name[datalen] = '\0';
588 
589 			memcpy(te->id->sha1, ite.id, SHA1_DIGEST_LENGTH);
590 			te->mode = ite.mode;
591 			SIMPLEQ_INSERT_TAIL(&(*tree)->entries, te, entry);
592 			nentries++;
593 			break;
594 		default:
595 			err = got_error(GOT_ERR_PRIVSEP_MSG);
596 			break;
597 		}
598 
599 		imsg_free(&imsg);
600 	}
601 done:
602 	if (*tree && (*tree)->nentries != nentries) {
603 		if (err == NULL)
604 			err = got_error(GOT_ERR_PRIVSEP_LEN);
605 		got_object_tree_close(*tree);
606 		*tree = NULL;
607 	}
608 
609 	return err;
610 }