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Date:: Thu Jul 7 22:16:43 2022 UTC
Message:: use got_privsep_flush_imsg instead of reinventing it ok stsp@
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1 /*
2  * Copyright 1986, Larry Wall
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following condition is met:
6  * 1. Redistributions of source code must retain the above copyright notice,
7  * this condition and the following disclaimer.
8  *
9  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND ANY
10  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
11  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
12  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
13  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
14  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
15  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
16  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
17  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
18  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
19  * SUCH DAMAGE.
20  */
21 
22 /*
23  * Copyright (c) 2022 Omar Polo <op@openbsd.org>
24  *
25  * Permission to use, copy, modify, and distribute this software for any
26  * purpose with or without fee is hereby granted, provided that the above
27  * copyright notice and this permission notice appear in all copies.
28  *
29  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
30  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
31  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
32  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
33  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
34  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
35  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
36  */
37 
38 #include <sys/types.h>
39 #include <sys/uio.h>
40 
41 #include <ctype.h>
42 #include <limits.h>
43 #include <paths.h>
44 #include <stdint.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <unistd.h>
49 
50 #include "got_error.h"
51 #include "got_object.h"
52 
53 #include "got_compat.h"
54 
55 #include "got_lib_delta.h"
56 #include "got_lib_object.h"
57 #include "got_lib_privsep.h"
58 #include "got_lib_sha1.h"
59 
60 struct imsgbuf ibuf;
61 
62 static const struct got_error *
63 send_patch(const char *oldname, const char *newname, const char *commitid,
64     const char *blob, int git)
65 {
66 	struct got_imsg_patch p;
67 
68 	memset(&p, 0, sizeof(p));
69 
70 	if (oldname != NULL)
71 		strlcpy(p.old, oldname, sizeof(p.old));
72 
73 	if (newname != NULL)
74 		strlcpy(p.new, newname, sizeof(p.new));
75 
76 	if (commitid != NULL)
77 		strlcpy(p.cid, commitid, sizeof(p.cid));
78 
79 	if (blob != NULL)
80 		strlcpy(p.blob, blob, sizeof(p.blob));
81 
82 	p.git = git;
83 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH, 0, 0, -1, &p, sizeof(p)) == -1)
84 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH");
85 	return NULL;
86 }
87 
88 static const struct got_error *
89 send_patch_done(void)
90 {
91 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_DONE, 0, 0, -1,
92 	    NULL, 0) == -1)
93 		return got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
94 	return got_privsep_flush_imsg(&ibuf);
95 }
96 
97 /* based on fetchname from usr.bin/patch/util.c */
98 static const struct got_error *
99 filename(const char *at, char **name)
100 {
101 	char	*tmp, *t;
102 
103 	*name = NULL;
104 	if (*at == '\0')
105 		return NULL;
106 
107 	while (isspace((unsigned char)*at))
108 		at++;
109 
110 	/* files can be created or removed by diffing against /dev/null */
111 	if (!strncmp(at, _PATH_DEVNULL, sizeof(_PATH_DEVNULL) - 1))
112 		return NULL;
113 
114 	tmp = strdup(at);
115 	if (tmp == NULL)
116 		return got_error_from_errno("strdup");
117 	if ((t = strchr(tmp, '\t')) != NULL)
118 		*t = '\0';
119 	if ((t = strchr(tmp, '\n')) != NULL)
120 		*t = '\0';
121 
122 	*name = strdup(tmp);
123 	free(tmp);
124 	if (*name == NULL)
125 		return got_error_from_errno("strdup");
126 	return NULL;
127 }
128 
129 static const struct got_error *
130 blobid(const char *line, char **blob, int git)
131 {
132 	uint8_t digest[SHA1_DIGEST_LENGTH];
133 	size_t len;
134 
135 	*blob = NULL;
136 
137 	len = strspn(line, "0123456789abcdefABCDEF");
138 	if ((*blob = strndup(line, len)) == NULL)
139 		return got_error_from_errno("strndup");
140 
141 	if (!git && !got_parse_sha1_digest(digest, *blob)) {
142 		/* silently ignore invalid blob ids */
143 		free(*blob);
144 		*blob = NULL;
145 	}
146 	return NULL;
147 }
148 
149 static const struct got_error *
150 patch_start(int *git, char **cid, FILE *fp)
151 {
152 	const struct got_error *err = NULL;
153 	char	*line = NULL;
154 	size_t	 linesize = 0;
155 	ssize_t	 linelen;
156 
157 	*git = 0;
158 
159 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
160 		if (!strncmp(line, "diff --git ", 11)) {
161 			*git = 1;
162 			free(*cid);
163 			*cid = NULL;
164 			break;
165 		} else if (!strncmp(line, "diff ", 5)) {
166 			*git = 0;
167 			free(*cid);
168 			*cid = NULL;
169 		} else if (!strncmp(line, "commit - ", 9)) {
170 			free(*cid);
171 			err = blobid(line + 9, cid, *git);
172 			if (err)
173 				break;
174 		} else if (!strncmp(line, "--- ", 4) ||
175 		    !strncmp(line, "+++ ", 4) ||
176 		    !strncmp(line, "blob - ", 7)) {
177 			/* rewind to previous line */
178 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
179 				err = got_error_from_errno("fseeko");
180 			break;
181 		}
182 	}
183 
184 	free(line);
185 	if (ferror(fp) && err == NULL)
186 		err = got_error_from_errno("getline");
187 	if (feof(fp) && err == NULL)
188 		err = got_error(GOT_ERR_NO_PATCH);
189 	return err;
190 }
191 
192 static const struct got_error *
193 find_diff(int *done, int *next, FILE *fp, int git, const char *commitid)
194 {
195 	const struct got_error *err = NULL;
196 	char	*old = NULL, *new = NULL;
197 	char	*blob = NULL;
198 	char	*line = NULL;
199 	size_t	 linesize = 0;
200 	ssize_t	 linelen;
201 	int	 create, rename = 0;
202 
203 	*done = 0;
204 	*next = 0;
205 	while ((linelen = getline(&line, &linesize, fp)) != -1) {
206 		/*
207 		 * Ignore the Index name like GNU and larry' patch,
208 		 * we don't have to follow POSIX.
209 		 */
210 
211 		if (!strncmp(line, "--- ", 4)) {
212 			free(old);
213 			err = filename(line+4, &old);
214 		} else if (rename && !strncmp(line, "rename from ", 12)) {
215 			free(old);
216 			err = filename(line+12, &old);
217 		} else if (!strncmp(line, "+++ ", 4)) {
218 			free(new);
219 			err = filename(line+4, &new);
220 		} else if (!git && !strncmp(line, "blob - ", 7)) {
221 			free(blob);
222 			err = blobid(line + 7, &blob, git);
223 		} else if (rename && !strncmp(line, "rename to ", 10)) {
224 			free(new);
225 			err = filename(line + 10, &new);
226 		} else if (git && !strncmp(line, "similarity index 100%", 21))
227 			rename = 1;
228 		else if (git && !strncmp(line, "index ", 6)) {
229 			free(blob);
230 			err = blobid(line + 6, &blob, git);
231 		} else if (!strncmp(line, "diff ", 5)) {
232 			/* rewind to previous line */
233 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
234 				err = got_error_from_errno("fseeko");
235 			*next = 1;
236 			break;
237 		}
238 
239 		if (err)
240 			break;
241 
242 		/*
243 		 * Git-style diffs with "similarity index 100%" don't
244 		 * have any hunks and ends with the "rename to foobar"
245 		 * line.
246 		 */
247 		if (rename && old != NULL && new != NULL) {
248 			*done = 1;
249 			err = send_patch(old, new, commitid,
250 			    blob, git);
251 			break;
252 		}
253 
254 		if (!strncmp(line, "@@ -", 4)) {
255 			create = !strncmp(line+4, "0,0", 3);
256 			if ((old == NULL && new == NULL) ||
257 			    (!create && old == NULL))
258 				err = got_error(GOT_ERR_PATCH_MALFORMED);
259 			else
260 				err = send_patch(old, new, commitid,
261 				    blob, git);
262 
263 			if (err)
264 				break;
265 
266 			/* rewind to previous line */
267 			if (fseeko(fp, -linelen, SEEK_CUR) == -1)
268 				err = got_error_from_errno("fseeko");
269 			break;
270 		}
271 	}
272 
273 	free(old);
274 	free(new);
275 	free(blob);
276 	free(line);
277 	if (ferror(fp) && err == NULL)
278 		err = got_error_from_errno("getline");
279 	if (feof(fp) && err == NULL)
280 		err = got_error(GOT_ERR_NO_PATCH);
281 	return err;
282 }
283 
284 static const struct got_error *
285 strtolnum(char **str, int *n)
286 {
287 	char		*p, c;
288 	const char	*errstr;
289 
290 	for (p = *str; isdigit((unsigned char)*p); ++p)
291 		/* nop */;
292 
293 	c = *p;
294 	*p = '\0';
295 
296 	*n = strtonum(*str, 0, INT_MAX, &errstr);
297 	if (errstr != NULL)
298 		return got_error(GOT_ERR_PATCH_MALFORMED);
299 
300 	*p = c;
301 	*str = p;
302 	return NULL;
303 }
304 
305 static const struct got_error *
306 parse_hdr(char *s, int *done, struct got_imsg_patch_hunk *hdr)
307 {
308 	static const struct got_error *err = NULL;
309 
310 	if (strncmp(s, "@@ -", 4)) {
311 		*done = 1;
312 		return NULL;
313 	}
314 
315 	s += 4;
316 	if (!*s)
317 		return NULL;
318 	err = strtolnum(&s, &hdr->oldfrom);
319 	if (err)
320 		return err;
321 	if (*s == ',') {
322 		s++;
323 		err = strtolnum(&s, &hdr->oldlines);
324 		if (err)
325 			return err;
326 	} else
327 		hdr->oldlines = 1;
328 
329 	if (*s == ' ')
330 		s++;
331 
332 	if (*s != '+' || !*++s)
333 		return got_error(GOT_ERR_PATCH_MALFORMED);
334 	err = strtolnum(&s, &hdr->newfrom);
335 	if (err)
336 		return err;
337 	if (*s == ',') {
338 		s++;
339 		err = strtolnum(&s, &hdr->newlines);
340 		if (err)
341 			return err;
342 	} else
343 		hdr->newlines = 1;
344 
345 	if (*s == ' ')
346 		s++;
347 
348 	if (*s != '@')
349 		return got_error(GOT_ERR_PATCH_MALFORMED);
350 
351 	if (hdr->oldfrom >= INT_MAX - hdr->oldlines ||
352 	    hdr->newfrom >= INT_MAX - hdr->newlines ||
353 	    /* not so sure about this one */
354 	    hdr->oldlines >= INT_MAX - hdr->newlines - 1 ||
355 	    (hdr->oldlines == 0 && hdr->newlines == 0))
356 		return got_error(GOT_ERR_PATCH_MALFORMED);
357 
358 	if (hdr->oldlines == 0) {
359 		/* larry says to "do append rather than insert"; I don't
360 		 * quite get it, but i trust him.
361 		 */
362 		hdr->oldfrom++;
363 	}
364 
365 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_HUNK, 0, 0, -1,
366 	    hdr, sizeof(*hdr)) == -1)
367 		return got_error_from_errno(
368 		    "imsg_compose GOT_IMSG_PATCH_HUNK");
369 	return NULL;
370 }
371 
372 static const struct got_error *
373 send_line(const char *line)
374 {
375 	static const struct got_error *err = NULL;
376 	char *p = NULL;
377 
378 	if (*line != '+' && *line != '-' && *line != ' ' && *line != '\\') {
379 		if (asprintf(&p, " %s", line) == -1)
380 			return got_error_from_errno("asprintf");
381 		line = p;
382 	}
383 
384 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_LINE, 0, 0, -1,
385 	    line, strlen(line) + 1) == -1)
386 		err = got_error_from_errno(
387 		    "imsg_compose GOT_IMSG_PATCH_LINE");
388 
389 	free(p);
390 	return err;
391 }
392 
393 static const struct got_error *
394 peek_special_line(FILE *fp)
395 {
396 	const struct got_error *err;
397 	int ch;
398 
399 	ch = fgetc(fp);
400 	if (ch != EOF && ch != '\\') {
401 		ungetc(ch, fp);
402 		return NULL;
403 	}
404 
405 	if (ch == '\\') {
406 		err = send_line("\\");
407 		if (err)
408 			return err;
409 	}
410 
411 	while (ch != EOF && ch != '\n')
412 		ch = fgetc(fp);
413 
414 	if (ch != EOF || feof(fp))
415 		return NULL;
416 	return got_error(GOT_ERR_IO);
417 }
418 
419 static const struct got_error *
420 parse_hunk(FILE *fp, int *done)
421 {
422 	static const struct got_error *err = NULL;
423 	struct got_imsg_patch_hunk hdr;
424 	char	*line = NULL, ch;
425 	size_t	 linesize = 0;
426 	ssize_t	 linelen;
427 	int	 leftold, leftnew;
428 
429 	linelen = getline(&line, &linesize, fp);
430 	if (linelen == -1) {
431 		*done = 1;
432 		goto done;
433 	}
434 
435 	err = parse_hdr(line, done, &hdr);
436 	if (err)
437 		goto done;
438 	if (*done) {
439 		if (fseeko(fp, -linelen, SEEK_CUR) == -1)
440 			err = got_error_from_errno("fseeko");
441 		goto done;
442 	}
443 
444 	leftold = hdr.oldlines;
445 	leftnew = hdr.newlines;
446 
447 	while (leftold > 0 || leftnew > 0) {
448 		linelen = getline(&line, &linesize, fp);
449 		if (linelen == -1) {
450 			if (ferror(fp)) {
451 				err = got_error_from_errno("getline");
452 				goto done;
453 			}
454 
455 			/* trailing newlines may be chopped */
456 			if (leftold < 3 && leftnew < 3) {
457 				*done = 1;
458 				break;
459 			}
460 
461 			err = got_error(GOT_ERR_PATCH_TRUNCATED);
462 			goto done;
463 		}
464 		if (line[linelen - 1] == '\n')
465 			line[linelen - 1] = '\0';
466 
467 		/* usr.bin/patch allows '=' as context char */
468 		if (*line == '=')
469 			*line = ' ';
470 
471 		ch = *line;
472 		if (ch == '\t' || ch == '\0')
473 			ch = ' ';	/* the space got eaten */
474 
475 		switch (ch) {
476 		case '-':
477 			leftold--;
478 			break;
479 		case ' ':
480 			leftold--;
481 			leftnew--;
482 			break;
483 		case '+':
484 			leftnew--;
485 			break;
486 		default:
487 			err = got_error(GOT_ERR_PATCH_MALFORMED);
488 			goto done;
489 		}
490 
491 		if (leftold < 0 || leftnew < 0) {
492 			err = got_error(GOT_ERR_PATCH_MALFORMED);
493 			goto done;
494 		}
495 
496 		err = send_line(line);
497 		if (err)
498 			goto done;
499 
500 		if ((ch == '-' && leftold == 0) ||
501 		    (ch == '+' && leftnew == 0)) {
502 			err = peek_special_line(fp);
503 			if (err)
504 				goto done;
505 		}
506 	}
507 
508 done:
509 	free(line);
510 	return err;
511 }
512 
513 static const struct got_error *
514 read_patch(struct imsgbuf *ibuf, int fd)
515 {
516 	const struct got_error *err = NULL;
517 	FILE *fp;
518 	int git, patch_found = 0;
519 	char *cid = NULL;
520 
521 	if ((fp = fdopen(fd, "r")) == NULL) {
522 		err = got_error_from_errno("fdopen");
523 		close(fd);
524 		return err;
525 	}
526 
527 	while ((err = patch_start(&git, &cid, fp)) == NULL) {
528 		int done, next;
529 
530 		err = find_diff(&done, &next, fp, git, cid);
531 		if (err)
532 			goto done;
533 		if (next)
534 			continue;
535 
536 		patch_found = 1;
537 
538 		while (!done) {
539 			err = parse_hunk(fp, &done);
540 			if (err)
541 				goto done;
542 		}
543 
544 		err = send_patch_done();
545 		if (err)
546 			goto done;
547 	}
548 
549 done:
550 	fclose(fp);
551 	free(cid);
552 
553 	/* ignore trailing gibberish */
554 	if (err != NULL && err->code == GOT_ERR_NO_PATCH && patch_found)
555 		err = NULL;
556 
557 	return err;
558 }
559 
560 int
561 main(int argc, char **argv)
562 {
563 	const struct got_error *err = NULL;
564 	struct imsg imsg;
565 #if 0
566 	static int attached;
567 	while (!attached)
568 		sleep(1);
569 #endif
570 
571 	imsg_init(&ibuf, GOT_IMSG_FD_CHILD);
572 #ifndef PROFILE
573 	/* revoke access to most system calls */
574 	if (pledge("stdio recvfd", NULL) == -1) {
575 		err = got_error_from_errno("pledge");
576 		got_privsep_send_error(&ibuf, err);
577 		return 1;
578 	}
579 
580 	/* revoke fs access */
581 	if (landlock_no_fs() == -1) {
582 		err = got_error_from_errno("landlock_no_fs");
583 		got_privsep_send_error(&ibuf, err);
584 		return 1;
585 	}
586 	if (cap_enter() == -1) {
587 		err = got_error_from_errno("cap_enter");
588 		got_privsep_send_error(&ibuf, err);
589 		return 1;
590 	}
591 #endif
592 
593 	err = got_privsep_recv_imsg(&imsg, &ibuf, 0);
594 	if (err)
595 		goto done;
596 	if (imsg.hdr.type != GOT_IMSG_PATCH_FILE || imsg.fd == -1) {
597 		err = got_error(GOT_ERR_PRIVSEP_MSG);
598 		goto done;
599 	}
600 
601 	err = read_patch(&ibuf, imsg.fd);
602 	if (err)
603 		goto done;
604 	if (imsg_compose(&ibuf, GOT_IMSG_PATCH_EOF, 0, 0, -1,
605 	    NULL, 0) == -1) {
606 		err = got_error_from_errno("imsg_compose GOT_IMSG_PATCH_EOF");
607 		goto done;
608 	}
609 	err = got_privsep_flush_imsg(&ibuf);
610 done:
611 	imsg_free(&imsg);
612 	if (err != NULL) {
613 		got_privsep_send_error(&ibuf, err);
614 		err = NULL;
615 	}
616 	if (close(GOT_IMSG_FD_CHILD) == -1 && err == NULL)
617 		err = got_error_from_errno("close");
618 	if (err && err->code != GOT_ERR_PRIVSEP_PIPE)
619 		fprintf(stderr, "%s: %s\n", getprogname(), err->msg);
620 	return err ? 1 : 0;
621 }