1 /*
2  * Copyright (c) 2022 Omar Polo <op@omarpolo.com>
3  * Copyright (c) 2007-2016 Reyk Floeter <reyk@openbsd.org>
4  * Copyright (c) 2004, 2005 Esben Norby <norby@openbsd.org>
5  * Copyright (c) 2004 Ryan McBride <mcbride@openbsd.org>
6  * Copyright (c) 2002, 2003, 2004 Henning Brauer <henning@openbsd.org>
7  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
8  * Copyright (c) 2001 Daniel Hartmeier.  All rights reserved.
9  * Copyright (c) 2001 Theo de Raadt.  All rights reserved.
10  *
11  * Permission to use, copy, modify, and distribute this software for any
12  * purpose with or without fee is hereby granted, provided that the above
13  * copyright notice and this permission notice appear in all copies.
14  *
15  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
16  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
17  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
18  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
19  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
20  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
21  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
22  */
23 
24 %{
25 #include <sys/types.h>
26 #include <sys/queue.h>
27 #include <sys/tree.h>
28 #include <sys/uio.h>
29 
30 #include <err.h>
31 #include <event.h>
32 #include <netdb.h>
33 #include <stdio.h>
34 #include <stdlib.h>
35 #include <limits.h>
36 #include <stdarg.h>
37 #include <stdint.h>
38 #include <string.h>
39 #include <unistd.h>
40 #include <ctype.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <pwd.h>
44 #include <imsg.h>
45 
46 #include "log.h"
47 #include "proc.h"
48 
49 #include "galileo.h"
50 
51 TAILQ_HEAD(files, file)		 files = TAILQ_HEAD_INITIALIZER(files);
52 static struct file {
53 	TAILQ_ENTRY(file)	 entry;
54 	FILE			*stream;
55 	char			*name;
56 	size_t			 ungetpos;
57 	size_t			 ungetsize;
58 	u_char			*ungetbuf;
59 	int			 eof_reached;
60 	int			 lineno;
61 	int			 errors;
62 } *file, *topfile;
63 struct file	*pushfile(const char *, int);
64 int		 popfile(void);
65 int		 yyparse(void);
66 int		 yylex(void);
67 int		 yyerror(const char *, ...)
68     __attribute__((__format__ (printf, 1, 2)))
69     __attribute__((__nonnull__ (1)));
70 int		 kw_cmp(const void *, const void *);
71 int		 lookup(char *);
72 int		 igetc(void);
73 int		 lgetc(int);
74 void		 lungetc(int);
75 int		 findeol(void);
76 
77 TAILQ_HEAD(symhead, sym)	 symhead = TAILQ_HEAD_INITIALIZER(symhead);
78 struct sym {
79 	TAILQ_ENTRY(sym)	 entry;
80 	int			 used;
81 	int			 persist;
82 	char			*nam;
83 	char			*val;
84 };
85 int		 symset(const char *, const char *, int);
86 char		*symget(const char *);
87 
88 int		 getservice(const char *);
89 
90 static struct galileo	*conf = NULL;
91 static struct proxy	*pr = NULL;
92 static int		 errors;
93 
94 typedef struct {
95 	union {
96 		int64_t		 number;
97 		char		*string;
98 	} v;
99 	int lineno;
100 } YYSTYPE;
101 
102 %}
103 
104 %token	INCLUDE ERROR
105 %token	CHROOT HOSTNAME NO PORT PREFORK PROXY SOURCE STYLESHEET TLS
106 %token	<v.number>	NUMBER
107 %token	<v.string>	STRING
108 %type	<v.number>	port
109 %type	<v.string>	string
110 
111 %%
112 
113 grammar		: /* empty */
114 		| grammar include '\n'
115 		| grammar '\n'
116 		| grammar varset '\n'
117 		| grammar main '\n'
118 		| grammar proxy '\n'
119 		| grammar error '\n'		{ file->errors++; }
120 		;
121 
122 include		: INCLUDE string {
123 			struct file *nfile;
124 
125 			if ((nfile = pushfile($2, 0)) == NULL) {
126 				yyerror("failed to include file %s", $2);
127 				free($2);
128 				YYERROR;
129 			}
130 			free($2);
131 
132 			file = nfile;
133 			lungetc('\n');
134 		}
135 		;
136 
137 varset		: STRING '=' STRING {
138 			char *s = $1;
139 			while (*s++) {
140 				if (isspace((unsigned char)*s)) {
141 					yyerror("macro name cannot contain "
142 					    "whitespace");
143 					free($1);
144 					free($3);
145 					YYERROR;
146 				}
147 			}
148 			if (symset($1, $3, 0) == -1)
149 				fatalx("cannot store variable");
150 			free($1);
151 			free($3);
152 		}
153 		;
154 
155 main		: PREFORK NUMBER {
156 			if ($2 <= 0 || $2 > PROC_MAX_INSTANCES) {
157 				yyerror("invalid number of preforked "
158 				    "proxies: %lld", $2);
159 				YYERROR;
160 			}
161 			conf->sc_prefork = $2;
162 		}
163 		| CHROOT STRING {
164 			size_t n;
165 
166 			n = strlcpy(conf->sc_chroot, $2,
167 			    sizeof(conf->sc_chroot));
168 			if (n >= sizeof(conf->sc_chroot))
169 				yyerror("chroot path too long!");
170 			free($2);
171 		}
172 		;
173 
174 proxy		: PROXY STRING {
175 			struct proxy	*p;
176 			size_t		 n;
177 
178 			if ((p = calloc(1, sizeof(*p))) == NULL)
179 				fatal("calloc");
180 
181 			n = strlcpy(p->pr_conf.host, $2,
182 			    sizeof(p->pr_conf.host));
183 			if (n >= sizeof(p->pr_conf.host)) {
184 				yyerror("server name too long");
185 				free($2);
186 				free(p);
187 				YYERROR;
188 			}
189 			free($2);
190 
191 			pr = p;
192 		} '{' optnl proxyopts_l '}' {
193 			/* check if duplicate */
194 			if (proxy_match(conf, pr->pr_conf.host) != NULL)
195 				yyerror("duplicate proxy `%s'",
196 				    pr->pr_conf.host);
197 
198 			TAILQ_INSERT_TAIL(&conf->sc_proxies, pr, pr_entry);
199 
200 			if (*pr->pr_conf.proxy_addr == '\0')
201 				yyerror("missing source in proxy block `%s'",
202 				    pr->pr_conf.host);
203 
204 			pr = NULL;
205 		}
206 		;
207 
208 proxyopts_l	: proxyopts_l proxyoptsl nl
209 		| proxyoptsl optnl
210 		;
211 
212 proxyoptsl	: SOURCE STRING proxyport {
213 			size_t n;
214 
215 			n = strlcpy(pr->pr_conf.proxy_addr, $2,
216 			    sizeof(pr->pr_conf.proxy_addr));
217 			if (n >= sizeof(pr->pr_conf.proxy_addr))
218 				yyerror("proxy source too long!");
219 
220 			if (*pr->pr_conf.proxy_name == '\0') {
221 				n = strlcpy(pr->pr_conf.proxy_name, $2,
222 				    sizeof(pr->pr_conf.proxy_name));
223 				if (n >= sizeof(pr->pr_conf.proxy_name))
224 					yyerror("proxy hostname too long!");
225 			}
226 
227 			free($2);
228 		}
229 		| HOSTNAME STRING {
230 			size_t n;
231 
232 			n = strlcpy(pr->pr_conf.proxy_name, $2,
233 			    sizeof(pr->pr_conf.proxy_name));
234 			if (n >= sizeof(pr->pr_conf.proxy_name))
235 				yyerror("proxy hostname too long!");
236 			free($2);
237 		}
238 		| STYLESHEET string {
239 			size_t n;
240 
241 			n = strlcpy(pr->pr_conf.stylesheet, $2,
242 			    sizeof(pr->pr_conf.stylesheet));
243 			if (n >= sizeof(pr->pr_conf.stylesheet))
244 				yyerror("stylesheet path too long!");
245 			free($2);
246 		}
247 		| NO TLS {
248 			pr->pr_conf.no_tls = 1;
249 		}
250 		;
251 
252 proxyport	: /* empty */ {
253 			strlcpy(pr->pr_conf.proxy_port, "1965",
254 			    sizeof(pr->pr_conf.proxy_port));
255 		}
256 		| PORT port {
257 			size_t len;
258 			int n;
259 
260 			len = sizeof(pr->pr_conf.proxy_port);
261 			n = snprintf(pr->pr_conf.proxy_port, len, "%lld", $2);
262 			if (n < 0 || (size_t)n >= len)
263 				fatal("port number too long?");
264 		};
265 
266 port		: NUMBER {
267 			if ($1 <= 0 || $1 > (int)USHRT_MAX) {
268 				yyerror("invalid port: %lld", $1);
269 				YYERROR;
270 			}
271 			$$ = $1;
272 		}
273 		| STRING {
274 			int val;
275 
276 			if ((val = getservice($1)) == -1) {
277 				yyerror("invalid port: %s", $1);
278 				free($1);
279 				YYERROR;
280 			}
281 			free($1);
282 			$$ = val;
283 		}
284 		;
285 
286 string		: STRING string {
287 			if (asprintf(&$$, "%s%s", $1, $2) == -1)
288 				fatal("asprintf string");
289 			free($1);
290 			free($2);
291 		}
292 		| STRING
293 		;
294 
295 optnl		: '\n' optnl
296 		|
297 		;
298 
299 nl		: '\n' optnl
300 		;
301 
302 %%
303 
304 struct keywords {
305 	const char	*k_name;
306 	int		 k_val;
307 };
308 
309 int
310 yyerror(const char *fmt, ...)
311 {
312 	va_list	 ap;
313 	char	*msg;
314 
315 	file->errors++;
316 	va_start(ap, fmt);
317 	if (vasprintf(&msg, fmt, ap) == -1)
318 		fatal("yyerror vasprintf");
319 	va_end(ap);
320 	log_warnx("%s:%d: %s", file->name, yylval.lineno, msg);
321 	free(msg);
322 	return (0);
323 }
324 
325 int
326 kw_cmp(const void *k, const void *e)
327 {
328 	return (strcmp(k, ((const struct keywords *)e)->k_name));
329 }
330 
331 int
332 lookup(char *s)
333 {
334 	/* this has to be sorted always */
335 	static const struct keywords keywords[] = {
336 		{ "chroot",	CHROOT },
337 		{ "hostname",	HOSTNAME },
338 		{ "include",	INCLUDE },
339 		{ "no",		NO },
340 		{ "port",	PORT },
341 		{ "prefork",	PREFORK },
342 		{ "proxy",	PROXY },
343 		{ "source",	SOURCE },
344 		{ "stylesheet",	STYLESHEET},
345 		{ "tls",	TLS },
346 	};
347 	const struct keywords	*p;
348 
349 	p = bsearch(s, keywords, nitems(keywords), sizeof(keywords[0]),
350 	    kw_cmp);
351 
352 	if (p)
353 		return (p->k_val);
354 	else
355 		return (STRING);
356 }
357 
358 #define START_EXPAND	1
359 #define DONE_EXPAND	2
360 
361 static int	expanding;
362 
363 int
364 igetc(void)
365 {
366 	int	c;
367 
368 	while (1) {
369 		if (file->ungetpos > 0)
370 			c = file->ungetbuf[--file->ungetpos];
371 		else
372 			c = getc(file->stream);
373 
374 		if (c == START_EXPAND)
375 			expanding = 1;
376 		else if (c == DONE_EXPAND)
377 			expanding = 0;
378 		else
379 			break;
380 	}
381 	return (c);
382 }
383 
384 int
385 lgetc(int quotec)
386 {
387 	int		c, next;
388 
389 	if (quotec) {
390 		if ((c = igetc()) == EOF) {
391 			yyerror("reached end of file while parsing "
392 			    "quoted string");
393 			if (file == topfile || popfile() == EOF)
394 				return (EOF);
395 			return (quotec);
396 		}
397 		return (c);
398 	}
399 
400 	while ((c = igetc()) == '\\') {
401 		next = igetc();
402 		if (next != '\n') {
403 			c = next;
404 			break;
405 		}
406 		yylval.lineno = file->lineno;
407 		file->lineno++;
408 	}
409 	if (c == '\t' || c == ' ') {
410 		/* Compress blanks to a single space. */
411 		do {
412 			c = getc(file->stream);
413 		} while (c == '\t' || c == ' ');
414 		ungetc(c, file->stream);
415 		c = ' ';
416 	}
417 
418 	if (c == EOF) {
419 		/*
420 		 * Fake EOL when hit EOF for the first time. This gets line
421 		 * count right if last line in included file is syntactically
422 		 * invalid and has no newline.
423 		 */
424 		if (file->eof_reached == 0) {
425 			file->eof_reached = 1;
426 			return ('\n');
427 		}
428 		while (c == EOF) {
429 			if (file == topfile || popfile() == EOF)
430 				return (EOF);
431 			c = igetc();
432 		}
433 	}
434 	return (c);
435 }
436 
437 void
438 lungetc(int c)
439 {
440 	if (c == EOF)
441 		return;
442 
443 	if (file->ungetpos >= file->ungetsize) {
444 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
445 		if (p == NULL)
446 			err(1, "%s", __func__);
447 		file->ungetbuf = p;
448 		file->ungetsize *= 2;
449 	}
450 	file->ungetbuf[file->ungetpos++] = c;
451 }
452 
453 int
454 findeol(void)
455 {
456 	int	c;
457 
458 	/* skip to either EOF or the first real EOL */
459 	while (1) {
460 		c = lgetc(0);
461 		if (c == '\n') {
462 			file->lineno++;
463 			break;
464 		}
465 		if (c == EOF)
466 			break;
467 	}
468 	return (ERROR);
469 }
470 
471 int
472 yylex(void)
473 {
474 	char	 buf[8096];
475 	char	*p, *val;
476 	int	 quotec, next, c;
477 	int	 token;
478 
479 top:
480 	p = buf;
481 	while ((c = lgetc(0)) == ' ' || c == '\t')
482 		; /* nothing */
483 
484 	yylval.lineno = file->lineno;
485 	if (c == '#')
486 		while ((c = lgetc(0)) != '\n' && c != EOF)
487 			; /* nothing */
488 	if (c == '$' && !expanding) {
489 		while (1) {
490 			if ((c = lgetc(0)) == EOF)
491 				return (0);
492 
493 			if (p + 1 >= buf + sizeof(buf) - 1) {
494 				yyerror("string too long");
495 				return (findeol());
496 			}
497 			if (isalnum(c) || c == '_') {
498 				*p++ = c;
499 				continue;
500 			}
501 			*p = '\0';
502 			lungetc(c);
503 			break;
504 		}
505 		val = symget(buf);
506 		if (val == NULL) {
507 			yyerror("macro '%s' not defined", buf);
508 			return (findeol());
509 		}
510 		p = val + strlen(val) - 1;
511 		lungetc(DONE_EXPAND);
512 		while (p >= val) {
513 			lungetc((unsigned char)*p);
514 			p--;
515 		}
516 		lungetc(START_EXPAND);
517 		goto top;
518 	}
519 
520 	switch (c) {
521 	case '\'':
522 	case '"':
523 		quotec = c;
524 		while (1) {
525 			if ((c = lgetc(quotec)) == EOF)
526 				return (0);
527 			if (c == '\n') {
528 				file->lineno++;
529 				continue;
530 			} else if (c == '\\') {
531 				if ((next = lgetc(quotec)) == EOF)
532 					return (0);
533 				if (next == quotec || next == ' ' ||
534 				    next == '\t')
535 					c = next;
536 				else if (next == '\n') {
537 					file->lineno++;
538 					continue;
539 				} else
540 					lungetc(next);
541 			} else if (c == quotec) {
542 				*p = '\0';
543 				break;
544 			} else if (c == '\0') {
545 				yyerror("syntax error");
546 				return (findeol());
547 			}
548 			if (p + 1 >= buf + sizeof(buf) - 1) {
549 				yyerror("string too long");
550 				return (findeol());
551 			}
552 			*p++ = c;
553 		}
554 		yylval.v.string = strdup(buf);
555 		if (yylval.v.string == NULL)
556 			fatal("yylex: strdup");
557 		return (STRING);
558 	}
559 
560 #define allowed_to_end_number(x) \
561 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
562 
563 	if (c == '-' || isdigit(c)) {
564 		do {
565 			*p++ = c;
566 			if ((size_t)(p-buf) >= sizeof(buf)) {
567 				yyerror("string too long");
568 				return (findeol());
569 			}
570 		} while ((c = lgetc(0)) != EOF && isdigit(c));
571 		lungetc(c);
572 		if (p == buf + 1 && buf[0] == '-')
573 			goto nodigits;
574 		if (c == EOF || allowed_to_end_number(c)) {
575 			const char *errstr = NULL;
576 
577 			*p = '\0';
578 			yylval.v.number = strtonum(buf, LLONG_MIN,
579 			    LLONG_MAX, &errstr);
580 			if (errstr) {
581 				yyerror("\"%s\" invalid number: %s",
582 				    buf, errstr);
583 				return (findeol());
584 			}
585 			return (NUMBER);
586 		} else {
587 nodigits:
588 			while (p > buf + 1)
589 				lungetc((unsigned char)*--p);
590 			c = (unsigned char)*--p;
591 			if (c == '-')
592 				return (c);
593 		}
594 	}
595 
596 #define allowed_in_string(x) \
597 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
598 	x != '{' && x != '}' && \
599 	x != '!' && x != '=' && x != '#' && \
600 	x != ','))
601 
602 	if (isalnum(c) || c == ':' || c == '_' || c == '/') {
603 		do {
604 			*p++ = c;
605 			if ((size_t)(p-buf) >= sizeof(buf)) {
606 				yyerror("string too long");
607 				return (findeol());
608 			}
609 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
610 		lungetc(c);
611 		*p = '\0';
612 		if ((token = lookup(buf)) == STRING)
613 			if ((yylval.v.string = strdup(buf)) == NULL)
614 				fatal("yylex: strdup");
615 		return (token);
616 	}
617 	if (c == '\n') {
618 		yylval.lineno = file->lineno;
619 		file->lineno++;
620 	}
621 	if (c == EOF)
622 		return (0);
623 	return (c);
624 }
625 
626 struct file *
627 pushfile(const char *name, int secret)
628 {
629 	struct file	*nfile;
630 
631 	if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
632 		log_warn("%s", __func__);
633 		return (NULL);
634 	}
635 	if ((nfile->name = strdup(name)) == NULL) {
636 		log_warn("%s", __func__);
637 		free(nfile);
638 		return (NULL);
639 	}
640 	if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
641 		free(nfile->name);
642 		free(nfile);
643 		return (NULL);
644 	}
645 	nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
646 	nfile->ungetsize = 16;
647 	nfile->ungetbuf = malloc(nfile->ungetsize);
648 	if (nfile->ungetbuf == NULL) {
649 		log_warn("%s", __func__);
650 		fclose(nfile->stream);
651 		free(nfile->name);
652 		free(nfile);
653 		return (NULL);
654 	}
655 	TAILQ_INSERT_TAIL(&files, nfile, entry);
656 	return (nfile);
657 }
658 
659 int
660 popfile(void)
661 {
662 	struct file	*prev;
663 
664 	if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
665 		prev->errors += file->errors;
666 
667 	TAILQ_REMOVE(&files, file, entry);
668 	fclose(file->stream);
669 	free(file->name);
670 	free(file->ungetbuf);
671 	free(file);
672 	file = prev;
673 	return (file ? 0 : EOF);
674 }
675 
676 int
677 parse_config(const char *filename, struct galileo *env)
678 {
679 	struct sym	*sym, *next;
680 	size_t		 n;
681 
682 	conf = env;
683 
684 	n = strlcpy(conf->sc_conffile, filename, sizeof(conf->sc_conffile));
685 	if (n >= sizeof(conf->sc_conffile)) {
686 		log_warn("path too long: %s", filename);
687 		return (-1);
688 	}
689 
690 	if ((file = pushfile(filename, 0)) == NULL) {
691 		log_warn("failed to open %s", filename);
692 		return (-1);
693 	}
694 	topfile = file;
695 	setservent(1);
696 
697 	yyparse();
698 	if (TAILQ_EMPTY(&conf->sc_proxies))
699 		yyerror("no proxies defined");
700 	errors = file->errors;
701 	popfile();
702 
703 	endservent();
704 
705 	/* Free macros and check which have not been used. */
706 	TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
707 		if (!sym->used)
708 			fprintf(stderr, "warning: macro `%s' not used\n",
709 			    sym->nam);
710 		if (!sym->persist) {
711 			free(sym->nam);
712 			free(sym->val);
713 			TAILQ_REMOVE(&symhead, sym, entry);
714 			free(sym);
715 		}
716 	}
717 
718 	if (errors)
719 		return (-1);
720 
721 	return (0);
722 }
723 
724 int
725 symset(const char *nam, const char *val, int persist)
726 {
727 	struct sym	*sym;
728 
729 	TAILQ_FOREACH(sym, &symhead, entry) {
730 		if (strcmp(nam, sym->nam) == 0)
731 			break;
732 	}
733 
734 	if (sym != NULL) {
735 		if (sym->persist == 1)
736 			return (0);
737 		else {
738 			free(sym->nam);
739 			free(sym->val);
740 			TAILQ_REMOVE(&symhead, sym, entry);
741 			free(sym);
742 		}
743 	}
744 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
745 		return (-1);
746 
747 	sym->nam = strdup(nam);
748 	if (sym->nam == NULL) {
749 		free(sym);
750 		return (-1);
751 	}
752 	sym->val = strdup(val);
753 	if (sym->val == NULL) {
754 		free(sym->nam);
755 		free(sym);
756 		return (-1);
757 	}
758 	sym->used = 0;
759 	sym->persist = persist;
760 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
761 	return (0);
762 }
763 
764 int
765 cmdline_symset(char *s)
766 {
767 	char	*sym, *val;
768 	int	ret;
769 
770 	if ((val = strrchr(s, '=')) == NULL)
771 		return (-1);
772 	sym = strndup(s, val - s);
773 	if (sym == NULL)
774 		fatal("%s: strndup", __func__);
775 	ret = symset(sym, val + 1, 1);
776 	free(sym);
777 
778 	return (ret);
779 }
780 
781 char *
782 symget(const char *nam)
783 {
784 	struct sym	*sym;
785 
786 	TAILQ_FOREACH(sym, &symhead, entry) {
787 		if (strcmp(nam, sym->nam) == 0) {
788 			sym->used = 1;
789 			return (sym->val);
790 		}
791 	}
792 	return (NULL);
793 }
794 
795 int
796 getservice(const char *n)
797 {
798 	struct servent	*s;
799 	const char	*errstr;
800 	long long	 llval;
801 
802 	llval = strtonum(n, 0, UINT16_MAX, &errstr);
803 	if (errstr) {
804 		s = getservbyname(n, "tcp");
805 		if (s == NULL)
806 			s = getservbyname(n, "udp");
807 		if (s == NULL)
808 			return (-1);
809 		return (ntohs(s->s_port));
810 	}
811 
812 	return ((unsigned short)llval);
813 }