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 server	*srv = 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 PORT PREFORK PROXY SERVER SOURCE STYLESHEET
106 %type	<v.number>	NUMBER
107 %type	<v.number>	port
108 %type	<v.string>	STRING
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 server '\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 				    "servers: %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 server		: SERVER STRING {
175 			struct server	*s;
176 			size_t		 n;
177 
178 			if ((s = calloc(1, sizeof(*s))) == NULL)
179 				fatal("calloc");
180 
181 			n = strlcpy(s->srv_conf.host, $2,
182 			    sizeof(s->srv_conf.host));
183 			if (n >= sizeof(s->srv_conf.host)) {
184 				yyerror("server name too long");
185 				free($2);
186 				free(s);
187 				YYERROR;
188 			}
189 			free($2);
190 
191 			srv = s;
192 			TAILQ_INSERT_TAIL(&conf->sc_servers, srv, srv_entry);
193 		} '{' optnl serveropts_l '}' {
194 			/* check if duplicate */
195 			/* eventually load the tls certs */
196 
197 			srv = NULL;
198 		}
199 		;
200 
201 serveropts_l	: serveropts_l serveroptsl nl
202 		| serveroptsl optnl
203 		;
204 
205 serveroptsl	: PROXY STRING	{
206 			/* ... */
207 		}
208 		| PROXY '{' optnl proxyopts_l '}'
209 		| STYLESHEET string { /* ... */ }
210 		;
211 
212 proxyopts_l	: proxyopts_l proxyoptsl nl
213 		| proxyoptsl optnl
214 		;
215 
216 proxyoptsl	: SOURCE STRING PORT port {
217 			size_t n;
218 
219 			n = strlcpy(srv->srv_conf.proxy_addr, $2,
220 			    sizeof(srv->srv_conf.proxy_addr));
221 			if (n >= sizeof(srv->srv_conf.proxy_addr))
222 				yyerror("proxy source too long!");
223 			srv->srv_conf.proxy_port = $4;
224 
225 			free($2);
226 		}
227 		| HOSTNAME STRING {
228 			size_t n;
229 
230 			n = strlcpy(srv->srv_conf.proxy_name, $2,
231 			    sizeof(srv->srv_conf.proxy_name));
232 			if (n >= sizeof(srv->srv_conf.proxy_name))
233 				yyerror("proxy hostname too long!");
234 			free($2);
235 		}
236 		;
237 
238 port		: NUMBER {
239 			if ($1 <= 0 || $1 > (int)USHRT_MAX) {
240 				yyerror("invalid port: %lld", $1);
241 				YYERROR;
242 			}
243 			$$ = $1;
244 		}
245 		| STRING {
246 			int val;
247 
248 			if ((val = getservice($1)) == -1) {
249 				yyerror("invalid port: %s", $1);
250 				free($1);
251 				YYERROR;
252 			}
253 			free($1);
254 			$$ = val;
255 		}
256 		;
257 
258 string		: STRING string {
259 			if (asprintf(&$$, "%s%s", $1, $2) == -1)
260 				fatal("asprintf string");
261 			free($1);
262 			free($2);
263 		}
264 		| STRING
265 		;
266 
267 optnl		: '\n' optnl
268 		|
269 		;
270 
271 nl		: '\n' optnl
272 		;
273 
274 %%
275 
276 struct keywords {
277 	const char	*k_name;
278 	int		 k_val;
279 };
280 
281 int
282 yyerror(const char *fmt, ...)
283 {
284 	va_list	 ap;
285 	char	*msg;
286 
287 	file->errors++;
288 	va_start(ap, fmt);
289 	if (vasprintf(&msg, fmt, ap) == -1)
290 		fatal("yyerror vasprintf");
291 	va_end(ap);
292 	log_warnx("%s:%d: %s", file->name, yylval.lineno, msg);
293 	free(msg);
294 	return (0);
295 }
296 
297 int
298 kw_cmp(const void *k, const void *e)
299 {
300 	return (strcmp(k, ((const struct keywords *)e)->k_name));
301 }
302 
303 int
304 lookup(char *s)
305 {
306 	/* this has to be sorted always */
307 	static const struct keywords keywords[] = {
308 		{ "chroot",	CHROOT },
309 		{ "hostname",	HOSTNAME },
310 		{ "include",	INCLUDE },
311 		{ "port",	PORT },
312 		{ "prefork",	PREFORK },
313 		{ "proxy",	PROXY },
314 		{ "server",	SERVER },
315 		{ "source",	SOURCE },
316 		{ "stylesheet",	STYLESHEET},
317 	};
318 	const struct keywords	*p;
319 
320 	p = bsearch(s, keywords, nitems(keywords), sizeof(keywords[0]),
321 	    kw_cmp);
322 
323 	if (p)
324 		return (p->k_val);
325 	else
326 		return (STRING);
327 }
328 
329 #define START_EXPAND	1
330 #define DONE_EXPAND	2
331 
332 static int	expanding;
333 
334 int
335 igetc(void)
336 {
337 	int	c;
338 
339 	while (1) {
340 		if (file->ungetpos > 0)
341 			c = file->ungetbuf[--file->ungetpos];
342 		else
343 			c = getc(file->stream);
344 
345 		if (c == START_EXPAND)
346 			expanding = 1;
347 		else if (c == DONE_EXPAND)
348 			expanding = 0;
349 		else
350 			break;
351 	}
352 	return (c);
353 }
354 
355 int
356 lgetc(int quotec)
357 {
358 	int		c, next;
359 
360 	if (quotec) {
361 		if ((c = igetc()) == EOF) {
362 			yyerror("reached end of file while parsing "
363 			    "quoted string");
364 			if (file == topfile || popfile() == EOF)
365 				return (EOF);
366 			return (quotec);
367 		}
368 		return (c);
369 	}
370 
371 	while ((c = igetc()) == '\\') {
372 		next = igetc();
373 		if (next != '\n') {
374 			c = next;
375 			break;
376 		}
377 		yylval.lineno = file->lineno;
378 		file->lineno++;
379 	}
380 	if (c == '\t' || c == ' ') {
381 		/* Compress blanks to a single space. */
382 		do {
383 			c = getc(file->stream);
384 		} while (c == '\t' || c == ' ');
385 		ungetc(c, file->stream);
386 		c = ' ';
387 	}
388 
389 	if (c == EOF) {
390 		/*
391 		 * Fake EOL when hit EOF for the first time. This gets line
392 		 * count right if last line in included file is syntactically
393 		 * invalid and has no newline.
394 		 */
395 		if (file->eof_reached == 0) {
396 			file->eof_reached = 1;
397 			return ('\n');
398 		}
399 		while (c == EOF) {
400 			if (file == topfile || popfile() == EOF)
401 				return (EOF);
402 			c = igetc();
403 		}
404 	}
405 	return (c);
406 }
407 
408 void
409 lungetc(int c)
410 {
411 	if (c == EOF)
412 		return;
413 
414 	if (file->ungetpos >= file->ungetsize) {
415 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
416 		if (p == NULL)
417 			err(1, "%s", __func__);
418 		file->ungetbuf = p;
419 		file->ungetsize *= 2;
420 	}
421 	file->ungetbuf[file->ungetpos++] = c;
422 }
423 
424 int
425 findeol(void)
426 {
427 	int	c;
428 
429 	/* skip to either EOF or the first real EOL */
430 	while (1) {
431 		c = lgetc(0);
432 		if (c == '\n') {
433 			file->lineno++;
434 			break;
435 		}
436 		if (c == EOF)
437 			break;
438 	}
439 	return (ERROR);
440 }
441 
442 int
443 yylex(void)
444 {
445 	char	 buf[8096];
446 	char	*p, *val;
447 	int	 quotec, next, c;
448 	int	 token;
449 
450 top:
451 	p = buf;
452 	while ((c = lgetc(0)) == ' ' || c == '\t')
453 		; /* nothing */
454 
455 	yylval.lineno = file->lineno;
456 	if (c == '#')
457 		while ((c = lgetc(0)) != '\n' && c != EOF)
458 			; /* nothing */
459 	if (c == '$' && !expanding) {
460 		while (1) {
461 			if ((c = lgetc(0)) == EOF)
462 				return (0);
463 
464 			if (p + 1 >= buf + sizeof(buf) - 1) {
465 				yyerror("string too long");
466 				return (findeol());
467 			}
468 			if (isalnum(c) || c == '_') {
469 				*p++ = c;
470 				continue;
471 			}
472 			*p = '\0';
473 			lungetc(c);
474 			break;
475 		}
476 		val = symget(buf);
477 		if (val == NULL) {
478 			yyerror("macro '%s' not defined", buf);
479 			return (findeol());
480 		}
481 		p = val + strlen(val) - 1;
482 		lungetc(DONE_EXPAND);
483 		while (p >= val) {
484 			lungetc((unsigned char)*p);
485 			p--;
486 		}
487 		lungetc(START_EXPAND);
488 		goto top;
489 	}
490 
491 	switch (c) {
492 	case '\'':
493 	case '"':
494 		quotec = c;
495 		while (1) {
496 			if ((c = lgetc(quotec)) == EOF)
497 				return (0);
498 			if (c == '\n') {
499 				file->lineno++;
500 				continue;
501 			} else if (c == '\\') {
502 				if ((next = lgetc(quotec)) == EOF)
503 					return (0);
504 				if (next == quotec || next == ' ' ||
505 				    next == '\t')
506 					c = next;
507 				else if (next == '\n') {
508 					file->lineno++;
509 					continue;
510 				} else
511 					lungetc(next);
512 			} else if (c == quotec) {
513 				*p = '\0';
514 				break;
515 			} else if (c == '\0') {
516 				yyerror("syntax error");
517 				return (findeol());
518 			}
519 			if (p + 1 >= buf + sizeof(buf) - 1) {
520 				yyerror("string too long");
521 				return (findeol());
522 			}
523 			*p++ = c;
524 		}
525 		yylval.v.string = strdup(buf);
526 		if (yylval.v.string == NULL)
527 			fatal("yylex: strdup");
528 		return (STRING);
529 	}
530 
531 #define allowed_to_end_number(x) \
532 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
533 
534 	if (c == '-' || isdigit(c)) {
535 		do {
536 			*p++ = c;
537 			if ((size_t)(p-buf) >= sizeof(buf)) {
538 				yyerror("string too long");
539 				return (findeol());
540 			}
541 		} while ((c = lgetc(0)) != EOF && isdigit(c));
542 		lungetc(c);
543 		if (p == buf + 1 && buf[0] == '-')
544 			goto nodigits;
545 		if (c == EOF || allowed_to_end_number(c)) {
546 			const char *errstr = NULL;
547 
548 			*p = '\0';
549 			yylval.v.number = strtonum(buf, LLONG_MIN,
550 			    LLONG_MAX, &errstr);
551 			if (errstr) {
552 				yyerror("\"%s\" invalid number: %s",
553 				    buf, errstr);
554 				return (findeol());
555 			}
556 			return (NUMBER);
557 		} else {
558 nodigits:
559 			while (p > buf + 1)
560 				lungetc((unsigned char)*--p);
561 			c = (unsigned char)*--p;
562 			if (c == '-')
563 				return (c);
564 		}
565 	}
566 
567 #define allowed_in_string(x) \
568 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
569 	x != '{' && x != '}' && \
570 	x != '!' && x != '=' && x != '#' && \
571 	x != ','))
572 
573 	if (isalnum(c) || c == ':' || c == '_' || c == '/') {
574 		do {
575 			*p++ = c;
576 			if ((size_t)(p-buf) >= sizeof(buf)) {
577 				yyerror("string too long");
578 				return (findeol());
579 			}
580 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
581 		lungetc(c);
582 		*p = '\0';
583 		if ((token = lookup(buf)) == STRING)
584 			if ((yylval.v.string = strdup(buf)) == NULL)
585 				fatal("yylex: strdup");
586 		return (token);
587 	}
588 	if (c == '\n') {
589 		yylval.lineno = file->lineno;
590 		file->lineno++;
591 	}
592 	if (c == EOF)
593 		return (0);
594 	return (c);
595 }
596 
597 struct file *
598 pushfile(const char *name, int secret)
599 {
600 	struct file	*nfile;
601 
602 	if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
603 		log_warn("%s", __func__);
604 		return (NULL);
605 	}
606 	if ((nfile->name = strdup(name)) == NULL) {
607 		log_warn("%s", __func__);
608 		free(nfile);
609 		return (NULL);
610 	}
611 	if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
612 		free(nfile->name);
613 		free(nfile);
614 		return (NULL);
615 	}
616 	nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
617 	nfile->ungetsize = 16;
618 	nfile->ungetbuf = malloc(nfile->ungetsize);
619 	if (nfile->ungetbuf == NULL) {
620 		log_warn("%s", __func__);
621 		fclose(nfile->stream);
622 		free(nfile->name);
623 		free(nfile);
624 		return (NULL);
625 	}
626 	TAILQ_INSERT_TAIL(&files, nfile, entry);
627 	return (nfile);
628 }
629 
630 int
631 popfile(void)
632 {
633 	struct file	*prev;
634 
635 	if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
636 		prev->errors += file->errors;
637 
638 	TAILQ_REMOVE(&files, file, entry);
639 	fclose(file->stream);
640 	free(file->name);
641 	free(file->ungetbuf);
642 	free(file);
643 	file = prev;
644 	return (file ? 0 : EOF);
645 }
646 
647 int
648 parse_config(const char *filename, struct galileo *env)
649 {
650 	struct sym	*sym, *next;
651 	size_t		 n;
652 
653 	conf = env;
654 
655 	n = strlcpy(conf->sc_conffile, filename, sizeof(conf->sc_conffile));
656 	if (n >= sizeof(conf->sc_conffile)) {
657 		log_warn("path too long: %s", filename);
658 		return (-1);
659 	}
660 
661 	if ((file = pushfile(filename, 0)) == NULL) {
662 		log_warn("failed to open %s", filename);
663 		return (-1);
664 	}
665 	topfile = file;
666 	setservent(1);
667 
668 	yyparse();
669 	errors = file->errors;
670 	popfile();
671 
672 	endservent();
673 
674 	/* Free macros and check which have not been used. */
675 	TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
676 		if (!sym->used)
677 			fprintf(stderr, "warning: macro `%s' not used\n",
678 			    sym->nam);
679 		if (!sym->persist) {
680 			free(sym->nam);
681 			free(sym->val);
682 			TAILQ_REMOVE(&symhead, sym, entry);
683 			free(sym);
684 		}
685 	}
686 
687 	if (errors)
688 		return (-1);
689 
690 	return (0);
691 }
692 
693 int
694 symset(const char *nam, const char *val, int persist)
695 {
696 	struct sym	*sym;
697 
698 	TAILQ_FOREACH(sym, &symhead, entry) {
699 		if (strcmp(nam, sym->nam) == 0)
700 			break;
701 	}
702 
703 	if (sym != NULL) {
704 		if (sym->persist == 1)
705 			return (0);
706 		else {
707 			free(sym->nam);
708 			free(sym->val);
709 			TAILQ_REMOVE(&symhead, sym, entry);
710 			free(sym);
711 		}
712 	}
713 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
714 		return (-1);
715 
716 	sym->nam = strdup(nam);
717 	if (sym->nam == NULL) {
718 		free(sym);
719 		return (-1);
720 	}
721 	sym->val = strdup(val);
722 	if (sym->val == NULL) {
723 		free(sym->nam);
724 		free(sym);
725 		return (-1);
726 	}
727 	sym->used = 0;
728 	sym->persist = persist;
729 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
730 	return (0);
731 }
732 
733 int
734 cmdline_symset(char *s)
735 {
736 	char	*sym, *val;
737 	int	ret;
738 
739 	if ((val = strrchr(s, '=')) == NULL)
740 		return (-1);
741 	sym = strndup(s, val - s);
742 	if (sym == NULL)
743 		fatal("%s: strndup", __func__);
744 	ret = symset(sym, val + 1, 1);
745 	free(sym);
746 
747 	return (ret);
748 }
749 
750 char *
751 symget(const char *nam)
752 {
753 	struct sym	*sym;
754 
755 	TAILQ_FOREACH(sym, &symhead, entry) {
756 		if (strcmp(nam, sym->nam) == 0) {
757 			sym->used = 1;
758 			return (sym->val);
759 		}
760 	}
761 	return (NULL);
762 }
763 
764 int
765 getservice(const char *n)
766 {
767 	struct servent	*s;
768 	const char	*errstr;
769 	long long	 llval;
770 
771 	llval = strtonum(n, 0, UINT16_MAX, &errstr);
772 	if (errstr) {
773 		s = getservbyname(n, "tcp");
774 		if (s == NULL)
775 			s = getservbyname(n, "udp");
776 		if (s == NULL)
777 			return (-1);
778 		return (ntohs(s->s_port));
779 	}
780 
781 	return ((unsigned short)llval);
782 }