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 PORT PREFORK PROXY SOURCE STYLESHEET
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 		;
248 
249 proxyport	: /* empty */ {
250 			strlcpy(pr->pr_conf.proxy_port, "1965",
251 			    sizeof(pr->pr_conf.proxy_port));
252 		}
253 		| PORT port {
254 			size_t len;
255 			int n;
256 
257 			len = sizeof(pr->pr_conf.proxy_port);
258 			n = snprintf(pr->pr_conf.proxy_port, len, "%lld", $2);
259 			if (n < 0 || (size_t)n >= len)
260 				fatal("port number too long?");
261 		};
262 
263 port		: NUMBER {
264 			if ($1 <= 0 || $1 > (int)USHRT_MAX) {
265 				yyerror("invalid port: %lld", $1);
266 				YYERROR;
267 			}
268 			$$ = $1;
269 		}
270 		| STRING {
271 			int val;
272 
273 			if ((val = getservice($1)) == -1) {
274 				yyerror("invalid port: %s", $1);
275 				free($1);
276 				YYERROR;
277 			}
278 			free($1);
279 			$$ = val;
280 		}
281 		;
282 
283 string		: STRING string {
284 			if (asprintf(&$$, "%s%s", $1, $2) == -1)
285 				fatal("asprintf string");
286 			free($1);
287 			free($2);
288 		}
289 		| STRING
290 		;
291 
292 optnl		: '\n' optnl
293 		|
294 		;
295 
296 nl		: '\n' optnl
297 		;
298 
299 %%
300 
301 struct keywords {
302 	const char	*k_name;
303 	int		 k_val;
304 };
305 
306 int
307 yyerror(const char *fmt, ...)
308 {
309 	va_list	 ap;
310 	char	*msg;
311 
312 	file->errors++;
313 	va_start(ap, fmt);
314 	if (vasprintf(&msg, fmt, ap) == -1)
315 		fatal("yyerror vasprintf");
316 	va_end(ap);
317 	log_warnx("%s:%d: %s", file->name, yylval.lineno, msg);
318 	free(msg);
319 	return (0);
320 }
321 
322 int
323 kw_cmp(const void *k, const void *e)
324 {
325 	return (strcmp(k, ((const struct keywords *)e)->k_name));
326 }
327 
328 int
329 lookup(char *s)
330 {
331 	/* this has to be sorted always */
332 	static const struct keywords keywords[] = {
333 		{ "chroot",	CHROOT },
334 		{ "hostname",	HOSTNAME },
335 		{ "include",	INCLUDE },
336 		{ "port",	PORT },
337 		{ "prefork",	PREFORK },
338 		{ "proxy",	PROXY },
339 		{ "source",	SOURCE },
340 		{ "stylesheet",	STYLESHEET},
341 	};
342 	const struct keywords	*p;
343 
344 	p = bsearch(s, keywords, nitems(keywords), sizeof(keywords[0]),
345 	    kw_cmp);
346 
347 	if (p)
348 		return (p->k_val);
349 	else
350 		return (STRING);
351 }
352 
353 #define START_EXPAND	1
354 #define DONE_EXPAND	2
355 
356 static int	expanding;
357 
358 int
359 igetc(void)
360 {
361 	int	c;
362 
363 	while (1) {
364 		if (file->ungetpos > 0)
365 			c = file->ungetbuf[--file->ungetpos];
366 		else
367 			c = getc(file->stream);
368 
369 		if (c == START_EXPAND)
370 			expanding = 1;
371 		else if (c == DONE_EXPAND)
372 			expanding = 0;
373 		else
374 			break;
375 	}
376 	return (c);
377 }
378 
379 int
380 lgetc(int quotec)
381 {
382 	int		c, next;
383 
384 	if (quotec) {
385 		if ((c = igetc()) == EOF) {
386 			yyerror("reached end of file while parsing "
387 			    "quoted string");
388 			if (file == topfile || popfile() == EOF)
389 				return (EOF);
390 			return (quotec);
391 		}
392 		return (c);
393 	}
394 
395 	while ((c = igetc()) == '\\') {
396 		next = igetc();
397 		if (next != '\n') {
398 			c = next;
399 			break;
400 		}
401 		yylval.lineno = file->lineno;
402 		file->lineno++;
403 	}
404 	if (c == '\t' || c == ' ') {
405 		/* Compress blanks to a single space. */
406 		do {
407 			c = getc(file->stream);
408 		} while (c == '\t' || c == ' ');
409 		ungetc(c, file->stream);
410 		c = ' ';
411 	}
412 
413 	if (c == EOF) {
414 		/*
415 		 * Fake EOL when hit EOF for the first time. This gets line
416 		 * count right if last line in included file is syntactically
417 		 * invalid and has no newline.
418 		 */
419 		if (file->eof_reached == 0) {
420 			file->eof_reached = 1;
421 			return ('\n');
422 		}
423 		while (c == EOF) {
424 			if (file == topfile || popfile() == EOF)
425 				return (EOF);
426 			c = igetc();
427 		}
428 	}
429 	return (c);
430 }
431 
432 void
433 lungetc(int c)
434 {
435 	if (c == EOF)
436 		return;
437 
438 	if (file->ungetpos >= file->ungetsize) {
439 		void *p = reallocarray(file->ungetbuf, file->ungetsize, 2);
440 		if (p == NULL)
441 			err(1, "%s", __func__);
442 		file->ungetbuf = p;
443 		file->ungetsize *= 2;
444 	}
445 	file->ungetbuf[file->ungetpos++] = c;
446 }
447 
448 int
449 findeol(void)
450 {
451 	int	c;
452 
453 	/* skip to either EOF or the first real EOL */
454 	while (1) {
455 		c = lgetc(0);
456 		if (c == '\n') {
457 			file->lineno++;
458 			break;
459 		}
460 		if (c == EOF)
461 			break;
462 	}
463 	return (ERROR);
464 }
465 
466 int
467 yylex(void)
468 {
469 	char	 buf[8096];
470 	char	*p, *val;
471 	int	 quotec, next, c;
472 	int	 token;
473 
474 top:
475 	p = buf;
476 	while ((c = lgetc(0)) == ' ' || c == '\t')
477 		; /* nothing */
478 
479 	yylval.lineno = file->lineno;
480 	if (c == '#')
481 		while ((c = lgetc(0)) != '\n' && c != EOF)
482 			; /* nothing */
483 	if (c == '$' && !expanding) {
484 		while (1) {
485 			if ((c = lgetc(0)) == EOF)
486 				return (0);
487 
488 			if (p + 1 >= buf + sizeof(buf) - 1) {
489 				yyerror("string too long");
490 				return (findeol());
491 			}
492 			if (isalnum(c) || c == '_') {
493 				*p++ = c;
494 				continue;
495 			}
496 			*p = '\0';
497 			lungetc(c);
498 			break;
499 		}
500 		val = symget(buf);
501 		if (val == NULL) {
502 			yyerror("macro '%s' not defined", buf);
503 			return (findeol());
504 		}
505 		p = val + strlen(val) - 1;
506 		lungetc(DONE_EXPAND);
507 		while (p >= val) {
508 			lungetc((unsigned char)*p);
509 			p--;
510 		}
511 		lungetc(START_EXPAND);
512 		goto top;
513 	}
514 
515 	switch (c) {
516 	case '\'':
517 	case '"':
518 		quotec = c;
519 		while (1) {
520 			if ((c = lgetc(quotec)) == EOF)
521 				return (0);
522 			if (c == '\n') {
523 				file->lineno++;
524 				continue;
525 			} else if (c == '\\') {
526 				if ((next = lgetc(quotec)) == EOF)
527 					return (0);
528 				if (next == quotec || next == ' ' ||
529 				    next == '\t')
530 					c = next;
531 				else if (next == '\n') {
532 					file->lineno++;
533 					continue;
534 				} else
535 					lungetc(next);
536 			} else if (c == quotec) {
537 				*p = '\0';
538 				break;
539 			} else if (c == '\0') {
540 				yyerror("syntax error");
541 				return (findeol());
542 			}
543 			if (p + 1 >= buf + sizeof(buf) - 1) {
544 				yyerror("string too long");
545 				return (findeol());
546 			}
547 			*p++ = c;
548 		}
549 		yylval.v.string = strdup(buf);
550 		if (yylval.v.string == NULL)
551 			fatal("yylex: strdup");
552 		return (STRING);
553 	}
554 
555 #define allowed_to_end_number(x) \
556 	(isspace(x) || x == ')' || x ==',' || x == '/' || x == '}' || x == '=')
557 
558 	if (c == '-' || isdigit(c)) {
559 		do {
560 			*p++ = c;
561 			if ((size_t)(p-buf) >= sizeof(buf)) {
562 				yyerror("string too long");
563 				return (findeol());
564 			}
565 		} while ((c = lgetc(0)) != EOF && isdigit(c));
566 		lungetc(c);
567 		if (p == buf + 1 && buf[0] == '-')
568 			goto nodigits;
569 		if (c == EOF || allowed_to_end_number(c)) {
570 			const char *errstr = NULL;
571 
572 			*p = '\0';
573 			yylval.v.number = strtonum(buf, LLONG_MIN,
574 			    LLONG_MAX, &errstr);
575 			if (errstr) {
576 				yyerror("\"%s\" invalid number: %s",
577 				    buf, errstr);
578 				return (findeol());
579 			}
580 			return (NUMBER);
581 		} else {
582 nodigits:
583 			while (p > buf + 1)
584 				lungetc((unsigned char)*--p);
585 			c = (unsigned char)*--p;
586 			if (c == '-')
587 				return (c);
588 		}
589 	}
590 
591 #define allowed_in_string(x) \
592 	(isalnum(x) || (ispunct(x) && x != '(' && x != ')' && \
593 	x != '{' && x != '}' && \
594 	x != '!' && x != '=' && x != '#' && \
595 	x != ','))
596 
597 	if (isalnum(c) || c == ':' || c == '_' || c == '/') {
598 		do {
599 			*p++ = c;
600 			if ((size_t)(p-buf) >= sizeof(buf)) {
601 				yyerror("string too long");
602 				return (findeol());
603 			}
604 		} while ((c = lgetc(0)) != EOF && (allowed_in_string(c)));
605 		lungetc(c);
606 		*p = '\0';
607 		if ((token = lookup(buf)) == STRING)
608 			if ((yylval.v.string = strdup(buf)) == NULL)
609 				fatal("yylex: strdup");
610 		return (token);
611 	}
612 	if (c == '\n') {
613 		yylval.lineno = file->lineno;
614 		file->lineno++;
615 	}
616 	if (c == EOF)
617 		return (0);
618 	return (c);
619 }
620 
621 struct file *
622 pushfile(const char *name, int secret)
623 {
624 	struct file	*nfile;
625 
626 	if ((nfile = calloc(1, sizeof(struct file))) == NULL) {
627 		log_warn("%s", __func__);
628 		return (NULL);
629 	}
630 	if ((nfile->name = strdup(name)) == NULL) {
631 		log_warn("%s", __func__);
632 		free(nfile);
633 		return (NULL);
634 	}
635 	if ((nfile->stream = fopen(nfile->name, "r")) == NULL) {
636 		free(nfile->name);
637 		free(nfile);
638 		return (NULL);
639 	}
640 	nfile->lineno = TAILQ_EMPTY(&files) ? 1 : 0;
641 	nfile->ungetsize = 16;
642 	nfile->ungetbuf = malloc(nfile->ungetsize);
643 	if (nfile->ungetbuf == NULL) {
644 		log_warn("%s", __func__);
645 		fclose(nfile->stream);
646 		free(nfile->name);
647 		free(nfile);
648 		return (NULL);
649 	}
650 	TAILQ_INSERT_TAIL(&files, nfile, entry);
651 	return (nfile);
652 }
653 
654 int
655 popfile(void)
656 {
657 	struct file	*prev;
658 
659 	if ((prev = TAILQ_PREV(file, files, entry)) != NULL)
660 		prev->errors += file->errors;
661 
662 	TAILQ_REMOVE(&files, file, entry);
663 	fclose(file->stream);
664 	free(file->name);
665 	free(file->ungetbuf);
666 	free(file);
667 	file = prev;
668 	return (file ? 0 : EOF);
669 }
670 
671 int
672 parse_config(const char *filename, struct galileo *env)
673 {
674 	struct sym	*sym, *next;
675 	size_t		 n;
676 
677 	conf = env;
678 
679 	n = strlcpy(conf->sc_conffile, filename, sizeof(conf->sc_conffile));
680 	if (n >= sizeof(conf->sc_conffile)) {
681 		log_warn("path too long: %s", filename);
682 		return (-1);
683 	}
684 
685 	if ((file = pushfile(filename, 0)) == NULL) {
686 		log_warn("failed to open %s", filename);
687 		return (-1);
688 	}
689 	topfile = file;
690 	setservent(1);
691 
692 	yyparse();
693 	if (TAILQ_EMPTY(&conf->sc_proxies))
694 		yyerror("no proxies defined");
695 	errors = file->errors;
696 	popfile();
697 
698 	endservent();
699 
700 	/* Free macros and check which have not been used. */
701 	TAILQ_FOREACH_SAFE(sym, &symhead, entry, next) {
702 		if (!sym->used)
703 			fprintf(stderr, "warning: macro `%s' not used\n",
704 			    sym->nam);
705 		if (!sym->persist) {
706 			free(sym->nam);
707 			free(sym->val);
708 			TAILQ_REMOVE(&symhead, sym, entry);
709 			free(sym);
710 		}
711 	}
712 
713 	if (errors)
714 		return (-1);
715 
716 	return (0);
717 }
718 
719 int
720 symset(const char *nam, const char *val, int persist)
721 {
722 	struct sym	*sym;
723 
724 	TAILQ_FOREACH(sym, &symhead, entry) {
725 		if (strcmp(nam, sym->nam) == 0)
726 			break;
727 	}
728 
729 	if (sym != NULL) {
730 		if (sym->persist == 1)
731 			return (0);
732 		else {
733 			free(sym->nam);
734 			free(sym->val);
735 			TAILQ_REMOVE(&symhead, sym, entry);
736 			free(sym);
737 		}
738 	}
739 	if ((sym = calloc(1, sizeof(*sym))) == NULL)
740 		return (-1);
741 
742 	sym->nam = strdup(nam);
743 	if (sym->nam == NULL) {
744 		free(sym);
745 		return (-1);
746 	}
747 	sym->val = strdup(val);
748 	if (sym->val == NULL) {
749 		free(sym->nam);
750 		free(sym);
751 		return (-1);
752 	}
753 	sym->used = 0;
754 	sym->persist = persist;
755 	TAILQ_INSERT_TAIL(&symhead, sym, entry);
756 	return (0);
757 }
758 
759 int
760 cmdline_symset(char *s)
761 {
762 	char	*sym, *val;
763 	int	ret;
764 
765 	if ((val = strrchr(s, '=')) == NULL)
766 		return (-1);
767 	sym = strndup(s, val - s);
768 	if (sym == NULL)
769 		fatal("%s: strndup", __func__);
770 	ret = symset(sym, val + 1, 1);
771 	free(sym);
772 
773 	return (ret);
774 }
775 
776 char *
777 symget(const char *nam)
778 {
779 	struct sym	*sym;
780 
781 	TAILQ_FOREACH(sym, &symhead, entry) {
782 		if (strcmp(nam, sym->nam) == 0) {
783 			sym->used = 1;
784 			return (sym->val);
785 		}
786 	}
787 	return (NULL);
788 }
789 
790 int
791 getservice(const char *n)
792 {
793 	struct servent	*s;
794 	const char	*errstr;
795 	long long	 llval;
796 
797 	llval = strtonum(n, 0, UINT16_MAX, &errstr);
798 	if (errstr) {
799 		s = getservbyname(n, "tcp");
800 		if (s == NULL)
801 			s = getservbyname(n, "udp");
802 		if (s == NULL)
803 			return (-1);
804 		return (ntohs(s->s_port));
805 	}
806 
807 	return ((unsigned short)llval);
808 }